draft-ietf-cellar-ffv1-00.txt   draft-ietf-cellar-ffv1-01.txt 
cellar M. Niedermayer cellar M. Niedermayer
Internet-Draft Internet-Draft
Intended status: Standards Track D. Rice Intended status: Standards Track D. Rice
Expires: January 3, 2018 Expires: July 30, 2018
J. Martinez J. Martinez
July 2, 2017 January 26, 2018
FF Video Codec 1 FF Video Codec 1
draft-ietf-cellar-ffv1-00 draft-ietf-cellar-ffv1-01
Abstract Abstract
This document defines FFV1, a lossless intra-frame video encoding This document defines FFV1, a lossless intra-frame video encoding
format. FFV1 is designed to efficiently compress video data in a format. FFV1 is designed to efficiently compress video data in a
variety of pixel formats. Compared to uncompressed video, FFV1 variety of pixel formats. Compared to uncompressed video, FFV1
offers storage compression, frame fixity, and self-description, which offers storage compression, frame fixity, and self-description, which
makes FFV1 useful as a preservation or intermediate video format. makes FFV1 useful as a preservation or intermediate video format.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Notation and Conventions . . . . . . . . . . . . . . . . . . 4 2. Notation and Conventions . . . . . . . . . . . . . . . . . . 4
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 5
2.2.1. Arithmetic operators . . . . . . . . . . . . . . . . 5 2.2.1. Arithmetic operators . . . . . . . . . . . . . . . . 5
2.2.2. Assignment operators . . . . . . . . . . . . . . . . 6 2.2.2. Assignment operators . . . . . . . . . . . . . . . . 6
2.2.3. Comparison operators . . . . . . . . . . . . . . . . 6 2.2.3. Comparison operators . . . . . . . . . . . . . . . . 6
2.2.4. Mathematical functions . . . . . . . . . . . . . . . 6 2.2.4. Mathematical functions . . . . . . . . . . . . . . . 7
2.2.5. Order of operation precedence . . . . . . . . . . . . 7 2.2.5. Order of operation precedence . . . . . . . . . . . . 7
2.2.6. Pseudo-code . . . . . . . . . . . . . . . . . . . . . 7 2.2.6. Pseudo-code . . . . . . . . . . . . . . . . . . . . . 8
2.2.7. Range . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2.7. Range . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.8. NumBytes . . . . . . . . . . . . . . . . . . . . . . 8 2.2.8. NumBytes . . . . . . . . . . . . . . . . . . . . . . 8
2.2.9. Bitstream functions . . . . . . . . . . . . . . . . . 8 2.2.9. Bitstream functions . . . . . . . . . . . . . . . . . 8
3. General Description . . . . . . . . . . . . . . . . . . . . . 8 3. General Description . . . . . . . . . . . . . . . . . . . . . 8
3.1. Border . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1. Border . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Samples . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2. Samples . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. Median predictor . . . . . . . . . . . . . . . . . . . . 9 3.3. Median predictor . . . . . . . . . . . . . . . . . . . . 10
3.4. Context . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.4. Context . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.5. Quantization Table Sets . . . . . . . . . . . . . . . . . 10 3.5. Quantization Table Sets . . . . . . . . . . . . . . . . . 11
3.6. Quantization Table Set indexes . . . . . . . . . . . . . 11 3.6. Quantization Table Set indexes . . . . . . . . . . . . . 11
3.7. Color space . . . . . . . . . . . . . . . . . . . . . . . 11 3.7. Color spaces . . . . . . . . . . . . . . . . . . . . . . 12
3.7.1. YCbCr . . . . . . . . . . . . . . . . . . . . . . . . 11 3.7.1. YCbCr . . . . . . . . . . . . . . . . . . . . . . . . 12
3.7.2. JPEG2000-RCT . . . . . . . . . . . . . . . . . . . . 12 3.7.2. RGB . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.8. Coding of the Sample Difference . . . . . . . . . . . . . 13 3.8. Coding of the Sample Difference . . . . . . . . . . . . . 14
3.8.1. Range coding mode . . . . . . . . . . . . . . . . . . 13 3.8.1. Range coding mode . . . . . . . . . . . . . . . . . . 14
3.8.2. Huffman coding mode . . . . . . . . . . . . . . . . . 17 3.8.2. Golomb Rice mode . . . . . . . . . . . . . . . . . . 17
4. Bitstream . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4. Bitstream . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1. Configuration Record . . . . . . . . . . . . . . . . . . 20 4.1. Configuration Record . . . . . . . . . . . . . . . . . . 20
4.1.1. reserved_for_future_use . . . . . . . . . . . . . . . 21 4.1.1. reserved_for_future_use . . . . . . . . . . . . . . . 21
4.1.2. configuration_record_crc_parity . . . . . . . . . . . 21 4.1.2. configuration_record_crc_parity . . . . . . . . . . . 21
4.1.3. Mapping FFV1 into Containers . . . . . . . . . . . . 21 4.1.3. Mapping FFV1 into Containers . . . . . . . . . . . . 21
4.2. Frame . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.2. Frame . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3. Slice . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.3. Slice . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.4. Slice Header . . . . . . . . . . . . . . . . . . . . . . 23 4.4. Slice Header . . . . . . . . . . . . . . . . . . . . . . 23
4.4.1. slice_x . . . . . . . . . . . . . . . . . . . . . . . 23 4.4.1. slice_x . . . . . . . . . . . . . . . . . . . . . . . 23
4.4.2. slice_y . . . . . . . . . . . . . . . . . . . . . . . 23 4.4.2. slice_y . . . . . . . . . . . . . . . . . . . . . . . 23
4.4.3. slice_width . . . . . . . . . . . . . . . . . . . . . 23 4.4.3. slice_width . . . . . . . . . . . . . . . . . . . . . 24
4.4.4. slice_height . . . . . . . . . . . . . . . . . . . . 23 4.4.4. slice_height . . . . . . . . . . . . . . . . . . . . 24
4.4.5. quant_table_set_index_count . . . . . . . . . . . . . 23 4.4.5. quant_table_set_index_count . . . . . . . . . . . . . 24
4.4.6. quant_table_set_index . . . . . . . . . . . . . . . . 24 4.4.6. quant_table_set_index . . . . . . . . . . . . . . . . 24
4.4.7. picture_structure . . . . . . . . . . . . . . . . . . 24 4.4.7. picture_structure . . . . . . . . . . . . . . . . . . 24
4.4.8. sar_num . . . . . . . . . . . . . . . . . . . . . . . 24 4.4.8. sar_num . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.9. sar_den . . . . . . . . . . . . . . . . . . . . . . . 24 4.4.9. sar_den . . . . . . . . . . . . . . . . . . . . . . . 25
4.4.10. reset_contexts . . . . . . . . . . . . . . . . . . . 24 4.4.10. reset_contexts . . . . . . . . . . . . . . . . . . . 25
4.4.11. slice_coding_mode . . . . . . . . . . . . . . . . . . 24 4.4.11. slice_coding_mode . . . . . . . . . . . . . . . . . . 25
4.5. Slice Content . . . . . . . . . . . . . . . . . . . . . . 25 4.5. Slice Content . . . . . . . . . . . . . . . . . . . . . . 25
4.5.1. primary_color_count . . . . . . . . . . . . . . . . . 25 4.5.1. primary_color_count . . . . . . . . . . . . . . . . . 25
4.5.2. plane_pixel_height . . . . . . . . . . . . . . . . . 25 4.5.2. plane_pixel_height . . . . . . . . . . . . . . . . . 26
4.5.3. slice_pixel_height . . . . . . . . . . . . . . . . . 25 4.5.3. slice_pixel_height . . . . . . . . . . . . . . . . . 26
4.5.4. slice_pixel_y . . . . . . . . . . . . . . . . . . . . 25 4.5.4. slice_pixel_y . . . . . . . . . . . . . . . . . . . . 26
4.6. Line . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.6. Line . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.6.1. plane_pixel_width . . . . . . . . . . . . . . . . . . 26 4.6.1. plane_pixel_width . . . . . . . . . . . . . . . . . . 26
4.6.2. slice_pixel_width . . . . . . . . . . . . . . . . . . 26 4.6.2. slice_pixel_width . . . . . . . . . . . . . . . . . . 27
4.6.3. slice_pixel_x . . . . . . . . . . . . . . . . . . . . 26 4.6.3. slice_pixel_x . . . . . . . . . . . . . . . . . . . . 27
4.7. Slice Footer . . . . . . . . . . . . . . . . . . . . . . 26 4.6.4. sample_difference . . . . . . . . . . . . . . . . . . 27
4.7. Slice Footer . . . . . . . . . . . . . . . . . . . . . . 27
4.7.1. slice_size . . . . . . . . . . . . . . . . . . . . . 27 4.7.1. slice_size . . . . . . . . . . . . . . . . . . . . . 27
4.7.2. error_status . . . . . . . . . . . . . . . . . . . . 27 4.7.2. error_status . . . . . . . . . . . . . . . . . . . . 27
4.7.3. slice_crc_parity . . . . . . . . . . . . . . . . . . 27 4.7.3. slice_crc_parity . . . . . . . . . . . . . . . . . . 28
4.8. Parameters . . . . . . . . . . . . . . . . . . . . . . . 27 4.8. Parameters . . . . . . . . . . . . . . . . . . . . . . . 28
4.8.1. version . . . . . . . . . . . . . . . . . . . . . . . 28 4.8.1. version . . . . . . . . . . . . . . . . . . . . . . . 29
4.8.2. micro_version . . . . . . . . . . . . . . . . . . . . 29 4.8.2. micro_version . . . . . . . . . . . . . . . . . . . . 30
4.8.3. coder_type . . . . . . . . . . . . . . . . . . . . . 30 4.8.3. coder_type . . . . . . . . . . . . . . . . . . . . . 31
4.8.4. state_transition_delta . . . . . . . . . . . . . . . 30 4.8.4. state_transition_delta . . . . . . . . . . . . . . . 31
4.8.5. colorspace_type . . . . . . . . . . . . . . . . . . . 30 4.8.5. colorspace_type . . . . . . . . . . . . . . . . . . . 31
4.8.6. chroma_planes . . . . . . . . . . . . . . . . . . . . 30 4.8.6. chroma_planes . . . . . . . . . . . . . . . . . . . . 32
4.8.7. bits_per_raw_sample . . . . . . . . . . . . . . . . . 31 4.8.7. bits_per_raw_sample . . . . . . . . . . . . . . . . . 32
4.8.8. h_chroma_subsample . . . . . . . . . . . . . . . . . 31 4.8.8. log2_h_chroma_subsample . . . . . . . . . . . . . . . 32
4.8.9. v_chroma_subsample . . . . . . . . . . . . . . . . . 31 4.8.9. log2_v_chroma_subsample . . . . . . . . . . . . . . . 32
4.8.10. alpha_plane . . . . . . . . . . . . . . . . . . . . . 31 4.8.10. alpha_plane . . . . . . . . . . . . . . . . . . . . . 32
4.8.11. num_h_slices . . . . . . . . . . . . . . . . . . . . 31 4.8.11. num_h_slices . . . . . . . . . . . . . . . . . . . . 33
4.8.12. num_v_slices . . . . . . . . . . . . . . . . . . . . 32 4.8.12. num_v_slices . . . . . . . . . . . . . . . . . . . . 33
4.8.13. quant_table_set_count . . . . . . . . . . . . . . . . 32 4.8.13. quant_table_set_count . . . . . . . . . . . . . . . . 33
4.8.14. states_coded . . . . . . . . . . . . . . . . . . . . 32 4.8.14. states_coded . . . . . . . . . . . . . . . . . . . . 33
4.8.15. initial_state_delta . . . . . . . . . . . . . . . . . 32 4.8.15. initial_state_delta . . . . . . . . . . . . . . . . . 33
