#9471: EAC3 native encoder is only gapless in the beginning, not in the end -------------------------------------+------------------------------------- Reporter: Balling | Owner: (none) Type: defect | Status: new Priority: normal | Component: ffmpeg Version: git-master | Resolution: Keywords: mp4 eac3 | Blocked By: editlist gapless | Blocking: | Reproduced by developer: 1 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Description changed by Balling: Old description:

Summary of the bug: edts atmos (editlist) has media time and media duration, yet even though media time is correctly written for EAC3 and AAC (native EAC3 encoder has 256 sample of silence (a.k.a. encoder delay) that are then removed from the beginning with native encoder and native AAC has 1024 samples that are also working great) the media duration is not correctly written. Even if it were to be correctly written media duration is not applied on decoding even for AAC, see for example https://bugs.chromium.org/p/chromium/issues/detail?id=668999 that is still present in git-master!!! How to reproduce: {{{ % ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -c:a eac3 outeac3.mp4 ffmpeg version N-104341-g933765aa0e-20211013 Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10-win32 (GCC) 20210408 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --enable-shared --disable-static --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable- avisynth --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable- libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable- librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable- libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra- version=20211013 libavutil 57. 7.100 / 57. 7.100 libavcodec 59. 12.100 / 59. 12.100 libavformat 59. 6.100 / 59. 6.100 libavdevice 59. 0.101 / 59. 0.101 libavfilter 8. 14.100 / 8. 14.100 libswscale 6. 1.100 / 6. 1.100 libswresample 4. 0.100 / 4. 0.100 libpostproc 56. 0.100 / 56. 0.100 Input #0, lavfi, from 'sine=frequency=1000:duration=5': Duration: N/A, start: 0.000000, bitrate: 705 kb/s Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s Stream mapping: Stream #0:0 -> #0:0 (pcm_s16le (native) -> eac3 (native)) Press [q] to stop, [?] for help Output #0, mp4, to 'outeac3.mp4': Metadata: encoder : Lavf59.6.100 Stream #0:0: Audio: eac3 (ec-3 / 0x332D6365), 44100 Hz, mono, fltp, 96 kb/s Metadata: encoder : Lavc59.12.100 eac3 size= 60kB time=00:00:05.00 bitrate= 98.2kbits/s speed= 487x video:0kB audio:59kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.166617% }}}

{{{ Track duration: 5010 (0x00001392) - 5010 (0x1392) ms Media time: 256 (0x00000100) - 256 (0x100) ms Media rate: 65536 (0x00010000) - 1.000 }}}

Now compare it to aac: ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -c:a aac fileaac.mp4:

{{{ Track duration: 5000 (0x00001388) - 5000 (0x1388) ms Media time: 1024 (0x00000400) - 1024 (0x400) Media rate: 65536 (0x00010000) - 1.000 }}} Unfortunately a) Mediainfo tracer is buggy in that part: https://github.com/MediaArea/MediaInfoLib/issues/1441 b) I am not sure that media duration is really buggy since it is not applied anyway! c) I checked it all decoding to wav and checking in Audacity. d) I dunno whether sbgp and sgpd are needed (whether EAC3 depends on previous frames)

