[Ffmpeg-devel] video4linux2 input format?

Luca Abeni lucabe72
Thu Jan 26 12:56:00 CET 2006

Hi Erik,

On Thu, 2006-01-26 at 12:27 +0100, Erik Slagter wrote:
> Please have a look at the the file import/v4l/import_v4l2.c from
> transcode (version > 0.6.14), which [ahem] I wrote and has some
> workarounds for these ehrm... "extra features". The source is not very
> much dependent on any other parts of the transcode source, so it
> shouldn't be too hard to follow.
Thanks; I'll have a look at it today, to check if I got the v4l2 abi

> Please note: the current implementation uses memory mapped i/o, which
> means memory is allocated by the kernel and passed to the user process.
Yes, this is what I am doing too: first, I want to have mmap working,
then I'll implement read-based grabbing (for very old card or broken
drivers?), and then I'll try the pointer-based I/O. The problem with it
is that the demo program included in the v4l2 specifications just
crashed my computer (debian unstable, 2.6.8 kernel, and a Bt878-based
card)... So, I assume the specifications are not very reliable regarding
pointer-based I/O ;-)

Anyway, I'll look at it after the mmap-based implementation is ok.

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