[FFmpeg-trac] #10406(undetermined:new): Change in audio track 'initial_padding' behaviour from ffmpeg v5 to ffmpeg v6

FFmpeg trac at avcodec.org
Thu Jun 8 08:50:50 EEST 2023


#10406: Change in audio track 'initial_padding' behaviour from ffmpeg v5 to ffmpeg
v6
-------------------------------------+-------------------------------------
             Reporter:  Garry        |                     Type:  defect
  Robertson                          |
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  6.0
  undetermined                       |
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 When converting EAC3 audio tracks to AC3 in Matroska containers, ffmpeg v6
 is setting a non-zero value on the 'initial_padding', 'start_pts', and
 'start_time' values for the audio track. This is a change in behaviour
 from ffmpeg v5.

 While the converted file is playing correctly in modern players, it is
 causing the audio codec not to be recognised in an older player (Sony TV).

 This change to 'initial_padding', etc does not happen if encoding into an
 mp4 container. The value remains as 0, consistant with ffmpeg v5.

 **Initial probe of eac3 file:**
 {{{
 % ffprobe -show_streams "AC3 v6.mkv"
 ffprobe version 6.0-full_build-www.gyan.dev Copyright (c) 2007-2023 the
 FFmpeg developers
   built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma
 --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
 --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
 --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d
 --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e
 --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl
 --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-
 libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-
 liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-
 amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec
 --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-
 libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-
 libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-
 libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora
 --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-
 libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex
 --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
 --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-
 chromaprint
   libavutil      58.  2.100 / 58.  2.100
   libavcodec     60.  3.100 / 60.  3.100
   libavformat    60.  3.100 / 60.  3.100
   libavdevice    60.  1.100 / 60.  1.100
   libavfilter     9.  3.100 /  9.  3.100
   libswscale      7.  1.100 /  7.  1.100
   libswresample   4. 10.100 /  4. 10.100
   libpostproc    57.  1.100 / 57.  1.100
 Input #0, matroska,webm, from '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\EAC3.mkv':
   Metadata:
     encoder         : libebml v1.4.4 + libmatroska v1.7.1
     creation_time   : 2023-06-08T03:57:29.000000Z
   Duration: 00:00:05.05, start: 0.000000, bitrate: 847 kb/s
   Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive),
 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
   Stream #0:1: Audio: eac3, 48000 Hz, 5.1(side), fltp, 768 kb/s (default)
 [STREAM]
 index=0
 codec_name=h264
 codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
 profile=High
 codec_type=video
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 width=1280
 height=720
 coded_width=1280
 coded_height=720
 closed_captions=0
 film_grain=0
 has_b_frames=1
 sample_aspect_ratio=1:1
 display_aspect_ratio=16:9
 pix_fmt=yuv420p
 level=31
 color_range=tv
 color_space=bt709
 color_transfer=bt709
 color_primaries=bt709
 chroma_location=topleft
 field_order=progressive
 refs=1
 is_avc=true
 nal_length_size=4
 id=N/A
 r_frame_rate=24000/1001
 avg_frame_rate=24000/1001
 time_base=1/1000
 start_pts=0
 start_time=0.000000
 duration_ts=N/A
 duration=N/A
 bit_rate=N/A
 max_bit_rate=N/A
 bits_per_raw_sample=8
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 extradata_size=50
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 TAG:language=eng
 [/STREAM]
 [STREAM]
 index=1
 codec_name=eac3
 codec_long_name=ATSC A/52B (AC-3, E-AC-3)
 profile=unknown
 codec_type=audio
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 sample_fmt=fltp
 sample_rate=48000
 channels=6
 channel_layout=5.1(side)
 bits_per_sample=0
 initial_padding=0  <------
 id=N/A
 r_frame_rate=0/0
 avg_frame_rate=0/0
 time_base=1/1000
 start_pts=0  <------
 start_time=0.000000  <------
 duration_ts=N/A
 duration=N/A
 bit_rate=768000
 max_bit_rate=N/A
 bits_per_raw_sample=N/A
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 [/STREAM]
 }}}

