Why does ffmpeg double the play time in a conversion from 48K to 44.1K?
If I turn off the Xing header in the conversion, the play time is correct.
See the eyeD3 times below. VLC shows these times as well.
Ubuntu 24.04.1 LTS - ffmpeg version 6.1.1-3ubuntu5+esm2
(also true for Ubunto 20.04.6 LTS - ffmpeg version 4.2.7-0ubuntu0.1+esm6)
$ ffmpeg -i i.mp3 -ar 44100 bad.mp3
ffmpeg version 6.1.1-3ubuntu5+esm2 Copyright (c) 2000-2023 the FFmpeg developers
built with gcc 13 (Ubuntu 13.2.0-23ubuntu4)
configuration: --prefix=/usr --extra-version=3ubuntu5+esm2
--toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
--incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
--disable-stripping --disable-omx --enable-gnutls --enable-libaom
--enable-libass --enable-libbs2b --enable-libcaca --enable-libcdio
--enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig
--enable-libfreetype --enable-libfribidi --enable-libglslang --enable-libgme
--enable-libgsm --enable-libharfbuzz --enable-libmp3lame --enable-libmysofa
--enable-libopenjpeg --enable-libopenmpt --enable-libopus
--enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr
--enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab
--enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265
--enable-libxml2 --enable-libxvid --enable-libzimg --enable-openal
--enable-opencl --enable-opengl --disable-sndio --enable-libvpl
--disable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883
--enable-chromaprint --enable-frei0r --enable-ladspa --enable-libbluray
--enable-libjack --enable-libpulse --enable-librabbitmq --enable-librist
--enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libx264
--enable-libzmq --enable-libzvbi --enable-lv2 --enable-sdl2 --enable-libplacebo
--enable-librav1e --enable-pocketsphinx --enable-librsvg --enable-libjxl
--enable-shared
libavutil 58. 29.100 / 58. 29.100
libavcodec 60. 31.102 / 60. 31.102
libavformat 60. 16.100 / 60. 16.100
libavdevice 60. 3.100 / 60. 3.100
libavfilter 9. 12.100 / 9. 12.100
libswscale 7. 5.100 / 7. 5.100
libswresample 4. 12.100 / 4. 12.100
libpostproc 57. 3.100 / 57. 3.100
Input #0, mp3, from 'i.mp3':
Metadata:
encoder : Lavf58.16.100
Duration: 00:08:31.56, start: 0.023021, bitrate: 256 kb/s
Stream #0:0: Audio: mp3, 48000 Hz, stereo, fltp, 256 kb/s
Metadata:
encoder : Lavc58.19
Stream mapping:
Stream #0:0 -> #0:0 (mp3 (mp3float) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to 'bad.mp3':
Metadata:
TSSE : Lavf60.16.100
Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp
Metadata:
encoder : Lavc60.31.102 libmp3lame
[libmp3lame @ 0x58d8c740ec80] Trying to remove 1152 samples, but the queue is
empty
[out#0/mp3 @ 0x58d8c740be40] video:0kB audio:7993kB subtitle:0kB other
streams:0kB global headers:0kB muxing overhead: 0.003091%
size= 7994kB time=00:08:31.53 bitrate= 128.0kbits/s speed=22.8x
$ ffmpeg -i i.mp3 -ar 44100 -write_xing 0 good.mp3
[...] same verbose output as above
$ eyeD3 i.mp3 bad.mp3 good.mp3
/xxxxxxxxxxxx/test_mp3/i.mp3 [ 15.61 MB ]
Time: 08:32 MPEG1, Layer III [ 256 kb/s @ 48000 Hz - Stereo ]
/xxxxxxxxxxxx/test_mp3/bad.mp3 [ 7.81 MB ]
Time: 17:08 MPEG1, Layer III [ 64 kb/s @ 44100 Hz - Stereo ]
/xxxxxxxxxxxx/test_mp3/good.mp3 [ 7.81 MB ]
Time: 08:33 MPEG1, Layer III [ 128 kb/s @ 44100 Hz - Joint stereo ]
Why is the Time doubled unless I suppress the Xing header?
Strangely, eyeD3 claims there is no Xing (LAME) header anywhere:
$ eyeD3 -P xing i.mp3 bad.mp3 good.mp3
/xxxxxxxxxxxx/test_mp3/i.mp3 [ 15.61 MB ]
No LAME Tag
/xxxxxxxxxxxx/test_mp3/bad.mp3 [ 7.81 MB ]
No LAME Tag
/xxxxxxxxxxxx/test_mp3/good.mp3 [ 7.81 MB ]
No LAME Tag
(All output of eyeD3 edited to remove unnecessary/irrelevant lines.)
--
| Ian! D. Allen, BA-Psych, MMath-CompSci idal...@idallen.ca Ottawa CANADA
| Home: www.idallen.com Contact Improvisation Dance: www.contactimprov.ca
| Former college professor of Free/Libre GNU+Linux @ teaching.idallen.com
| Improve democracy www.fairvote.ca and defend digital freedom www.eff.org
_______________________________________________
ffmpeg-user mailing list
ffmpeg-user@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
