[FFmpeg-devel] [PATCH 3/5] lavf: replace FFERROR_REDO with AVERROR(EAGAIN)

[Nicolas George]

Anton Khirnov (12022-11-09):
> > Well, it has actionable consequences: if you treat EAGAIN like REDO you
> > introduce a busy wait,
> In most devices it's a sleep rather than a busy wait. And in those where
> it isn't, it should be.

I do not know how your sentence connects to mine.

> Furthermore, since the caller has no way of knowing how long to wait,
> there is little they can do other than sleeping for a random period and
> hoping for the best.

This is why I have wanted to fix the design of demuxers and demuxer-like
components for years, but it is a tremendous work. In the meantime, we
just do with "av_usleep(1000)" and it is terrible.

> I highly doubt that returning control back to the caller will cause any
> slowdown in and of itself, it's more about what the caller will do in
> response. If they choose to sleep for a random amount of time, then
> maybe they should stop doing that (which is exactly what this patchset
> does).

Sleeping is the only correct reaction to EAGAIN.

-- 
  Nicolas George