4.8.16. ec . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.8.16. ec . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.8.17. intra . . . . . . . . . . . . . . . . . . . . . . . . 32 4.8.17. intra . . . . . . . . . . . . . . . . . . . . . . . . 34
4.9. Quantization Table Set . . . . . . . . . . . . . . . . . 33 4.9. Quantization Table Set . . . . . . . . . . . . . . . . . 34
4.9.1. quant_tables . . . . . . . . . . . . . . . . . . . . 34 4.9.1. quant_tables . . . . . . . . . . . . . . . . . . . . 35
4.9.2. context_count . . . . . . . . . . . . . . . . . . . . 34 4.9.2. context_count . . . . . . . . . . . . . . . . . . . . 35
5. Restrictions . . . . . . . . . . . . . . . . . . . . . . . . 34 5. Restrictions . . . . . . . . . . . . . . . . . . . . . . . . 35
6. Security Considerations . . . . . . . . . . . . . . . . . . . 35 6. Security Considerations . . . . . . . . . . . . . . . . . . . 36
7. Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . 35 7. Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.1. Decoder implementation suggestions . . . . . . . . . . . 36 7.1. Decoder implementation suggestions . . . . . . . . . . . 37
7.1.1. Multi-threading support and independence of slices . 36 7.1.1. Multi-threading support and independence of slices . 37
8. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 36 8. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9. ToDo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 9. ToDo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 37 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.1. Normative References . . . . . . . . . . . . . . . . . . 37 10.1. Normative References . . . . . . . . . . . . . . . . . . 38
10.2. Informative References . . . . . . . . . . . . . . . . . 37 10.2. Informative References . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction 1. Introduction
This document describes FFV1, a lossless video encoding format. The This document describes FFV1, a lossless video encoding format. The
design of FFV1 considers the storage of image characteristics, data design of FFV1 considers the storage of image characteristics, data
fixity, and the optimized use of encoding time and storage fixity, and the optimized use of encoding time and storage
requirements. FFV1 is designed to support a wide range of lossless requirements. FFV1 is designed to support a wide range of lossless
video applications such as long-term audiovisual preservation, video applications such as long-term audiovisual preservation,
scientific imaging, screen recording, and other video encoding scientific imaging, screen recording, and other video encoding
scenarios that seek to avoid the generational loss of lossy video scenarios that seek to avoid the generational loss of lossy video
skipping to change at page 4, line 50 skipping to change at page 4, line 50
[YCbCr]. [YCbCr].
2. Notation and Conventions 2. Notation and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2.1. Definitions 2.1. Definitions
"Sample": The smallest addressable representation of a color
component or a luma component in a frame. Examples of sample are
Luma, Blue Chrominance, Red Chrominance, Alpha, Red, Green, Blue.
"Pixel": The smallest addressable representation of a color in a
frame. It is composed of 1 or more samples.
"ESC": An ESCape symbol to indicate that the symbol to be stored is "ESC": An ESCape symbol to indicate that the symbol to be stored is
too large for normal storage and that an alternate storage method. too large for normal storage and that an alternate storage method.
"MSB": Most Significant Bit, the bit that can cause the largest "MSB": Most Significant Bit, the bit that can cause the largest
change in magnitude of the symbol. change in magnitude of the symbol.
"RCT": Reversible Color Transform, a near linear, exactly reversible "RCT": Reversible Color Transform, a near linear, exactly reversible
integer transform that converts between RGB and YCbCr representations integer transform that converts between RGB and YCbCr representations
of a sample. of a Pixel.
"VLC": Variable Length Code, a code which maps source symbols to a "VLC": Variable Length Code, a code which maps source symbols to a
variable number of bits. variable number of bits.
"RGB": A reference to the method of storing the value of a sample by "RGB": A reference to the method of storing the value of a Pixel by
using three numeric values that represent Red, Green, and Blue. using three numeric values that represent Red, Green, and Blue.
"YCbCr": A reference to the method of storing the value of a sample "YCbCr": A reference to the method of storing the value of a Pixel by
by using three numeric values that represent the luminance of the using three numeric values that represent the luma of the Pixel (Y)
sample (Y) and the chrominance of the sample (Cb and Cr). and the chrominance of the Pixel (Cb and Cr). YCbCr word is used for
historical reasons and currently references any color space relying
on 1 luma and 2 chrominances e.g. YCbCr, YCgCo or ICtCp. Exact
meaning of the three numeric values is unspecified.
"TBA": To Be Announced. Used in reference to the development of "TBA": To Be Announced. Used in reference to the development of
future iterations of the FFV1 specification. future iterations of the FFV1 specification.
2.2. Conventions 2.2. Conventions
Note: the operators and the order of precedence are the same as used Note: the operators and the order of precedence are the same as used
in the C programming language [ISO.9899.1990]. in the C programming language [ISO.9899.1990].
2.2.1. Arithmetic operators 2.2.1. Arithmetic operators
skipping to change at page 8, line 7 skipping to change at page 8, line 21
programming language [ISO.9899.1990] as uses its "if/else", "while" programming language [ISO.9899.1990] as uses its "if/else", "while"
and "for" functions as well as functions defined within this and "for" functions as well as functions defined within this
document. document.
2.2.7. Range 2.2.7. Range
"a...b" means any value starting from a to b, inclusive. "a...b" means any value starting from a to b, inclusive.
2.2.8. NumBytes 2.2.8. NumBytes
NumBytes is a non-negative integer that expresses the size in 8-bit "NumBytes" is a non-negative integer that expresses the size in 8-bit
octets of particular FFV1 components such as the Configuration Record octets of particular FFV1 components such as the "Configuration
and Frame. FFV1 relies on its container to store the NumBytes Record" and "Frame". FFV1 relies on its container to store the
values, see Section 4.1.3. "NumBytes" values, see Section 4.1.3.
2.2.9. Bitstream functions 2.2.9. Bitstream functions
2.2.9.1. remaining_bits_in_bitstream 2.2.9.1. remaining_bits_in_bitstream
"remaining_bits_in_bitstream( )" means the count of remaining bits "remaining_bits_in_bitstream( )" means the count of remaining bits
after the current position in that bitstream component. It is after the pointer in that bitstream component. It is computed from
computed from the NumBytes value multiplied by 8 minus the count of the "NumBytes" value multiplied by 8 minus the count of bits of that
bits of that component already read by the bitstream parser. component already read by the bitstream parser.
2.2.9.2. byte_aligned 2.2.9.2. byte_aligned
"byte_aligned( )" is true if "remaining_bits_in_bitstream( NumBytes "byte_aligned( )" is true if "remaining_bits_in_bitstream( NumBytes
)" is a multiple of 8, otherwise false. )" is a multiple of 8, otherwise false.
2.2.9.3. get_bits
"get_bits( i )" is the action to read the next "i" bits in the
bitstream, from most significant bit to least significant bit, and to
return the corresponding value. The pointer is increased by "i".
3. General Description 3. General Description
Samples within a plane are coded in raster scan order (left->right, Samples within a plane are coded in raster scan order (left->right,
top->bottom). Each sample is predicted by the median predictor from top->bottom). Each sample is predicted by the median predictor from
samples in the same plane and the difference is stored see samples in the same plane and the difference is stored see
Section 3.8. Section 3.8.
3.1. Border 3.1. Border
A border is assumed for each coded slice for the purpose of the A border is assumed for each coded slice for the purpose of the
predictor and context according to the following rules: predictor and context according to the following rules:
o one column of samples to the left of the coded slice is assumed as o one column of samples to the left of the coded slice is assumed as
identical to the samples of the leftmost column of the coded slice identical to the samples of the leftmost column of the coded slice
shifted down by one row shifted down by one row. The value of the topmost sample of the
column of samples to the left of the coded slice is assumed to be
"0"
o one column of samples to the right of the coded slice is assumed o one column of samples to the right of the coded slice is assumed
as identical to the samples of the rightmost column of the coded as identical to the samples of the rightmost column of the coded
slice slice
o an additional column of samples to the left of the coded slice and o an additional column of samples to the left of the coded slice and
two rows of samples above the coded slice are assumed to be "0" two rows of samples above the coded slice are assumed to be "0"
The following table depicts a slice of samples "a,b,c,d,e,f,g,h,i" The following table depicts a slice of samples "a,b,c,d,e,f,g,h,i"
along with its assumed border. along with its assumed border.
skipping to change at page 9, line 31 skipping to change at page 10, line 5
Positions used for context and median predictor are: Positions used for context and median predictor are:
+---+---+---+---+ +---+---+---+---+
| | | T | | | | | T | |
+---+---+---+---+ +---+---+---+---+
| |tl | t |tr | | |tl | t |tr |
+---+---+---+---+ +---+---+---+---+
| L | l | X | | | L | l | X | |
+---+---+---+---+ +---+---+---+---+
"X" is the current processed Sample. "X" is the current processed Sample. The identifiers are made of the
The identifers are made of the first letters of the words Top, Left first letters of the words Top, Left and Right.
and Right.
