James REGIS wrote:
Hi Michel Bardiaux Thanks for your Answer ...
Can you give me a sample of your code please ?
I strongly recommend you read the FAQ I mentionned, then have a look at
the source code of any serious capture application. Personnally, I base
my work on FFMPEG ( ffmpeg.sourceforge.net ) but there is also xawtv,
nvrec, and you say you use fbtv.
Do you think it is possible to make YUV420P with a RGB camera ??
You have to try the VIDIOCMCAPTURE ioctl. But even if it works, it does
not mean YUV (or RGB for that matter) is the 'native' pixel format.
You say this is a 'RGB' camera. What do you mean exactly? What brand and
model is it?
At 10:46 09/07/2003 +0200, vous avez écrit:
James REGIS wrote:
hi,I am make program to capture from v4l device, when I use 640x480,
it can't do 12.5 frame per second,this speed is common, with 320x240,
it also do 12.5 fps,it's too slow, why? I compare with the fbtv in
console mode, 640x480 it can do 12.5 fps, the same as mine, but with
resolution 320x240,it can do 24~25 fps, the source code of fbtv is
fairly complex and now I have no much time to read it. can anyone
give me a sugguest to improve the capture speed! I attache my code
for ref .thanks!
Many cards are slower as soon as you dont use the standard size
704x576 and/or the preferred pixel format (usually YUV420P) I have no
problems grabbing 25fps at this size and format *provided* the code
uses the multi-buffer, interleaved capture as described in the
"Programming-FAQ" that comes with the xawtv distro. *Then* I do the
scaling, cropping, etc by software.
--
Michel Bardiaux
Peaktime Belgium S.A. Bd. du Souverain, 191 B-1160 Bruxelles
Tel : +32 2 790.29.41
