[aklug] Re: FriLinux

On Mon, Nov 22, 2010 at 2:09 PM, Jim Gribbin <jimgribbin@gmail.com> wrote:
> I've noticed there is a difference between recording a video stream and j=
ust streaming it. If I just use Cheese to watch the output of my camera, I =
seem to be able to set it at anything I want. I have also done Skype Video =
on Linux using a P3x1GHz. Both seemed to work OK.
>
> I did attempt recording using VLC, but didn't get anywhere. I am thinking=
 now that my issues may have been available power more than failing to figu=
re out the appropriate command line. I may attempt it again now that I have=
 access to a faster processor.

You'd definitely want a P4 at least for most modern sizes, and forget
about realtime h.264 unless you have at least a Core Duo. When I first
started encoding, ahem, MPEG4 video on a PII or PIII, it used to take
about 10x realtime!

VLC can transcode and save to quite a few formats. I haven't tried it
on linux, but it may be instructive to use the streaming/encoding
wizard (on Windows? or maybe on both?) to see what command-line
options it spits out. I've used that as a starting point before with
good results.

> My Blue Eyeball is advertised as being capable of up to 1600 x 1200 x 30f=
ps, but I don't have an interface that will keep up.

By interface, you mean disk interface?

Uncompressed HD has high bandwidth requirements to disk. It's possible
to play video from camera to screen much faster than most people can
save it. I don't have a fast array for that, but I do have the cores
to transcode using one or the other of the various wavelet encodings,
saving enough disk bandwidth to be able to save 'practically lossless'
video at HD resolutions. Hence encoding in realtime to MPEG4 with VLC,
although that will be much lower quality.

jermudgeon
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Received on Mon Nov 22 14:19:47 2010