3.3. Median predictor 3.3. Median predictor
The prediction for any sample value at position "X" may be computed The prediction for any sample value at position "X" may be computed
based upon the relative neighboring values of "l", "t", and "tl" via based upon the relative neighboring values of "l", "t", and "tl" via
this equation: this equation:
"median(l, t, l + t - tl)". "median(l, t, l + t - tl)".
Note, this prediction template is also used in [ISO.14495-1.1999] and Note, this prediction template is also used in [ISO.14495-1.1999] and
[HuffYUV]. [HuffYUV].
Exception for the media predictor: if colorspace_type == 0 && Exception for the media predictor: if "colorspace_type == 0 &&
bits_per_raw_sample == 16 && ( coder_type == 1 || coder_type == 2 ), bits_per_raw_sample == 16 && ( coder_type == 1 || coder_type == 2 )",
the following media predictor MUST be used: the following media predictor MUST be used:
"median(left16s, top16s, left16s + top16s - diag16s)" "median(left16s, top16s, left16s + top16s - diag16s)"
where: where:
left16s = l >= 32768 ? ( l - 65536 ) : l left16s = l >= 32768 ? ( l - 65536 ) : l
top16s = t >= 32768 ? ( t - 65536 ) : t top16s = t >= 32768 ? ( t - 65536 ) : t
diag16s = tl >= 32768 ? ( tl - 65536 ) : tl diag16s = tl >= 32768 ? ( tl - 65536 ) : tl
Background: a two's complement signed 16-bit signed integer was used Background: a two's complement signed 16-bit signed integer was used
for storing pixel values in all known implementations of FFV1 for storing sample values in all known implementations of FFV1
bitstream. So in some circumstances, the most significant bit was bitstream. So in some circumstances, the most significant bit was
wrongly interpreted (used as a sign bit instead of the 16th bit of an wrongly interpreted (used as a sign bit instead of the 16th bit of an
unsigned integer). Note that when the issue is discovered, the only unsigned integer). Note that when the issue is discovered, the only
configuration of all known implementations being impacted is 16-bit configuration of all known implementations being impacted is 16-bit
YCbCr color space with Range Coder coder, as other potentially YCbCr with no Pixel transformation with Range Coder coder, as other
impacted configurations (e.g. 15/16-bit JPEG2000-RCT color space with potentially impacted configurations (e.g. 15/16-bit JPEG2000-RCT with
Range Coder coder, or 16-bit any color space with Golomb Rice coder) Range Coder coder, or 16-bit content with Golomb Rice coder) were
were implemented nowhere. In the meanwhile, 16-bit JPEG2000-RCT implemented nowhere. In the meanwhile, 16-bit JPEG2000-RCT with
color space with Range Coder coder was implemented without this issue Range Coder coder was implemented without this issue in one
in one implementation and validated by one conformance checker. It implementation and validated by one conformance checker. It is
is expected (to be confirmed) to remove this exception for the media expected (to be confirmed) to remove this exception for the media
predictor in the next version of the bitstream. predictor in the next version of the FFV1 bitstream.
3.4. Context 3.4. Context
Relative to any sample "X", the Quantized Sample Differences "L-l", Relative to any sample "X", the Quantized Sample Differences "L-l",
"l-tl", "tl-t", "T-t", and "t-tr" are used as context: "l-tl", "tl-t", "T-t", and "t-tr" are used as context:
context = Q_{0}[l - tl] + context = Q_{0}[l - tl] +
Q_{1}[tl - t] + Q_{1}[tl - t] +
Q_{2}[t - tr] + Q_{2}[t - tr] +
Q_{3}[L - l] + Q_{3}[L - l] +
Q_{4}[T - t] Q_{4}[T - t]
If "context >= 0" then "context" is used and the difference between If "context >= 0" then "context" is used and the difference between
the sample and its predicted value is encoded as is, else "-context" the sample and its predicted value is encoded as is, else "-context"
is used and the difference between the sample and its predicted value is used and the difference between the sample and its predicted value
is encoded with a flipped sign. is encoded with a flipped sign.
3.5. Quantization Table Sets 3.5. Quantization Table Sets
The bitstream contains 1 or more Quantization Table Sets. The FFV1 bitstream contains 1 or more Quantization Table Sets. Each
Each Quantization Table Set contains exactly 5 Quantization Tables, Quantization Table Set contains exactly 5 Quantization Tables, each
each Quantization Table corresponding to 1 of the 5 Quantized Sample Quantization Table corresponding to 1 of the 5 Quantized Sample
Differences. Differences. For each Quantization Table, both the number of
For each Quantization Table, both the number of quantization steps quantization steps and their distribution are stored in the FFV1
and their distribution are stored in the bitstream; each Quantization bitstream; each Quantization Table has exactly 256 entries, and the 8
Table has exactly 256 entries, and the 8 least significant bits of least significant bits of the Quantized Sample Difference are used as
the Quantized Sample Difference are used as index: index:
Q_{j}[k] = quant_tables[i][j][k&255] Q_{j}[k] = quant_tables[i][j][k&255]
In this formula, "i" is the Quantization Table Set index, "j" is the In this formula, "i" is the Quantization Table Set index, "j" is the
Quantized Table index, "k" the Quantized Sample Difference. Quantized Table index, "k" the Quantized Sample Difference.
3.6. Quantization Table Set indexes 3.6. Quantization Table Set indexes
For each plane of each slice, a Quantization Table Set is selected For each plane of each slice, a Quantization Table Set is selected
from an index: from an index:
skipping to change at page 11, line 23 skipping to change at page 11, line 47
o For Y plane, "quant_table_set_index [ 0 ]" index is used o For Y plane, "quant_table_set_index [ 0 ]" index is used
o For Cb and Cr planes, "quant_table_set_index [ 1 ]" index is used o For Cb and Cr planes, "quant_table_set_index [ 1 ]" index is used
o For Alpha plane, "quant_table_set_index [ (version <= 3 || o For Alpha plane, "quant_table_set_index [ (version <= 3 ||
chroma_planes) ? 2 : 1 ]" index is used chroma_planes) ? 2 : 1 ]" index is used
Background: in first implementations of FFV1 bitstream, the index for Background: in first implementations of FFV1 bitstream, the index for
Cb and Cr planes was stored even if it is not used (chroma_planes set Cb and Cr planes was stored even if it is not used (chroma_planes set
to 0), this index is kept for version <= 3 in order to keep to 0), this index is kept for version <= 3 in order to keep
compatibility with bitstreams in the wild. compatibility with FFV1 bitstreams in the wild.
3.7. Color space 3.7. Color spaces
FFV1 supports two color spaces: YCbCr and JPEG2000-RCT. Both color FFV1 supports two color spaces: YCbCr and RGB. Both color spaces
spaces allow an optional Alpha plane that can be used to code allow an optional Alpha plane that can be used to code transparency
transparency data. data.
3.7.1. YCbCr 3.7.1. YCbCr
In YCbCr color space, the Cb and Cr planes are optional, but if used In YCbCr color space, the Cb and Cr planes are optional, but if used
then MUST be used together. Omitting the Cb and Cr planes codes the then MUST be used together. Omitting the Cb and Cr planes codes the
frames in grayscale without color data. An FFV1 frame using YCbCr frames in grayscale without color data. An FFV1 "Frame" using YCbCr
MUST use one of the following arrangements: MUST use one of the following arrangements:
o Y o Y
o Y, Alpha o Y, Alpha
o Y, Cb, Cr o Y, Cb, Cr
o Y, Cb, Cr, Alpha o Y, Cb, Cr, Alpha
When FFV1 uses the YCbCr color space, the Y plane MUST be coded The Y plane MUST be coded first. If the Cb and Cr planes are used
first. If the Cb and Cr planes are used then they MUST be coded then they MUST be coded after the Y plane. If an Alpha
after the Y plane. If an Alpha (transparency) plane is used, then it (transparency) plane is used, then it MUST be coded last.
MUST be coded last.
3.7.2. JPEG2000-RCT 3.7.2. RGB
JPEG2000-RCT is a Reversible Color Transform that codes RGB (red, JPEG2000-RCT is a Reversible Color Transform that codes RGB (red,
green, blue) planes losslessly in a modified YCbCr color space. green, blue) planes losslessly in a modified YCbCr color space.
Reversible conversions between YCbCr and RGB use the following Reversible Pixel transformations between YCbCr and RGB use the
formulae. following formulae.
Cb=b-g Cb=b-g
Cr=r-g Cr=r-g
Y=g+(Cb+Cr)>>2 Y=g+(Cb+Cr)>>2
g=Y-(Cb+Cr)>>2 g=Y-(Cb+Cr)>>2
r=Cr+g r=Cr+g
b=Cb+g b=Cb+g
Exception for the reversible conversions between YCbCr and RGB: if Exception for the JPEG2000-RCT conversion: if bits_per_raw_sample is
bits_per_raw_sample is between 9 and 15 inclusive, the following between 9 and 15 inclusive, the following formulae for reversible
formulae for reversible conversions between YCbCr and RGB MUST be conversions between YCbCr and RGB MUST be used instead of the ones
used instead of the ones above: above:
Cb=g-b Cb=g-b
Cr=r-b Cr=r-b
Y=b+(Cb+Cr)>>2 Y=b+(Cb+Cr)>>2
b=Y-(Cb+Cr)>>2 b=Y-(Cb+Cr)>>2
r=Cr+b r=Cr+b
g=Cb+b g=Cb+b
Background: At the time of this writing, in all known implementations Background: At the time of this writing, in all known implementations
of FFV1 bitstream, when bits_per_raw_sample was between 9 and 15 of FFV1 bitstream, when bits_per_raw_sample was between 9 and 15
inclusive, GBR planes were used as BGR planes during both encoding inclusive, GBR planes were used as BGR planes during both encoding
and decoding. In the meanwhile, 16-bit JPEG2000-RCT color space was and decoding. In the meanwhile, 16-bit JPEG2000-RCT was implemented
implemented without this issue in one implementation and validated by without this issue in one implementation and validated by one
one conformance checker. Methods to address this exception for the conformance checker. Methods to address this exception for the
transform are under consideration for the next version of the transform are under consideration for the next version of the FFV1
bitstream. bitstream.
