Transitions Sometimes Cause Flickering

[gerowen]

I love Shotcut. I’ve gotten used to the interface and have thoroughly enjoyed producing content with it. However, I’ve been using Shotcut for a little while now and have ran into two problems. One of them I’ve learned to work around, but I’ll detail it as well since I wasn’t able to find anything that sounded like the exact same issue I’m having with the search (maybe I just used bad search terms, I’m not sure).

I’m using the snap version of Shotcut 19.04.3 on Ubuntu 19.04.

Issue 1: Sometimes when encoding a video, the video will “flicker” during or at either end of a transition. This flicker is never apparent when playing the video from the timeline, and I haven’t been able to nail down any editing behavior on my part that leads to the problem. Sometimes when it happens I can simply re-encode the same video and it will disappear, but might re-appear at a later point in the video. Here’s a video I did yesterday that exhibits the issue. This link should take you directly to a point a couple of seconds before the stutter. If it doesn’t, just fast forward to about 0:53.

Edit: For reference, I’m achieving the fade transition by dragging one clip over another to overlap the beginning and end by, in this case, 0.5s.

There’s another one here, or at time stamp 3:52 of the same video:

Issue 2: When editing audio in the timeline, it sometimes introduces echo or other types of audio distortion in the resulting video when encoded. This issue does appear sometimes when playing the video back in the timeline, but simply moving the playback point to some other place and then back usually fixes it. I’ve worked around it by simply doing my audio processing and editing in Audacity beforehand and then just dropping the finalized track into my timeline. Sometimes however I find something while editing the video that I want to change, and if I make any breaks in the audio track with Shotcut, there’s about a 50/50 chance that from that break point on there will be echoing (like the track being played over top of itself with a half second or so delay) or some other weirdness.

Edit:
System specs
CPU: AMD FX 8370 (not overclocked)
RAM: 16GB DDR3 1866 Mhz
GPU: MSI Radeon RX 480 8GB (factory overclocked, but not oc’d any further by me)
OS: Ubuntu 19.04
Shotcut version: 19.04.3 (from snapcraft)

[DvS]

About the flickers:
Did you use any filters in the filmclips AFTER setting the transitions?

[samth]

Did these flickers occur in more than one project? If yes, you could try to export with Parallel processing disabled. I did not have issues concerning flickering but artifacts and maybe the same setting is causing the flickers.

[gerowen]

Actually yes, both of the flickers in the above video occur in the first and last clips, and I added the fade-in and fade-out filters after applying the transitions.

[gerowen]

I think I’ve tried disabling parallel processing before and it didn’t fix it, but I’ll try it again just in case.

[DvS]

That’s the cause!
Always use filters BEFORE you cut and set transitions!
That is my experiences.

[gerowen]

That makes sense, so in the future I’ll just do jump cuts during editing and then add all my transitions after everything else is done,

[samth]

If you already tried that, I would expect some differences. So it likely isn’t the cause.
The tip with using filters before transitions is something I’ll try to remember for my next projects. Thanks DvS!