Installed 2.93.4 using the prebuilt binary on CentOS 8.4 downloaded 9/23/2021. If the clip editor is opened and an MP4 video (from an Android phone) is loaded an image appears and a "reasonable" number of frames are indicated on the bar along the bottom. However, when it "plays" the image never changes. I tried changing some of the playback options but none had any effect. There are no errors or warnings related to this shown in dmesg or /var/log/messages. The computer is a Dell T110 II server with limited graphics. It will play this video without problem using "vlc" though, and it has 8Gb of memory, which should be more than enough for this short clip. I'm guessing that playback may be using some OpenGL feature which is not quite right for this hardware/software. OpenGL info shown by glxinfo is:
OpenGL vendor string: Mesa/X.org OpenGL renderer string: llvmpipe (LLVM 9.0.1, 256 bits) OpenGL core profile version string: 4.5 (Core Profile) Mesa 20.3.4 OpenGL core profile shading language version string: 4.50 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL version string: 3.1 Mesa 20.3.4 OpenGL shading language version string: 1.40 OpenGL context flags: (none) OpenGL extensions: OpenGL ES profile version string: OpenGL ES 3.2 Mesa 20.3.4 OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20 OpenGL ES profile extensions:
Note that if I click on the horizontal "frame bar" the pointers are updated, but the image is not. It seems to be stuck on the first frame, or at least as far as I can tell the image shown corresponds to the first frame that vlc shows. It might actually be a nearby frame.
If Playback -> Play In -> Movie Clip Editor
is toggled it makes no difference, checked or no, only the single frame shows.