[FFmpeg-trac] #8624(avcodec:new): Codec Copy Reencodes AAC VBR Audio
FFmpeg
trac at avcodec.org
Sun Apr 19 21:16:27 EEST 2020
#8624: Codec Copy Reencodes AAC VBR Audio
------------------------------------+--------------------------------------
Reporter: aminhusni | Type: defect
Status: new | Priority: normal
Component: avcodec | Version: git-master
Keywords: AAC MP4 TS | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
------------------------------------+--------------------------------------
Summary of the bug:
Codec Copy or Audio Codec Copy Reencodes AAC VBR Audio
Flow: .ts -> .mp4
Tried with -c:a copy and -codec copy and both does not give expected
result.
The original .ts file has a VBR audio.
When copying into .mp4, it reencodes the audio into CBR and byte
comparison for the audio track does not match with original AAC that comes
from the .ts file.
How to reproduce:
{{{
% ffmpeg -i .\sample_media.ts -c:v copy -c:a copy .\vacopy.mp4
ffmpeg git-2020-04-17-889ad93
built on gcc 9.3.1 (GCC) 20200328
}}}
Additional console log:
{{{
ffmpeg version git-2020-04-17-889ad93 Copyright (c) 2000-2020 the FFmpeg
developers
built with gcc 9.3.1 (GCC) 20200328
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-
libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
--enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr
--enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx
--enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265
--enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp
--enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-
amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-
libaom --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-
cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec
--enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
libavutil 56. 42.102 / 56. 42.102
libavcodec 58. 80.100 / 58. 80.100
libavformat 58. 42.100 / 58. 42.100
libavdevice 58. 9.103 / 58. 9.103
libavfilter 7. 77.101 / 7. 77.101
libswscale 5. 6.101 / 5. 6.101
libswresample 3. 6.100 / 3. 6.100
libpostproc 55. 6.100 / 55. 6.100
[h264 @ 0000022e104ecfc0] missing picture in access unit with size 8
Input #0, mpegts, from '.\sample_media.ts':
Duration: 00:00:04.05, start: 12.027933, bitrate: 6135 kb/s
Stream #0:0[0x100]: Video: h264 (Main), yuv420p(tv,
bt709/unknown/unknown, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 29.97
fps, 29.97 tbr, 90k tbn, 59.94 tbc
Stream #0:1[0x101]: Audio: aac (LC), 44100 Hz, stereo, fltp, 229 kb/s
Output #0, mp4, to '.\vacopy.mp4':
Metadata:
encoder : Lavf58.42.100
Stream #0:0: Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv,
bt709/unknown/unknown, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31,
29.97 fps, 29.97 tbr, 90k tbn, 90k tbc
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 229 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[NULL @ 0000022e104ecfc0] missing picture in access unit with size 8
[mp4 @ 0000022e10bd8040] Timestamps are unset in a packet for stream 0.
This is deprecated and will stop working in the future. Fix your code to
set the timestamps properly
[mp4 @ 0000022e10bd8040] pts has no value
frame= 121 fps=0.0 q=-1.0 Lsize= 2955kB time=00:00:03.98
bitrate=6070.3kbits/s speed= 499x
video:2825kB audio:126kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.148198%
}}}
The issue might be similar to ticket #4546
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8624>
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