Archive for November, 2008

RV: a small update

Sunday, November 23rd, 2008

Hereby I declare that my RV40 decoder changed its status from “Well, it’s better than nothing” to “Good enough”. While there are still problems with chroma and jitter in B-frames due to wrong motion vectors prediction, luma decoding is bitexact on I- and P-frames.
I hope to weed them out and have decoding enabled in FFmpeg before next year. Maybe RV30 too.

For those who ask specs on RealVideo:


I hope the message is clear enough.

RV3/4 decoders present state: stalled again

Tuesday, November 4th, 2008

I’ve been very busy with the things outside FFmpeg yet I’ve managed to do something on RV3/4 decoders too:

  • Found and fixed an old bug with quantisation for DC coefficients.
  • Cleaned a bit RV4 loop filter.
  • Fixed chroma MC bug in RV3 decoder.
  • B-frames motion vectors are now closer to the reality in RV3.

What is missing:

  • RV3 loop filter
  • correct RV3 motion vectors calculation
  • RV4 motion compensation incompatibilities

The main problem is that I don’t quite understand why it’s working in the way it works and (in some parts) how it works. Hopefully it will be clearer next time I’ll look at it.