[FFmpeg-trac] #10942(ffmpeg:new): Transcoding to mp2 within an mp4 container will be recognized as mp3
FFmpeg
trac at avcodec.org
Tue Apr 9 16:35:55 EEST 2024
#10942: Transcoding to mp2 within an mp4 container will be recognized as mp3
-------------------------------------+----------------------------------
Reporter: Olaf Ahrens | Owner: (none)
Type: defect | Status: new
Priority: normal | Component: ffmpeg
Version: git-master | Resolution:
Keywords: mp4 mp2 | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+----------------------------------
Description changed by Olaf Ahrens:
Old description:
> Summary of the bug:
> When transcoding to an mp4 container with mp2 audio codec, the audio
> codec is marked non-conclusively. This results in ffmpeg itself
> incorrectly recognizing the audio codec in the transcoded video as mp3,
> while other programs recognize it as the intended mp2:
>
> **ffmpeg**
> {{{
> ffmpeg -i TargetAsMp4.mp4
> results in [...]Stream #0:1[...]Audio: mp3 (mp3float) (mp4a /
> 0x6134706D)[...]
> }}}
>
> **MediaInfo**
> * Format ''MPEG audio''
> * Format version ''Version 1''
> * Format profile ''Layer 2''
> * Codec ID ''mp4a-6b''
>
> **VLC Media Player**
> * Codec ''MPEG Audio layer 1/2 (mpga)''
>
> However, if another container format is used, for example mkv, the audio
> codec will be recognized correctly by all programs:
>
> **ffmpeg**
> {{{
> ffmpeg -i TargetAsMkv.mkv
> results in [...]Stream #0:1[...]Audio: mp2[...]
> }}}
>
> **MediaInfo**
> * Format ''MPEG audio''
> * Format version ''Version 1''
> * Format profile ''layer 2''
> * Codec ID ''A_MPEG/L2''
> * Codec ID/hint ''MP2''
> **VLC Media Player**
> * Codec ''MPEG Audio layer 1/2 (mpga)''
>
> What is noticeable is the audio codec ID 0x6134706D shown within the mp4
> container, which as far as I know is associated with the aac codec, but
> neither with mp2 nor with mp3.
>
> How to reproduce:
> {{{
> % ffmpeg -i Source.mp4 -c:v h264 -c:a mp2 TargetAsMp4.mp4
> ffmpeg version 2024-03-28-git-5d71f97e0e-full_build-www.gyan.dev
> Copyright (c) 2000-2024 the FFmpeg developers
> built with gcc 13.2.0 (Rev5, Built by MSYS2 project)
> configuration: --enable-gpl --enable-version3 --enable-static --pkg-
> config=pkgconf --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-libaribcaption --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-libharfbuzz --enable-liblensfun
> --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf
> --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va
> --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec
> --enable-nvenc --enable-vaapi --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-libcodec2 --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 59. 10.100 / 59. 10.100
> libavcodec 61. 4.100 / 61. 4.100
> libavformat 61. 2.100 / 61. 2.100
> libavdevice 61. 2.100 / 61. 2.100
> libavfilter 10. 2.100 / 10. 2.100
> libswscale 8. 2.100 / 8. 2.100
> libswresample 5. 2.100 / 5. 2.100
> libpostproc 58. 2.100 / 58. 2.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Source.mp4':
> Metadata:
> major_brand : isom
> minor_version : 512
> compatible_brands: isomiso2avc1mp41
> creation_time : 2024-03-30T09:24:24.000000Z
> encoder : Lavf60.23.100
> Duration: 00:00:05.75, start: 0.000000, bitrate: 1531 kb/s
> Stream #0:0[0x1](und): Video: h264 (Main) (avc1 / 0x31637661),
> yuv420p(progressive), 720x406 [SAR 406:405 DAR 16:9], 1373 kb/s, 30 fps,
