On Mon, Aug 14, 2023 at 1:14 AM Tomas Härdin <g...@haerdin.se> wrote: > > lör 2023-08-12 klockan 13:31 -0700 skrev p...@sandflow.com: > > From: Pierre-Anthony Lemieux <p...@palemieux.com> > > > > Intended to replace > > https://patchwork.ffmpeg.org/project/ffmpeg/patch/20230802000135.26482-3-mich...@niedermayer.cc/ > > with a more accurate block decoding magnitude bound. > > > > --- > > libavcodec/jpeg2000htdec.c | 34 +++++++++++++++++++++++++++++++++- > > 1 file changed, 33 insertions(+), 1 deletion(-) > > > > diff --git a/libavcodec/jpeg2000htdec.c b/libavcodec/jpeg2000htdec.c > > index 2c4cea5dd9..a7329206de 100644 > > --- a/libavcodec/jpeg2000htdec.c > > +++ b/libavcodec/jpeg2000htdec.c > > @@ -572,6 +572,14 @@ static int > > jpeg2000_decode_ht_cleanup_segment(const Jpeg2000DecoderContext *s, > > > > const uint8_t *vlc_buf = Dcup + Pcup; > > > > + /* > > + * Bound on the recision needed to process the codeblock. The > > number of > > precision > > > + * decoded bit planes is equal to at most cblk->zbp + 2 since > > S_blk = P if > > + * there are no placeholder passes or HT Sets and P = cblk->zbp. > > See Rec. > > + * ITU-T T.814, 7.6. > > + */ > > + int maxbp = cblk->zbp + 2; > > + > > /* convert to raster-scan */ > > const uint16_t is_border_x = width % 2; > > const uint16_t is_border_y = height % 2; > > @@ -590,6 +598,12 @@ static int > > jpeg2000_decode_ht_cleanup_segment(const Jpeg2000DecoderContext *s, > > goto free; > > } > > > > + /* do we have enough precision, assuming a 32-bit decoding path > > */ > > + if (maxbp >= 32) { > > + return AVERROR_INVALIDDATA; > > + goto free; > > + } > > Why not move this check to just after maxbp is declared? That way a > bunch of allocations are avoided
I had it that way but then the compiler complained about mixing declarations and code. > > The rest of the patch looks fine, though I haven't studied the HT spec > deeply. The +2 on maxbp is familiar. > > /Tomas > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".