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Allow the lossless cruncher to work for alpha.

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Change-Id: I7185e75404fae8c739e0536026f4687d25decad7
This commit is contained in:
Vincent Rabaud 2017-08-04 19:40:43 +02:00
parent b8821dbd81
commit 1aef4c710b
1 changed files with 6 additions and 3 deletions
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9
src/enc/alpha_enc.c
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@ -48,7 +48,7 @@
static int EncodeLossless(const uint8_t* const data, int width, int height,
int effort_level, // in [0..6] range
VP8LBitWriter* const bw,
int use_quality_100, VP8LBitWriter* const bw,
WebPAuxStats* const stats) {
int ok = 0;
WebPConfig config;
@ -76,7 +76,10 @@ static int EncodeLossless(const uint8_t* const data, int width, int height,
// Set a low default quality for encoding alpha. Ensure that Alpha quality at
// lower methods (3 and below) is less than the threshold for triggering
// costly 'BackwardReferencesTraceBackwards'.
config.quality = 8.f * effort_level;
// If the alpha quality is set to 100 and the method to 6, allow for a high
// lossless quality to trigger the cruncher.
config.quality =
(use_quality_100 && effort_level == 6) ? 100 : 8.f * effort_level;
assert(config.quality >= 0 && config.quality <= 100.f);
// TODO(urvang): Temporary fix to avoid generating images that trigger
@ -134,7 +137,7 @@ static int EncodeAlphaInternal(const uint8_t* const data, int width, int height,
if (method != ALPHA_NO_COMPRESSION) {
ok = VP8LBitWriterInit(&tmp_bw, data_size >> 3);
ok = ok && EncodeLossless(alpha_src, width, height, effort_level,
&tmp_bw, &result->stats);
!reduce_levels, &tmp_bw, &result->stats);
if (ok) {
output = VP8LBitWriterFinish(&tmp_bw);
output_size = VP8LBitWriterNumBytes(&tmp_bw);