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

New description: Summary of the bug: edts atom (editlist) has media time and media duration, yet even though media time is correctly written for EAC3 and AAC (native EAC3 encoder has 256 sample of silence (a.k.a. encoder delay) that are then removed from the beginning with native encoder and native AAC has 1024 samples that are also working great) the media duration is not correctly written. Even if it were to be correctly written media duration is not applied on decoding even for AAC, see for example https://bugs.chromium.org/p/chromium/issues/detail?id=668999 that is still present in git-master!!! How to reproduce: {{{ % ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -c:a eac3 outeac3.mp4 ffmpeg version N-104341-g933765aa0e-20211013 Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10-win32 (GCC) 20210408 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --enable-shared --disable-static --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable- avisynth --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable- libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable- librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable- libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra- version=20211013 libavutil 57. 7.100 / 57. 7.100 libavcodec 59. 12.100 / 59. 12.100 libavformat 59. 6.100 / 59. 6.100 libavdevice 59. 0.101 / 59. 0.101 libavfilter 8. 14.100 / 8. 14.100 libswscale 6. 1.100 / 6. 1.100 libswresample 4. 0.100 / 4. 0.100 libpostproc 56. 0.100 / 56. 0.100 Input #0, lavfi, from 'sine=frequency=1000:duration=5': Duration: N/A, start: 0.000000, bitrate: 705 kb/s Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s Stream mapping: Stream #0:0 -> #0:0 (pcm_s16le (native) -> eac3 (native)) Press [q] to stop, [?] for help Output #0, mp4, to 'outeac3.mp4': Metadata: encoder : Lavf59.6.100 Stream #0:0: Audio: eac3 (ec-3 / 0x332D6365), 44100 Hz, mono, fltp, 96 kb/s Metadata: encoder : Lavc59.12.100 eac3 size= 60kB time=00:00:05.00 bitrate= 98.2kbits/s speed= 487x video:0kB audio:59kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.166617% }}} {{{ Track duration: 5010 (0x00001392) - 5010 (0x1392) ms Media time: 256 (0x00000100) - 256 (0x100) ms Media rate: 65536 (0x00010000) - 1.000 }}} Now compare it to aac: ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -c:a aac fileaac.mp4: {{{ Track duration: 5000 (0x00001388) - 5000 (0x1388) ms Media time: 1024 (0x00000400) - 1024 (0x400) Media rate: 65536 (0x00010000) - 1.000 }}} Unfortunately a) Mediainfo tracer is buggy in that part: https://github.com/MediaArea/MediaInfoLib/issues/1441 b) I am not sure that media duration is really buggy since it is not applied anyway! c) I checked it all decoding to wav and checking in Audacity. d) I dunno whether sbgp and sgpd are needed (whether EAC3 depends on previous frames) Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker. -- -- Ticket URL: <https://trac.ffmpeg.org/ticket/9471#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#9471: EAC3 native encoder is only gapless in the beginning, not in the end -------------------------------------+------------------------------------- Reporter: Balling | Owner: (none) Type: defect | Status: open Priority: normal | Component: ffmpeg Version: git-master | Resolution: Keywords: mp4 eac3 | Blocked By: editlist gapless | Blocking: | Reproduced by developer: 1 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by Balling): * status: new => open Comment: Okay, so now after c2424b1f35a1c6c06f1f9fe5f77a7157ed84e1cd it writres before editlist duration (as is in -ignore_editlist 1 to wav) in mdhd and dumb warning in mediainfo that was warning about mdhd_Duration: xxxxx being wrong is gone. But still wrong amount media duration is written. -- Ticket URL: <https://trac.ffmpeg.org/ticket/9471#comment:3> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#9471: EAC3 native encoder is only gapless in the beginning, not in the end -------------------------------------+------------------------------------- Reporter: Balling | Owner: (none) Type: defect | Status: open Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: eac3 | Blocked By: gapless | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by Carl Eugen Hoyos): * keywords: mp4 eac3 editlist gapless => eac3 gapless * component: ffmpeg => undetermined * reproduced: 1 => 0 -- Ticket URL: <https://trac.ffmpeg.org/ticket/9471#comment:5> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#9471: EAC3 native encoder is only gapless in the beginning, not in the end -------------------------------------+------------------------------------- Reporter: Balling | Owner: (none) Type: defect | Status: open Priority: normal | Component: avformat Version: git-master | Resolution: Keywords: eac3 | Blocked By: gapless mp4 editlist | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by MasterQuestionable): * cc: MasterQuestionable (added) * keywords: eac3 gapless => eac3 gapless mp4 editlist * component: undetermined => avformat Comment: ͏    I think similar problems are essentially caused by the unjustifiable complexity and poor design of many things. ͏    See also: https://trac.ffmpeg.org/ticket/11002#comment:9 -- Ticket URL: <https://trac.ffmpeg.org/ticket/9471#comment:7> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker

#9471: EAC3 native encoder is only gapless in the beginning, not in the end -------------------------------------+------------------------------------- Reporter: Balling | Owner: (none) Type: defect | Status: open Priority: normal | Component: avformat Version: git-master | Resolution: Keywords: eac3 | Blocked By: gapless mp4 editlist | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by j7n): The padding from E-AC-3 tracks is still not being removed as of May 2025. The delay and padding can be variable. The current practice with music encoding is to prepend 1 or 2 syncframes shared with the end of the previous track to have the decoder prerolled with actual audio data and not silence. An "elst" box my contain the following data, where 38FE80 is the correct end point in samples, and 800 is the delay: {{{ 00000000000000010038FE800000080000010000 }}} ffmpeg reports {{{ Chapter #0:0: start 0.042667, end 77.816000 }}} But the decoded file has a duration approximately 77.781 and includes extra samples up to the end of the stream. Older E-AC-3 files in the wild may contain garbage at the end without an elst element. I observe a delay of 256 in Adobe Audition when producing an EC3 elementary stream. With old encoders the delay depended on whether the 90° phase filter was active. -- Ticket URL: <https://trac.ffmpeg.org/ticket/9471#comment:9> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker