With Version 23.05.07 the Video-Playback starts very slow with SSD

What is your operating system?
Windows 10

What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?

Can you repeat the problem? If so, what are the steps?
(Please be specific and use the names as seen in Shotcut, preferably English. Include a screenshot or screen recording if you can. Also, you can attach logs from either View > Application Log or right-click a job and choose View Log.)

Yes, the issue arrise if I do changes to the timeline (simple but large video file) like cutting different tracks (audio and video) and want to play. Then Shotcut uses the SSD (on which the Source Video File is placed) and seems to retrieve already available data from that file. And playback just waits for it. That wasn’t the case for the previous versions where it just started. The Playback can wait for many seconds (~10-15).

On a SSD?

Was there any change on this topic? And why this new behaviour?

One addition here:

If I am simultaniously render/exporting a video to this SSD then Shotcut completely refuses to play after I did a change to the timeline.

It seems that the new version completely loads a specific section of the timeline from disk to preview instead of using the already loaded data of the section.

For now this update is not suitable for me to work.

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So also checked my previous installed version (22.12.21, on which I rolled back now) and there the Video Playback is much smoother than in the most current version. No real noticable SSD usage.

Version 23.05.07:
Average SSD Usage while this Bug: 300 MB/s

Version 22.12.21:
Average SSD Usage overall: max. 10 MB/s (even while Exporting another movie)

Can this be related to one of these commits?

I have compared the two Tags with this link here: Comparing v22.12.21...v23.05.07 · mltframework/shotcut · GitHub

Is this related to a specific type of video? I noticed a massive improvement regarding playback speed (especially gopro videos) in the latest update.

@daniel47 Actually not.

They are “simple” MKV-Videos made/recorded in OBS.

I have three tracks (1 Video and two Audio tracks of the same video) with a few filters (Normalize and Limiter) applied.

EDIT: Image added

That is weird, and I have not experienced this.

You should try some completely different videos to see if it is related to how these were created. Often, OBS does not make “simple” videos but rather one that are variable frame rate (not suitable for editing) and with multiple audio tracks. Maybe it is related to one of these characteristics.

I have also problems with video playback on the new version.
The files which i tested were DVB-transport-streams (*.ts) from european TV-broadcasting stations.

The playback with 1x, 2x and 4x speed is perfect, very smooth, but with 8x, 16x or faster the playback is stuttering and jerking with about 1 frame per second. In previous versions this worked much better.

Unfortunately i had to do a rollback to the previous version, this works for me.

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I tested one of my existing project on my linux laptop with a MX150 and on the Win11 PC with a GTX1660 and both did crash on playback when the source video is changing. My filters are fade in & fade out, stabilization and color grading.

That is not related to this thread, but it is to

I am using 4k images from a FZ1000 and i did test this today. It does not crash on every transition from one video to the other. Some of the images are 4 GB large. All images do have the stabilization feature, but they are not activated on all of them. And dark theme does not work here, too.

This is fixed for the next version for 8 through 64x speeds (or press and hold page-down key to skip by seconds). Beyond that, not so. It is due to a change that significantly improves the open and start playback speed for certain or very heavy videos especially on non-super speedy storage. What could be considered a bug in all previous versions - similar I think to what this original report is about, but I do not reproduce that any more.

That sounds very good. Thank you for your great work!