I try to optimize playback performance.
In the documentation I wasn't able to find answers for the offered settings on the screenshot.
Can you help me to understand what changes would make sense for me?
I have nvidia GPU acceleration and the CUDA packages, 64GB RAM and 28 CPU Threads (14 Cores).
You already have the Project SMP CPUs set to your 14 in the Performance tab, which is good so that when CinGG can use threads, it will be able to use multiple cpus. EDIT START here: actually if you really have 28 cpus, not 14, you should increase this number (execute lscpu and check CPU(s) number). STOP EDIT. However, sometimes it may be better to lower the number of threads to leave some for the system and for the plugins in use -- I have never tested this theory because in the next paragraph, the "framerate achieved" for me has always been at full framerate.
For Playback, if you check the Playback A tab and watch while playing your video, the Video Out, Framerate achieved number and compare that to your video's framerate, then you will know if you are playing as fast as possible.
Cache size is important also and you have yours set to 1024 which is usually a happy medium. You can optimize RAM utilization with Cache size and Seconds to preroll render parameters, Please read this manual section:
https://cinelerra-gg.org/download/CinelerraGG_Manual/Cache_size_Seconds_preroll_.html
And finally if you are not getting full "framerate achieved" on playback and are playing large format files such as 4K, you may want to switch the Playback A tab to the X11 video driver choice with "Use direct x11 render if possible" checked nstead of X11-OpenGL (I am assuming that that is what you are currently using which is almost always your best choice when you have a good graphics card with its software installed). X11 will playback faster than either X11-XV or X11-OpenGL in some cases. I also have not been able to verify this on my laptop because it already keeps up.
EDIT START here: https://cinelerra-gg.org/download/CinelerraGG_Manual/Performance_section.html describes the basics of all of the Performance tab items. But I think that the section on Performance Tips is more explanatory: https://cinelerra-gg.org/download/CinelerraGG_Manual/Performance_other_Tips.html to include tips for smaller computers. EDIT STOP.
Thank you very much for your detailed post.
It looks I already have done all possible performance settings.
It's a very good idea to check the achieved framerate during playback. I'm going to do that. This is like a benchmark.
