Just though I'd share. As Kdenlive is becoming an incredibly good editor and continues to get even better, it's just so useful that we'll all be spending a lot of time editing and making more and longer movies. So, a problem crops up: time wasted rendering is becoming a hassle, tying up your machine. It would be nice to have a render farm or some simple way to use a spare machine to do some rendering.

I'm on Ubuntu 9.04 64, Kdenlive 0.7.5. I often would rather keep editing and doing other stuff, and rendering can take many hours and run both cores to 100%. Moreover I like to render a 1080p version as well as a 720p and a 480p in h264 of most videos. This can take me 10-20 hrs or more to complete all three, especially with 2-pass high quality encoding.

I happen to have access to a pretty nice quad core machine, that often just sits there. Unfortunately it needs to run Windows (Vista 64) 24-7. Of course Kdenlive has no Windows version. I thought maybe setting up a virtual machine with Ubuntu on it - but that's a lot of hassle and disc space required and multi-core support is not real good on VM's right now.

I've hit on a decent solution though. Background: I am editing in 1080p30 from a Canon AVCHD camcorder, and first transcoding all footage to DNxHD. This makes editing pretty fast and stable in Kdenlive. If you have a lot of disc space, it's a pretty good near lossless codec. So, I thought, how about rendering a single finished 'master' video in 1080p into DNxHD. Then, transfer just that file over the LAN to the other computer and use a transcode program to make all my h264 final renders. Again, you need some disc space, as a 20 minute video in DNxHD runs about 35GB. But that's okay with me.

Of course, I still have to use my main Ubuntu machine to render the DNxHD file. But, as it turns out, rendering to DNxHD in Kdenlive is far faster than h264, like less than an hour rather than 6 hours or something.

Over on the Windows machine, I've used HandBrake to do the rendering. It's pretty flexible and open source and the h264 seems to play fine on Windows and Linux. Also, you can set up multiple renders in a queue, much like Kdenlive. On the Core2 quad core, rendering a 1080p video 20 minutes long to h264 takes about 2.5 hrs. Not that I really care, as that machine sits there idling much of the time.

Incidentally, this is also a good solution because right now a few of my files just won't render at all to h264 in Kdenlive, even with a very current SVN build of ffmpeg and x264. Hopefully that will be ironed out in the next few months.


As a further thought, it would be pretty slick if there were some in-built way for Kdenlive to use some other machine's processing power to render. Look at the way Blender handles distributed rendering, they have a solution that will work across a pretty massive 'farm' of machines, as I understand. Again, until we all have 64 core machines or something, this is going to be an increasing concern.

I don't know about distributed rendering, but as far as your H.264 not rendering with recent ffmpeg and x264, the recency is the problem. Go back to x264 0.65 and an ffmpeg that supports it (anything before yesterday) and it should work. I had the same issue. See this thread: http://www.kdenlive.org/forum/any-attempt-h264-fails-produce-video