[PD] pix_video metro

[Mathieu Bouchard]

On Mon, 10 Jan 2005, sara kolster wrote:

> I'm trying to figure something out [again] with pix_video. How does
> the playback from pix_video work and can I influence the playback with
> a different metro? Right now, I've a webcam connected and the playback
> seems to be a little slow and a bit blurry; I just want to try what I
> can do to change speed of the playback, but cannot find anything in
> the helpfile of pix_video. I tried to connect a metro [40] to
> pix_video but that doesn't work.

Most camera/digitiser hardware has a maximum framerate, so for example
there is almost no hardware that allows you to drive it with better than
[metro 33.3667] (which is 1000 divided by the north-american TV
framerate). When using PAL (European TV), the best possible is instead
[metro 41.708].

Webcams often have much lower framerates. For example, I have USB cameras
that can't do better than [metro 100] or even [metro 285] (really!). In
some cases, the camera is advertised to be quick, but it uses a
compression scheme that is considered a trade secret, so that you often
cannot get the full speed unless you are using the manufacturer's driver,
and that requires using one of the manufacturer's preferred OS'es. (and
this is currently the topic of hot debates on some other mailing-lists,
especially the big one called "linux-kernel")

_____________________________________________________________________
Mathieu Bouchard -=- Montréal QC Canada -=- http://artengine.ca/matju