draft-ietf-cellar-ffv1-06.txt   draft-ietf-cellar-ffv1-07.txt 
cellar M. Niedermayer cellar M. Niedermayer
Internet-Draft Internet-Draft
Intended status: Informational D. Rice Intended status: Informational D. Rice
Expires: April 21, 2019 Expires: August 10, 2019
J. Martinez J. Martinez
October 18, 2018 February 6, 2019
FFV1 Video Coding Format Version 0, 1, and 3 FFV1 Video Coding Format Version 0, 1, and 3
draft-ietf-cellar-ffv1-06 draft-ietf-cellar-ffv1-07
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
skipping to change at page 1, line 36 skipping to change at page 1, line 36
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This Internet-Draft will expire on April 21, 2019. This Internet-Draft will expire on August 10, 2019.
Copyright Notice Copyright Notice
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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 . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1. Pseudo-code . . . . . . . . . . . . . . . . . . . . . 6 2.2.1. Pseudo-code . . . . . . . . . . . . . . . . . . . . . 6
2.2.2. Arithmetic Operators . . . . . . . . . . . . . . . . 6 2.2.2. Arithmetic Operators . . . . . . . . . . . . . . . . 6
2.2.3. Assignment Operators . . . . . . . . . . . . . . . . 6 2.2.3. Assignment Operators . . . . . . . . . . . . . . . . 6
2.2.4. Comparison Operators . . . . . . . . . . . . . . . . 7 2.2.4. Comparison Operators . . . . . . . . . . . . . . . . 7
2.2.5. Mathematical Functions . . . . . . . . . . . . . . . 7 2.2.5. Mathematical Functions . . . . . . . . . . . . . . . 7
2.2.6. Order of Operation Precedence . . . . . . . . . . . . 8 2.2.6. Order of Operation Precedence . . . . . . . . . . . . 8
2.2.7. Range . . . . . . . . . . . . . . . . . . . . . . . . 8 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. Sample Coding . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Sample Coding . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Border . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1. Border . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Samples . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2. Samples . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3. Median Predictor . . . . . . . . . . . . . . . . . . . . 10 3.3. Median Predictor . . . . . . . . . . . . . . . . . . . . 10
3.4. Context . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4. Context . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.5. Quantization Table Sets . . . . . . . . . . . . . . . . . 11 3.5. Quantization Table Sets . . . . . . . . . . . . . . . . . 11
3.6. Quantization Table Set Indexes . . . . . . . . . . . . . 12 3.6. Quantization Table Set Indexes . . . . . . . . . . . . . 12
3.7. Color spaces . . . . . . . . . . . . . . . . . . . . . . 12 3.7. Color spaces . . . . . . . . . . . . . . . . . . . . . . 12
3.7.1. YCbCr . . . . . . . . . . . . . . . . . . . . . . . . 12 3.7.1. YCbCr . . . . . . . . . . . . . . . . . . . . . . . . 12
3.7.2. RGB . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.7.2. RGB . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.8. Coding of the Sample Difference . . . . . . . . . . . . . 14 3.8. Coding of the Sample Difference . . . . . . . . . . . . . 14
3.8.1. Range Coding Mode . . . . . . . . . . . . . . . . . . 14 3.8.1. Range Coding Mode . . . . . . . . . . . . . . . . . . 15
3.8.2. Golomb Rice Mode . . . . . . . . . . . . . . . . . . 18 3.8.2. Golomb Rice Mode . . . . . . . . . . . . . . . . . . 19
4. Bitstream . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4. Bitstream . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1. Parameters . . . . . . . . . . . . . . . . . . . . . . . 21 4.1. Parameters . . . . . . . . . . . . . . . . . . . . . . . 24
4.1.1. version . . . . . . . . . . . . . . . . . . . . . . . 22 4.1.1. version . . . . . . . . . . . . . . . . . . . . . . . 25
4.1.2. micro_version . . . . . . . . . . . . . . . . . . . . 23 4.1.2. micro_version . . . . . . . . . . . . . . . . . . . . 26
4.1.3. coder_type . . . . . . . . . . . . . . . . . . . . . 23 4.1.3. coder_type . . . . . . . . . . . . . . . . . . . . . 26
4.1.4. state_transition_delta . . . . . . . . . . . . . . . 24 4.1.4. state_transition_delta . . . . . . . . . . . . . . . 27
4.1.5. colorspace_type . . . . . . . . . . . . . . . . . . . 24 4.1.5. colorspace_type . . . . . . . . . . . . . . . . . . . 27
4.1.6. chroma_planes . . . . . . . . . . . . . . . . . . . . 24 4.1.6. chroma_planes . . . . . . . . . . . . . . . . . . . . 27
4.1.7. bits_per_raw_sample . . . . . . . . . . . . . . . . . 24 4.1.7. bits_per_raw_sample . . . . . . . . . . . . . . . . . 28
4.1.8. log2_h_chroma_subsample . . . . . . . . . . . . . . . 25 4.1.8. log2_h_chroma_subsample . . . . . . . . . . . . . . . 28
4.1.9. log2_v_chroma_subsample . . . . . . . . . . . . . . . 25 4.1.9. log2_v_chroma_subsample . . . . . . . . . . . . . . . 28
4.1.10. alpha_plane . . . . . . . . . . . . . . . . . . . . . 25 4.1.10. extra_plane . . . . . . . . . . . . . . . . . . . . . 28
4.1.11. num_h_slices . . . . . . . . . . . . . . . . . . . . 25 4.1.11. num_h_slices . . . . . . . . . . . . . . . . . . . . 28
4.1.12. num_v_slices . . . . . . . . . . . . . . . . . . . . 25 4.1.12. num_v_slices . . . . . . . . . . . . . . . . . . . . 29
4.1.13. quant_table_set_count . . . . . . . . . . . . . . . . 26 4.1.13. quant_table_set_count . . . . . . . . . . . . . . . . 29
4.1.14. states_coded . . . . . . . . . . . . . . . . . . . . 26 4.1.14. states_coded . . . . . . . . . . . . . . . . . . . . 29
4.1.15. initial_state_delta . . . . . . . . . . . . . . . . . 26 4.1.15. initial_state_delta . . . . . . . . . . . . . . . . . 29