[ISO.15444-1.2016] [ISO.15444-1.2016]
An FFV1 frame using JPEG2000-RCT MUST use one of the following
arrangements:
o Y, Cb, Cr When FFV1 uses the JPEG2000-RCT, the horizontal lines are interleaved
to improve caching efficiency since it is most likely that the RCT
o Y, Cb, Cr, Alpha will immediately be converted to RGB during decoding. The
interleaved coding order is also Y, then Cb, then Cr, and then if
When FFV1 uses the JPEG2000-RCT color space, the horizontal lines are
interleaved to improve caching efficiency since it is most likely
that the RCT will immediately be converted to RGB during decoding.
The interleaved coding order is also Y, then Cb, then Cr, and then if
used Alpha. used Alpha.
As an example, a frame that is two pixels wide and two pixels high, As an example, a "Frame" that is two pixels wide and two pixels high,
could be comprised of the following structure: could be comprised of the following structure:
+------------------------+------------------------+ +------------------------+------------------------+
| Pixel[1,1] | Pixel[2,1] | | Pixel[1,1] | Pixel[2,1] |
| Y[1,1] Cb[1,1] Cr[1,1] | Y[2,1] Cb[2,1] Cr[2,1] | | Y[1,1] Cb[1,1] Cr[1,1] | Y[2,1] Cb[2,1] Cr[2,1] |
+------------------------+------------------------+ +------------------------+------------------------+
| Pixel[1,2] | Pixel[2,2] | | Pixel[1,2] | Pixel[2,2] |
| Y[1,2] Cb[1,2] Cr[1,2] | Y[2,2] Cb[2,2] Cr[2,2] | | Y[1,2] Cb[1,2] Cr[1,2] | Y[2,2] Cb[2,2] Cr[2,2] |
+------------------------+------------------------+ +------------------------+------------------------+
In JPEG2000-RCT color space, the coding order would be left to right In JPEG2000-RCT, the coding order would be left to right and then top
and then top to bottom, with values interleaved by lines and stored to bottom, with values interleaved by lines and stored in this order:
in this order:
Y[1,1] Y[2,1] Cb[1,1] Cb[2,1] Cr[1,1] Cr[2,1] Y[1,2] Y[2,2] Cb[1,2] Y[1,1] Y[2,1] Cb[1,1] Cb[2,1] Cr[1,1] Cr[2,1] Y[1,2] Y[2,2] Cb[1,2]
Cb[2,2] Cr[1,2] Cr[2,2] Cb[2,2] Cr[1,2] Cr[2,2]
3.8. Coding of the Sample Difference 3.8. Coding of the Sample Difference
Instead of coding the n+1 bits of the Sample Difference with Huffman Instead of coding the n+1 bits of the Sample Difference with Huffman
or Range coding (or n+2 bits, in the case of RCT), only the n (or or Range coding (or n+2 bits, in the case of RCT), only the n (or
n+1) least significant bits are used, since this is sufficient to n+1) least significant bits are used, since this is sufficient to
recover the original sample. In the equation below, the term "bits" recover the original sample. In the equation below, the term "bits"
skipping to change at page 17, line 37 skipping to change at page 17, line 46
175,189,179,181,186,183,192,185,200,187,191,188,190,197,193,196, 175,189,179,181,186,183,192,185,200,187,191,188,190,197,193,196,
197,194,195,196,198,202,199,201,210,203,207,204,205,206,208,214, 197,194,195,196,198,202,199,201,210,203,207,204,205,206,208,214,
209,211,221,212,213,215,224,216,217,218,219,220,222,228,223,225, 209,211,221,212,213,215,224,216,217,218,219,220,222,228,223,225,
226,224,227,229,240,230,231,232,233,234,235,236,238,239,237,242, 226,224,227,229,240,230,231,232,233,234,235,236,238,239,237,242,
241,243,242,244,245,246,247,248,249,250,251,252,252,253,254,255, 241,243,242,244,245,246,247,248,249,250,251,252,252,253,254,255,
3.8.2. Huffman coding mode 3.8.2. Golomb Rice mode
This coding mode uses Golomb Rice codes. The VLC code is split into This coding mode uses Golomb Rice codes. The VLC is split into 2
2 parts, the prefix stores the most significant bits, the suffix parts, the prefix stores the most significant bits, the suffix stores
stores the k least significant bits or stores the whole number in the the k least significant bits or stores the whole number in the ESC
ESC case. The end of the bitstream (of the frame) is filled with case. The end of the bitstream of the "Frame" is filled with 0-bits
0-bits until that the bitstream contains a multiple of 8 bits. until that the bitstream contains a multiple of 8 bits.
3.8.2.1. Prefix 3.8.2.1. Prefix
+----------------+-------+ +----------------+-------+
| bits | value | | bits | value |
+----------------+-------+ +----------------+-------+
| 1 | 0 | | 1 | 0 |
| 01 | 1 | | 01 | 1 |
| ... | ... | | ... | ... |
| 0000 0000 0001 | 11 | | 0000 0000 0001 | 11 |
| 0000 0000 0000 | ESC | | 0000 0000 0000 | ESC |
+----------------+-------+ +----------------+-------+
skipping to change at page 19, line 17 skipping to change at page 19, line 17
log2_run[41]={ | log2_run[41]={ |
0, 0, 0, 0, 1, 1, 1, 1, | 0, 0, 0, 0, 1, 1, 1, 1, |
2, 2, 2, 2, 3, 3, 3, 3, | 2, 2, 2, 2, 3, 3, 3, 3, |
4, 4, 5, 5, 6, 6, 7, 7, | 4, 4, 5, 5, 6, 6, 7, 7, |
8, 9,10,11,12,13,14,15, | 8, 9,10,11,12,13,14,15, |
16,17,18,19,20,21,22,23, | 16,17,18,19,20,21,22,23, |
24, | 24, |
}; | }; |
| |
if (run_count == 0 && run_mode == 1) { | if (run_count == 0 && run_mode == 1) { |
if (get_bits1()) { | if (get_bits(1)) { |
run_count = 1 << log2_run[run_index]; | run_count = 1 << log2_run[run_index]; |
if (x + run_count <= w) | if (x + run_count <= w) |
run_index++; | run_index++; |
} else { | } else { |
if (log2_run[run_index]) | if (log2_run[run_index]) |
run_count = get_bits(log2_run[run_index]); | run_count = get_bits(log2_run[run_index]); |
else | else |
run_count = 0; | run_count = 0; |
if (run_index) | if (run_index) |
run_index--; | run_index--; |
skipping to change at page 20, line 24 skipping to change at page 20, line 24
| sr | Range coded signed scalar symbol coded with the method | | sr | Range coded signed scalar symbol coded with the method |
| | described in Section 3.8.1.2 | | | described in Section 3.8.1.2 |
+--------+----------------------------------------------------------+ +--------+----------------------------------------------------------+
The same context which is initialized to 128 is used for all fields The same context which is initialized to 128 is used for all fields
in the header. in the header.
The following MUST be provided by external means during The following MUST be provided by external means during
initialization of the decoder: initialization of the decoder:
"frame_pixel_width" is defined as frame width in pixels. "frame_pixel_width" is defined as "Frame" width in pixels.
"frame_pixel_height" is defined as frame height in pixels. "frame_pixel_height" is defined as "Frame" height in pixels.
Default values at the decoder initialization phase: Default values at the decoder initialization phase:
"ConfigurationRecordIsPresent" is set to 0. "ConfigurationRecordIsPresent" is set to 0.
4.1. Configuration Record 4.1. Configuration Record
In the case of a bitstream with "version >= 3", a Configuration In the case of a FFV1 bitstream with "version >= 3", a "Configuration
Record is stored in the underlying container, at the track header Record" is stored in the underlying container, at the track header
level. It contains the parameters used for all frames. The size of level. It contains the parameters used for all instances of "Frame".
the Configuration Record, NumBytes, is supplied by the underlying The size of the "Configuration Record", "NumBytes", is supplied by
container. the underlying container.
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
ConfigurationRecord( NumBytes ) { | ConfigurationRecord( NumBytes ) { |
ConfigurationRecordIsPresent = 1 | ConfigurationRecordIsPresent = 1 |
Parameters( ) | Parameters( ) |
while( remaining_bits_in_bitstream( NumBytes ) > 32 ) | while( remaining_bits_in_bitstream( NumBytes ) > 32 ) |
reserved_for_future_use | u(1) reserved_for_future_use | u(1)
configuration_record_crc_parity | u(32) configuration_record_crc_parity | u(32)
} | } |
4.1.1. reserved_for_future_use 4.1.1. reserved_for_future_use
"reserved_for_future_use" has semantics that are reserved for future "reserved_for_future_use" has semantics that are reserved for future
use. Encoders conforming to this version of this specification use.
SHALL NOT write this value. Decoders conforming to this version of Encoders conforming to this version of this specification SHALL NOT
this specification SHALL ignore its value. write this value.
Decoders conforming to this version of this specification SHALL
ignore its value.
4.1.2. configuration_record_crc_parity 4.1.2. configuration_record_crc_parity
"configuration_record_crc_parity" 32 bits that are chosen so that the "configuration_record_crc_parity" 32 bits that are chosen so that the
Configuration Record as a whole has a crc remainder of 0. This is "Configuration Record" as a whole has a crc remainder of 0.
equivalent to storing the crc remainder in the 32-bit parity. The This is equivalent to storing the crc remainder in the 32-bit parity.
CRC generator polynomial used is the standard IEEE CRC polynomial The CRC generator polynomial used is the standard IEEE CRC polynomial
(0x104C11DB7) with initial value 0. (0x104C11DB7) with initial value 0.
4.1.3. Mapping FFV1 into Containers 4.1.3. Mapping FFV1 into Containers
This Configuration Record can be placed in any file format supporting This "Configuration Record" can be placed in any file format
Configuration Records, fitting as much as possible with how the file supporting "Configuration Records", fitting as much as possible with
format uses to store Configuration Records. The Configuration Record how the file format uses to store "Configuration Records". The
storage place and NumBytes are currently defined and supported by "Configuration Record" storage place and "NumBytes" are currently
this version of this specification for the following container defined and supported by this version of this specification for the
formats: following container formats:
4.1.3.1. In AVI File Format 4.1.3.1. AVI File Format
The Configuration Record extends the stream format chunk ("AVI ", The "Configuration Record" extends the stream format chunk ("AVI ",
"hdlr", "strl", "strf") with the ConfigurationRecord bitstream. See "hdlr", "strl", "strf") with the ConfigurationRecord bitstream.
[AVI] for more information about chunks. See [AVI] for more information about chunks.
"NumBytes" is defined as the size, in bytes, of the strf chunk "NumBytes" is defined as the size, in bytes, of the strf chunk
indicated in the chunk header minus the size of the stream format indicated in the chunk header minus the size of the stream format
structure. structure.
4.1.3.2. In ISO/IEC 14496-12 (MP4 File Format) 4.1.3.2. ISO Base Media File Format
The Configuration Record extends the sample description box ("moov", The "Configuration Record" extends the sample description box
"trak", "mdia", "minf", "stbl", "stsd") with a "glbl" box which ("moov", "trak", "mdia", "minf", "stbl", "stsd") with a "glbl" box
contains the ConfigurationRecord bitstream. See [ISO.14496-12.2015] which contains the ConfigurationRecord bitstream. See
for more information about boxes. [ISO.14496-12.2015] for more information about boxes.
"NumBytes" is defined as the size, in bytes, of the "glbl" box "NumBytes" is defined as the size, in bytes, of the "glbl" box
indicated in the box header minus the size of the box header. indicated in the box header minus the size of the box header.
4.1.3.3. In NUT File Format 4.1.3.3. NUT File Format
The codec_specific_data element (in "stream_header" packet) contains The codec_specific_data element (in "stream_header" packet) contains
the ConfigurationRecord bitstream. See [NUT] for more information the ConfigurationRecord bitstream. See [NUT] for more information
about elements. about elements.
"NumBytes" is defined as the size, in bytes, of the "NumBytes" is defined as the size, in bytes, of the
codec_specific_data element as indicated in the "length" field of codec_specific_data element as indicated in the "length" field of
codec_specific_data codec_specific_data
4.1.3.4. In Matroska File Format 4.1.3.4. Matroska File Format
FFV1 SHOULD use "V_FFV1" as the Matroska "Codec ID". For FFV1 FFV1 SHOULD use "V_FFV1" as the Matroska "Codec ID". For FFV1
versions 2 or less, the Matroska "CodecPrivate" Element SHOULD NOT be versions 2 or less, the Matroska "CodecPrivate" Element SHOULD NOT be
used. For FFV1 versions 3 or greater, the Matroska "CodecPrivate" used. For FFV1 versions 3 or greater, the Matroska "CodecPrivate"
Element MUST contain the FFV1 Configuration Record structure and no Element MUST contain the FFV1 "Configuration Record" structure and no
other data. See [Matroska] for more information about elements. other data. See [Matroska] for more information about elements.
"NumBytes" is defined as the "Element Data Size" of the
"CodecPrivate" Element.
4.2. Frame 4.2. Frame
A frame consists of the keyframe field, parameters (if version <=1), A "Frame" consists of the keyframe field, parameters (if version
and a sequence of independent slices. <=1), and a sequence of independent slices.
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
Frame( NumBytes ) { | Frame( NumBytes ) { |
keyframe | br keyframe | br
if (keyframe && !ConfigurationRecordIsPresent | if (keyframe && !ConfigurationRecordIsPresent |
Parameters( ) | Parameters( ) |
while ( remaining_bits_in_bitstream( NumBytes ) ) | while ( remaining_bits_in_bitstream( NumBytes ) ) |
Slice( ) | Slice( ) |
} | } |
skipping to change at page 23, line 24 skipping to change at page 23, line 37
slice_width - 1 | ur slice_width - 1 | ur
slice_height - 1 | ur slice_height - 1 | ur
for( i = 0; i < quant_table_set_index_count; i++ ) | for( i = 0; i < quant_table_set_index_count; i++ ) |
quant_table_set_index [ i ] | ur quant_table_set_index [ i ] | ur
picture_structure | ur picture_structure | ur
sar_num | ur sar_num | ur
sar_den | ur sar_den | ur
if (version >= 4) { | if (version >= 4) { |
reset_contexts | br reset_contexts | br
slice_coding_mode | ur slice_coding_mode | ur
} | } |
} | } |
4.4.1. slice_x 4.4.1. slice_x
"slice_x" indicates the x position on the slice raster formed by "slice_x" indicates the x position on the slice raster formed by
num_h_slices. Inferred to be 0 if not present. num_h_slices.
Inferred to be 0 if not present.
4.4.2. slice_y 4.4.2. slice_y
"slice_y" indicates the y position on the slice raster formed by "slice_y" indicates the y position on the slice raster formed by
num_v_slices. Inferred to be 0 if not present. num_v_slices.
Inferred to be 0 if not present.
4.4.3. slice_width 4.4.3. slice_width
"slice_width" indicates the width on the slice raster formed by "slice_width" indicates the width on the slice raster formed by
num_h_slices. Inferred to be 1 if not present. num_h_slices.
Inferred to be 1 if not present.
4.4.4. slice_height 4.4.4. slice_height
"slice_height" indicates the height on the slice raster formed by "slice_height" indicates the height on the slice raster formed by
num_v_slices. Inferred to be 1 if not present. num_v_slices.
Inferred to be 1 if not present.
4.4.5. quant_table_set_index_count 4.4.5. quant_table_set_index_count
"quant_table_set_index_count" is defined as 1 + ( ( chroma_planes || "quant_table_set_index_count" is defined as "1 + ( ( chroma_planes ||
version <= 3 ) ? 1 : 0 ) + ( alpha_plane ? 1 : 0 ). version \<= 3 ) ? 1 : 0 ) + ( alpha_plane ? 1 : 0 )".
4.4.6. quant_table_set_index 4.4.6. quant_table_set_index
"quant_table_set_index" indicates the Quantization Table Set index to "quant_table_set_index" indicates the Quantization Table Set index to
select the Quantization Table Set and the initial states for the select the Quantization Table Set and the initial states for the
slice. Inferred to be 0 if not present. slice.
Inferred to be 0 if not present.
4.4.7. picture_structure 4.4.7. picture_structure
"picture_structure" specifies the picture structure. Inferred to be "picture_structure" specifies the temporal and spatial relationship
0 if not present. of each line of the "Frame".
Inferred to be 0 if not present.
+-------+-------------------------+ +-------+-------------------------+
| value | picture structure used | | value | picture structure used |
+-------+-------------------------+ +-------+-------------------------+
| 0 | unknown | | 0 | unknown |
| 1 | top field first | | 1 | top field first |
| 2 | bottom field first | | 2 | bottom field first |
| 3 | progressive | | 3 | progressive |
| Other | reserved for future use | | Other | reserved for future use |
+-------+-------------------------+ +-------+-------------------------+
4.4.8. sar_num 4.4.8. sar_num
"sar_num" specifies the sample aspect ratio numerator. Inferred to "sar_num" specifies the sample aspect ratio numerator.
be 0 if not present. MUST be 0 if sample aspect ratio is unknown. Inferred to be 0 if not present.
MUST be 0 if sample aspect ratio is unknown.
4.4.9. sar_den 4.4.9. sar_den
"sar_den" specifies the sample aspect ratio numerator. Inferred to "sar_den" specifies the sample aspect ratio numerator.
be 0 if not present. MUST be 0 if sample aspect ratio is unknown. Inferred to be 0 if not present.
MUST be 0 if sample aspect ratio is unknown.
4.4.10. reset_contexts 4.4.10. reset_contexts
"reset_contexts" indicates if slice contexts must be reset. Inferred "reset_contexts" indicates if slice contexts must be reset.
to be 0 if not present. Inferred to be 0 if not present.
4.4.11. slice_coding_mode 4.4.11. slice_coding_mode
"slice_coding_mode" indicates the slice coding mode. Inferred to be "slice_coding_mode" indicates the slice coding mode.
0 if not present. Inferred to be 0 if not present.
+-------+----------------------------+ +-------+-----------------------------+
| value | slice coding mode | | value | slice coding mode |
+-------+----------------------------+ +-------+-----------------------------+
| 0 | normal Range Coding or VLC | | 0 | Range Coding or Golomb Rice |
| 1 | raw PCM | | 1 | raw PCM |
| Other | reserved for future use | | Other | reserved for future use |
+-------+----------------------------+ +-------+-----------------------------+
4.5. Slice Content 4.5. Slice Content
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
SliceContent( ) { | SliceContent( ) { |
if (colorspace_type == 0) { | if (colorspace_type == 0) { |
for( p = 0; p < primary_color_count; p++ ) { | for( p = 0; p < primary_color_count; p++ ) |
for( y = 0; y < plane_pixel_height[ p ]; y++ ) | for( y = 0; y < plane_pixel_height[ p ]; y++ ) |
Line( p, y ) | Line( p, y ) |
} else if (colorspace_type == 1) { | } else if (colorspace_type == 1) { |
for( y = 0; y < slice_pixel_height; y++ ) | for( y = 0; y < slice_pixel_height; y++ ) |
for( p = 0; p < primary_color_count; p++ ) { | for( p = 0; p < primary_color_count; p++ ) |
Line( p, y ) | Line( p, y ) |
} | } |
} | } |
4.5.1. primary_color_count 4.5.1. primary_color_count
"primary_color_count" is defined as 1 + ( chroma_planes ? 2 : 0 ) + ( "primary_color_count" is defined as 1 + ( chroma_planes ? 2 : 0 ) + (
alpha_plane ? 1 : 0 ). alpha_plane ? 1 : 0 ).
4.5.2. plane_pixel_height 4.5.2. plane_pixel_height
"plane_pixel_height[ p ]" is the height in pixels of plane p of the "plane_pixel_height[ p ]" is the height in pixels of plane p of the
slice. "plane_pixel_height[ 0 ]" and "plane_pixel_height[ 1 + ( slice.
chroma_planes ? 2 : 0 ) ]" value is "slice_pixel_height". If "plane_pixel_height[ 0 ]" and "plane_pixel_height[ 1 + (
"chroma_planes" is set to 1, "plane_pixel_height[ 1 ]" and chroma_planes ? 2 : 0 ) ]" value is "slice_pixel_height".
If "chroma_planes" is set to 1, "plane_pixel_height[ 1 ]" and
"plane_pixel_height[ 2 ]" value is "ceil(slice_pixel_height / "plane_pixel_height[ 2 ]" value is "ceil(slice_pixel_height /
v_chroma_subsample)". log2_v_chroma_subsample)".
4.5.3. slice_pixel_height 4.5.3. slice_pixel_height
"slice_pixel_height" is the height in pixels of the slice. Its value "slice_pixel_height" is the height in pixels of the slice.
is "floor(( slice_y + slice_height ) * slice_pixel_height / Its value is "floor(( slice_y + slice_height ) * slice_pixel_height /
num_v_slices) - slice_pixel_y". num_v_slices) - slice_pixel_y".
4.5.4. slice_pixel_y 4.5.4. slice_pixel_y
"slice_pixel_y" is the slice vertical position in pixels. Its value "slice_pixel_y" is the slice vertical position in pixels.
is "floor(slice_y * frame_pixel_height / num_v_slices)". Its value is "floor(slice_y * frame_pixel_height / num_v_slices)".
4.6. Line 4.6. Line
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
Line( p, y ) { | Line( p, y ) { |
if (colorspace_type == 0) { | if (colorspace_type == 0) { |
for( x = 0; x < plane_pixel_width[ p ]; x++ ) | for( x = 0; x < plane_pixel_width[ p ]; x++ ) |
Pixel( p, y, x ) | sample_difference[ p ][ y ][ x ] |
} else if (colorspace_type == 1) { | } else if (colorspace_type == 1) { |
for( x = 0; x < slice_pixel_width; x++ ) | for( x = 0; x < slice_pixel_width; x++ ) |
Pixel( p, y, x ) | sample_difference[ p ][ y ][ x ] |
} | } |
} | } |
4.6.1. plane_pixel_width 4.6.1. plane_pixel_width
"plane_pixel_width[ p ]" is the width in pixels of plane p of the "plane_pixel_width[ p ]" is the width in pixels of plane p of the
slice. "plane_pixel_width[ 0 ]" and "plane_pixel_width[ 1 + ( slice.
chroma_planes ? 2 : 0 ) ]" value is "slice_pixel_width". If "plane_pixel_width[ 0 ]" and "plane_pixel_width[ 1 + ( chroma_planes
"chroma_planes" is set to 1, "plane_pixel_width[ 1 ]" and ? 2 : 0 ) ]" value is "slice_pixel_width".
"plane_pixel_width[ 2 ]" value is "ceil(slice_pixel_width / If "chroma_planes" is set to 1, "plane_pixel_width[ 1 ]" and
v_chroma_subsample)". "plane_pixel_width[ 2 ]" value is "ceil(slice_pixel_width / (1 <<
log2_h_chroma_subsample))".
4.6.2. slice_pixel_width 4.6.2. slice_pixel_width
"slice_pixel_width" is the width in pixels of the slice. Its value "slice_pixel_width" is the width in pixels of the slice.
is "floor(( slice_x + slice_width ) * slice_pixel_width / Its value is "floor(( slice_x + slice_width ) * slice_pixel_width /
num_h_slices) - slice_pixel_x". num_h_slices) - slice_pixel_x".
4.6.3. slice_pixel_x 4.6.3. slice_pixel_x
"slice_pixel_x" is the slice horizontal position in pixels. Its "slice_pixel_x" is the slice horizontal position in pixels.
value is "floor(slice_x * frame_pixel_width / num_h_slices)". Its value is "floor(slice_x * frame_pixel_width / num_h_slices)".
4.6.4. sample_difference
"sample_difference[ p ][ y ][ x ]" is the sample difference for
sample at plane "p", y position "y" and x position "x". Sample value
is computed based on prediction and context described in Section 3.2.
4.7. Slice Footer 4.7. Slice Footer
Note: slice footer is always byte aligned. Note: slice footer is always byte aligned.
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
SliceFooter( ) { | SliceFooter( ) { |
slice_size | u(24) slice_size | u(24)
if (ec) { | if (ec) { |
error_status | u(8) error_status | u(8)
slice_crc_parity | u(32) slice_crc_parity | u(32)
} | } |
} | } |
4.7.1. slice_size 4.7.1. slice_size
"slice_size" indicates the size of the slice in bytes. Note: this "slice_size" indicates the size of the slice in bytes.
allows finding the start of slices before previous slices have been Note: this allows finding the start of slices before previous slices
fully decoded. And allows this way parallel decoding as well as have been fully decoded. And allows this way parallel decoding as
error resilience. well as error resilience.
4.7.2. error_status 4.7.2. error_status
"error_status" specifies the error status. "error_status" specifies the error status.
+-------+--------------------------------------+ +-------+--------------------------------------+
| value | error status | | value | error status |
+-------+--------------------------------------+ +-------+--------------------------------------+
| 0 | no error | | 0 | no error |
| 1 | slice contains a correctable error | | 1 | slice contains a correctable error |
| 2 | slice contains a uncorrectable error | | 2 | slice contains a uncorrectable error |
| Other | reserved for future use | | Other | reserved for future use |
+-------+--------------------------------------+ +-------+--------------------------------------+
4.7.3. slice_crc_parity 4.7.3. slice_crc_parity
"slice_crc_parity" 32 bits that are chosen so that the slice as a "slice_crc_parity" 32 bits that are chosen so that the slice as a
whole has a crc remainder of 0. This is equivalent to storing the whole has a crc remainder of 0.
crc remainder in the 32-bit parity. The CRC generator polynomial This is equivalent to storing the crc remainder in the 32-bit parity.
used is the standard IEEE CRC polynomial (0x104C11DB7) with initial The CRC generator polynomial used is the standard IEEE CRC polynomial
value 0. (0x104C11DB7) with initial value 0.
4.8. Parameters 4.8. Parameters
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
Parameters( ) { | Parameters( ) { |
version | ur version | ur
if (version >= 3) | if (version >= 3) |
micro_version | ur micro_version | ur
coder_type | ur coder_type | ur
if (coder_type > 1) | if (coder_type > 1) |
for (i = 1; i < 256; i++) | for (i = 1; i < 256; i++) |
state_transition_delta[ i ] | sr state_transition_delta[ i ] | sr
colorspace_type | ur colorspace_type | ur
if (version >= 1) | if (version >= 1) |
bits_per_raw_sample | ur bits_per_raw_sample | ur
chroma_planes | br chroma_planes | br
log2( h_chroma_subsample ) | ur log2_h_chroma_subsample | ur
log2( v_chroma_subsample ) | ur log2_v_chroma_subsample | ur
alpha_plane | br alpha_plane | br
if (version >= 3) { | if (version >= 3) { |
num_h_slices - 1 | ur num_h_slices - 1 | ur
num_v_slices - 1 | ur num_v_slices - 1 | ur
quant_table_set_count | ur quant_table_set_count | ur
} | } |
for( i = 0; i < quant_table_set_count; i++ ) | for( i = 0; i < quant_table_set_count; i++ ) |
QuantizationTableSet( i ) | QuantizationTableSet( i ) |
if (version >= 3) { | if (version >= 3) { |
for( i = 0; i < quant_table_set_count; i++ ) { | for( i = 0; i < quant_table_set_count; i++ ) { |
skipping to change at page 28, line 43 skipping to change at page 29, line 43
for( k = 0; k < CONTEXT_SIZE; k++ ) | for( k = 0; k < CONTEXT_SIZE; k++ ) |
initial_state_delta[ i ][ j ][ k ] | sr initial_state_delta[ i ][ j ][ k ] | sr
} | } |
ec | ur ec | ur
intra | ur intra | ur
} | } |
} | } |
4.8.1. version 4.8.1. version
"version" specifies the version of the bitstream. Each version is "version" specifies the version of the FFV1 bitstream.
incompatible with others versions: decoders SHOULD reject a file due Each version is incompatible with others versions: decoders SHOULD
to unknown version. Decoders SHOULD reject a file with version <= 1 reject a file due to unknown version.
&& ConfigurationRecordIsPresent == 1. Decoders SHOULD reject a file Decoders SHOULD reject a file with version <= 1 &&
with version >= 3 && ConfigurationRecordIsPresent == 0. ConfigurationRecordIsPresent == 1.
Decoders SHOULD reject a file with version >= 3 &&
ConfigurationRecordIsPresent == 0.
+-------+-------------------------+ +-------+-------------------------+
| value | version | | value | version |
+-------+-------------------------+ +-------+-------------------------+
| 0 | FFV1 version 0 | | 0 | FFV1 version 0 |
| 1 | FFV1 version 1 | | 1 | FFV1 version 1 |
| 2 | reserved* | | 2 | reserved* |
| 3 | FFV1 version 3 | | 3 | FFV1 version 3 |
| Other | reserved for future use | | Other | reserved for future use |
+-------+-------------------------+ +-------+-------------------------+
* Version 2 was never enabled in the encoder thus version 2 files * Version 2 was never enabled in the encoder thus version 2 files
SHOULD NOT exist, and this document does not describe them to keep SHOULD NOT exist, and this document does not describe them to keep
the text simpler. the text simpler.
