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Old 29th August 2005, 16:15   #31  |  Link
akupenguin
x264 developer
 
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Join Date: Sep 2004
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Quote:
Originally Posted by DeathTheSheep
The bitrate variability feature controls how much your datarate can fluxuate at any given time. That is, if you plan on encoding at 500kbps and set this value to 40, the maximum amount of bitrate given to more complex scenes is 700kbps.
No. See some explanations I gave to Chen.

Quote:
Generally lower framerates (12-15 as opposed to 23.976-29.97) need a higher estimation range.
why that?
Because at lower framerates, objects have moved farther between consecutive frames. => need to search farther on average to find an object. OTOH, I can't think of any situation where I would reduce framerate below 24 without also reducing resolution, and low resolutions can use smaller search range. So it may cancel out.

Quote:
If a certain frame's reference is far off into the file, the entire file becomes unplayable until the video is downloaded up to that reference.
No, multiple references have no effect on seekability. (BTW, they also have no effect on AVI compatibility.) All reference frames would have to decoded anyway, because they're between the current frame and the previous keyframe. (B-pyramid does add a few extra dependencies, but again it's independent of the number of reference frames.)

Quote:
positive values of loop will tend to remove details -> smaller filesize
Not necessarily. If the codec encodes some details, and then loopfilter wipes them away, and then it has to code the details again in the next frame...
I'm not saying that the net effect is to increase size at a given QP (I don't know offhand; all of my loopfilter comparisons were 2pass, because it's the only fair way), just that you can't deduce the global effect from the definition of loopfilter.
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