Bug 398828

Summary:	.mlt clips in timeline audio unaffected by effects added
Product:	[Applications] kdenlive	Reporter:	Evert Vorster <evorster>
Component:	User Interface & Miscellaneous	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED FIXED
Severity:	grave	CC:	fritzibaby
Priority:	NOR	Flags:	fritzibaby: timeline_corruption+
Version First Reported In:	18.08.1
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Evert Vorster 2018-09-19 06:17:40 UTC

Running Arch Linux.

Kdenlive compiled from git, 18.08 branch.
mlt compiled from master, pulled 2018-09-18

I have used the clip job "vidstab stabilize" to produce .mlt files which have been added to the project.

However, some of these clips are pretty noisy, but no matter what I do, I am unable to mute them.

The audio part of the clip is automatically split out. Adding the mute effect to this audio has no effect.

Gain correction with volume of 0 also has no effect.

Ungrouping the video and audio and deleting the audio has no effect, the noise is still there on the project monitor and on the render.

I don't know what to do now, I have to have the clip and many others stabilized, they are not usable otherwise. The stabilize effects on the timeline are useless, vidstab does not apply, vidstab detect and transform actually applies, but does not work. The clip job stabilizes the video but then adds in the audio track, which kdenlive seems to be unable to manipulate.

I know you guys are busy with the timeline refactoring, and technically this is a timeline thing, but the timeline refactoring branch is unusable for me at the moment, as too many features are missing.

About the only quick hack that I can think of is a clip job especially for .mlt files, which is to render the .mlt file and add it to the project bin automatically, as this is what I will have to do manually for each of the .mlt files now.
Actually, this has been a feature I have been asking for about for a while.

Comment 1 Evert Vorster 2018-09-27 07:10:37 UTC

I tried this in the refactoring branch as well, and it seems that the issue is present there as well. 

This issue makes it currently impossible to use shaky noisy video clips without quite a few extra processing steps. 

Sorry, but this one is a biggy for me. 

Kind regards,
-Evert-

Comment 2 Evert Vorster 2018-09-27 07:15:59 UTC

Ah, when I mute the entire track, the .mlt clip is muted. As a workaround for now I can make an extra muted track, and just ungroup the .mlt audio and place it in there.

Comment 3 Evert Vorster 2018-09-27 07:36:15 UTC

Creating an extra muted audio track for the .mlt files audio does not seem to work in the release version of kdenlive. 

I can only conclude that audio is not properly split from .mlt files. 

Hmm... just toying with it some more....

When proxy clips are enabled, the .mlt file audio track behaves normally in the project monitor. Weird, but at least the fix is easy. Always make a proxy clip of .mlt files, and make it impossible to disable the proxies on them. 
It might actually be an idea to be able to have a proxy profile just for .mlt files when proxies are disabled on a project, so that a high quality preview can be made.

Comment 4 Evert Vorster 2018-09-27 07:42:08 UTC

Unfortunately, while the project monitor now plays back the proxied clip properly, when rendering it out the audio is not handled properly. I suspect that this is because the source of the project monitor is a rendered proxy file, and the source for the final render is still the .mlt file.

In conclusion, kdenlive does not apply any audio effect to an .mlt file on the timeline. Video effects seem fine, though.

Comment 5 Evert Vorster 2018-09-27 07:52:42 UTC

Aha!!!

I have automatically splitting audio enabled. 

For some reason, my video tracks still have an audio component. 

When I disable audio on the video tracks, the .mlt file is handled normally, and rendered correctly. So, when splitting audio from video, normally the audio component is split, but for some reason the audio component in .mlt files survives.

In the short term, I can just mute my video tracks, but when enabling automatically splitting audio from video, there should be no audio component to video tracks, in my humble opinion.

It may be a good idea that when selecting track type, there should be 3 types: 
Video
Audio 
Video + Audio

Simple, clear and concise.

Comment 6 Jean-Baptiste Mardelle 2018-09-28 12:32:30 UTC

This should be fixed in the refactoring branch. Video tracks now only allow video and audio tracks audio. Dropping an .mlt file in timeline will create 2 clips: 1 video and 1 audio. You can then disable or delete the audio part.

In previous Kdenlive versions, muting a clip was only working on plain video clips, not on .mlt playlists

Comment 7 Evert Vorster 2018-10-09 04:29:45 UTC

Thanks for the hard wirk, JBM!