> 30 tbr, 15360 tbn (default)
> Metadata:
> creation_time : 2024-03-30T09:24:24.000000Z
> handler_name : VideoHandler
> vendor_id : [0][0][0][0]
> encoder : Lavc60.41.100 libx264
> Stream #0:1[0x2](eng): Audio: mp3 (mp3float) (mp4a / 0x6134706D), 44100
> Hz, stereo, fltp, 160 kb/s (default)
> Metadata:
> creation_time : 2024-03-30T09:24:24.000000Z
> handler_name : SoundHandler
> vendor_id : [0][0][0][0]
> Stream mapping:
> Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
> Stream #0:1 -> #0:1 (mp3 (mp3float) -> mp2 (native))
> Press [q] to stop, [?] for help
> [libx264 @ 000002ae3902bc00] using SAR=406/405
> [libx264 @ 000002ae3902bc00] using cpu capabilities: MMX2 SSE2Fast SSSE3
> SSE4.2 AVX FMA3 BMI2 AVX2
> [libx264 @ 000002ae3902bc00] profile High, level 3.0, 4:2:0, 8-bit
> [libx264 @ 000002ae3902bc00] 264 - core 164 r3190 7ed753b - H.264/MPEG-4
> AVC codec - Copyleft 2003-2024 - http://www.videolan.org/x264.html -
> options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7
> psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
> 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=13
> lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0
> bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
> b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
> scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
> qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
> Output #0, mp4, to 'TargetAsMp4.mp4':
> Metadata:
> major_brand : isom
> minor_version : 512
> compatible_brands: isomiso2avc1mp41
> encoder : Lavf61.2.100
> Stream #0:0(und): Video: h264 (avc1 / 0x31637661),
> yuv420p(progressive), 720x406 [SAR 406:405 DAR 16:9], q=2-31, 30 fps,
> 15360 tbn (default)
> Metadata:
> creation_time : 2024-03-30T09:24:24.000000Z
> handler_name : VideoHandler
> vendor_id : [0][0][0][0]
> encoder : Lavc61.4.100 libx264
> Side data:
> cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
> Stream #0:1(eng): Audio: mp2 (mp4a / 0x6134706D), 44100 Hz, stereo,
> s16, 384 kb/s (default)
> Metadata:
> creation_time : 2024-03-30T09:24:24.000000Z
> handler_name : SoundHandler
> vendor_id : [0][0][0][0]
> encoder : Lavc61.4.100 mp2
> [out#0/mp4 @ 000002ae39007cc0] video:819KiB audio:271KiB subtitle:0KiB
> other streams:0KiB global headers:0KiB muxing overhead: 0.608235%
> frame= 171 fps= 81 q=-1.0 Lsize= 1097KiB time=00:00:05.63
> bitrate=1594.7kbits/s speed=2.66x
> [libx264 @ 000002ae3902bc00] frame I:1 Avg QP:24.65 size: 83042
> [libx264 @ 000002ae3902bc00] frame P:43 Avg QP:25.31 size: 14442
> [libx264 @ 000002ae3902bc00] frame B:127 Avg QP:30.79 size: 1058
> [libx264 @ 000002ae3902bc00] consecutive B-frames: 0.6% 0.0% 3.5%
> 95.9%
> [libx264 @ 000002ae3902bc00] mb I I16..4: 0.7% 5.3% 94.0%
> [libx264 @ 000002ae3902bc00] mb P I16..4: 0.1% 0.4% 0.6% P16..4:
> 56.6% 17.3% 18.2% 0.0% 0.0% skip: 6.9%
> [libx264 @ 000002ae3902bc00] mb B I16..4: 0.0% 0.0% 0.0% B16..8:
> 49.2% 4.7% 1.0% direct: 0.7% skip:44.4% L0:44.2% L1:46.1% BI: 9.7%
> [libx264 @ 000002ae3902bc00] 8x8 transform intra:14.8% inter:28.0%
> [libx264 @ 000002ae3902bc00] coded y,uvDC,uvAC intra: 88.1% 96.4% 80.8%
> inter: 16.1% 12.5% 2.9%
> [libx264 @ 000002ae3902bc00] i16 v,h,dc,p: 43% 10% 38% 9%
> [libx264 @ 000002ae3902bc00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 37% 15% 18%
> 3% 4% 4% 4% 4% 10%
> [libx264 @ 000002ae3902bc00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 19% 11%