4.1.16. ec . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.1.16. ec . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.17. intra . . . . . . . . . . . . . . . . . . . . . . . . 26 4.1.17. intra . . . . . . . . . . . . . . . . . . . . . . . . 30
4.2. Configuration Record . . . . . . . . . . . . . . . . . . 27 4.2. Configuration Record . . . . . . . . . . . . . . . . . . 30
4.2.1. reserved_for_future_use . . . . . . . . . . . . . . . 27 4.2.1. reserved_for_future_use . . . . . . . . . . . . . . . 30
4.2.2. configuration_record_crc_parity . . . . . . . . . . . 27 4.2.2. configuration_record_crc_parity . . . . . . . . . . . 30
4.2.3. Mapping FFV1 into Containers . . . . . . . . . . . . 28 4.2.3. Mapping FFV1 into Containers . . . . . . . . . . . . 31
4.3. Frame . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.3. Frame . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.4. Slice . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.4. Slice . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.5. Slice Header . . . . . . . . . . . . . . . . . . . . . . 30 4.5. Slice Header . . . . . . . . . . . . . . . . . . . . . . 33
4.5.1. slice_x . . . . . . . . . . . . . . . . . . . . . . . 31 4.5.1. slice_x . . . . . . . . . . . . . . . . . . . . . . . 34
4.5.2. slice_y . . . . . . . . . . . . . . . . . . . . . . . 31 4.5.2. slice_y . . . . . . . . . . . . . . . . . . . . . . . 34
4.5.3. slice_width . . . . . . . . . . . . . . . . . . . . . 31 4.5.3. slice_width . . . . . . . . . . . . . . . . . . . . . 34
4.5.4. slice_height . . . . . . . . . . . . . . . . . . . . 31 4.5.4. slice_height . . . . . . . . . . . . . . . . . . . . 34
4.5.5. quant_table_set_index_count . . . . . . . . . . . . . 31 4.5.5. quant_table_set_index_count . . . . . . . . . . . . . 34
4.5.6. quant_table_set_index . . . . . . . . . . . . . . . . 31 4.5.6. quant_table_set_index . . . . . . . . . . . . . . . . 34
4.5.7. picture_structure . . . . . . . . . . . . . . . . . . 32 4.5.7. picture_structure . . . . . . . . . . . . . . . . . . 35
4.5.8. sar_num . . . . . . . . . . . . . . . . . . . . . . . 32 4.5.8. sar_num . . . . . . . . . . . . . . . . . . . . . . . 35
4.5.9. sar_den . . . . . . . . . . . . . . . . . . . . . . . 32 4.5.9. sar_den . . . . . . . . . . . . . . . . . . . . . . . 35
4.6. Slice Content . . . . . . . . . . . . . . . . . . . . . . 32 4.6. Slice Content . . . . . . . . . . . . . . . . . . . . . . 35
4.6.1. primary_color_count . . . . . . . . . . . . . . . . . 33 4.6.1. primary_color_count . . . . . . . . . . . . . . . . . 36
4.6.2. plane_pixel_height . . . . . . . . . . . . . . . . . 33 4.6.2. plane_pixel_height . . . . . . . . . . . . . . . . . 36
4.6.3. slice_pixel_height . . . . . . . . . . . . . . . . . 33 4.6.3. slice_pixel_height . . . . . . . . . . . . . . . . . 36
4.6.4. slice_pixel_y . . . . . . . . . . . . . . . . . . . . 33 4.6.4. slice_pixel_y . . . . . . . . . . . . . . . . . . . . 36
4.7. Line . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.7. Line . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.7.1. plane_pixel_width . . . . . . . . . . . . . . . . . . 34 4.7.1. plane_pixel_width . . . . . . . . . . . . . . . . . . 37
4.7.2. slice_pixel_width . . . . . . . . . . . . . . . . . . 34 4.7.2. slice_pixel_width . . . . . . . . . . . . . . . . . . 37
4.7.3. slice_pixel_x . . . . . . . . . . . . . . . . . . . . 34 4.7.3. slice_pixel_x . . . . . . . . . . . . . . . . . . . . 37
4.7.4. sample_difference . . . . . . . . . . . . . . . . . . 34 4.7.4. sample_difference . . . . . . . . . . . . . . . . . . 37
4.8. Slice Footer . . . . . . . . . . . . . . . . . . . . . . 34 4.8. Slice Footer . . . . . . . . . . . . . . . . . . . . . . 37
4.8.1. slice_size . . . . . . . . . . . . . . . . . . . . . 35 4.8.1. slice_size . . . . . . . . . . . . . . . . . . . . . 38
4.8.2. error_status . . . . . . . . . . . . . . . . . . . . 35 4.8.2. error_status . . . . . . . . . . . . . . . . . . . . 38
4.8.3. slice_crc_parity . . . . . . . . . . . . . . . . . . 35 4.8.3. slice_crc_parity . . . . . . . . . . . . . . . . . . 38
4.9. Quantization Table Set . . . . . . . . . . . . . . . . . 35 4.9. Quantization Table Set . . . . . . . . . . . . . . . . . 38
4.9.1. quant_tables . . . . . . . . . . . . . . . . . . . . 36 4.9.1. quant_tables . . . . . . . . . . . . . . . . . . . . 39
4.9.2. context_count . . . . . . . . . . . . . . . . . . . . 37 4.9.2. context_count . . . . . . . . . . . . . . . . . . . . 40
5. Restrictions . . . . . . . . . . . . . . . . . . . . . . . . 37 5. Restrictions . . . . . . . . . . . . . . . . . . . . . . . . 40
6. Security Considerations . . . . . . . . . . . . . . . . . . . 37 6. Security Considerations . . . . . . . . . . . . . . . . . . . 40
7. Media Type Definition . . . . . . . . . . . . . . . . . . . . 38 7. Media Type Definition . . . . . . . . . . . . . . . . . . . . 41
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 43
9. Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . 40 9. Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.1. Decoder implementation suggestions . . . . . . . . . . . 40 9.1. Decoder implementation suggestions . . . . . . . . . . . 43
9.1.1. Multi-threading Support and Independence of Slices . 40 9.1.1. Multi-threading Support and Independence of Slices . 43
10. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 40 10. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 40 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.1. Normative References . . . . . . . . . . . . . . . . . . 40 11.1. Normative References . . . . . . . . . . . . . . . . . . 43
11.2. Informative References . . . . . . . . . . . . . . . . . 41 11.2. Informative References . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 46
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
encodings. encodings.
