[MEncoder-users] Flashvideo for YouTube using mencoder

Ben jultus at gmail.com
Tue Feb 26 00:29:22 CET 2008


On Fri, Feb 22, 2008 at 3:03 PM, Rich Felker <dalias at aerifal.cx> wrote:
> On Fri, Feb 22, 2008 at 08:10:27AM +0100, Ben wrote:
>  > Hmm.. isn't the keyframe the one frame saved in maximum quality?
>
>  No, it's one frame saved independently of previous frames to
>  facilitate seeking. If keyint is too large it reduces the number of
>  possible seek destinations but always improves quality.

>From the MPEG specs on intra and inter frame compression
(see if you can at least understand what this is saying, you
seem to have completely misunderstood wikipedia's explanation):

"What is the best compression ratio for MPEG ?

The MPEG sweet spot is about 1.2 bits/pel Intra and .35 bits/pel
inter. Experimentation has shown that intra frame coding with the
familiar DCT-Quantization-Entropy hybrid algorithm achieves optimal
performance at about an average of 1.2 bits/sample or about 6:1
compression ratio. Below this point, artifacts become noticeable."



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