> 7% 7% 7% 8% 7% 13%
> [libx264 @ 000002ae3902bc00] i8c dc,h,v,p: 44% 25% 19% 12%
> [libx264 @ 000002ae3902bc00] Weighted P-Frames: Y:9.3% UV:0.0%
> [libx264 @ 000002ae3902bc00] ref P L0: 59.9% 19.3% 7.2% 12.6% 1.1%
> [libx264 @ 000002ae3902bc00] ref B L0: 78.0% 19.7% 2.3%
> [libx264 @ 000002ae3902bc00] ref B L1: 84.1% 15.9%
> [libx264 @ 000002ae3902bc00] kb/s:1176.68
>
> ffmpeg version 2024-03-28-git-5d71f97e0e-full_build-www.gyan.dev
> built for Windows 7 ff
> }}}
>
> OS on which the tests were run: Windows 11 Pro Version 10.0.22631 Build
> 22631
New description:
Summary of the bug:
When transcoding to an mp4 container with mp2 audio codec, the audio codec
is marked non-conclusively. This results in ffmpeg itself incorrectly
recognizing the audio codec in the transcoded video as mp3, while other
programs recognize it as the intended mp2:
**ffmpeg -i TargetAsMp4.mp4**
{{{
[...]Stream #0:1[...]Audio: mp3 (mp3float) (mp4a / 0x6134706D)[...]
}}}
**Mediainfo**
{{{
Format - MPEG audio
Format version - Version 1
Format profile - Layer 2
Codec ID - mp4a-6b
}}}
**VLC Media Player**
{{{
Codec - MPEG Audio layer 1/2 (mpga)
}}}
However, if another container format is used, for example mkv, the audio
codec will be recognized correctly by all programs:
**ffmpeg -i TargetAsMkv.mkv**
{{{
[...]Stream #0:1[...]Audio: mp2[...]
}}}
**Mediainfo**
{{{
Format - MPEG audio
Format version - Version 1
Format profile - layer 2
Codec ID - A_MPEG/L2
Codec ID/hint - MP2
}}}
**VLC Media Player**
{{{
Codec - MPEG Audio layer 1/2 (mpga)
}}}
What is noticeable is the audio codec ID 0x6134706D shown within the mp4
container, which as far as I know is associated with the aac codec, but
neither with mp2 nor with mp3.
How to reproduce:
{{{
% ffmpeg -i Source.mp4 -c:v h264 -c:a mp2 TargetAsMp4.mp4
ffmpeg version 2024-03-28-git-5d71f97e0e-full_build-www.gyan.dev Copyright
(c) 2000-2024 the FFmpeg developers
built with gcc 13.2.0 (Rev5, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --pkg-
config=pkgconf --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-libaribcaption --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-libharfbuzz --enable-liblensfun
--enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf
--enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va
--enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec
--enable-nvenc --enable-vaapi --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-libcodec2 --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 59. 10.100 / 59. 10.100
libavcodec 61. 4.100 / 61. 4.100
libavformat 61. 2.100 / 61. 2.100
libavdevice 61. 2.100 / 61. 2.100
libavfilter 10. 2.100 / 10. 2.100
libswscale 8. 2.100 / 8. 2.100
libswresample 5. 2.100 / 5. 2.100
libpostproc 58. 2.100 / 58. 2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Source.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
creation_time : 2024-03-30T09:24:24.000000Z
encoder : Lavf60.23.100
Duration: 00:00:05.75, start: 0.000000, bitrate: 1531 kb/s
Stream #0:0[0x1](und): Video: h264 (Main) (avc1 / 0x31637661),
yuv420p(progressive), 720x406 [SAR 406:405 DAR 16:9], 1373 kb/s, 30 fps,
30 tbr, 15360 tbn (default)
Metadata:
creation_time : 2024-03-30T09:24:24.000000Z
handler_name : VideoHandler
vendor_id : [0][0][0][0]
encoder : Lavc60.41.100 libx264
Stream #0:1[0x2](eng): Audio: mp3 (mp3float) (mp4a / 0x6134706D), 44100
