#5121: Wrong sample rate read from / written to opus webm file
-------------------------------------+-------------------------------------
Reporter: pszemus | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: unspecified | undetermined
Keywords: | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
-------------------------------------+-------------------------------------
Comment (by pszemus):
No, I want the ffmpeg to create with and report the correct sample rate
value.
Let's create an opus file like this:
{{{
$ ffmpeg -i
http://www.soundsnap.com/audio/play/72210%3A1448291371%3Ab4326304c013a3a61b3b87d83158c91b
-c:a libopus -b:a 64k -ar 24000 /tmp/tmp.opus
ffmpeg version N-77704-g68eb208 Copyright (c) 2000-2016 the FFmpeg
developers
built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-4)
configuration: --prefix=/home/pszemus/ffmpeg/build --enable-pic
--enable-pthreads --enable-libmp3lame --enable-version3 --enable-libfaac
--enable-gpl --enable-nonfree --enable-libvpx --enable-libvorbis --enable-
libopus --enable-libx264 --enable-libwebp --enable-protocol=https
--enable-openssl --extra-cflags=-I/opt/WP/common.libs/include --extra-
ldflags='-L/opt/WP/common.libs/lib -ldl'
libavutil 55. 12.100 / 55. 12.100
libavcodec 57. 21.100 / 57. 21.100
libavformat 57. 21.100 / 57. 21.100
libavdevice 57. 0.100 / 57. 0.100
libavfilter 6. 23.100 / 6. 23.100
libswscale 4. 0.100 / 4. 0.100
libswresample 2. 0.101 / 2. 0.101
libpostproc 54. 0.100 / 54. 0.100
[mp3 @ 0x3c683a0] Skipping 0 bytes of junk at 0.
[mp3 @ 0x3c683a0] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from
'http://www.soundsnap.com/audio/play/72210%3A1448291371%3Ab4326304c013a3a61b3b87d83158c91b':
Metadata:
title : PleaseRefesh2015_1
date : 2015
track : 1
Duration: 00:00:04.13, start: 0.000000, bitrate: 192 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
Output #0, opus, to '/tmp/tmp.opus':
Metadata:
title : PleaseRefesh2015_1
date : 2015
track : 1
encoder : Lavf57.21.100
Stream #0:0: Audio: opus (libopus), 24000 Hz, stereo, s16, 64 kb/s
Metadata:
encoder : Lavc57.21.100 libopus
title : PleaseRefesh2015_1
date : 2015
TRACKNUMBER : 1
Stream mapping:
Stream #0:0 -> #0:0 (mp3 (native) -> opus (libopus))
Press [q] to stop, [?] for help
size= 36kB time=00:00:04.13 bitrate= 71.0kbits/s speed=15.3x
video:0kB audio:35kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 1.533776%
}}}
Now compare the output form FFmpeg and opusinfo (from opus-tools)
analysis:
{{{
$ ffmpeg -i /tmp/tmp.opus
ffmpeg version N-77704-g68eb208 Copyright (c) 2000-2016 the FFmpeg
developers
built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-4)
configuration: --prefix=/home/pszemus/ffmpeg/build --enable-pic
--enable-pthreads --enable-libmp3lame --enable-version3 --enable-libfaac
--enable-gpl --enable-nonfree --enable-libvpx --enable-libvorbis --enable-
libopus --enable-libx264 --enable-libwebp --enable-protocol=https
--enable-openssl --extra-cflags=-I/opt/WP/common.libs/include --extra-
ldflags='-L/opt/WP/common.libs/lib -ldl'
libavutil 55. 12.100 / 55. 12.100
libavcodec 57. 21.100 / 57. 21.100
libavformat 57. 21.100 / 57. 21.100
libavdevice 57. 0.100 / 57. 0.100
libavfilter 6. 23.100 / 6. 23.100
libswscale 4. 0.100 / 4. 0.100
libswresample 2. 0.101 / 2. 0.101
libpostproc 54. 0.100 / 54. 0.100
Input #0, ogg, from '/tmp/tmp.opus':
Duration: 00:00:04.13, start: 0.000000, bitrate: 70 kb/s
Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp
Metadata:
ENCODER : Lavc57.21.100 libopus
TITLE : PleaseRefesh2015_1
DATE : 2015
track : 1
At least one output file must be specified
}}}
{{{
$ opusinfo /tmp/tmp.opus
Processing file "/tmp/tmp.opus"...
New logical stream (#1, serial: 281a7d51): type opus
Encoded with Lavf57.21.100
User comments section follows...
encoder=Lavc57.21.100 libopus
title=PleaseRefesh2015_1
date=2015
TRACKNUMBER=1
Opus stream 1:
Pre-skip: 156
Playback gain: 0 dB
Channels: 2
Original sample rate: 24000Hz
Packet duration: 20.0ms (max), 20.0ms (avg), 20.0ms (min)
Page duration: 1000.0ms (max), 828.0ms (avg), 140.0ms (min)
Total data length: 36674 bytes (overhead: 1.51%)
Playback length: 0m:04.130s
Average bitrate: 71.03 kb/s, w/o overhead: 69.96 kb/s
Logical stream 1 ended
}}}
Where this inconsistency come from? Why does FFmpeg and Firefox report
48kHz sample rate when MediaInfo and opusinfo show 24kHz?
--
Ticket URL: <https://trac.ffmpeg.org/ticket/5121#comment:2>
FFmpeg <https://ffmpeg.org>
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