 **NOTE: Audio initial_padding=0, etc.**

 **How to reproduce with ffmpeg v6:**
 {{{
 % ffmpeg -y -i EAC3.mkv -c:v copy -c:a ac3 "AC3 v6.mkv"
 ffmpeg version 6.0-full_build-www.gyan.dev Copyright (c) 2000-2023 the
 FFmpeg developers
   built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma
 --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
 --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
 --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d
 --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e
 --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl
 --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-
 libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-
 liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-
 amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec
 --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-
 libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-
 libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-
 libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora
 --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-
 libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex
 --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
 --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-
 chromaprint
   libavutil      58.  2.100 / 58.  2.100
   libavcodec     60.  3.100 / 60.  3.100
   libavformat    60.  3.100 / 60.  3.100
   libavdevice    60.  1.100 / 60.  1.100
   libavfilter     9.  3.100 /  9.  3.100
   libswscale      7.  1.100 /  7.  1.100
   libswresample   4. 10.100 /  4. 10.100
   libpostproc    57.  1.100 / 57.  1.100
 Input #0, matroska,webm, from '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\EAC3.mkv':
   Metadata:
     encoder         : libebml v1.4.4 + libmatroska v1.7.1
     creation_time   : 2023-06-08T03:57:29.000000Z
   Duration: 00:00:05.05, start: 0.000000, bitrate: 847 kb/s
   Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive),
 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
   Stream #0:1: Audio: eac3, 48000 Hz, 5.1(side), fltp, 768 kb/s (default)
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
   Stream #0:1 -> #0:1 (eac3 (native) -> ac3 (native))
 Press [q] to stop, [?] for help
 Output #0, matroska, to '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\AC3 v6.mkv':
   Metadata:
     encoder         : Lavf60.3.100
   Stream #0:0(eng): Video: h264 (High) (H264 / 0x34363248), yuv420p(tv,
 bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 23.98 fps, 23.98
 tbr, 1k tbn (default)
   Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side),
 fltp, 448 kb/s (default)
     Metadata:
       encoder         : Lavc60.3.100 ac3
 frame=  121 fps=0.0 q=-1.0 Lsize=     322kB time=00:00:04.98 bitrate=
 529.3kbits/s speed= 114x
 video:45kB audio:275kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.816106%
 }}}

 **Probe of new ac3 file:**
 {{{
 % ffprobe -show_streams "AC3 v6.mkv"
 ffprobe version 6.0-full_build-www.gyan.dev Copyright (c) 2007-2023 the
 FFmpeg developers
   built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma
 --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
 --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
 --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d
 --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e
 --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl
 --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-
 libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-
 liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-
 amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec
 --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-
 libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-
 libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-
 libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora
 --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-
 libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex
 --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
 --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-
 chromaprint
   libavutil      58.  2.100 / 58.  2.100
   libavcodec     60.  3.100 / 60.  3.100
   libavformat    60.  3.100 / 60.  3.100
   libavdevice    60.  1.100 / 60.  1.100
   libavfilter     9.  3.100 /  9.  3.100
   libswscale      7.  1.100 /  7.  1.100
   libswresample   4. 10.100 /  4. 10.100
   libpostproc    57.  1.100 / 57.  1.100
 Input #0, matroska,webm, from '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\AC3 v6.mkv':
   Metadata:
     ENCODER         : Lavf60.3.100
   Duration: 00:00:05.05, start: -0.005000, bitrate: 523 kb/s
   Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive),
 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
     Metadata:
       DURATION        : 00:00:05.046000000
   Stream #0:1: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s (default)
     Metadata:
       ENCODER         : Lavc60.3.100 ac3
       DURATION        : 00:00:05.024000000
 [STREAM]
 index=0
 codec_name=h264
 codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
 profile=High
 codec_type=video
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 width=1280
 height=720
 coded_width=1280
 coded_height=720
 closed_captions=0
 film_grain=0
 has_b_frames=1
 sample_aspect_ratio=1:1
 display_aspect_ratio=16:9
 pix_fmt=yuv420p
 level=31
 color_range=tv
 color_space=bt709
 color_transfer=bt709
 color_primaries=bt709
 chroma_location=topleft
 field_order=progressive
 refs=1
 is_avc=true
 nal_length_size=4
 id=N/A
 r_frame_rate=24000/1001
 avg_frame_rate=24000/1001
 time_base=1/1000
 start_pts=0
 start_time=0.000000
 duration_ts=N/A
 duration=N/A
 bit_rate=N/A
 max_bit_rate=N/A
 bits_per_raw_sample=8
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 extradata_size=50
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 TAG:language=eng
 TAG:DURATION=00:00:05.046000000
 [/STREAM]
 [STREAM]
 index=1
 codec_name=ac3
 codec_long_name=ATSC A/52A (AC-3)
 profile=unknown
 codec_type=audio
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 sample_fmt=fltp
 sample_rate=48000
 channels=6
 channel_layout=5.1(side)
 bits_per_sample=0
 initial_padding=256  <------
 id=N/A
 r_frame_rate=0/0
 avg_frame_rate=0/0
 time_base=1/1000
 start_pts=-5  <------
 start_time=-0.005000  <------
 duration_ts=N/A
 duration=N/A
 bit_rate=448000
 max_bit_rate=N/A
 bits_per_raw_sample=N/A
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 TAG:ENCODER=Lavc60.3.100 ac3
 TAG:DURATION=00:00:05.024000000
 [/STREAM]
 }}}

