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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2011-12-16 21:42:04 +0000 |
|---|---|---|
| committer | Mans Rullgard <mans@mansr.com> | 2011-12-17 14:03:41 +0000 |
| commit | 8cfbbd928cc94b4de6ad0a937cb818e999c7d75d (patch) | |
| tree | 554918ba1509d4c296738f7e4a7313685ee92c41 /libavformat/avc.h | |
| parent | a1e98f198e9db4e5ddfc2f777014179d3d7bc4d2 (diff) | |
| download | ffmpeg-8cfbbd928cc94b4de6ad0a937cb818e999c7d75d.tar.gz | |
get_bits: introduce safe bitreading to prevent overreads.
When turned on, H264/CAVLC gets ~15% (CVPCMNL1_SVA_C.264) slower for
ultra-high-bitrate files, or ~2.5% (CVFI1_SVA_C.264) for lower-bitrate
files. Other codecs are affected to a lesser extent because they are
less optimized; e.g., VC-1 slows down by less than 1% (all on x86).
The patch generated 3 extra instructions (cmp, cmovae and mov) per
call to get_bits().
The performance penalty on ARM is within the error margin for most
files, up to 4% in extreme cases such as CVPCMNL1_SVA_C.264.
Based on work (for GCI) by Aneesh Dogra <lionaneesh@gmail.com>, and
inspired by patch in Chromium by Chris Evans <cevans@chromium.org>.
Diffstat (limited to 'libavformat/avc.h')
0 files changed, 0 insertions, 0 deletions