[FFmpeg-trac] #8700(avformat:new): MP2 audio stream in MP4 container is recognized as MP3
FFmpeg
trac at avcodec.org
Mon Jun 1 17:40:05 EEST 2020
#8700: MP2 audio stream in MP4 container is recognized as MP3
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Reporter: Nomis101 | Type: defect
Status: new | Priority: normal
Component: avformat | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug:
An MP4 file that contains an MP2 audio stream is incorrectly recognized as
MP3 stream. Mediainfo recognizes the same stream as "MPEG Audio (Version
1) (Layer 2)" and VLC as "MPEG Audio Layer 1/2 (mpga)".
How to reproduce:
I have an MKV file that contains MP2 audio. I converted this into MP4.
% ffmpeg -i /Volumes/Developer/Testfile.mkv -c copy
/Volumes/Developer/Testfile.mp4
ffmpeg version N-98021-g2a9ffd89fc Copyright (c) 2000-2020 the FFmpeg
developers
built with Apple clang version 11.0.3 (clang-1103.0.32.62)
configuration: --pkg-config-flags=--static --enable-swscale --enable-
avfilter --enable-fontconfig --enable-gpl --enable-version3 --enable-
libass --enable-libbluray --enable-libfreetype --enable-libsoxr --enable-
libaom --enable-libmp3lame --enable-librav1e --enable-libtheora --enable-
libvorbis --enable-libvpx --enable-libwavpack --disable-debug --enable-
libmysofa --enable-libx264 --enable-libx265 --enable-libxvid --enable-
nonfree --enable-libfdk-aac --enable-muxer=mov --enable-muxer=mp4
--enable-muxer=ipod --enable-encoder=eac3 --enable-encoder=ac3 --enable-
encoder=flac --enable-ffplay --enable-librtmp --enable-libsmbclient
--enable-opencl --enable-libssh --enable-openssl --enable-encoder=truehd
--enable-bsf=aac_adtstoasc --enable-encoder=h264_videotoolbox --enable-
encoder=hevc_videotoolbox --enable-sdl --extra-ldflags=-L/opt/local/lib
libavutil 56. 49.100 / 56. 49.100
libavcodec 58. 90.100 / 58. 90.100
libavformat 58. 44.100 / 58. 44.100
libavdevice 58. 9.103 / 58. 9.103
libavfilter 7. 84.100 / 7. 84.100
libswscale 5. 6.101 / 5. 6.101
libswresample 3. 6.100 / 3. 6.100
libpostproc 55. 6.100 / 55. 6.100
Input #0, matroska,webm, from '/Volumes/Developer/Testfile.mkv':
Metadata:
title : Elephant's Dream
ENCODER : Lavf58.42.101
Duration: 00:00:03.33, start: 0.000000, bitrate: 9360 kb/s
Stream #0:0(eng): Video: vp9 (Profile 3), yuv444p10le(tv,
bt709/unknown/unknown), 1920x1080, SAR 1:1 DAR 16:9, 24 fps, 24 tbr, 1k
tbn, 1k tbc (default)
Metadata:
DURATION : 00:00:03.332000000
Stream #0:1(eng): Audio: mp2, 48000 Hz, stereo, s16p, 384 kb/s
(default)
Metadata:
ENCODER : Lavc58.82.100 mp2
DURATION : 00:00:03.317000000
Output #0, mp4, to '/Volumes/Developer/Testfile.mp4':
Metadata:
title : Elephant's Dream
encoder : Lavf58.44.100
Stream #0:0(eng): Video: vp9 (Profile 3) (vp09 / 0x39307076),
yuv444p10le(tv, bt709/unknown/unknown), 1920x1080 [SAR 1:1 DAR 16:9],
q=2-31, 24 fps, 24 tbr, 16k tbn, 1k tbc (default)
Metadata:
DURATION : 00:00:03.332000000
Stream #0:1(eng): Audio: mp2 (mp4a / 0x6134706D), 48000 Hz, stereo,
s16p, 384 kb/s (default)
Metadata:
ENCODER : Lavc58.82.100 mp2
DURATION : 00:00:03.317000000
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 80 fps=0.0 q=-1.0 Lsize= 3808kB time=00:00:03.29
bitrate=9473.1kbits/s speed=38.5x
video:3653kB audio:152kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.081670%
It seems everything went fine. But inspecting the MP4 file with FFmpeg,
gives:
% ffmpeg -i /Volumes/Developer/Testfile.mp4
ffmpeg version N-98021-g2a9ffd89fc Copyright (c) 2000-2020 the FFmpeg
developers
built with Apple clang version 11.0.3 (clang-1103.0.32.62)
configuration: --pkg-config-flags=--static --enable-swscale --enable-
avfilter --enable-fontconfig --enable-gpl --enable-version3 --enable-
libass --enable-libbluray --enable-libfreetype --enable-libsoxr --enable-
libaom --enable-libmp3lame --enable-librav1e --enable-libtheora --enable-
libvorbis --enable-libvpx --enable-libwavpack --disable-debug --enable-
libmysofa --enable-libx264 --enable-libx265 --enable-libxvid --enable-
nonfree --enable-libfdk-aac --enable-muxer=mov --enable-muxer=mp4
--enable-muxer=ipod --enable-encoder=eac3 --enable-encoder=ac3 --enable-
encoder=flac --enable-ffplay --enable-librtmp --enable-libsmbclient
--enable-opencl --enable-libssh --enable-openssl --enable-encoder=truehd
--enable-bsf=aac_adtstoasc --enable-encoder=h264_videotoolbox --enable-
encoder=hevc_videotoolbox --enable-sdl --extra-ldflags=-L/opt/local/lib
libavutil 56. 49.100 / 56. 49.100
libavcodec 58. 90.100 / 58. 90.100
libavformat 58. 44.100 / 58. 44.100
libavdevice 58. 9.103 / 58. 9.103
libavfilter 7. 84.100 / 7. 84.100
libswscale 5. 6.101 / 5. 6.101
libswresample 3. 6.100 / 3. 6.100
libpostproc 55. 6.100 / 55. 6.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Volumes/Developer/Testfile.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
title : Elephant's Dream
encoder : Lavf58.44.100
Duration: 00:00:03.33, start: 0.000000, bitrate: 9362 kb/s
Stream #0:0(eng): Video: vp9 (Profile 3) (vp09 / 0x39307076),
yuv444p10le(tv, bt709/unknown/unknown), 1920x1080, 8981 kb/s, SAR 1:1 DAR
16:9, 24.01 fps, 24 tbr, 16k tbn, 16k tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo,
fltp, 384 kb/s (default)
Metadata:
handler_name : SoundHandler
At least one output file must be specified
Now, it tells it is MP3, but it is MP2 audio. I have attached both files.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8700>
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