4.8.2. micro_version 4.8.2. micro_version
"micro_version" specifies the micro-version of the bitstream. After "micro_version" specifies the micro-version of the FFV1 bitstream.
a version is considered stable (a micro-version value is assigned to After a version is considered stable (a micro-version value is
be the first stable variant of a specific version), each new micro- assigned to be the first stable variant of a specific version), each
version after this first stable variant is compatible with the new micro-version after this first stable variant is compatible with
previous micro-version: decoders SHOULD NOT reject a file due to an the previous micro-version: decoders SHOULD NOT reject a file due to
unknown micro-version equal or above the micro-version considered as an unknown micro-version equal or above the micro-version considered
stable. as stable.
Meaning of micro_version for version 3: Meaning of micro_version for version 3:
+-------+-------------------------+ +-------+-------------------------+
| value | micro_version | | value | micro_version |
+-------+-------------------------+ +-------+-------------------------+
| 0...3 | reserved* | | 0...3 | reserved* |
| 4 | first stable variant | | 4 | first stable variant |
| Other | reserved for future use | | Other | reserved for future use |
+-------+-------------------------+ +-------+-------------------------+
* were development versions which may be incompatible with the stable * development versions which may be incompatible with the stable
variants. variants.
Meaning of micro_version for version 4 (note: at the time of writing Meaning of micro_version for version 4 (note: at the time of writing
of this specification, version 4 is not considered stable so the of this specification, version 4 is not considered stable so the
first stable version value is to be announced in the future): first stable version value is to be announced in the future):
+---------+-------------------------+ +---------+-------------------------+
| value | micro_version | | value | micro_version |
+---------+-------------------------+ +---------+-------------------------+
| 0...TBA | reserved* | | 0...TBA | reserved* |
| TBA | first stable variant | | TBA | first stable variant |
| Other | reserved for future use | | Other | reserved for future use |
+---------+-------------------------+ +---------+-------------------------+
* were development versions which may be incompatible with the stable * development versions which may be incompatible with the stable
variants. variants.
4.8.3. coder_type 4.8.3. coder_type
"coder_type" specifies the coder used "coder_type" specifies the coder used.
+-------+-------------------------------------------------+ +-------+-------------------------------------------------+
| value | coder used | | value | coder used |
+-------+-------------------------------------------------+ +-------+-------------------------------------------------+
| 0 | Golomb Rice | | 0 | Golomb Rice |
| 1 | Range Coder with default state transition table | | 1 | Range Coder with default state transition table |
| 2 | Range Coder with custom state transition table | | 2 | Range Coder with custom state transition table |
| Other | reserved for future use | | Other | reserved for future use |
+-------+-------------------------------------------------+ +-------+-------------------------------------------------+
4.8.4. state_transition_delta 4.8.4. state_transition_delta
"state_transition_delta" specifies the Range coder custom state "state_transition_delta" specifies the Range coder custom state
transition table. If state_transition_delta is not present in the transition table.
bitstream, all Range coder custom state transition table elements are If state_transition_delta is not present in the FFV1 bitstream, all
assumed to be 0. Range coder custom state transition table elements are assumed to be
0.
4.8.5. colorspace_type 4.8.5. colorspace_type
"colorspace_type" specifies the color space. "colorspace_type" specifies color space losslessly encoded, Pixel
transformation used by the encoder, as well as interleave method.
+-------+-------------------------+ +-------+---------------------+------------------+------------------+
| value | color space used | | value | color space | transformation | interleave |
+-------+-------------------------+ | | losslessly encoded | | method |
| 0 | YCbCr | +-------+---------------------+------------------+------------------+
| 1 | JPEG2000-RCT | | 0 | YCbCr | No Pixel | plane then line |
| Other | reserved for future use | | | | transformation | |
+-------+-------------------------+ | 1 | RGB | JPEG2000-RCT | line then plane |
| Other | reserved for future | reserved for | reserved for |
| | use | future use | future use |
+-------+---------------------+------------------+------------------+
Restrictions:
If "colorspace_type" is 1, "chroma_planes" MUST be 1,
"h_chroma_subsample" MUST be 1, "v_chroma_subsample" MUST be 1.
4.8.6. chroma_planes 4.8.6. chroma_planes
"chroma_planes" indicates if chroma (color) planes are present. "chroma_planes" indicates if chroma (color) planes are present.
+-------+-------------------------------+ +-------+-------------------------------+
| value | color space used | | value | presence |
+-------+-------------------------------+ +-------+-------------------------------+
| 0 | chroma planes are not present | | 0 | chroma planes are not present |
| 1 | chroma planes are present | | 1 | chroma planes are present |
+-------+-------------------------------+ +-------+-------------------------------+
4.8.7. bits_per_raw_sample 4.8.7. bits_per_raw_sample
"bits_per_raw_sample" indicates the number of bits for each luma and "bits_per_raw_sample" indicates the number of bits for each sample.
chroma sample. Inferred to be 8 if not present. Inferred to be 8 if not present.
+-------+-------------------------------------------------+ +-------+---------------------------------+
| value | bits for each luma and chroma sample | | value | bits for each sample |
+-------+-------------------------------------------------+ +-------+---------------------------------+
| 0 | reserved* | | 0 | reserved* |
| Other | the actual bits for each luma and chroma sample | | Other | the actual bits for each sample |
+-------+-------------------------------------------------+ +-------+---------------------------------+
* Encoders MUST NOT store bits_per_raw_sample = 0 Decoders SHOULD * Encoders MUST NOT store bits_per_raw_sample = 0 Decoders SHOULD
accept and interpret bits_per_raw_sample = 0 as 8. accept and interpret bits_per_raw_sample = 0 as 8.
4.8.8. h_chroma_subsample 4.8.8. log2_h_chroma_subsample
"h_chroma_subsample" indicates the subsample factor between luma and "log2_h_chroma_subsample" indicates the subsample factor, stored in
chroma width ("chroma_width = 2^(-log2_h_chroma_subsample) * powers to which the number 2 must be raised, between luma and chroma
luma_width"). width ("chroma_width = 2^(-log2_h_chroma_subsample) * luma_width").
4.8.9. v_chroma_subsample 4.8.9. log2_v_chroma_subsample
"v_chroma_subsample" indicates the subsample factor between luma and "log2_v_chroma_subsample" indicates the subsample factor, stored in
chroma height ("chroma_height=2^(-log2_v_chroma_subsample) * powers to which the number 2 must be raised, between luma and chroma
luma_height"). height ("chroma_height=2^(-log2_v_chroma_subsample) * luma_height").
4.8.10. alpha_plane 4.8.10. alpha_plane
alpha_plane "alpha_plane" indicates if a transparency plane is present.
indicates if a transparency plane is present.
+-------+-----------------------------------+ +-------+-----------------------------------+
| value | color space used | | value | presence |
+-------+-----------------------------------+ +-------+-----------------------------------+
| 0 | transparency plane is not present | | 0 | transparency plane is not present |
| 1 | transparency plane is present | | 1 | transparency plane is present |
+-------+-----------------------------------+ +-------+-----------------------------------+
4.8.11. num_h_slices 4.8.11. num_h_slices
"num_h_slices" indicates the number of horizontal elements of the "num_h_slices" indicates the number of horizontal elements of the
slice raster. Inferred to be 1 if not present. slice raster.
Inferred to be 1 if not present.
4.8.12. num_v_slices 4.8.12. num_v_slices
"num_v_slices" indicates the number of vertical elements of the slice "num_v_slices" indicates the number of vertical elements of the slice
raster. Inferred to be 1 if not present. raster.
Inferred to be 1 if not present.
4.8.13. quant_table_set_count 4.8.13. quant_table_set_count
"quant_table_set_count" indicates the number of Quantization "quant_table_set_count" indicates the number of Quantization
Table Sets. Inferred to be 1 if not present. MUST NOT be 0. Table Sets.
Inferred to be 1 if not present.
MUST NOT be 0.
4.8.14. states_coded 4.8.14. states_coded
"states_coded" indicates if the respective Quantization Table Set has "states_coded" indicates if the respective Quantization Table Set has
the initial states coded. Inferred to be 0 if not present. the initial states coded.
Inferred to be 0 if not present.
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| value | initial states | | value | initial states |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| 0 | initial states are not present and are assumed to be all | | 0 | initial states are not present and are assumed to be all |
| | 128 | | | 128 |
| 1 | initial states are present | | 1 | initial states are present |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
4.8.15. initial_state_delta 4.8.15. initial_state_delta
"initial_state_delta" [ i ][ j ][ k ] indicates the initial Range "initial_state_delta[ i ][ j ][ k ]" indicates the initial Range
coder state, it is encoded using k as context index and pred = j ? coder state, it is encoded using "k" as context index and
initial_states[ i ][j - 1][ k ] : 128 initial_state[ i ][ j ][ k ] =
( pred + initial_state_delta[ i ][ j ][ k ] ) & 255 pred = j ? initial_states[ i ][j - 1][ k ] : 128
initial_state[ i ][ j ][ k ] =
( pred + initial_state_delta[ i ][ j ][ k ] ) & 255
4.8.16. ec 4.8.16. ec
"ec" indicates the error detection/correction type. "ec" indicates the error detection/correction type.
+-------+--------------------------------------------+ +-------+--------------------------------------------+
| value | error detection/correction type | | value | error detection/correction type |
+-------+--------------------------------------------+ +-------+--------------------------------------------+
| 0 | 32-bit CRC on the global header | | 0 | 32-bit CRC on the global header |
| 1 | 32-bit CRC per slice and the global header | | 1 | 32-bit CRC per slice and the global header |
| Other | reserved for future use | | Other | reserved for future use |
+-------+--------------------------------------------+ +-------+--------------------------------------------+
4.8.17. intra 4.8.17. intra
"intra" indicates the relationship between frames. Inferred to be 0 "intra" indicates the relationship between the instances of "Frame".
if not present. Inferred to be 0 if not present.
