Frameserver -> Ripbot264

relaxvideo wrote on 11/26/2013, 2:46 AM

Hi

i really like the quality of this free utility.
Even at lower bitrate it produce much better mp4-s
(no shaprness change at gop, etc) than the internal encoder.
And it works with debugmode frameserver too!

The only issue: the rendered file will have a lower contrast with a little shifted hue as i see (especially at reds)

Why is that? How can i fix it?
I like to use this frameserver method, don't want to render big uncompressed avis, etc. I search a small utility to convert the colorspace what ripbot can right interpret.
(virtualdub filter? avisynth command?)

thanks!

Comments

Warper wrote on 11/26/2013, 6:03 AM

Why is that?
Your output does not conform to what ripbot expects.
1) AFAIK ripbot expects uncompressed RGB to be in sRGB (not studio RGB) gamma with computer RGB levels (0=black, 255=white). Your projects levels on timeline is probably in studio levels (if you do proper color correction for sony avc and similar rendering) or even simply is wrongly formatted levels-wise (typical situation for camera footage if you don't do color correction).
2) There is a probability Ripbot applies bt.601 color matrix conversion (RGB->YUV) while h264 streams are supposed to use bt.709 color matrix. It might be the cause of "shifted hue" you mentioned.
Proper avisynth scripts for input avoid this problem.

How can i fix it?
There is no single definitive answer as levels of material can change. You have to experiment a bit.
But if my assumptions are right, try this:
1) Set up Output FX in Vegas, apply Color Levels filter with Studio RGB to Computer RGB preset. It should fix "washed out" colors issue.
2) Set up avisynth script in RipBot. Use aviSource with pixel_type="RGB32" or RGB24, then add line:
ConvertToYV12(matrix="Rec709")

relaxvideo wrote on 11/26/2013, 10:01 AM

Great!
That avisynth script solved all of the problems

AviSource("frameserved.avi")
ConvertToYV12(matrix="PC.709")

No washed out blacks, no color shifting. Finally!

I recommend this to all who want to create quality x264 (mp4, mkv) files.

thanks!