dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-16 05:49:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

use 16bit counters for recording proba counts

Browse Source 
This proved being ok, even for large pictures, provided one
takes care of overflow. When an overflow is bound to occur, the
counters are renormalized.
Overall, shaves ~12k of memory.

Change-Id: I2ba21a407964fe1a34c352371cba15166e0c4548
This commit is contained in:
Pascal Massimino
2012-01-23 17:50:58 -08:00
parent 7f23678da0
commit 0de3096b3a
3 changed files with 46 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/enc/cost.h
View File

@ -26,18 +26,12 @@ static WEBP_INLINE int VP8BitCost(int bit, uint8_t proba) {
return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba];
}
// Cost of coding 'nb' 1's and 'total-nb' 0's using 'proba' probability.
static WEBP_INLINE uint64_t VP8BranchCost(uint64_t nb, uint64_t total,
uint8_t proba) {
return nb * VP8BitCost(1, proba) + (total - nb) * VP8BitCost(0, proba);
}
// Level cost calculations
extern const uint16_t VP8LevelCodes[MAX_VARIABLE_LEVEL][2];
void VP8CalculateLevelCosts(VP8Proba* const proba);
static WEBP_INLINE int VP8LevelCost(const uint16_t* const table, int level) {
return VP8LevelFixedCosts[level]
+ table[level > MAX_VARIABLE_LEVEL ? MAX_VARIABLE_LEVEL : level];
+ table[(level > MAX_VARIABLE_LEVEL) ? MAX_VARIABLE_LEVEL : level];
}
// Mode costs