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add stats for lossless

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* Extend AuxStats with new fields
  it's slightly ABI-incompatible, but i guess it's ok for 0.1.99+
  I expect to add more stats later, possibly (predictor stats, etc.)
* Have cwebp report the features used by lossless
  compression (either for alpha or full lossless coding)
* Print the PSNR for alpha (useful in case of -alpha_q)
* clean-up alpha.c signatures
+ misc cleanup (added const '* const ptr', etc.)

Change-Id: I157a21581f1793cb0c6cc0882e7b0a2dde68a970
This commit is contained in:
Pascal Massimino
2012-07-24 16:15:36 -07:00
parent d39177b74c
commit 7d853d79dc
7 changed files with 143 additions and 75 deletions
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41
src/enc/vp8l.c
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@ -610,7 +610,7 @@ static int EncodeImageInternal(VP8LBitWriter* const bw,
// Check if it would be a good idea to subtract green from red and blue. We
// only impact entropy in red/blue components, don't bother to look at others.
static int EvalAndApplySubtractGreen(const VP8LEncoder* const enc,
static int EvalAndApplySubtractGreen(VP8LEncoder* const enc,
int width, int height,
VP8LBitWriter* const bw) {
if (!enc->use_palette_) {
@ -639,7 +639,8 @@ static int EvalAndApplySubtractGreen(const VP8LEncoder* const enc,
free(histo);
// Check if subtracting green yields low entropy.
if (bit_cost_after < bit_cost_before) {
enc->use_subtract_green_ = (bit_cost_after < bit_cost_before);
if (enc->use_subtract_green_) {
VP8LWriteBits(bw, 1, TRANSFORM_PRESENT);
VP8LWriteBits(bw, 2, SUBTRACT_GREEN);
VP8LSubtractGreenFromBlueAndRed(enc->argb_, width * height);
@ -938,6 +939,7 @@ WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
const int width = picture->width;
const int height = picture->height;
VP8LEncoder* const enc = VP8LEncoderNew(config, picture);
const size_t byte_position = VP8LBitWriterNumBytes(bw);
if (enc == NULL) {
err = VP8_ENC_ERROR_OUT_OF_MEMORY;
@ -1017,6 +1019,20 @@ WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
goto Error;
}
if (picture->stats != NULL) {
WebPAuxStats* const stats = picture->stats;
stats->lossless_features = 0;
if (enc->use_predict_) stats->lossless_features |= 1;
if (enc->use_cross_color_) stats->lossless_features |= 2;
if (enc->use_subtract_green_) stats->lossless_features |= 4;
if (enc->use_palette_) stats->lossless_features |= 8;
stats->histogram_bits = enc->histo_bits_;
stats->transform_bits = enc->transform_bits_;
stats->cache_bits = enc->cache_bits_;
stats->palette_size = enc->palette_size_;
stats->lossless_size = VP8LBitWriterNumBytes(bw) - byte_position;
}
Error:
VP8LEncoderDelete(enc);
return err;
@ -1045,6 +1061,16 @@ int VP8LEncodeImage(const WebPConfig* const config,
err = VP8_ENC_ERROR_USER_ABORT;
goto Error;
}
// Reset stats (for pure lossless coding)
if (picture->stats != NULL) {
WebPAuxStats* const stats = picture->stats;
memset(stats, 0, sizeof(*stats));
stats->PSNR[0] = 99.;
stats->PSNR[1] = 99.;
stats->PSNR[2] = 99.;
stats->PSNR[3] = 99.;
stats->PSNR[4] = 99.;
}
// Write image size.
VP8LBitWriterInit(&bw, (width * height) >> 1);
@ -1075,15 +1101,10 @@ int VP8LEncodeImage(const WebPConfig* const config,
if (!WebPReportProgress(picture, 100, &percent)) goto UserAbort;
// Collect some stats if needed.
// Save size.
if (picture->stats != NULL) {
WebPAuxStats* const stats = picture->stats;
memset(stats, 0, sizeof(*stats));
stats->PSNR[0] = 99.;
stats->PSNR[1] = 99.;
stats->PSNR[2] = 99.;
stats->PSNR[3] = 99.;
stats->coded_size = (int)coded_size;
picture->stats->coded_size += (int)coded_size;
picture->stats->lossless_size = (int)coded_size;
}
if (picture->extra_info != NULL) {