This document defines a version 0, 1, and 3 of FFV1. The This document defines version 0, 1 and 3 of FFV1. The distinctions
distinctions of the versions are provided throughout the document, of the versions are provided throughout the document, but in summary:
but in summary:
o Version 0 of FFV1 was the original implementation of FFV1 and has o Version 0 of FFV1 was the original implementation of FFV1 and has
been in non-experimental use since April 14, 2006 [FFV1_V0]. been in non-experimental use since April 14, 2006 [FFV1_V0].
o Version 1 of FFV1 adds support of more video bit depths and has o Version 1 of FFV1 adds support of more video bit depths and has
been in use since April 24, 2009 [FFV1_V1]. been in use since April 24, 2009 [FFV1_V1].
o Version 2 of FFV1 only existed in experimental form and is not o Version 2 of FFV1 only existed in experimental form and is not
described by this document, but is available as a LyX file at described by this document, but is available as a LyX file at
<https://github.com/FFmpeg/FFV1/ <https://github.com/FFmpeg/FFV1/
skipping to change at page 5, line 12 skipping to change at page 5, line 12
"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
"Container": Format that encapsulates "Frames" (see Section 4.3) and "Container": Format that encapsulates "Frames" (see Section 4.3) and
(when required) a "Configuration Record" into a bitstream. (when required) a "Configuration Record" into a bitstream.
"Sample": The smallest addressable representation of a color "Sample": The smallest addressable representation of a color
component or a luma component in a "Frame". Examples of "Sample" are component or a luma component in a "Frame". Examples of "Sample" are
Luma, Blue Chrominance, Red Chrominance, Alpha, Red, Green, and Blue. Luma, Blue Chrominance, Red Chrominance, Transparency, Red, Green,
and Blue.
"Plane": A discrete component of a static image comprised of "Plane": A discrete component of a static image comprised of
"Samples" that represent a specific quantification of "Samples" of "Samples" that represent a specific quantification of "Samples" of
that image. that image.
"Pixel": The smallest addressable representation of a color in a "Pixel": The smallest addressable representation of a color in a
"Frame". It is composed of 1 or more "Samples". "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 is
used.
"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 "Pixel". of a "Pixel".
"VLC": Variable Length Code, a code that maps source symbols to a "VLC": Variable Length Code, a code that 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 "Pixel" 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 "Pixel" "YCbCr": A reference to the method of storing the value of a "Pixel"
by using three numeric values that represent the luma of the "Pixel" by using three numeric values that represent the luma of the "Pixel"
(Y) and the chrominance of the "Pixel" (Cb and Cr). YCbCr word is (Y) and the chrominance of the "Pixel" (Cb and Cr). YCbCr word is
used for historical reasons and currently references any color space used for historical reasons and currently references any color space
relying on 1 luma "Sample" and 2 chrominance "Samples" e.g. YCbCr, relying on 1 luma "Sample" and 2 chrominance "Samples", e.g. YCbCr,
YCgCo or ICtCp. Exact meaning of the three numeric values is YCgCo or ICtCp. The exact meaning of the three numeric values is
unspecified. 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
2.2.1. Pseudo-code 2.2.1. Pseudo-code
The FFV1 bitstream is described in this document using pseudo-code. The FFV1 bitstream is described in this document using pseudo-code.
Note that the pseudo-code is used for clarity in order to illustrate Note that the pseudo-code is used for clarity in order to illustrate
the structure of FFV1 and not intended to specify any particular the structure of FFV1 and not intended to specify any particular
implementation. The pseudo-code used is based upon the C programming implementation. The pseudo-code used is based upon the C programming
language [ISO.9899.1990] and uses its "if/else", "while" and "for" language [ISO.9899.1990] and uses its "if/else", "while" and "for"
functions as well as functions defined within this document. functions as well as functions defined within this document.
2.2.2. Arithmetic Operators 2.2.2. Arithmetic Operators
skipping to change at page 6, line 28 skipping to change at page 6, line 31
"a + b" means a plus b. "a + b" means a plus b.
"a - b" means a minus b. "a - b" means a minus b.
"-a" means negation of a. "-a" means negation of a.
"a * b" means a multiplied by b. "a * b" means a multiplied by b.
"a / b" means a divided by b. "a / b" means a divided by b.
"a ^ b" means a raised to the b-th power.
"a & b" means bit-wise "and" of a and b. "a & b" means bit-wise "and" of a and b.
"a | b" means bit-wise "or" of a and b. "a | b" means bit-wise "or" of a and b.
"a >> b" means arithmetic right shift of two's complement integer "a >> b" means arithmetic right shift of two's complement integer
representation of a by b binary digits. representation of a by b binary digits.
