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karl_lillevold · 18th February 2004, 07:14

bond: Yes, as I was trying out the latest XviD myself, I was curious how it managed to keep the quants so constant during the 2nd pass, leading to great quality in the high action parts. So I had to learn the simple and elegant curve compression technique. Now if the GPL had been compatible with the Helix open-source RPSL license, it might have been possible to have used the XviD RC with all its advanced options as an open-source plugin in Helix for anyone to tweak on, but alas, I had to implement it from scratch. The basic technique is not too complicated, but the advanced settings are a little troublesome to get right, and are left out for now. Using a common first pass analysis format is very useful that since the .pass file can then be read by already existing tools, for instance this Java tool:
http://atlas2.tgv.net/~media-video/f...pic.php?t=3594
(And this same tool can also plot graphs indicating motion, and frame type distribution. Very nice. EDIT: version 0.40 of this tool had a minor bug where it would not read the realvideo .pass file, but the developer fixed it right after I mentioned it to him. Try it out!)

CruNcher: Agreed, finally: inloop is now an option, it took some time to convince us. First after making the rate control work as well as XviD's I realized there was still something missing. Your low + high action videos continue to be challenging for accurate rate control. For instance, one of my test clips has a profile like this:

With the new rate control, there is no overspending or filling the MSL buffer, even for this high action towards the end clip.

18th February 2004, 07:14	#16 \| Link
karl_lillevold Moderator Join Date: Oct 2002 Location: Seattle Posts: 1,584	bond: Yes, as I was trying out the latest XviD myself, I was curious how it managed to keep the quants so constant during the 2nd pass, leading to great quality in the high action parts. So I had to learn the simple and elegant curve compression technique. Now if the GPL had been compatible with the Helix open-source RPSL license, it might have been possible to have used the XviD RC with all its advanced options as an open-source plugin in Helix for anyone to tweak on, but alas, I had to implement it from scratch. The basic technique is not too complicated, but the advanced settings are a little troublesome to get right, and are left out for now. Using a common first pass analysis format is very useful that since the .pass file can then be read by already existing tools, for instance this Java tool: http://atlas2.tgv.net/~media-video/f...pic.php?t=3594 (And this same tool can also plot graphs indicating motion, and frame type distribution. Very nice. EDIT: version 0.40 of this tool had a minor bug where it would not read the realvideo .pass file, but the developer fixed it right after I mentioned it to him. Try it out!) CruNcher: Agreed, finally: inloop is now an option, it took some time to convince us. First after making the rate control work as well as XviD's I realized there was still something missing. Your low + high action videos continue to be challenging for accurate rate control. For instance, one of my test clips has a profile like this: With the new rate control, there is no overspending or filling the MSL buffer, even for this high action towards the end clip. __________________ This information is provided "AS IS" with no warranties, grants no rights, and reflects my personal opinion. Last edited by karl_lillevold; 22nd February 2004 at 05:46.