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FastMBAnalyze() for quick i16/i4 decision

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The decision is based on the variance between DC values of each
sub-4x4 block. This heuristic is rather ok for predicting whether
the 2nd transform (intra-16) is going to help or not.
The decision threshold varies with quality (=quantization).

It's only used for -m 0 and -m 1, where no full RD-opt is performed.
It actually makes these modes quite faster, with RD curve much
closer to the -m 2 mode.

Change-Id: I15f972db97ba4082cbd1dfd16bee3eb2eca701a8
This commit is contained in:
skal
2016-07-15 11:21:08 -07:00
parent 567e697776
commit 5b60db5c9d
5 changed files with 89 additions and 9 deletions
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5
src/dsp/dsp.h
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@ -185,6 +185,11 @@ typedef int (*VP8WMetric)(const uint8_t* pix, const uint8_t* ref,
// 4 by 4 symmetric matrix.
extern VP8WMetric VP8TDisto4x4, VP8TDisto16x16;
// Compute the average (DC) of four 4x4 blocks.
// Each sub-4x4 block #i sum is stored in dc[i].
typedef void (*VP8MeanMetric)(const uint8_t* ref, uint32_t dc[4]);
extern VP8MeanMetric VP8Mean16x4;
typedef void (*VP8BlockCopy)(const uint8_t* src, uint8_t* dst);
extern VP8BlockCopy VP8Copy4x4;
extern VP8BlockCopy VP8Copy16x8;