a8ab68bffe
The V4L1 spec says that the image size should be with with VIDIOCSWIN before requesting buffers with VIDIOCGMBUF and capturing into them with VIDIOCMCAPTURE. But it seems that many apps don't do this. They set the size using the fields in the VIDIOCMCAPTURE ioctl. The driver doesn't know what size to capture until it actually starts to capture. In particular, it doesn't know what size to capture until it has already mmap the captured buffers. Which is quite stupid. Why V4L1 has size and format fields for VIDIOCMCAPTURE I have no idea. Many drivers don't support this, including those using v4l1-compat. The bttv does, which is probably the only reason such broken software is so prevalent. But, the driver doesn't adjust its idea of what size is being captured when it is set this way. If you try to query the driver's current setting with v4l2-ctl, it won't be correct. Signed-off-by: Trent Piepho <xyzzy@speakeasy.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org> |
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| common | ||
| dvb | ||
| radio | ||
| video | ||
| Kconfig | ||
| Makefile | ||