[FFmpeg-devel] [PATCH] HLS problem

[Martin Storsjö]

On Wed, 12 Jan 2011, aviad rozenhek wrote:

> On Wed, Dec 15, 2010 at 21:38, Reimar D?ffinger <Reimar.Doeffinger at gmx.de>wrote:
> 
> > Index: libavformat/aviobuf.c
> > ===================================================================
> > --- libavformat/aviobuf.c       (revision 25928)
> > +++ libavformat/aviobuf.c       (working copy)
> > @@ -603,7 +603,7 @@
> >
> >     if (init_put_byte(*s, buffer, buffer_size,
> >                       (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
> > -                      url_read, url_write, url_seek) < 0) {
> > +                      url_read_complete, url_write, url_seek) < 0) {
> >         av_free(buffer);
> >         av_freep(s);
> >         return AVERROR(EIO);
> >
> >
> > Needs someone to review and/or test it properly.
> >
> >
> I'm pledging a 100$ for a fix to this issue.
> any takers?

Which was the exact issue that you wanted fixed? These error messages, 
right?

[aac @ 030aeeb0] channel element 3.15 is not allocated
[aac @ 030aeeb0] Input buffer exhausted before END element found

Despite these, it does seem to play back quite fine for me, but I do hear 
a small audio glitch at the segment boundaries.

Did you test the patch above, which Reimar suggested, did it make any 
difference to you? Since to me, it doesn't affect the playback of the 
sample stream you sent at all.

I did take a closer look on the stream, and it seems that the issue is 
that the mpegts stream is cut into segments in arbitrary positions. Our 
applehttp demuxer demuxes each file individually, and due to that, it will 
return incomplete packets at the end of each segment (leading to these 
errors), if the segment files are cut in this way.

Initially, I tried to implement Apple HTTP live streaming as an 
urlprotocol, which returns a concatenated stream of all the segment files 
in the playlist. Ronald preferred doing it as a demuxer, which does have a 
few other advantages, but this is one of the disadvantages.

I still kept the original approach in a branch, which I rebased onto the 
latest master. You can test the attached patch and see if it works better 
for you in that way. When using that approach, preprend applehttp:// to 
the normal http:// url to the m3u8 file, so you'd get e.g. 
applehttp://http://71.170.161.23:8080/downloads/ch5/03.m3u8. (For some 
reason, this seems to be able to avoid buffer underruns better than the 
current demuxer approach.)

// Martin
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