unsafe use of avio_r*() functions could cause demuxers into wrong state

[bbcallen]

Many demuxers are parsing frames by using
avio_r*() functions without checking EOF/error

Take libavformat/flvdec.c as an example:
(Line 903):

// 1. return 0 for EOF/Error
// 2. mark s->eof_reached to 1, so far, so good.
size = avio_rb32(s->pb); 

// 1. make a successful seek to the wrong place
// 2. reset s->eof_reached to 0
avio_seek(s->pb, fsize - 3 - size, SEEK_SET);

// continue to read at wrong place.
if (size == avio_rb24(s->pb) + 11) {
    ...

[Hendrik]

"Generic" error reports are unlikely to get any attention.

If you think there is an actual error in a demuxer, you should point out which demuxer and ideally a file with which it can be reproduced.

[bbcallen]

Thanks for your advise.

Actually, too many 'errors' in different demuxers to fix them once and for all. At least, flv and mov in my situation.

I'll submit a patch to ffmpeg-devel as a basis of discuss.

[Michael Niedermayer]

Iam closing this as its not a specific bug that a human could fix. Aka this is way to broad and generic. Please open separate tickets or submit patches, one per issue if there are issues remaining after your patches
Thanks