Gerd Knorr writes:
> > So there doesn't seem to be a big difference. Is there something a v4l
> > driver has to implement, so that xv scaling will work.
> > Both drivers deliver YUV422 and can write into video memory.
>
> Hmm, should have worked, the v4l module tries to use yuv422 for
> hardware-scaled overlay. Below is the piece of code which the
> v4l module uses to check whenever it can do hw scaling or not.
>
> Gerd
>
> --------------------------- cut here ------------------------
> /* test v4l device for yuv support: check if the driver
> accepts VIDEO_PALETTE_YUV422 */
> ioctl(fd,VIDIOCGPICT,&pPPriv->pict);
> pPPriv->pict.palette = VIDEO_PALETTE_YUV422;
> pPPriv->pict.depth = 16;
> if (0 == ioctl(fd,VIDIOCSPICT,&pPPriv->pict)) {
> ioctl(fd,VIDIOCGPICT,&pPPriv->pict);
> if (VIDEO_PALETTE_YUV422 == pPPriv->pict.palette) {
> /* works, check screen capabilities */
Ok, I see my mistake. The older revisions of the saa7146 cannot
byteswap their UYVY format to YUYV. For grabbing this is done in
software by the driver, but for dma into video memory that won't do.
But since the G200/400 can do UYVY it should be possible to patch the
v4l module to check for that format and do the scaling. So I will see
what can be done.
Marcus
