[FFmpeg-devel] Bugreport: PAFF crashes ffplay, more info than older report, appendix

Thorsten Jordan tjordan
Thu May 3 16:37:18 CEST 2007


a "possible fix" or hack is to mark pictures that would be BOTTOM_FIELDs
also as TOP_FIELDs, e.g. add a line after line 4662 in h264.c

s->picture_structure= PICT_TOP_FIELD + get_bits1(&s->gb);
s->picture_structure= PICT_TOP_FIELD; //TJ: hack to avoid bottom fields
(glibc/segfault later)
av_log(h->s.avctx, AV_LOG_ERROR, "PAFF interlacing is not implemented\n");

but i bet if i'd suggest this as patch, the ffmpeg developers would want
to rip my head off. It fixes the crash, but very hackish.

I fear that the problem goes deeper and is also there for other codecs
that have bottom fields. While testing during the last half of an hour
we had another "glibc: double free or corruption" bug, so there must be
more places where memory is overwritten.

I suggest to link efence or DUMA to ffplay and try running it in gdb to
find these bugs. Very work intensive though.

Regards, Thorsten

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