#10038: Wrong duration / speed in audio recording made with ffmpeg -f
avfoundation
-------------------------------------+-------------------------------------
Reporter: Raimondas | Owner: (none)
Type: defect | Status: new
Priority: normal | Component:
| undetermined
Version: git-master | Resolution:
Keywords: | Blocked By:
avfoundation |
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Comment (by Raimondas):
The crux of the problem may be that capture? encoding? happens at some
arbitrary, lower bitrate, but output file bitrate matches the expected
bitrate for sampling rate.
Here's capture at 192k:
{{{
...
Input #0, avfoundation, from ':0':
Duration: N/A, start: 12238.164484, bitrate: 12288 kb/s
Stream #0:0, 1, 1/1000000: Audio: pcm_f32le, 192000 Hz, stereo, flt,
12288 kb/s
...
Output #0, wav, to '192-24.wav':
Metadata:
ISFT : Lavf59.27.100
Stream #0:0, 0, 1/192000: Audio: pcm_s24le ([1][0][0][0] / 0x0001),
192000 Hz, stereo, s32, 9216 kb/s
Metadata:
encoder : Lavc59.37.100 pcm_s24le
size= 2904kB time=00:00:09.99 bitrate=2380.9kbits/s speed=0.999x
}}}
and at 44.1k:
{{{
...
Input #0, avfoundation, from ':0':
Duration: N/A, start: 12528.771497, bitrate: 2822 kb/s
Stream #0:0, 1, 1/1000000: Audio: pcm_f32le, 44100 Hz, stereo, flt, 2822
kb/s
...
Output #0, wav, to '44-24.wav':
Metadata:
ISFT : Lavf59.27.100
Stream #0:0, 0, 1/44100: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 44100
Hz, stereo, s32, 2116 kb/s
Metadata:
encoder : Lavc59.37.100 pcm_s24le
size= 2512kB time=00:00:10.00 bitrate=2057.9kbits/s speed=0.998x
}}}
attaching logs for 3 recordings, at 192, 96, 44.1k, all showing the same
problem
--
Ticket URL: <https://trac.ffmpeg.org/ticket/10038#comment:4>
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