Manually feeding x264 with my own motion data?

Question

I am trying to encode a stream using x264 (by feeding individual images), but what's unusual is that I already have some motion information for my frames. I know exactly which areas have been modified in each frame, and I know where motion has occurred in the frame.

Is there a way to feed x264 my own motion information? I'd like to give it motion vectors for given areas in the frame, and somehow tell it that certain areas in the frame are guaranteed to not have had any motion in them.

I think this might significantly improve the performance of the encoding (because I'm allowing the codec to completely skip the motion estimation phase), and should also somewhat increase quality in cases where the encoder's motion estimation algos might have missed the motion that actually occurred.

Do I need to modify the encoder in order to do this, or is this supported in the existing API?

Answer 1

Short answer: No you can't feed in your motion estimation data to x264.

Long Answer: IIRC, x264 does it's work by being fed in the raw frame, with no extra data. To accommodate the motion estimation data you have, you'd have to modify the x264 source code to accomplish this.

You may be able to find what you need within common\mvpred.c or encoder\me.c. I'm not sure how many of the x264 developers actually visit Stack overflow (I know one of their lead developers has an account here) but you can try talking to them through their usual channels on their IRC channel or on the doom9 forums.

• doom9: http://forum.doom9.org/forumdisplay.php?f=77
• doom10:http://doom10.org/index.php?board=5.0 IRC:
• irc://irc.freenode.net/x264 and irc://irc.freenode.net/x264dev
• Mailing list: http://mailman.videolan.org/listinfo/x264-devel

I wish I could give you more information, but unfortunately I'm not particularly well versed in the code base. The developers are always willing and able to help anyone wishing to work on x264 though.