Seeking Issues

If you have an issue playing a video and not seeing it in the Compositor (just see a black screen), it is most likely due to the media not being designed to be editable. It is most likely not damaged. Generally it just does not have keyframes which are needed for seeking which is what is done when you move around the media and start playing in the middle. The media plays just fine in the compositor if you always play from the beginning because then you don’t need keyframes to seek. You can get around this problem if you proxy the media. A good choice to use for the proxy would be use scalar, ffmpeg/mp4 and size of ${\frac{{1}}{{2}}}$. The proxied media can then seek and you will see it play in the compositor because keyframes exist.

The CINELERRA-GG Community, 2021
https://www.cinelerra-gg.org