"a << b" means arithmetic left shift of two's complement integer "a << b" means arithmetic left shift of two's complement integer
representation of a by b binary digits. representation of a by b binary digits.
skipping to change at page 8, line 15 skipping to change at page 8, line 16
2.2.6. Order of Operation Precedence 2.2.6. Order of Operation Precedence
When order of precedence is not indicated explicitly by use of When order of precedence is not indicated explicitly by use of
parentheses, operations are evaluated in the following order (from parentheses, operations are evaluated in the following order (from
top to bottom, operations of same precedence being evaluated from top to bottom, operations of same precedence being evaluated from
left to right). This order of operations is based on the order of left to right). This order of operations is based on the order of
operations used in Standard C. operations used in Standard C.
a++, a-- a++, a--
!a, -a !a, -a
a ^ b
a * b, a / b, a % b a * b, a / b, a % b
a + b, a - b a + b, a - b
a << b, a >> b a << b, a >> b
a < b, a <= b, a > b, a >= b a < b, a <= b, a > b, a >= b
a == b, a != b a == b, a != b
a & b a & b
a | b a | b
a && b a && b
a || b a || b
a ? b : c a ? b : c
a = b, a += b, a -= b, a *= b a = b, a += b, a -= b, a *= b
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 "Configuration Record" or "Frame". FFV1 octets of a particular FFV1 "Configuration Record" or "Frame". FFV1
relies on its "Container" to store the "NumBytes" values, see relies on its "Container" to store the "NumBytes" values, see
Section 4.2.3. Section 4.2.3.
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 pointer in that "Configuration Record" or "Frame". It is after the pointer in that "Configuration Record" or "Frame". It is
computed from the "NumBytes" value multiplied by 8 minus the count of computed from the "NumBytes" value multiplied by 8 minus the count of
bits of that "Configuration Record" or "Frame" already read by the bits of that "Configuration Record" or "Frame" already read by the
bitstream parser. bitstream parser.
2.2.9.2. byte_aligned 2.2.9.2. remaining_symbols_in_syntax
"remaining_symbols_in_syntax( )" is true as long as the RangeCoder
has not consumed all the given input bytes.
2.2.9.3. 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 2.2.9.4. get_bits
"get_bits( i )" is the action to read the next "i" bits in the "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 bitstream, from most significant bit to least significant bit, and to
return the corresponding value. The pointer is increased by "i". return the corresponding value. The pointer is increased by "i".
3. Sample Coding 3. Sample Coding
For each "Slice" (as described in Section 4.4) of a "Frame", the For each "Slice" (as described in Section 4.4) of a "Frame", the
"Planes", "Lines", and "Samples" are coded in an order determined by "Planes", "Lines", and "Samples" are coded in an order determined by
the "Color Space" (see Section 3.7). Each "Sample" is predicted by the "Color Space" (see Section 3.7). Each "Sample" is predicted by
skipping to change at page 12, line 22 skipping to change at page 12, line 22
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:
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 o For Cb and Cr "Planes", "quant_table_set_index [ 1 ]" index is
used used
o For Alpha "Plane", "quant_table_set_index [ (version <= 3 || o For extra "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 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 set to 0), this index is kept for version <= 3 in order to keep
compatibility with FFV1 bitstreams in the wild. compatibility with FFV1 bitstreams in the wild.
3.7. Color spaces 3.7. Color spaces
FFV1 supports two color spaces: YCbCr and RGB. Both color spaces FFV1 supports several color spaces. The count of allowed coded
allow an optional Alpha "Plane" that can be used to code transparency planes and the meaning of the extra "Plane" are determined by the
data. selected color space.
The FFV1 bitstream interleaves data in an order determined by the The FFV1 bitstream interleaves data in an order determined by the
color space. In YCbCr for each "Plane", each "Line" is coded from color space. In YCbCr for each "Plane", each "Line" is coded from
top to bottom and for each "Line", each "Sample" is coded from left top to bottom and for each "Line", each "Sample" is coded from left
to right. In JPEG2000-RCT for each "Line" from top to bottom, each to right. In JPEG2000-RCT for each "Line" from top to bottom, each
"Plane" is coded and for each "Plane", each "Sample" is encoded from "Plane" is coded and for each "Plane", each "Sample" is encoded from
left to right. left to right.
3.7.1. YCbCr 3.7.1. YCbCr
In YCbCr color space, the Cb and Cr "Planes" are optional, but if This color space allows 1 to 4 "Planes".
used then MUST be used together. Omitting the Cb and Cr "Planes" The Cb and Cr "Planes" are optional, but if used then MUST be used
codes the frames in grayscale without color data. An FFV1 "Frame" together. Omitting the Cb and Cr "Planes" codes the frames in
using YCbCr MUST use one of the following arrangements: grayscale without color data.
An optional transparency "Plane" can be used to code transparency
data.
An FFV1 "Frame" using YCbCr MUST use one of the following
arrangements:
o Y o Y
o Y, Alpha
o Y, Transparency
o Y, Cb, Cr o Y, Cb, Cr
o Y, Cb, Cr, Alpha o Y, Cb, Cr, Transparency
The Y "Plane" MUST be coded first. If the Cb and Cr "Planes" are The Y "Plane" MUST be coded first. If the Cb and Cr "Planes" are
used then they MUST be coded after the Y "Plane". If an Alpha used then they MUST be coded after the Y "Plane". If a transparency
(transparency) "Plane" is used, then it MUST be coded last. "Plane" is used, then it MUST be coded last.
3.7.2. RGB 3.7.2. RGB
This color space allows 3 or 4 "Planes".
An optional transparency "Plane" can be used to code transparency
data.
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
[ISO.15444-1.2016]. Reversible Pixel transformations between YCbCr [ISO.15444-1.2016]. Reversible Pixel transformations between YCbCr
and RGB use the following formulae. and RGB use the 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 JPEG2000-RCT conversion: if bits_per_raw_sample is Exception for the JPEG2000-RCT conversion: if bits_per_raw_sample is
between 9 and 15 inclusive and alpha_plane is 0, the following between 9 and 15 inclusive and extra_plane is 0, the following
formulae for reversible conversions between YCbCr and RGB MUST be formulae for reversible conversions between YCbCr and RGB MUST be
used instead of the ones above: used instead of the ones 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 and alpha_plane is 0, GBR "Planes" were used as BGR inclusive and extra_plane is 0, GBR "Planes" were used as BGR
"Planes" during both encoding and decoding. In the meanwhile, 16-bit "Planes" during both encoding and decoding. In the meanwhile, 16-bit
JPEG2000-RCT was implemented without this issue in one implementation JPEG2000-RCT was implemented without this issue in one implementation
and validated by one conformance checker. Methods to address this and validated by one conformance checker. Methods to address this
exception for the transform are under consideration for the next exception for the transform are under consideration for the next
version of the FFV1 bitstream. version of the FFV1 bitstream.
