On Sat, Dec 19, 2015 at 09:19:27PM +0100, Andreas Cadhalpun wrote: > On 19.12.2015 21:12, Michael Niedermayer wrote: > > On Sat, Dec 19, 2015 at 06:13:37PM +0100, Andreas Cadhalpun wrote: > >> If it is negative, it triggers the assertion in > >> dct_unquantize_h263_intra. > >> > >> This is somehow related to the second hunk of commit 9251942: reverting > >> that prevents these crashes, but breaks the sample from ticket 302. > >> > >> Signed-off-by: Andreas Cadhalpun <andreas.cadhal...@googlemail.com> > >> --- > >> > >> Note that the sample from ticket 302 is currently broken anyway, printing > >> lots of "slice end not reached but screenspace end" errors. > >> This still works fine with ffmpeg 2.8. > >> > >> --- > >> libavcodec/mpegvideo.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c > >> index 6d9e265..e8e54ff 100644 > >> --- a/libavcodec/mpegvideo.c > >> +++ b/libavcodec/mpegvideo.c > >> @@ -2402,6 +2402,10 @@ unhandled: > >> static inline void put_dct(MpegEncContext *s, > >> int16_t *block, int i, uint8_t *dest, int > >> line_size, int qscale) > >> { > >> + if (s->block_last_index[i] < 0) { > >> + av_log(s->avctx, AV_LOG_WARNING, "Invalid block_last_index in > >> put_dct.\n"); > >> + return; > >> + } > > > > how does block_last_index become negative for this ? > > It's set to -1 in mpeg4_decode_block. > > > this fix doesnt look correct put_dct() is too late to check for any > > bitstream errors > > Better ideas are very much welcome. :)
> I can also send you a sample showing this problem. please do [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The greatest way to live with honor in this world is to be what we pretend to be. -- Socrates
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