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webp_quality: detect lossless format and features

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lossless bitstream are returned as quality 101

Change-Id: I8b28287169b710ecf8d4d694abbf0cedc6447908
This commit is contained in:
Pascal Massimino
2016-07-22 00:02:17 -07:00
parent ebee57f4d1
commit eb98d8d87c
3 changed files with 13 additions and 3 deletions
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8
extras/quality_estimate.c
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@ -12,6 +12,7 @@
// Author: Skal (pascal.massimino@gmail.com)
#include "./extras.h"
#include "webp/decode.h"
#include <math.h>
@ -46,9 +47,16 @@ int VP8EstimateQuality(const uint8_t* const data, size_t size) {
uint64_t sig = 0x00;
int ok = 0;
int Q = -1;
WebPBitstreamFeatures features;
if (data == NULL) return -1;
if (WebPGetFeatures(data, size, &features) != VP8_STATUS_OK) {
return -1; // invalid file
}
if (features.format == 2) return 101; // lossless
if (features.format == 0 || features.has_animation) return -1; // mixed
while (pos < size) {
sig = (sig >> 8) | ((uint64_t)data[pos++] << 40);
if ((sig >> 24) == 0x2a019dull) {