[FFmpeg-devel] [PATCH] Yield on AVERROR(EAGAIN).

[Ramiro Polla]

On Fri, Mar 5, 2010 at 10:13 AM, Nicolas George
<nicolas.george at normalesup.org> wrote:
> Le quartidi 14 vent?se, an CCXVIII, Ramiro Polla a ?crit?:
>> ? ? ? ? ?ret = av_read_frame_internal(ic, &pkt1);
>> - ? ? ? ?if(ret == AVERROR(EAGAIN))
>> + ? ? ? ?if(ret == AVERROR(EAGAIN)) {
>> + ? ? ? ? ? ?ff_yield();
>> ? ? ? ? ? ? ?continue;
>> + ? ? ? ?}
>
> What gain do you expect from that code, be it the current or modified
> version?

CPU usage.

> Reading from a source in a non-blocking way makes sense if we do something
> else, something useful, when there is no data available. If we just run
> around waiting for more data, that is useless, whether it eats CPU or not:

> just put the source in blocking mode and be done with it.

If we could toggle nonblock after the device has been init'ed, yes
that would be better.