Hello Luvcview uses SDL if I remember well since a few months when I looked into the sources. As I know there is no direct support or control in SDL over which rendering engine is used behind the scenes. With XVideo you normally get yuv formats and sometimes and for some video drivers/cards you also get RGB.
Mpeg2 is a compressed format that is decompressed most of the times into an accelerated YUV format. YUV formats can be directly sent to the video card using XVideo - if that's available. You should look in your case what part: mpeg2 decompression or display takes up the CPU time. Now on the other side if your card uses the vesa drivers to display to the screen XVideo extension is never available for that driver. UVC does provide 2D accelerated formats (it mostly provides only those and MJPEG) 1) Take a look into Xorg.0.log and check the video used driver. 2) Check the times spent by the mpeg decompression task. 3) xvinfo - should help you see if XVideo can be used at all and what formats are available. XVideo is just a way to pass let's say a video format encoded on (for example) 2 bytes/pixels YUV instead of 4 (RGBA) - to the video card. The video card then knows to display those video formats and knows how to scale them as well (eating only GPU processing time and not CPU). Usually this means passing just pointers to the video frame (as got from the video capture device) to the video card for display. Adrian _____ From: [email protected] [mailto:[email protected]] On Behalf Of Asho Yeh - ?? Sent: Wednesday, June 09, 2010 5:19 AM To: [email protected] Subject: [Linux-uvc-devel] XVideo support? Hi, I am new to the UVC project. Currently I am working on video conferencing on Linux and met some performance issues. I hope you experts can help me to solve these. My target board is VIA CLE266 which onboard an VIA C3 1Ghz CPU. 512MB DDR333 Dimm. Logitech C100 webcam. 480p mpeg2 video playback with mplayer and xvideo costs 20~30% of CPU powers. 50~70% of CPU powers with 720p mpeg2 video file. However, when I execute luvcvideo, the console shows Video driver: x11 A window manager is available I was wondering that luvcview lacks XVideo support or UVCVideo doesn't provide the video format that supports XVideo? Another problem is skype. In skype chat & video window, it ate 100% of CPU powers and A/V was out of sync. I didn't know which one is the bottleneck in skype. That's why I asked for help here. I am new to the video processing in Linux, so some problems are conceptual. Any information and wikis are welcome. Thanks for reading this mail. Best regards, Asho
_______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
