It looks like the value in s->error also comes from an earlier call to avio_read(). ogg_read_page tries to read 4439 bytes from the file. It has 524 bytes already buffered. fill_buffer() fails with an EIO, but because of the buffered bytes, avio_read() returns 524 and leaves the EIO in s->error.
/Fredrik "Hubbe" Hubinette On Mon, Mar 20, 2017 at 1:53 PM, Fredrik Hubinette <hu...@google.com> wrote: > > On Mon, Mar 20, 2017 at 1:35 PM, Michael Niedermayer < > mich...@niedermayer.cc> wrote: > >> On Mon, Mar 20, 2017 at 10:21:08AM -0700, Fredrik Hubinette wrote: >> > In some cases (when parsing OGG) non-fatal errors can happen, which >> > will cause s->error to be set. In most cases, this is not a problem >> beucase >> > s->error is not checked unless an actual error has occurred. However, >> > when avio_read() fails to read more bytes, it checks s->error to decide >> if >> > it just reached the end of the file, or an error occurred. Since >> s->error is >> > not modified if no error occurred, this is not reliable unless we first >> > clear >> > s->error before reading. >> > >> > --- >> > libavformat/aviobuf.c | 2 ++ >> > >> > 2 files changed, 7 insertions(+) >> >> how can the issue you describe be reproduced >> >> > I don't currently have a simple repro. I discovered it while trying to add > some buffering > between the demuxer and decoder in chrome. One of our tests fails, and when > looked into it, I discovered that s->error was already 5 (EIO) when > entering > avio_read. I have not yet tracked down where the EIO came from originally. > > also thats not a valid git patc >> > > Ops, I had a chrome patch and I removed the chrome-specific parts, but > I must have messed it up. I will make a better patch. > > >> [...] >> -- >> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB >> >> Those who are best at talking, realize last or never when they are wrong. >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
