Max,

I have another observation, from your original email in this thread:

> One little detail: this does not happen if I'm using Flash 8 Encoder
> to produce flv file, but only if I'm using Sorensen Squeeze 4.5 (VP6
> 2-pass VBR 256Kbit).

A two-pass variable bit rate encoding of a FLV file, by the intended
nature of the process, is to produce the smallest, most efficient
(bandwidth-wise) file possible.

This is great if you're concerned about keeping the bandwidth requirements
low, but not so effective if what you really want is for people to be able
to seek around and playback a file from lots of different timecode
positions.

This means that in portions of the video where there is less action - the
movement or color of pixels from one frame to the next remains static -
don't need (or get) a keyframe as often.  Since a keyframe is sort of like
a still image snapshot, it takes up more data.  Whereas being able to
stretch out the duration between keyframes, relying on "delta" frames to
hold the portions that are changing and borrow the pixels from the
previous frame that didn't change, means you get a lower overall file
size.  What you lose is the ability to seek around smoothly, since there
are fewer keyframes for the playhead to "get close to" in the video.


Nathan


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