[FFmpeg-trac] #5891(undetermined:new): "-t" not applied to streams when using channelsplit filter
FFmpeg
trac at avcodec.org
Fri Oct 14 13:51:09 EEST 2016
#5891: "-t" not applied to streams when using channelsplit filter
-------------------------------------+-------------------------------------
Reporter: MReedAustin | Type: defect
Status: new | Priority: normal
Component: | Version:
undetermined | unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
I was using volumedetect to check each channel of a file to ensure that
program start handles were mute, and got misleading readings when the
incoming audio was split (using channelsplit). I have fixed my code by
using atrim instead of -t but though the inconsistency was worth
highlighting.
How to reproduce:
{{{
(Any stereo audio source)
ffmpeg -ss 149 -i [stereo wav] -filter_complex "[0:0]
channelsplit=channel_layout=2c [A1] [A2], [A2] anullsink, [A1]
volumedetect" -t 0.96 -vn -f null -
Results in:
[Parsed_volumedetect_2 @ 0000000002a463a0] n_samples: '''135634560'''
[Parsed_volumedetect_2 @ 0000000002a463a0] mean_volume: -25.3 dB
[Parsed_volumedetect_2 @ 0000000002a463a0] max_volume: -7.7 dB
[Parsed_volumedetect_2 @ 0000000002a463a0] histogram_7db: 57
[Parsed_volumedetect_2 @ 0000000002a463a0] histogram_8db: 40871
[Parsed_volumedetect_2 @ 0000000002a463a0] histogram_9db: 98220
whereas:
ffmppeg -ss 149 -i [stereo wav] -filter_complex "[0:0]
channelsplit=channel_layout=2c [A1] [A2], [A2] anullsink, [A1]
atrim=start=0:duration=0.96, volumedetect" -vn -f null -
results in:
[Parsed_volumedetect_3 @ 00000000003400c0] n_samples: '''46080'''
[Parsed_volumedetect_3 @ 00000000003400c0] mean_volume: -91.0 dB
[Parsed_volumedetect_3 @ 00000000003400c0] max_volume: -91.0 dB
[Parsed_volumedetect_3 @ 00000000003400c0] histogram_91db: 46080
ffmpeg version N-81894-g54220ce
Zeranoe build
}}}
Patches should be submitted to the ffmpeg-devel mailing list and not this
bug tracker.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/5891>
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