[MEncoder-users] Flashvideo for YouTube using mencoder

[Ben]

On Mon, Feb 25, 2008 at 9:01 PM, Rich Felker <dalias at aerifal.cx> wrote:

>  > Still, a keyframe is the frame saved in high(er) quality, as I stated before.
>
>  This is simply false.

I think you have totally misunderstood video-encoding of Intra frames.
Try and understand this:
http://www.wipo.int/pctdb/en/wo.jsp?WO=1998%2F38800&IA=WO1998%2F38800&DISPLAY=DESC
It's not much different in compression for FLV1 Sorenson H263.
The keyframe will not be compressed harder or stronger, it
deliberately holds more
value to the codec and stream. The keyframe will be bigger in size
than any other
frame in the stream. Hence its quality will be higher. Which by the way is clear
to test too; Leave out your bitrate requirement, encode a video with keyint=1
and encode the same video with keyint=5000, you'll see which one is best.

>  No, because each keyframe uses as many bits as 10-100 nonkey frames
>  and thus to keep the bitrate the same you have to lower the quality globally.

Bitrate in a flashvideo stream isn't holding a constant value throughout.
So again, you're wrong there too.

>  Naturally. There is no confusion here except your own.

You mean yours. You probably confuse Intra with Inter frames, a
mistake often made in the video world.

JB