ffmpeg | branch: master | Michael Niedermayer <mich...@niedermayer.cc> | Sun Oct 22 21:20:25 2023 +0200| [356b1ba765623ec1640a366e587232f1631800f8] | committer: Michael Niedermayer
avcodec/vlc: Skip subtable entries in multi VLC These entries do not correspond to VLC symbols that can be used they do corrupt various variables like min/max bits This also no longer assumes that there is a single non subtable entry Probably fixes some infinite loops too Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=356b1ba765623ec1640a366e587232f1631800f8 --- libavcodec/vlc.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/libavcodec/vlc.c b/libavcodec/vlc.c index aa84ca6b3c..f1c638e304 100644 --- a/libavcodec/vlc.c +++ b/libavcodec/vlc.c @@ -469,15 +469,23 @@ static int vlc_multi_gen(VLC_MULTI_ELEM *table, const VLC *single, int minbits, maxbits, max = nb_codes-1; unsigned count[VLC_MULTI_MAX_SYMBOLS-1] = { 0, }; VLC_MULTI_ELEM info = { { 0, }, 0, 0, }; + int count0 = 0; - minbits = buf[0].bits; - maxbits = buf[0].bits; + for (int j = 0; j < 1<<numbits; j++) { + if (single->table[j].len > 0) { + count0 ++; + j += (1 << (numbits - single->table[j].len)) - 1; + } + } + + minbits = 32; + maxbits = 0; - for (int n = 1; n < nb_codes; n++) { + for (int n = nb_codes - count0; n < nb_codes; n++) { minbits = FFMIN(minbits, buf[n].bits); maxbits = FFMAX(maxbits, buf[n].bits); } - maxbits = FFMIN(maxbits, numbits); + av_assert0(maxbits <= numbits); while (max >= nb_codes/2) { if (buf[max].bits+minbits > maxbits) _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
