The only way I found to get frame by frame audio scrubbing is to enable openGL video playback. Default playback does not play audio when doing frame by frame. I need this to do good cuts in audio speech.

Problem is: openGL uses almost three times processor power to playback videos in timeline. only one layer, no effects, no transitions, just a single clip, proxy enabled correctly. In the dual core machine without openGL the processor usage keeps around 36% - 42% With openGL enabled the processor usage keeps around 78% - 83% and it stutters a little bit. In the quad core, without opengl is around 14% - 18% processor usage, with opengl it is around 38% - 45% no sttuter due to more powerful processor.

No matter if I use the onboard graphics or the discrete pci-e GPU. I did try on both, I even removed and reinstaled the pci-e GPU to try the difference. The openGL is processor hungry with both, the onboard or the pci-e.

So I need to chose: real time dissolve and good performance in color correction or audio scrubbing. I cannot get both because audio scrubbing needs openGL which is processor hungry. this happens even with a low resolution proxy.

It would be good to make the audio frame by frame scrubbing to work properly without the openGL. This way audio frame by frame scrubbing editing and video transitions and color correction editing performance would be ok using less processor power.

Information: I am using AVLinux distro with Kdenlive 0.9.10 I did not install any graphics drivers, the distro itself makes the graphics to work ok on the dvi 1920x1080 monitor or in the vga 1600x900 monitor. The quad core is the 2500K and its onboard graphics always crashes, never works good, with nvidia gpu it is ok. The dual core is the E5400, the onboard graphics is ok on it, maybe because it is not inside the processor, but because it is in the north bridge G31 chipset.

Would a graphics driver installation makes the openGL to be less processor hungry??? or is there a way to correct this issue in kdenlive???

thanks.

Edit post: I did a few more tests with 320x180 proxy size and this does not improve the openGL realtime playback. Even with this low size proxy the E5400 2.7GHZ dual core keeps around a 87% maximum cpu usage and shows a slightly sttuter. It seems that the E5800 3.2GHZ would be the minimum to work with openGL video playback enabled for a 24p proxy and maybe not enough for a 30p proxy.. Better go for a quad core cpu for openGL video playback performance. Or find a solution in Kdenlive settings or video drivers...

Best solution for the moment is to enable openGL video playback to use audio scrubbing for speech editing, and after finish the cuts, disable openGL video playback to do the video color correction / effects / transitions.

Edit post again: I installed the nvidia proprietary graphics driver and the openGL playback keep using the same amount of processor power, the video driver does not lower the processor usage when openGL video playback is enabled. Also the video driver does not make the audio scrubbing to work without openGL playback. So no improvements. Better use a quad core or enable openGL playback for audio scrubbing and disable it for color correction / video effects preview when using a low end machine.

Interesting thing: even in the quad core machine, the openGL video playback enabled makes the dissolve between two clips sttuter. The processor usage is around 41% in the first clip, when dissolve starts the processor usage decreases and the preview sttuter. With openGL disabled it does not sttuter, the preview is realtime and the processor usage increases in the dissolve moment as expected to be, in first clip it is around 15% and in the dissolve moment it is around 41%. This test was done with the nvidia video driver instaled. It seems that the openGL video playback only works good if the software is optimized for it, including the timeline single clip code, the effects code, the transitions code.