[SoX-devel] [ sox-Bugs-2725810 ] Silence effect does not work correctly with replay gain

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Bugs item #2725810, was opened at 2009-04-01 22:34
Message generated for change (Comment added) made by sf-robot
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Category: None
Group: unverified
>Status: Closed
Resolution: None
Priority: 5
Private: No
Submitted By: Ulrich Klauer (uklauer)
Assigned to: robs (robs)
Summary: Silence effect does not work correctly with replay gain

Initial Comment:
In some cases, the silence effect does not remove perfect silence (all-zero) when replay gain is being applied.

Please see the attached file short.flac. About two seconds at the end are "digital silence", i.e. all-zero. The command
sox -V -V --replay-gain=off short.flac t3.wav silence 1 00:00:02.0 0% 1 00:00:00.4 0.01%
trims those last seconds, reducing the number of samples from 326488 to 239517. This is the expected behaviour. (I will attach a transcript of the output, rp-off.log.)

The similar command
sox -V -V --replay-gain=track short.flac t3.wav silence 1 00:00:02.0 0% 1 00:00:00.4 0.01%
is expected to do the same trimming. However, it does not: The silence at the end is preserved, the sample count stays at 326488. (See rp-track.log.)

As play has a default replay gain setting of "track", the silence effect does not work there, either. An obvious workaround is to do the silence effect first, in a separate sox incarnation, and then to apply replay gain and possibly other effects:
sox -V -V --replay-gain=track "| sox short.flac -p silence 1 00:00:02.0 0% 1 00:00:00.4 0.01%" t3.wav

Please note that short.flac is the last bit of a longer file; the replay gain information contained refers to this original file, so the peak and gain values are not actually correct for this excerpt. The problem described occurs in processing the original file, too.

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>Comment By: SourceForge Robot (sf-robot)
Date: 2009-04-19 02:21

Message:
This Tracker item was closed automatically by the system. It was
previously set to a Pending status, and the original submitter
did not respond within 14 days (the time period specified by
the administrator of this Tracker).

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Comment By: robs (robs)
Date: 2009-04-04 19:41

Message:
An attempt to fix this is now in CVS

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110706&aid=2725810&group_id=10706