Optimize build for video editing?

I would like to build a Gentoo optimized for kdenlive video editing. Are there any suggestions:

kernel: preempt low-latency?

cgroup?

software build options?

suggestions/ideas?

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I help deploy Linux in schools and have found that Ubuntu Studio is a bit choppy for kdenlive video playback on AMD Sempron. The video/audio is currently choppy and from what I read on the Forums is that it may be related to MLT. However I'm willing to try to do an optimized build specifically for kdenlive video editing. I like kdenlive interface and would like it be a viable option for students/teachers.

We currently can only offer Kino because the editor imports/converts the videos before editing.

We found that an optimized build did not help in regards to choppy video playback and slow rendering. The solution was to move to a faster CPU: AMD Athlon(tm) II X2 250 Processor.

I was trying to edit 1080p AVCHD footage on an i5-750, it was very slow and choppy. I thought I needed a better faster OS, software or computer. Then I read a guy complaining that AVCHD is annoyingly slow on his dual 6-core Xeon!

Well, the standard thing to do is transcode AVCHD (or any vid that uses complex codec) to a high quality or lossless codec, Matroska or DNxHD. While the files are bigger, seeking, editing and rendering is much faster. The vids will play back without choppiness. You just need more storage, I bought me a 2nd 1 Tb hard drive last week.

Just right click the video(s) you want to transcode in kdenlive and choose Transcode, there's also a tick box option to add them to Kdenlive after transcoding.

Thanks for sharing this easy tips!!

On AVCHD, FFmpeg is slow at seeking _accurately_ and _cleanly_, which is needed for video editing. No amount of hardware you throw at it will help (except perhaps SSD, which I do not have to test). Hmm, I wonder if a fast remux from .mts to .mov would be another option (to DNxHD and proxy clips). Testing that out... yeah, it does help considerably!

ffmpeg -i in.mts -vcodec copy -acodec copy out.mov

You can put that into a Kdenlive Transcode preset.

Since I was having the same problem with 1080i AVCHD files, I tried this and it works much better. Transcoding the audio stream to FLAC/WAV seems to help a bit too.

One question remains: when my system (i7-2600) is tediously slow handling the original AVCHD files, there is virtually no CPU-load or excessive hard-disk action. This could mean there's a serious bug in ffmpeg, or all processing is being done in GPU?

Just curious...

(I'm using Ubuntu 11.04 32 bits and the Sunab ppa)