On Wed, 2008-02-06 at 01:35 +0100, Herman Robak wrote: > I read Heroine's documentation of the two here... > http://www.heroinewarrior.com/cinelerra/cinelerra.html#VIDEO-OUT > > ...and found that the Preload buffer hardly was relevant, but that > "Decode frames asynchronously" certainly was. > > "If you have lots of memory and more than one CPU, this option can improve > playback performance by decoding video on one CPU as fast as possible > while dedicating other CPU to displaying video only. It assumes all > playback operations are forward and no frames are dropped. Operations > involving reverse playback or frame dropping are negatively impacted." > > I was dismayed that I could only enable it if "play every frame" > was toggled, but it _certainly_ helped forward playback! Now there > were no pauses around edits anymore. (my laptop is a Core Duo) > > Backward playback, however, was slooow. I would love to have > some combination of frame-dropping and asynchronous playback, > as this would make HDV editing in Cinelerra truly usable on a > Core Duo. For single-track projects, I could do fine without > proxies, even on a laptop. Herman, I tested the code change tonight. Previous to making the change, I didn't have a problem or slow downs playing back HDV video, as my box is pretty powerful. I usually get 30FPS on video that isn't under a transition or effect of some kind. This performance was achieved with "Play Every Frame" and "Decode Frames Async" off. When I enabled "PEF & Decode frames asynchronously", my video playback slowed down terribly, to 6-8fps.
Then I made the code change and recompiled. I found no difference while "Play Every Frame" and "Decode frames asynchronously" were unchecked. However, I did see that playback improved when those two options were selected. Playback increased to about 20fps. Alas, when playback would hit an effect or transition, it would slow down quite a bit. For my taste, I will stick with "Play Every Frame" and "Decode.." switched off. But the code tweak did show forward playback improvement for me. And yes, backward playback was very slow. scott _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