 **NOTE: Audio initial_padding=256, etc.**

 **How to reproduce with ffmpeg v5:**
 {{{
 % ffmpeg -y -i EAC3.mkv -c:v copy -c:a ac3 "AC3 v5.mkv"
 ffmpeg version 5.1.2-essentials_build-www.gyan.dev Copyright (c) 2000-2022
 the FFmpeg developers
   built with gcc 12.1.0 (Rev2, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib
 --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth
 --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-
 libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-
 libass --enable-libfreetype --enable-libfribidi --enable-libvidstab
 --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm
 --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-
 d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt
 --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora
 --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb
 --enable-libopus --enable-libspeex --enable-libvorbis --enable-
 librubberband
   libavutil      57. 28.100 / 57. 28.100
   libavcodec     59. 37.100 / 59. 37.100
   libavformat    59. 27.100 / 59. 27.100
   libavdevice    59.  7.100 / 59.  7.100
   libavfilter     8. 44.100 /  8. 44.100
   libswscale      6.  7.100 /  6.  7.100
   libswresample   4.  7.100 /  4.  7.100
   libpostproc    56.  6.100 / 56.  6.100
 Input #0, matroska,webm, from '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\EAC3.mkv':
   Metadata:
     encoder         : libebml v1.4.4 + libmatroska v1.7.1
     creation_time   : 2023-06-08T03:57:29.000000Z
   Duration: 00:00:05.05, start: 0.000000, bitrate: 847 kb/s
   Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive),
 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
   Stream #0:1: Audio: eac3, 48000 Hz, 5.1(side), fltp, 768 kb/s (default)
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
   Stream #0:1 -> #0:1 (eac3 (native) -> ac3 (native))
 Press [q] to stop, [?] for help
 Output #0, matroska, to '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\AC3 v5.mkv':
   Metadata:
     encoder         : Lavf59.27.100
   Stream #0:0(eng): Video: h264 (High) (H264 / 0x34363248), yuv420p(tv,
 bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 23.98 fps, 23.98
 tbr, 1k tbn (default)
   Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side),
 fltp, 448 kb/s (default)
     Metadata:
       encoder         : Lavc59.37.100 ac3
 frame=  121 fps=0.0 q=-1.0 Lsize=     322kB time=00:00:05.01 bitrate=
 525.9kbits/s speed= 176x
 video:45kB audio:275kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.815495%
 }}}

