From d5c396a902069109f2bfb52891f323be75133ca2 Mon Sep 17 00:00:00 2001 From: Jingning Han Date: Thu, 11 Dec 2014 11:04:49 -0800 Subject: [PATCH] Replace division with bit shift in choose_partitioning This commit explicitly uses the bit shift operation instead of division for computing block variance. Change-Id: Id19c0ff27dd1d1ae4aceee6657e1aad0d406bd74 --- vp9/encoder/vp9_encodeframe.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c index d63062d9a..7d8d8bdb1 100644 --- a/vp9/encoder/vp9_encodeframe.c +++ b/vp9/encoder/vp9_encodeframe.c @@ -278,7 +278,7 @@ static void set_block_size(VP9_COMP * const cpi, typedef struct { int64_t sum_square_error; int64_t sum_error; - int count; + int log2_count; int variance; } var; @@ -374,21 +374,18 @@ static void tree_to_node(void *data, BLOCK_SIZE bsize, variance_node *node) { static void fill_variance(int64_t s2, int64_t s, int c, var *v) { v->sum_square_error = s2; v->sum_error = s; - v->count = c; + v->log2_count = c; } static void get_variance(var *v) { - if (v->count > 0) - v->variance = (int)(256 * - (v->sum_square_error - v->sum_error * v->sum_error / - v->count) / v->count); - else - v->variance = 0; + v->variance = (int)(256 * (v->sum_square_error - + ((v->sum_error * v->sum_error) >> v->log2_count)) >> v->log2_count); } void sum_2_variances(const var *a, const var *b, var *r) { + assert(a->log2_count == b->log2_count); fill_variance(a->sum_square_error + b->sum_square_error, - a->sum_error + b->sum_error, a->count + b->count, r); + a->sum_error + b->sum_error, a->log2_count + 1, r); } static void fill_variance_tree(void *data, BLOCK_SIZE bsize) { @@ -585,7 +582,7 @@ static void choose_partitioning(VP9_COMP *cpi, // If variance is based on 8x8 downsampling, we stop here and have // one sample for 8x8 block (so use 1 for count in fill_variance), // which of course means variance = 0 for 8x8 block. - fill_variance(sse, sum, 1, &vst->split[k].part_variances.none); + fill_variance(sse, sum, 0, &vst->split[k].part_variances.none); } else { // For key frame, go down to 4x4. v8x8 *vst2 = &vst->split[k]; @@ -603,7 +600,7 @@ static void choose_partitioning(VP9_COMP *cpi, // If variance is based on 4x4 downsampling, we stop here and have // one sample for 4x4 block (so use 1 for count in fill_variance), // which of course means variance = 0 for 4x4 block. - fill_variance(sse, sum, 1, &vst2->split[m].part_variances.none); + fill_variance(sse, sum, 0, &vst2->split[m].part_variances.none); } } } -- 2.40.0