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| value | relationship | | value | relationship |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| 0 | frames are independent or dependent (keyframes and non | | 0 | Frames are independent or dependent (keyframes and non |
| | keyframes) | | | keyframes) |
| 1 | frames are independent (keyframes only) | | 1 | Frames are independent (keyframes only) |
| Other | reserved for future use | | Other | reserved for future use |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
4.9. Quantization Table Set 4.9. Quantization Table Set
The Quantization Table Sets are stored by storing the number of equal The Quantization Table Sets are stored by storing the number of equal
entries -1 of the first half of the table (represented as "len - 1" entries -1 of the first half of the table (represented as "len - 1"
in the pseudo-code below) using the method described in in the pseudo-code below) using the method described in
Section 3.8.1.2. The second half doesn't need to be stored as it is Section 3.8.1.2. The second half doesn't need to be stored as it is
identical to the first with flipped sign. identical to the first with flipped sign.
skipping to change at page 34, line 46 skipping to change at page 35, line 46
5. Restrictions 5. Restrictions
To ensure that fast multithreaded decoding is possible, starting To ensure that fast multithreaded decoding is possible, starting
version 3 and if frame_pixel_width * frame_pixel_height is more than version 3 and if frame_pixel_width * frame_pixel_height is more than
101376, slice_width * slice_height MUST be less or equal to 101376, slice_width * slice_height MUST be less or equal to
num_h_slices * num_v_slices / 4. Note: 101376 is the frame size in num_h_slices * num_v_slices / 4. Note: 101376 is the frame size in
pixels of a 352x288 frame also known as CIF ("Common Intermediate pixels of a 352x288 frame also known as CIF ("Common Intermediate
Format") frame size format. Format") frame size format.
For each frame, each position in the slice raster MUST be filled by For each "Frame", each position in the slice raster MUST be filled by
one and only one slice of the frame (no missing slice position, no one and only one slice of the "Frame" (no missing slice position, no
slice overlapping). slice overlapping).
For each Frame with keyframe value of 0, each slice MUST have the For each "Frame" with keyframe value of 0, each slice MUST have the
same value of slice_x, slice_y, slice_width, slice_height as a slice same value of slice_x, slice_y, slice_width, slice_height as a slice
in the previous frame, except if reset_contexts is 1. in the previous "Frame", except if reset_contexts is 1.
6. Security Considerations 6. Security Considerations
Like any other codec, (such as [RFC6716]), FFV1 should not be used Like any other codec, (such as [RFC6716]), FFV1 should not be used
with insecure ciphers or cipher-modes that are vulnerable to known with insecure ciphers or cipher-modes that are vulnerable to known
plaintext attacks. Some of the header bits as well as the padding plaintext attacks. Some of the header bits as well as the padding
are easily predictable. are easily predictable.
Implementations of the FFV1 codec need to take appropriate security Implementations of the FFV1 codec need to take appropriate security
considerations into account, as outlined in [RFC4732]. It is considerations into account, as outlined in [RFC4732]. It is
extremely important for the decoder to be robust against malicious extremely important for the decoder to be robust against malicious
payloads. Malicious payloads must not cause the decoder to overrun payloads. Malicious payloads must not cause the decoder to overrun
its allocated memory or to take an excessive amount of resources to its allocated memory or to take an excessive amount of resources to
decode. Although problems in encoders are typically rarer, the same decode. Although problems in encoders are typically rarer, the same
applies to the encoder. Malicious video streams must not cause the applies to the encoder. Malicious video streams must not cause the
encoder to misbehave because this would allow an attacker to attack encoder to misbehave because this would allow an attacker to attack
transcoding gateways. A frequent security problem in image and video transcoding gateways. A frequent security problem in image and video
codecs is also to not check for integer overflows in pixel count codecs is also to not check for integer overflows in Pixel count
computations, that is to allocate width * height without considering computations, that is to allocate width * height without considering
that the multiplication result may have overflowed the arithmetic that the multiplication result may have overflowed the arithmetic
types range. types range.
The reference implementation [REFIMPL] contains no known buffer The reference implementation [REFIMPL] contains no known buffer
overflow or cases where a specially crafted packet or video segment overflow or cases where a specially crafted packet or video segment
could cause a significant increase in CPU load. could cause a significant increase in CPU load.
The reference implementation [REFIMPL] was validated in the following The reference implementation [REFIMPL] was validated in the following
conditions: conditions:
skipping to change at page 36, line 8 skipping to change at page 37, line 8
inside the [VALGRIND] memory debugger as well as clangs address inside the [VALGRIND] memory debugger as well as clangs address
sanitizer [Address-Sanitizer], which track reads and writes to sanitizer [Address-Sanitizer], which track reads and writes to
invalid memory regions as well as the use of uninitialized memory. invalid memory regions as well as the use of uninitialized memory.
There were no errors reported on any of the tested conditions. There were no errors reported on any of the tested conditions.
7. Appendixes 7. Appendixes
7.1. Decoder implementation suggestions 7.1. Decoder implementation suggestions
7.1.1. Multi-threading support and independence of slices 7.1.1. Multi-threading support and independence of slices
The bitstream is parsable in two ways: in sequential order as The FFV1 bitstream is parsable in two ways: in sequential order as
described in this document or with the pre-analysis of the footer of described in this document or with the pre-analysis of the footer of
each slice. Each slice footer contains a slice_size field so the each slice. Each slice footer contains a slice_size field so the
boundary of each slice is computable without having to parse the boundary of each slice is computable without having to parse the
slice content. That allows multi-threading as well as independence slice content. That allows multi-threading as well as independence
of slice content (a bitstream error in a slice header or slice of slice content (a bitstream error in a slice header or slice
content has no impact on the decoding of the other slices). content has no impact on the decoding of the other slices).
After having checked keyframe field, a decoder SHOULD parse After having checked keyframe field, a decoder SHOULD parse
slice_size fields, from slice_size of the last slice at the end of slice_size fields, from slice_size of the last slice at the end of
the frame up to slice_size of the first slice at the beginning of the the "Frame" up to slice_size of the first slice at the beginning of
frame, before parsing slices, in order to have slices boundaries. A the "Frame", before parsing slices, in order to have slices
decoder MAY fallback on sequential order e.g. in case of corrupted boundaries. A decoder MAY fallback on sequential order e.g. in case
frame (frame size unknown, slice_size of slices not coherent...) or of a corrupted "Frame" (frame size unknown, slice_size of slices not
if there is no possibility of seek into the stream. coherent...) or if there is no possibility of seek into the stream.
Architecture overview of slices in a frame: Architecture overview of slices in a "Frame":
+-----------------------------------------------------------------+ +-----------------------------------------------------------------+
| first slice header | | first slice header |
| first slice content | | first slice content |
| first slice footer | | first slice footer |
| --------------------------------------------------------------- | | --------------------------------------------------------------- |
| second slice header | | second slice header |
| second slice content | | second slice content |
| second slice footer | | second slice footer |
| --------------------------------------------------------------- | | --------------------------------------------------------------- |
skipping to change at page 37, line 21 skipping to change at page 38, line 21
"Information technology -- JPEG 2000 image coding system: "Information technology -- JPEG 2000 image coding system:
Core coding system", October 2016. Core coding system", October 2016.
[ISO.9899.1990] [ISO.9899.1990]
International Organization for Standardization, International Organization for Standardization,
"Programming languages - C", ISO Standard 9899, 1990. "Programming languages - C", ISO Standard 9899, 1990.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
10.2. Informative References 10.2. Informative References
[Address-Sanitizer] [Address-Sanitizer]
The Clang Team, "ASAN AddressSanitizer website", undated, The Clang Team, "ASAN AddressSanitizer website", undated,
<https://clang.llvm.org/docs/AddressSanitizer.html>. <https://clang.llvm.org/docs/AddressSanitizer.html>.
[AVI] Microsoft, "AVI RIFF File Reference", undated, [AVI] Microsoft, "AVI RIFF File Reference", undated,
<https://msdn.microsoft.com/en-us/library/windows/desktop/ <https://msdn.microsoft.com/en-us/library/windows/desktop/
dd318189%28v=vs.85%29.aspx>. dd318189%28v=vs.85%29.aspx>.
skipping to change at page 38, line 41 skipping to change at page 39, line 41
Institution of Electronic and Radio Engineers Institution of Electronic and Radio Engineers
International Conference on Video and Data Recording , International Conference on Video and Data Recording ,
July 1979. July 1979.
[REFIMPL] Niedermayer, M., "The reference FFV1 implementation / the [REFIMPL] Niedermayer, M., "The reference FFV1 implementation / the
FFV1 codec in FFmpeg", undated, <https://ffmpeg.org>. FFV1 codec in FFmpeg", undated, <https://ffmpeg.org>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732, Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006, DOI 10.17487/RFC4732, December 2006,
<http://www.rfc-editor.org/info/rfc4732>. <https://www.rfc-editor.org/info/rfc4732>.
[RFC6716] Valin, JM., Vos, K., and T. Terriberry, "Definition of the [RFC6716] Valin, JM., Vos, K., and T. Terriberry, "Definition of the
Opus Audio Codec", RFC 6716, DOI 10.17487/RFC6716, Opus Audio Codec", RFC 6716, DOI 10.17487/RFC6716,
September 2012, <http://www.rfc-editor.org/info/rfc6716>. September 2012, <https://www.rfc-editor.org/info/rfc6716>.
[VALGRIND] [VALGRIND]
Valgrind Developers, "Valgrind website", undated, Valgrind Developers, "Valgrind website", undated,
<https://valgrind.org/>. <https://valgrind.org/>.
[YCbCr] Wikipedia, "YCbCr", undated, <https://en.wikipedia.org/w/ [YCbCr] Wikipedia, "YCbCr", undated,
index.php?title=YCbCr>. <https://en.wikipedia.org/w/index.php?title=YCbCr>.
Authors' Addresses Authors' Addresses
Michael Niedermayer Michael Niedermayer
Email: michael@niedermayer.cc Email: michael@niedermayer.cc
Dave Rice Dave Rice
Email: dave@dericed.com Email: dave@dericed.com
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