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| author | Vikas Arora <vikasa@google.com> | 2013-03-13 16:43:18 -0700 |
|---|---|---|
| committer | Vikas Arora <vikasa@google.com> | 2013-03-14 10:15:22 -0700 |
| commit | 1e7bf8805bd030c19924a5306837ecd72c295751 (patch) | |
| tree | 20a7189518b1824f7805016e9718e26e9c3a6668 /src/dsp/lossless.h | |
| parent | b6dbce6bfeaabde2a7b581c4c6888d532d32f3ac (diff) | |
| download | webp-tools_r22.2.tar.gz | |
Sync-patch with libwebp (ChangeId: Ia5475247)android-4.3_r3.1android-4.3_r3android-4.3_r2.3android-4.3_r2.2android-4.3_r2.1android-4.3_r2android-4.3_r1.1android-4.3_r1android-4.3_r0.9.1android-4.3_r0.9android-4.3.1_r1tools_r22.2jb-mr2.0.0-releasejb-mr2.0-releasejb-mr2-releasejb-mr2-dev
Added 16bit swapping of RGB565 / RGB4444 colorspace.
Added ARM/NEON code for decoder/encoder modules.
Speedup in WebP compression (method 3 and above).
Change-Id: I95a697338bef7c3ea08054eb5f850a97d1889eb9
Diffstat (limited to 'src/dsp/lossless.h')
| -rw-r--r-- | src/dsp/lossless.h | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/dsp/lossless.h b/src/dsp/lossless.h index 22a91cbf..f14e2ea7 100644 --- a/src/dsp/lossless.h +++ b/src/dsp/lossless.h @@ -59,10 +59,20 @@ static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size, return (size + (1 << sampling_bits) - 1) >> sampling_bits; } -// Faster logarithm for integers, with the property of log2(0) == 0. -float VP8LFastLog2(int v); +// Faster logarithm for integers. Small values use a look-up table. +#define LOG_LOOKUP_IDX_MAX 256 +extern const float kLog2Table[LOG_LOOKUP_IDX_MAX]; +extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX]; +extern float VP8LFastLog2Slow(int v); +extern float VP8LFastSLog2Slow(int v); +static WEBP_INLINE float VP8LFastLog2(int v) { + return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v); +} // Fast calculation of v * log2(v) for integer input. -static WEBP_INLINE float VP8LFastSLog2(int v) { return VP8LFastLog2(v) * v; } +static WEBP_INLINE float VP8LFastSLog2(int v) { + return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v); +} + // In-place difference of each component with mod 256. static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) { |