Hz, stereo, fltp, 160 kb/s (default)
Metadata:
creation_time : 2024-03-30T09:24:24.000000Z
handler_name : SoundHandler
vendor_id : [0][0][0][0]
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (mp3 (mp3float) -> mp2 (native))
Press [q] to stop, [?] for help
[libx264 @ 000002ae3902bc00] using SAR=406/405
[libx264 @ 000002ae3902bc00] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000002ae3902bc00] profile High, level 3.0, 4:2:0, 8-bit
[libx264 @ 000002ae3902bc00] 264 - core 164 r3190 7ed753b - H.264/MPEG-4
AVC codec - Copyleft 2003-2024 - http://www.videolan.org/x264.html -
options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7
psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=13
lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0
bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25
scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0
qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'TargetAsMp4.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf61.2.100
Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p(progressive),
720x406 [SAR 406:405 DAR 16:9], q=2-31, 30 fps, 15360 tbn (default)
Metadata:
creation_time : 2024-03-30T09:24:24.000000Z
handler_name : VideoHandler
vendor_id : [0][0][0][0]
encoder : Lavc61.4.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
Stream #0:1(eng): Audio: mp2 (mp4a / 0x6134706D), 44100 Hz, stereo, s16,
384 kb/s (default)
Metadata:
creation_time : 2024-03-30T09:24:24.000000Z
handler_name : SoundHandler
vendor_id : [0][0][0][0]
encoder : Lavc61.4.100 mp2
[out#0/mp4 @ 000002ae39007cc0] video:819KiB audio:271KiB subtitle:0KiB
other streams:0KiB global headers:0KiB muxing overhead: 0.608235%
frame= 171 fps= 81 q=-1.0 Lsize= 1097KiB time=00:00:05.63
bitrate=1594.7kbits/s speed=2.66x
[libx264 @ 000002ae3902bc00] frame I:1 Avg QP:24.65 size: 83042
[libx264 @ 000002ae3902bc00] frame P:43 Avg QP:25.31 size: 14442
[libx264 @ 000002ae3902bc00] frame B:127 Avg QP:30.79 size: 1058
[libx264 @ 000002ae3902bc00] consecutive B-frames: 0.6% 0.0% 3.5% 95.9%
[libx264 @ 000002ae3902bc00] mb I I16..4: 0.7% 5.3% 94.0%
[libx264 @ 000002ae3902bc00] mb P I16..4: 0.1% 0.4% 0.6% P16..4:
56.6% 17.3% 18.2% 0.0% 0.0% skip: 6.9%
[libx264 @ 000002ae3902bc00] mb B I16..4: 0.0% 0.0% 0.0% B16..8:
49.2% 4.7% 1.0% direct: 0.7% skip:44.4% L0:44.2% L1:46.1% BI: 9.7%
[libx264 @ 000002ae3902bc00] 8x8 transform intra:14.8% inter:28.0%
[libx264 @ 000002ae3902bc00] coded y,uvDC,uvAC intra: 88.1% 96.4% 80.8%
inter: 16.1% 12.5% 2.9%
[libx264 @ 000002ae3902bc00] i16 v,h,dc,p: 43% 10% 38% 9%
[libx264 @ 000002ae3902bc00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 37% 15% 18%
3% 4% 4% 4% 4% 10%
[libx264 @ 000002ae3902bc00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 19% 11%
7% 7% 7% 8% 7% 13%
[libx264 @ 000002ae3902bc00] i8c dc,h,v,p: 44% 25% 19% 12%
[libx264 @ 000002ae3902bc00] Weighted P-Frames: Y:9.3% UV:0.0%
[libx264 @ 000002ae3902bc00] ref P L0: 59.9% 19.3% 7.2% 12.6% 1.1%
[libx264 @ 000002ae3902bc00] ref B L0: 78.0% 19.7% 2.3%
[libx264 @ 000002ae3902bc00] ref B L1: 84.1% 15.9%
[libx264 @ 000002ae3902bc00] kb/s:1176.68
ffmpeg version 2024-03-28-git-5d71f97e0e-full_build-www.gyan.dev
built for Windows 7 ff
}}}
OS on which the tests were run: Windows 11 Pro Version 10.0.22631 Build
22631
--
--
Ticket URL: <https://trac.ffmpeg.org/ticket/10942#comment:2>
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