[FFmpeg-devel] [PATCH 3/3] lavd/openal: return EAGAIN if no samples are available

[Marton Balint]

On Fri, 30 Sep 2016, Nicolas George wrote:

> Le nonidi 9 vendémiaire, an CCXXV, Marton Balint a écrit :
>> Alsa dev and v4l2 seem to work this way regardless if non blocking mode is
>> set or not,
>
> After a quick glance, no, they do not, at least provided the kernel and
> system libraries keep the same promise (which, AFAIK, they do).
>

Hmm, apparently I missed the flag, you are right, sorry.

>> 	      and ffmpeg.c also waits if it encounters AVERROR(EAGAIN) in
>> av_read_frame.
>
> It should not have to, but for a long time the demuxers were opened in
> non-blocking mode, I suppose the code was not updated when it was changed.
>
>> 		 So AVERROR(EAGAIN) return value seems to be consistent with
>> existing code, which assumes that if EAGAIN is returned from av_read_frame,
>> wait a bit.
>>
>> If what you wrote is the way to move forward, then at least send a
>> documentation patch, to establish this av_read_frame return value behaviour.
>
> I will consider doing that when time permit. But the behaviour is directly
> copied from the Unix behaviour.
>

Thanks, I will rework the patch to work as the other devices.

Regards,
Marton