Radium wrote:
> [email protected] wrote:
>
> > It could be linear PCM (wave format type 1),
> > it could be MPEG (wave format type 80).
>
> I am sorry. I didn't know that.

Indeed.

> Is there a linear PCM format for video?

Linear PCM is simply a format for representing signals. Those
signals could be audio, they could be video, they could be
telemetry data from a distant planet.

As such, there most certainly could be and indeed are linear
PCM video streams. Consider the data rate. Typical NTSC TV
images, 30 frames/second, 525 lines per frame of which 35
are blanked. Assume 400 lines horizontal resolution, that
means a data rate of 30*490*400 about 6 Mhz. Assume 12 bits
per pixel, that's a data rate of 9 Mhz.

Not a lot of storage can sustain that rate forever without a
hiccup and, who cars, because there's no need to. Unlike audio,
it's actually pretty easy to get gross nearly lossless compression
of video. FOr example, unlike audio, video comes packaged in
convenient frames, so its possible to compare one frame to the next
and send only what's different per frame. One can also do things
like run-length encoding of otherwise identical pixels and the like.

As a result, video is, to save bandwidth and stroage, very often
compressed. I'm not talking MPEG, I'm talking simple reduction
of highly redundant data.