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IDProjectCategoryView StatusDate SubmittedLast Update
0002330KdenliveUser Interfacepublic2011-09-24 16:482012-08-24 21:41
Assigned Toj-b-m 
Platformx86_64OSLinuxOS Version3.0.4
Product VersionRecent git 
Target VersionFixed in Version 
Summary0002330: Muting an audio channel affects audio effects on other channels.
DescriptionI use cross fade the audio in video clips quite often, and suddenly the cross fading was not working properly.
It sounded as if the clip that should be fading out is suddenly muted as the other clip starts fading in.

It took a while to track down. The only thing I did differently was to load an audio clip first, but when doing my favorite cross-fades, the sound was getting in the way, so I just muted the whole channel by clicking on the speaker button on the left of that channel.
Steps To Reproduceload a few clips on the timeline.
make them overlap in time.
Fade out and in so that you get a cross fade effect.
test that the cross fading works as expected.
Load an music clip into one of the audio channels.
mute the audio channel, not the clip.
Now cross-fading does not work anymore.

This bug is also transferred to rendering, ie if you render a scene where the cross-fading does not work properly, it also does not work properly in the rendered output.
Additional InformationAs a workaround, one could just select all clips in the audio channel and mute them individually. Cross-fading works fine like that. Also, muting an empty channel has no effect on audio effects in other channels...
TagsNo tags attached.
Build/Install MethodManual build from SVN
Attached Files

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-  Notes
evorster (reporter)
2011-09-25 16:46

This is issue is still present with the latest git version of mlt. I don't think it's in mlt anyways, as the rendered result is exactly the same as the preview.

Another way to describe it is that if a channel is muted, all the other channels do fades, but no two channels can produce sound at the same time... ie: there is no more mixing of audio channels if a completely unrelated channel is muted.

Strange thing is that this only becomes apparent if there is a clip in the channel that is getting muted. Just muting an empty channel has no effect on the other channels, as it should have.
j-b-m (administrator)
2011-09-26 10:57

Confirmed, but the issue only seems to be triggered when muting the lowest used track. It seems to be a problem in the way MLT handles mixing, I am trying to find a workaround...

- Issue History
Date Modified Username Field Change
2011-09-24 16:48 evorster New Issue
2011-09-25 16:46 evorster Note Added: 0007368
2011-09-26 10:57 j-b-m Note Added: 0007370
2011-09-26 10:57 j-b-m Assigned To => j-b-m
2011-09-26 10:57 j-b-m Status new => acknowledged

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