When FFV1 uses the JPEG2000-RCT, the horizontal "Lines" are When FFV1 uses the JPEG2000-RCT, the horizontal "Lines" are
interleaved to improve caching efficiency since it is most likely interleaved to improve caching efficiency since it is most likely
that the JPEG2000-RCT will immediately be converted to RGB during that the JPEG2000-RCT will immediately be converted to RGB during
decoding. The interleaved coding order is also Y, then Cb, then Cr, decoding. The interleaved coding order is also Y, then Cb, then Cr,
and then if used Alpha. and then if used transparency.
As an example, a "Frame" that is two "Pixels" wide and two "Pixels" As an example, a "Frame" that is two "Pixels" wide and two "Pixels"
high, could be comprised of the following structure: high, 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] |
skipping to change at page 15, line 12 skipping to change at page 15, line 21
from H.264 as defined in [ISO.14496-10.2014] but due to the uncertain from H.264 as defined in [ISO.14496-10.2014] but due to the uncertain
patent/royalty situation, as well as its slightly worse performance, patent/royalty situation, as well as its slightly worse performance,
CABAC was replaced by a Range coder based on an algorithm defined by CABAC was replaced by a Range coder based on an algorithm defined by
G. Nigel and N. Martin in 1979 [range-coding]. G. Nigel and N. Martin in 1979 [range-coding].
3.8.1.1. Range Binary Values 3.8.1.1. Range Binary Values
To encode binary digits efficiently a Range coder is used. "C_{i}" To encode binary digits efficiently a Range coder is used. "C_{i}"
is the i-th Context. "B_{i}" is the i-th byte of the bytestream. is the i-th Context. "B_{i}" is the i-th byte of the bytestream.
"b_{i}" is the i-th Range coded binary value, "S_{0,i}" is the i-th "b_{i}" is the i-th Range coded binary value, "S_{0,i}" is the i-th
initial state, which is 128. The length of the bytestream encoding n initial state. The length of the bytestream encoding n binary
binary symbols is "j_{n}" bytes. symbols is "j_{n}" bytes.
r_{i} = floor( ( R_{i} * S_{i,C_{i}} ) / 2^8 ) r_{i} = floor( ( R_{i} * S_{i,C_{i}} ) / 2^8 )
S_{i+1,C_{i}} = zero_state_{S_{i,C_{i}}} XOR S_{i+1,C_{i}} = zero_state_{S_{i,C_{i}}} XOR
l_i = L_i XOR l_i = L_i XOR
t_i = R_i - r_i <== t_i = R_i - r_i <==
b_i = 0 <==> b_i = 0 <==>
L_i < R_i - r_i L_i < R_i - r_i
S_{i+1,C_{i}} = one_state_{S_{i,C_{i}}} XOR S_{i+1,C_{i}} = one_state_{S_{i,C_{i}}} XOR
skipping to change at page 15, line 44 skipping to change at page 16, line 4
t_{i} < 2^8 t_{i} < 2^8
R_{i+1} = t_{i} XOR R_{i+1} = t_{i} XOR
L_{i+1} = l_{i} XOR L_{i+1} = l_{i} XOR
j_{i+1} = j_{i} <== j_{i+1} = j_{i} <==
t_{i} >= 2^8 t_{i} >= 2^8
R_{0} = 65280 R_{0} = 65280
L_{0} = 2^8 * B_{0} + B_{1} L_{0} = 2^8 * B_{0} + B_{1}
j_{0} = 2 j_{0} = 2
3.8.1.1.1. Termination
The range coder can be used in 3 modes.
o In "Open mode" when decoding, every symbol the reader attempts to
read is available. In this mode arbitrary data can have been
appended without affecting the range coder output. This mode is
not used in FFV1.
o In "Closed mode" the length in bytes of the bytestream is provided
to the range decoder. Bytes beyond the length are read as 0 by
the range decoder. This is generally 1 byte shorter than the open
mode.
o In "Sentinel mode" the exact length in bytes is not known and thus
the range decoder MAY read into the data that follows the range
coded bytestream by one byte. In "Sentinel mode", the end of the
range coded bytestream is a binary symbol with state 129, which
value SHALL be discarded. After reading this symbol, the range
decoder will have read one byte beyond the end of the range coded
bytestream. This way the byte position of the end can be
determined. Bytestreams written in "Sentinel mode" can be read in
"Closed mode" if the length can be determined, in this case the
last (sentinel) symbol will be read non-corrupted and be of value
0.
Above describes the range decoding, encoding is defined as any
process which produces a decodable bytestream.
There are 3 places where range coder termination is needed in FFV1.
First is in the "Configuration Record", in this case the size of the
range coded bytestream is known and handled as "Closed mode". Second
is the switch from the "Slice Header" which is range coded to Golomb
coded slices as "Sentinel mode". Third is the end of range coded
Slices which need to terminate before the CRC at their end. This can
be handled as "Sentinel mode" or as "Closed mode" if the CRC position
has been determined.
3.8.1.2. Range Non Binary Values 3.8.1.2. Range Non Binary Values
To encode scalar integers, it would be possible to encode each bit To encode scalar integers, it would be possible to encode each bit
separately and use the past bits as context. However that would mean separately and use the past bits as context. However that would mean
255 contexts per 8-bit symbol that is not only a waste of memory but 255 contexts per 8-bit symbol that is not only a waste of memory but
also requires more past data to reach a reasonably good estimate of also requires more past data to reach a reasonably good estimate of
the probabilities. Alternatively assuming a Laplacian distribution the probabilities. Alternatively assuming a Laplacian distribution
and only dealing with its variance and mean (as in Huffman coding) and only dealing with its variance and mean (as in Huffman coding)
would also be possible, however, for maximum flexibility and would also be possible, however, for maximum flexibility and
simplicity, the chosen method uses a single symbol to encode if a simplicity, the chosen method uses a single symbol to encode if a
number is 0 and if not encodes the number using its exponent, number is 0, and if not, encodes the number using its exponent,
mantissa and sign. The exact contexts used are best described by the mantissa and sign. The exact contexts used are best described by the
following code, followed by some comments. following code, followed by some comments.
