OS: Windows 10 Pro 20H2 (and Ubuntu 20.04 LTS)
Shotcut version: 21.02.27 64bit installer version
If I import a video recorded by a Google Pixel 5 device in 4K60FPS, move it to the timeline and then export it with the default settings, Shotcut only produce an mp4 file without video stream and a few hundred kB of size.
The problem can be reproducible with 21.02.27 appimage version on Ubuntu 20.04 LTS on a different hardware.
One time (I don’t know how) I made a successful export and I saved the log from it. Looks like the hardware acceleration is not important in this case, the process creates a file without video stream with and without it.
The sample video what I want to cut is here https://photos.app.goo.gl/bib9Y4i3XdrC1Pco8
The failed output mp4 of the export and the export logs can be found here: https://drive.google.com/drive/folders/1uD-mEcpD-I-jqqP0R5VIlj-q4kwJDpdB?usp=sharing
Looks like the problem is the proxy feature. If I turn it off, the export will be OK.
How the proxy feature can be a problem? Without it I can only get a lagging preview what makes almost impossible to edit.
This has come up before, but we do have a solution for it. Proxy does not always work with all sorts of media. In this case, the first stream is a data stream that ffmpeg is unable to retain when creating a proxy. This results in stream indexes (see audio_index and video_index in the XML) that mismatch between the proxy and source that creates this problem. Thus, the proxy has media index values starting from 0 whereas they are 1 in the source. A workaround is to convert the clip using Properties > Convert and then optionally make a proxy of that.
Converting the video is advised anyways because this file is variable frame rate, which is not safe for editing. As a result, edits may not be accurate between the source and proxy, and there is really no hope for fixing that.
2 Likes
I see. My last problem is the missing warning dialog about the variable framerate. Firs time I clicked on the option to never show again, but now I’d like to see it again because of your words.
If I uninstall the app and delete the ‘%LOCALAPPDATA%\Meltytech’ folder, the warning message still missing.
App data directory does not typically hold settings. This is in the FAQ and here:
https://shotcut.org/notes/configuration/
Also, FYI, the engine has on its road map to add a new relative stream index - Nth audio or Nth video - to address this.
Thanks for the answers. I’ve made a script with ffmpeg to convert all of my VFR source videos to CFR because I don’t want to handle VFR problem every time when I import a source file to Shotcut.
I’m looking forward to the relative stream index, If you know an ETA for that feature please let me know.