[FFmpeg-devel] [PATCH] handle EAGAIN case in ffmpeg.c
Wed Sep 12 13:07:29 CEST 2007
Luca Abeni wrote:
> Hi Benoit,
> Benoit Fouet wrote:
>>>> what i'm trying to do is having v4l2 working
>>> Unless something broke in the last two or three weeks, v4l2 should be
>>> already working... What's the problem you are seeing?
>> shouldn't the DQBUF return EAGAIN when it has no frame available ?
> According to my understanding of the v4l2 specification, EAGAIN is only
> returned if the video device has been opened using the O_NONBLOCK flag.
>>> The way is currently works is that the v4l2 input format blocks until
>>> there is an available frame (unless you specify the
>>> AVFMT_FLAG_NONBLOCK... In that case you have to modify ffmpeg.c)
>> i thought the DQBUF was always a non blocking ioctl, isn't it the case ?
> According to
> (which should be the authoritative reference, I think)
> "By default VIDIOC_DQBUF blocks when no buffer is in the outgoing queue.
> When the O_NONBLOCK flag was given to the open() function, VIDIOC_DQBUF
> returns immediately with an EAGAIN error code when no buffer is available."
> So, the current code should be ok... As I said, it worked fine last time
> I tested it :)
ok, i'll check the driver then :)
> What's the behaviour you see when you try to capture video with ffmpeg?
> Which capture card (and drivers) are you using?
not standard ones but ours, so i'll check them ;)
Purple Labs S.A.
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