Module: libav Branch: master Commit: 9699b3a2d7ebc62ae58c4e70997190f5f7b45d27
Author: Alberto Delmás <[email protected]> Committer: Kostya Shishkov <[email protected]> Date: Mon Sep 3 17:32:01 2012 +0200 mss12: avoid unnecessary division in arith*_get_bit() That division can be replaced with a comparison: ((c->value - c->low) << 1) + 1 >= range By expanding 'range' definition and simplifying this inequation we obtain the final expression. Suggested by Michael Niedermayer <[email protected]> Signed-off-by: Kostya Shishkov <[email protected]> --- libavcodec/mss12.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/libavcodec/mss12.h b/libavcodec/mss12.h index 678a0c0..f5d0366 100644 --- a/libavcodec/mss12.h +++ b/libavcodec/mss12.h @@ -103,7 +103,7 @@ av_cold int ff_mss12_decode_end(MSS12Context *ctx); static int arith ## VERSION ## _get_bit(ArithCoder *c) \ { \ int range = c->high - c->low + 1; \ - int bit = (((c->value - c->low) << 1) + 1) / range; \ + int bit = 2 * c->value - c->low >= c->high; \ \ if (bit) \ c->low += range >> 1; \ _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
