[FFmpeg-devel] [RFC][PATCH] avformat/flvdec: avoid reseting eof_reached to 0 silently

[Michael Niedermayer]

On Sun, Apr 12, 2015 at 12:00:18PM +0800, Zhang Rui wrote:
> 2015-04-10 22:04 GMT+08:00 wm4 <nfxjfg at googlemail.com>:
> > On Fri, 10 Apr 2015 21:17:42 +0800
> > Zhang Rui <bbcallen at gmail.com> wrote:
> >>
> >> This kind of error handling need some more work in aviobuf.c,
> >> and more advises from ffmpeg developers.
> >> And i prefer this way than the patch I posted.
> >
> > stdio.h does it this way: FILE has an error flag that is set when
> > something goes wrong.
> 
> AVIOContext has an error field, too. But I don't think it's enough
> for EAGAIN situation without some convention.
> At least, ffplay doesn't show that.
> 
> >> > Also, why doesn't avio_skip() return an error if the skip count is not
> >> > 0 and the stream has reached EOF?
> >>
> >> The eof handling is quite confusing in ffplay for me. AVERROR_EOF is
> >> clear enough.
> >
> > Well, I have no idea what avio_skip() even returns... it just calls
> > avio_seek(), which is a goddamn fucked up mess thanks to years of
> > people adding hacks.
> 
> Is there any correct direction to fix it?
> 
> > ffplay probably does it wrong. Wouldn't be surprising. It checks
> > avio_feof() after a av_read_frame() call, which doesn't look correct.
> > File EOF has absolutely nothing to do with whether a demuxer still has
> > data.
> >
> > On a side note, I'm not sure whether av_read_frame() returning
> > AVERROR_EOF is an error at all, or just signals that the end of the
> > file was reached. The doxygen on this function isn't helpful either.
> 
> Is there any ideas, or any helpful keywords or threads in mail list archive?

a simple error_count field could be added that way one could easily
check if the count increased over any series of function call(s)

it also could be presented at verbose level by the user application,
showing how many io errors where encountered which where not fatal

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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