[FFmpeg-devel] [PATCH] ffprobe: do not exit in case the demuxer returns AVERROR(EAGAIN)

[Stefano Sabatini]

On date Tuesday 2015-11-17 15:20:32 +0100, wm4 encoded:
> On Tue, 17 Nov 2015 15:13:02 +0100
> Stefano Sabatini <stefasab at gmail.com> wrote:
> 
> > Fix demuxing of files for which the demuxer returns AVERROR(EAGAIN) at
> > some point. Also returns error code to the caller in case of different
> > non EOF error.
> > ---
> >  ffprobe.c | 11 ++++++++++-
> >  1 file changed, 10 insertions(+), 1 deletion(-)
> > 
> > diff --git a/ffprobe.c b/ffprobe.c
> > index c304a6d..481ff0b 100644
> > --- a/ffprobe.c
> > +++ b/ffprobe.c
> > @@ -2027,7 +2027,16 @@ static int read_interval_packets(WriterContext *w, AVFormatContext *fmt_ctx,
> >          ret = AVERROR(ENOMEM);
> >          goto end;
> >      }
> > -    while (!av_read_frame(fmt_ctx, &pkt)) {
> > +    while (1) {
> > +        ret = av_read_frame(fmt_ctx, &pkt);
> > +        if (ret == AVERROR(EAGAIN))
> > +            continue;
> > +        if (ret < 0) {
> > +            if (ret == AVERROR_EOF)
> > +                ret = 0;
> > +            break;
> > +        }
> > +
> >          if (fmt_ctx->nb_streams > nb_streams) {
> >              REALLOCZ_ARRAY_STREAM(nb_streams_frames,  nb_streams, fmt_ctx->nb_streams);
> >              REALLOCZ_ARRAY_STREAM(nb_streams_packets, nb_streams, fmt_ctx->nb_streams);
> 

> Couldn't this get stuck forever if the API just keeps returning a
> demuxer error without making progress?

No, just in case ret == AVERROR(EAGAIN), in all other failure cases it
will exit the loop immediately.

BTW, the same problem affects some API usage examples.
-- 
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