From 8f279596cbb7a6a3016fdc00624bc33ba36641bf Mon Sep 17 00:00:00 2001 From: Yaowu Xu Date: Wed, 19 Jan 2011 16:21:01 -0800 Subject: [PATCH] change the threshold of DC check for encode breakout Previously, the DC check is to make sure there is no code-able DC shift for quantizer Q0, which has been verified rather conservative. This commit changes the criteria to have two components, DC and AC, to address the conservativeness. First, it checks if all AC energy is enough to contribute a single non-zero quantized AC coefficient. Second, for DC, the decision to skip further considers two possible scenarios: 1. There is no code-able 2nd order DC coefficient at all; 2 The residue is relatively flat, but the uniform DC change is very small, i.e. less than 1/2 gray level per pixel. Comparing to previous criteria, the new criteria is about 10% to 15% faster in encoding time with a very small quality loss. (threshold ~1000 and quality range 33db-45db) It should be noted that this commit enables "automatic" static threshold for encodebreakout if a non-zero small value is passed in to encoder. Change-Id: I0f77719a1ac2c2dfddbd950d84920df374515ce3 --- vp8/encoder/rdopt.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/vp8/encoder/rdopt.c b/vp8/encoder/rdopt.c index 36420aa..fcff747 100644 --- a/vp8/encoder/rdopt.c +++ b/vp8/encoder/rdopt.c @@ -2267,22 +2267,28 @@ int vp8_rd_pick_inter_mode(VP8_COMP *cpi, MACROBLOCK *x, int recon_yoffset, int else if (x->encode_breakout) { int sum, sse; + int threshold = (xd->block[0].dequant[1] + * xd->block[0].dequant[1] >>4); + + if(threshold < x->encode_breakout) + threshold = x->encode_breakout; VARIANCE_INVOKE(&cpi->rtcd.variance, get16x16var) (x->src.y_buffer, x->src.y_stride, x->e_mbd.predictor, 16, (unsigned int *)(&sse), &sum); - if (sse < x->encode_breakout) + if (sse < threshold) { // Check u and v to make sure skip is ok int sse2 = 0; - - // add dc check - if (abs(sum) < (cpi->common.Y2dequant[0][0] << 2)) + /* If theres is no codeable 2nd order dc + or a very small uniform pixel change change */ + if (abs(sum) < (xd->block[24].dequant[0]<<2)|| + ((sum * sum>>8) > sse && abs(sum) <128)) { sse2 = VP8_UVSSE(x, IF_RTCD(&cpi->rtcd.variance)); - if (sse2 * 2 < x->encode_breakout) + if (sse2 * 2 < threshold) { x->skip = 1; distortion2 = sse + sse2; @@ -2428,6 +2434,7 @@ int vp8_rd_pick_inter_mode(VP8_COMP *cpi, MACROBLOCK *x, int recon_yoffset, int if (x->skip) break; + } // Reduce the activation RD thresholds for the best choice mode -- 2.7.4