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
void put_symbol(RangeCoder *c, uint8_t *state, int v, int \ | void put_symbol(RangeCoder *c, uint8_t *state, int v, int \ |
is_signed) { | is_signed) { |
int i; | int i; |
put_rac(c, state+0, !v); | put_rac(c, state+0, !v); |
if (v) { | if (v) { |
skipping to change at page 18, line 39 skipping to change at page 19, line 39
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. Golomb Rice Mode 3.8.2. Golomb Rice Mode
The end of the bitstream of the "Frame" is filled with 0-bits until
that the bitstream contains a multiple of 8 bits.
3.8.2.1. Signed Golomb Rice Codes
This coding mode uses Golomb Rice codes. The VLC is split into 2 This coding mode uses Golomb Rice codes. The VLC is split into 2
parts, the prefix stores the most significant bits and the suffix parts, the prefix stores the most significant bits and the suffix
stores the k least significant bits or stores the whole number in the stores the k least significant bits or stores the whole number in the
ESC case. The end of the bitstream of the "Frame" is filled with ESC case.
0-bits until that the bitstream contains a multiple of 8 bits.
pseudo-code | type
--------------------------------------------------------------|-----
int get_ur_golomb(k) { |
for (prefix = 0; prefix < 12; prefix++) { |
if ( get_bits(1) ) |
return get_bits(k) + (prefix << k) |
} |
return get_bits(bits) + 11 |
} |
|
int get_sr_golomb(k) { |
v = get_ur_golomb(k); |
if (v & 1) return - (v >> 1) - 1; |
else return (v >> 1); |
}
3.8.2.1.1. 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 |
+----------------+-------+ +----------------+-------+
3.8.2.2. Suffix 3.8.2.1.2. Suffix
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| non | the k least significant bits MSB first | | non | the k least significant bits MSB first |
| ESC | | | ESC | |
| ESC | the value - 11, in MSB first order, ESC may only be used | | ESC | the value - 11, in MSB first order, ESC may only be used |
| | if the value cannot be coded as non ESC | | | if the value cannot be coded as non ESC |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
3.8.2.3. Examples 3.8.2.1.3. Examples
+-----+-------------------------+-------+ +-----+-------------------------+-------+
| k | bits | value | | k | bits | value |
+-----+-------------------------+-------+ +-----+-------------------------+-------+
| 0 | "1" | 0 | | 0 | "1" | 0 |
| 0 | "001" | 2 | | 0 | "001" | 2 |
| 2 | "1 00" | 0 | | 2 | "1 00" | 0 |
| 2 | "1 10" | 2 | | 2 | "1 10" | 2 |
| 2 | "01 01" | 5 | | 2 | "01 01" | 5 |
| any | "000000000000 10000000" | 139 | | any | "000000000000 10000000" | 139 |
+-----+-------------------------+-------+ +-----+-------------------------+-------+
3.8.2.4. Run Mode 3.8.2.2. Run Mode
Run mode is entered when the context is 0 and left as soon as a non-0 Run mode is entered when the context is 0 and left as soon as a non-0
difference is found. The level is identical to the predicted one. difference is found. The level is identical to the predicted one.
The run and the first different level are coded. The run and the first different level are coded.
3.8.2.5. Run Length Coding 3.8.2.2.1. Run Length Coding
The run value is encoded in 2 parts, the prefix part stores the more The run value is encoded in 2 parts, the prefix part stores the more
significant part of the run as well as adjusting the run_index that significant part of the run as well as adjusting the run_index that
determines the number of bits in the less significant part of the determines the number of bits in the less significant part of the
run. The 2nd part of the value stores the less significant part of run. The 2nd part of the value stores the less significant part of
the run as it is. The run_index is reset for each "Plane" and slice the run as it is. The run_index is reset for each "Plane" and slice
to 0. to 0.
pseudo-code | type pseudo-code | type
--------------------------------------------------------------|----- --------------------------------------------------------------|-----
skipping to change at page 20, line 34 skipping to change at page 22, line 34
else | else |
run_count = 0; | run_count = 0; |
if (run_index) | if (run_index) |
run_index--; | run_index--; |
run_mode = 2; | run_mode = 2; |
} | } |
} | } |
The log2_run function is also used within [ISO.14495-1.1999]. The log2_run function is also used within [ISO.14495-1.1999].
3.8.2.6. Level Coding 3.8.2.2.2. Level Coding
Level coding is identical to the normal difference coding with the Level coding is identical to the normal difference coding with the
exception that the 0 value is removed as it cannot occur: exception that the 0 value is removed as it cannot occur:
if (diff>0) diff--; diff = get_vlc_symbol(context_state);
encode(diff); if (diff >= 0)
diff++;
Note, this is different from JPEG-LS, which doesn't use prediction in Note, this is different from JPEG-LS, which doesn't use prediction in
run mode and uses a different encoding and context model for the last run mode and uses a different encoding and context model for the last
difference On a small set of test "Samples" the use of prediction difference On a small set of test "Samples" the use of prediction
slightly improved the compression rate. slightly improved the compression rate.
3.8.2.3. Scalar Mode
Each difference is coded with the per context mean prediction removed
and a per context value for k.
get_vlc_symbol(state) {
i = state->count;
k = 0;
while (i < state->error_sum) {
k++;
i += i;
}
v = get_sr_golomb(k);
if (2 * state->drift < -state->count)
v = - 1 - v;
ret = sign_extend(v + state->bias, bits);
state->error_sum += abs(v);
state->drift += v;
if (state->count == 128) {
state->count >>= 1;
state->drift >>= 1;
state->error_sum >>= 1;
}
state->count++;
if (state->drift <= -state->count) {
state->bias = max(state->bias - 1, -128);
state->drift = max(state->drift + state->count,
-state->count + 1);
} else if (state->drift > 0) {
state->bias = min(state->bias + 1, 127);
state->drift = min(state->drift - state->count, 0);
}
return ret;
}
3.8.2.4. Initial Values for the VLC context state
At keyframes all coder state variables are set to their initial
state.
drift = 0;
error_sum = 4;
bias = 0;
count = 1;
4. Bitstream 4. Bitstream
An FFV1 bitstream is composed of a series of 1 or more "Frames" and An FFV1 bitstream is composed of a series of 1 or more "Frames" and
(when required) a "Configuration Record". (when required) a "Configuration Record".
