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.
HaND, -- Michel Bardiaux Peaktime Belgium S.A. Bd. du Souverain, 191 B-1160 Bruxelles Tel : +32 2 790.29.41