 **v5 Probe of new ac3 (v5) file:**
 {{{
 % ffprobe -show_streams "AC3 v5.mkv"
 ffprobe version 5.1.2-essentials_build-www.gyan.dev Copyright (c)
 2007-2022 the FFmpeg developers
   built with gcc 12.1.0 (Rev2, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static --disable-
 w32threads --disable-autodetect --enable-fontconfig --enable-iconv
 --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib
 --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth
 --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-
 libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-
 libass --enable-libfreetype --enable-libfribidi --enable-libvidstab
 --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm
 --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-
 d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt
 --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora
 --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb
 --enable-libopus --enable-libspeex --enable-libvorbis --enable-
 librubberband
   libavutil      57. 28.100 / 57. 28.100
   libavcodec     59. 37.100 / 59. 37.100
   libavformat    59. 27.100 / 59. 27.100
   libavdevice    59.  7.100 / 59.  7.100
   libavfilter     8. 44.100 /  8. 44.100
   libswscale      6.  7.100 /  6.  7.100
   libswresample   4.  7.100 /  4.  7.100
   libpostproc    56.  6.100 / 56.  6.100
 Input #0, matroska,webm, from '\\THISTLEDOWN\Media Server
 3\Miscellaneous\Convertor Test\AC3 v5.mkv':
   Metadata:
     ENCODER         : Lavf59.27.100
   Duration: 00:00:05.05, start: 0.000000, bitrate: 522 kb/s
   Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive),
 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
     Metadata:
       DURATION        : 00:00:05.051000000
   Stream #0:1: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s (default)
     Metadata:
       ENCODER         : Lavc59.37.100 ac3
       DURATION        : 00:00:05.024000000
 [STREAM]
 index=0
 codec_name=h264
 codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
 profile=High
 codec_type=video
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 width=1280
 height=720
 coded_width=1280
 coded_height=720
 closed_captions=0
 film_grain=0
 has_b_frames=1
 sample_aspect_ratio=1:1
 display_aspect_ratio=16:9
 pix_fmt=yuv420p
 level=31
 color_range=tv
 color_space=bt709
 color_transfer=bt709
 color_primaries=bt709
 chroma_location=topleft
 field_order=progressive
 refs=1
 is_avc=true
 nal_length_size=4
 id=N/A
 r_frame_rate=24000/1001
 avg_frame_rate=24000/1001
 time_base=1/1000
 start_pts=5
 start_time=0.005000
 duration_ts=N/A
 duration=N/A
 bit_rate=N/A
 max_bit_rate=N/A
 bits_per_raw_sample=8
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 extradata_size=50
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 TAG:language=eng
 TAG:DURATION=00:00:05.051000000
 [/STREAM]
 [STREAM]
 index=1
 codec_name=ac3
 codec_long_name=ATSC A/52A (AC-3)
 profile=unknown
 codec_type=audio
 codec_tag_string=[0][0][0][0]
 codec_tag=0x0000
 sample_fmt=fltp
 sample_rate=48000
 channels=6
 channel_layout=5.1(side)
 bits_per_sample=0
 id=N/A
 r_frame_rate=0/0
 avg_frame_rate=0/0
 time_base=1/1000
 start_pts=0  <------
 start_time=0.000000  <------
 duration_ts=N/A
 duration=N/A
 bit_rate=448000
 max_bit_rate=N/A
 bits_per_raw_sample=N/A
 nb_frames=N/A
 nb_read_frames=N/A
 nb_read_packets=N/A
 DISPOSITION:default=1
 DISPOSITION:dub=0
 DISPOSITION:original=0
 DISPOSITION:comment=0
 DISPOSITION:lyrics=0
 DISPOSITION:karaoke=0
 DISPOSITION:forced=0
 DISPOSITION:hearing_impaired=0
 DISPOSITION:visual_impaired=0
 DISPOSITION:clean_effects=0
 DISPOSITION:attached_pic=0
 DISPOSITION:timed_thumbnails=0
 DISPOSITION:captions=0
 DISPOSITION:descriptions=0
 DISPOSITION:metadata=0
 DISPOSITION:dependent=0
 DISPOSITION:still_image=0
 TAG:ENCODER=Lavc59.37.100 ac3
 TAG:DURATION=00:00:05.024000000
 [/STREAM]
 }}}

 **A probe of this v5 file shows audio 'start_pts=0', etc. Interestingly,
 'initial_padding' is not reported, although it shows up as zero if v6
 version of ffprobe is used**

 It's not clear to me whether this is a bug, or a deliberate change in
 behaviour. However, its impact is preventing me adopting use of ffmpeg v6.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10406>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list