Within the following sub-sections, pseudo-code is used to explain the Within the following sub-sections, pseudo-code is used to explain the
structure of each FFV1 bitstream component, as described in structure of each FFV1 bitstream component, as described in
Section 2.2.1. The following table lists symbols used to annotate Section 2.2.1. The following table lists symbols used to annotate
that pseudo-code in order to define the storage of the data that pseudo-code in order to define the storage of the data
referenced in that line of pseudo-code. referenced in that line of pseudo-code.
skipping to change at page 22, line 21 skipping to change at page 25, line 21
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 extra_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++ ) { |
states_coded | br states_coded | br
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initial_state_delta[ i ][ j ][ k ] | sr initial_state_delta[ i ][ j ][ k ] | sr
} | } |
ec | ur ec | ur
intra | ur intra | ur
} | } |
} | } |
4.1.1. version 4.1.1. version
"version" specifies the version of the FFV1 bitstream. "version" specifies the version of the FFV1 bitstream.
Each version is incompatible with others versions: decoders SHOULD Each version is incompatible with other versions: decoders SHOULD
reject a file due to unknown version. reject a file due to an unknown version.
Decoders SHOULD reject a file with version <= 1 && Decoders SHOULD reject a file with version <= 1 &&
ConfigurationRecordIsPresent == 1. ConfigurationRecordIsPresent == 1.
Decoders SHOULD reject a file with version >= 3 && Decoders SHOULD reject a file with version >= 3 &&
ConfigurationRecordIsPresent == 0. ConfigurationRecordIsPresent == 0.
+-------+-------------------------+ +-------+-------------------------+
| value | version | | value | version |
+-------+-------------------------+ +-------+-------------------------+
| 0 | FFV1 version 0 | | 0 | FFV1 version 0 |
| 1 | FFV1 version 1 | | 1 | FFV1 version 1 |
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4.1.4. state_transition_delta 4.1.4. state_transition_delta
"state_transition_delta" specifies the Range coder custom state "state_transition_delta" specifies the Range coder custom state
transition table. transition table.
If state_transition_delta is not present in the FFV1 bitstream, all If state_transition_delta is not present in the FFV1 bitstream, all
Range coder custom state transition table elements are assumed to be Range coder custom state transition table elements are assumed to be
0. 0.
4.1.5. colorspace_type 4.1.5. colorspace_type
"colorspace_type" specifies the color space losslessly encoded, the "colorspace_type" specifies the color space encoded, the pixel
Pixel transformation used by the encoder, as well as interleave transformation used by the encoder, the extra plane content, as well
method. as interleave method.
+-------+---------------------+------------------+------------------+ +-------+-----------+----------------+---------------+--------------+
| value | color space | transformation | interleave | | value | color | pixel | extra plane | interleave |
| | losslessly encoded | | method | | | space | transformation | content | method |
+-------+---------------------+------------------+------------------+ | | encoded | | | |
| 0 | YCbCr | No Pixel | "Plane" then | +-------+-----------+----------------+---------------+--------------+
| | | transformation | "Line" | | 0 | YCbCr | None | Transparency | "Plane" then |
| 1 | RGB | JPEG2000-RCT | "Line" then | | | | | | "Line" |
| | | | "Plane" | | 1 | RGB | JPEG2000-RCT | Transparency | "Line" then |
| Other | reserved for future | reserved for | reserved for | | | | | | "Plane" |
| | use | future use | future use | | Other | reserved | reserved for | reserved for | reserved for |
+-------+---------------------+------------------+------------------+ | | for | future use | future use | future use |
| | future | | | |
| | use | | | |
+-------+-----------+----------------+---------------+--------------+
Restrictions: Restrictions:
If "colorspace_type" is 1, then "chroma_planes" MUST be 1, If "colorspace_type" is 1, then "chroma_planes" MUST be 1,
"log2_h_chroma_subsample" MUST be 0, and "log2_v_chroma_subsample" "log2_h_chroma_subsample" MUST be 0, and "log2_v_chroma_subsample"
MUST be 0. MUST be 0.
4.1.6. chroma_planes 4.1.6. chroma_planes
"chroma_planes" indicates if chroma (color) "Planes" are present. "chroma_planes" indicates if chroma (color) "Planes" are present.
skipping to change at page 25, line 27 skipping to change at page 28, line 32
"log2_h_chroma_subsample" indicates the subsample factor, stored in "log2_h_chroma_subsample" indicates the subsample factor, stored in
powers to which the number 2 must be raised, between luma and chroma powers to which the number 2 must be raised, between luma and chroma
width ("chroma_width = 2^(-log2_h_chroma_subsample) * luma_width"). width ("chroma_width = 2^(-log2_h_chroma_subsample) * luma_width").
4.1.9. log2_v_chroma_subsample 4.1.9. log2_v_chroma_subsample
"log2_v_chroma_subsample" indicates the subsample factor, stored in "log2_v_chroma_subsample" indicates the subsample factor, stored in
powers to which the number 2 must be raised, between luma and chroma powers to which the number 2 must be raised, between luma and chroma
height ("chroma_height=2^(-log2_v_chroma_subsample) * luma_height"). height ("chroma_height=2^(-log2_v_chroma_subsample) * luma_height").
4.1.10. alpha_plane 4.1.10. extra_plane
"alpha_plane" indicates if a transparency "Plane" is present. "extra_plane" indicates if an extra "Plane" is present.
