[FFmpeg-devel] [FFmpeg-cvslog] libavcodec/libx264: add user data unregistered SEI encoding

[Michael Niedermayer]

Hi

On Mon, Oct 18, 2021 at 12:15:11PM +0000, Brad Hards wrote:
> ffmpeg | branch: master | Brad Hards <bradh at frogmouth.net> | Fri Aug  6 19:16:33 2021 +1000| [7c08cad280a16b346c0a5e0efdfd8333ec54f095] | committer: Derek Buitenhuis
> 
> libavcodec/libx264: add user data unregistered SEI encoding
> 
> MISB ST 0604 and ST 2101 require user data unregistered SEI messages
> (precision timestamps and sensor identifiers) to be included. That
> currently isn't supported for libx264. This patch adds support
> for user data unregistered SEI messages in accordance with ISO/IEC
> 14496-10:2020(E) section D.1.7 (syntax) and D.2.7 (semantics).
> 
> This code is based on a similar change for libx265 (commit
> 1f58503013720700a5adfd72c708e6275aefc165).
> 
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> 
> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7c08cad280a16b346c0a5e0efdfd8333ec54f095
> ---

This code breaks bitexact mode for some files, i have not looked into this
any deeper yet.

example: 
./ffmpeg  -i tickets/5356/framestep_fails.mov -map 0:v:0 -filter:v "framestep=step=2" -codec:v libx264 -t 0.1 -an -bitexact -y file5414.mp4 && md5sum file5414.mp4
59441c644fc3d269ef6689f1c450abda  file5414.mp4
62740d54583fd475efd808a638730c1e  file5414.mp4


#extradata 0:       49, 0xb4861385
#software: Lavf59.6.100
#tb 0: 1/15000
#media_type 0: video
#codec_id 0: h264
#dimensions 0: 1920x1080
#sar 0: 0/1
0,          0,          0,     1001,     1879, 0x2fd508ad
0,       1001,       1001,     1001,    13178, 0xfe8c5a6b, F=0x0

#extradata 0:       49, 0xb4861385
#software: Lavf59.6.100
#tb 0: 1/15000
#media_type 0: video
#codec_id 0: h264
#dimensions 0: 1920x1080
#sar 0: 0/1
0,          0,          0,     1001,     1879, 0x67fb0880
0,       1001,       1001,     1001,    13178, 0xf33a5a3e, F=0x0

#extradata 0:       49, 0xb4861385
#software: Lavf59.6.100
#tb 0: 1/15000
#media_type 0: video
#codec_id 0: h264
#dimensions 0: 1920x1080
#sar 0: 0/1
0,          0,          0,     1001,     1879, 0xb39a0891
0,       1001,       1001,     1001,    13178, 0x5e155a4f, F=0x0

Heres another examples:
./ffmpeg -i tickets/4012/IMG_4596.MOV -movflags +faststart -pix_fmt yuv420p -c:v libx264 -c:a aac -bitexact -t 0.5 -vprofile baseline -acodec aac -y  test.mov && md5sum test.mov
the link to the sample file is on:
https://trac.ffmpeg.org/ticket/4012


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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