+-------+-------------------------------------+ +-------+------------------------------+
| value | presence | | value | presence |
+-------+-------------------------------------+ +-------+------------------------------+
| 0 | transparency "Plane" is not present | | 0 | extra "Plane" is not present |
| 1 | transparency "Plane" is present | | 1 | extra "Plane" is present |
+-------+-------------------------------------+ +-------+------------------------------+
4.1.11. num_h_slices 4.1.11. 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. slice raster.
Inferred to be 1 if not present. Inferred to be 1 if not present.
4.1.12. num_v_slices 4.1.12. 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
skipping to change at page 27, line 22 skipping to change at page 30, line 27
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
4.2. Configuration Record 4.2. Configuration Record
In the case of a FFV1 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 instances of level. It contains the "Parameters" used for all instances of
"Frame". The size of the "Configuration Record", "NumBytes", is "Frame". The size of the "Configuration Record", "NumBytes", is
supplied by the underlying "Container". supplied by 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_symbols_in_syntax( NumBytes - 4 ) ) |
reserved_for_future_use | u(1) reserved_for_future_use | br/ur/sr
configuration_record_crc_parity | u(32) configuration_record_crc_parity | u(32)
} | } |
4.2.1. reserved_for_future_use 4.2.1. 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. use.
Encoders conforming to this version of this specification SHALL NOT Encoders conforming to this version of this specification SHALL NOT
write this value. write this value.
Decoders conforming to this version of this specification SHALL Decoders conforming to this version of this specification SHALL
ignore its value. ignore its value.
skipping to change at page 31, line 46 skipping to change at page 34, line 46
4.5.4. slice_height 4.5.4. 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. num_v_slices.
Inferred to be 1 if not present. Inferred to be 1 if not present.
4.5.5. quant_table_set_index_count 4.5.5. 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 ) + ( extra_plane ? 1 : 0 )".
4.5.6. quant_table_set_index 4.5.6. 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. slice.
Inferred to be 0 if not present. Inferred to be 0 if not present.
4.5.7. picture_structure 4.5.7. picture_structure
skipping to change at page 33, line 22 skipping to change at page 36, line 22
} 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 ) |
} | } |
} | } |
4.6.1. primary_color_count 4.6.1. 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 )". ( extra_plane ? 1 : 0 )".
4.6.2. plane_pixel_height 4.6.2. 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. slice.
"plane_pixel_height[ 0 ]" and "plane_pixel_height[ 1 + ( "plane_pixel_height[ 0 ]" and "plane_pixel_height[ 1 + (
chroma_planes ? 2 : 0 ) ]" value is "slice_pixel_height". chroma_planes ? 2 : 0 ) ]" value is "slice_pixel_height".
If "chroma_planes" is set to 1, "plane_pixel_height[ 1 ]" and 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 /
log2_v_chroma_subsample)". log2_v_chroma_subsample)".
skipping to change at page 37, line 46 skipping to change at page 40, line 46
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 range coder could, if implemented naively, read one
byte over the end. The implementation must ensure that no read
outside allocated and initialized memory occurs.
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:
o Sending the decoder valid packets generated by the reference o Sending the decoder valid packets generated by the reference
encoder and verifying that the decoder's output matches the encoder and verifying that the decoder's output matches the
skipping to change at page 39, line 15 skipping to change at page 42, line 15
bits_per_raw_sample: The version of the FFV1 encoding as defined by bits_per_raw_sample: The version of the FFV1 encoding as defined by
Section 4.1.7. Section 4.1.7.
max-slices: The value of max-slices is an integer indicating the max-slices: The value of max-slices is an integer indicating the
maximum count of slices with a frames of the FFV1 encoding. maximum count of slices with a frames of the FFV1 encoding.
Encoding considerations: Encoding considerations:
This media type is defined for encapsulation in several audiovisual This media type is defined for encapsulation in several audiovisual
container formats and contains binary data; see Section 4.2.3. This container formats and contains binary data; see Section 4.2.3. This
media type is framed binary data Section 4.8 of [RFC4288]. media type is framed binary data Section 4.8 of [RFC6838].
Security considerations: Security considerations:
See Section 6 of this document. See Section 6 of this document.
Interoperability considerations: None. Interoperability considerations: None.
Published specification: Published specification:
[I-D.ietf-cellar-ffv1] and RFC XXXX. [I-D.ietf-cellar-ffv1] and RFC XXXX.
skipping to change at page 40, line 44 skipping to change at page 43, line 44
See <https://github.com/FFmpeg/FFV1/commits/master> See <https://github.com/FFmpeg/FFV1/commits/master>
11. References 11. References
11.1. Normative References 11.1. Normative References
[I-D.ietf-cellar-ffv1] [I-D.ietf-cellar-ffv1]
Niedermayer, M., Rice, D., and J. Martinez, "FFV1 Video Niedermayer, M., Rice, D., and J. Martinez, "FFV1 Video
Coding Format Version 0, 1, and 3", draft-ietf-cellar- Coding Format Version 0, 1, and 3", draft-ietf-cellar-
ffv1-05 (work in progress), September 2018. ffv1-06 (work in progress), October 2018.
[ISO.15444-1.2016] [ISO.15444-1.2016]
International Organization for Standardization, International Organization for Standardization,
"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,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
Registration Procedures", RFC 4288, DOI 10.17487/RFC4288,
December 2005, <https://www.rfc-editor.org/info/rfc4288>.
[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,
<https://www.rfc-editor.org/info/rfc4732>. <https://www.rfc-editor.org/info/rfc4732>.
[RFC4855] Casner, S., "Media Type Registration of RTP Payload [RFC4855] Casner, S., "Media Type Registration of RTP Payload
Formats", RFC 4855, DOI 10.17487/RFC4855, February 2007, Formats", RFC 4855, DOI 10.17487/RFC4855, February 2007,
<https://www.rfc-editor.org/info/rfc4855>. <https://www.rfc-editor.org/info/rfc4855>.
[RFC6716] Valin, JM., Vos, K., and T. Terriberry, "Definition of the [RFC6716] Valin, JM., Vos, K., and T. Terriberry, "Definition of the
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