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multi-thread decoding: ~25-30% faster

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To be enabled with the flag WEBP_USE_THREAD.
For now it's only available on unix (pthread), when using Makefile.unix
Will be switched on more generally later.

In-loop filtering and output (=rescaling/yuv->rgb conversion)
is done in parallel to bitstream decoding, lagging 1 row behind.

Example:
examples/dwebp bryce.webp -v
Time to decode picture: 0.680s

examples/dwebp bryce.webp -v -mt
Time to decode picture: 0.515s

Change-Id: Ic30a897423137a3bdace9c4e30465ef758fe53f2
This commit is contained in:
Pascal Massimino
2011-07-22 13:09:10 -07:00
parent acd8ba4229
commit fc7815d692
16 changed files with 519 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
src/dec/vp8.c
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@ -43,6 +43,7 @@ VP8Decoder* VP8New(void) {
VP8Decoder* dec = (VP8Decoder*)calloc(1, sizeof(VP8Decoder));
if (dec) {
SetOk(dec);
WebPWorkerInit(&dec->worker_);
dec->ready_ = 0;
}
return dec;
@ -682,15 +683,21 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) {
return (!token_br->eof_);
}
void VP8InitScanline(VP8Decoder* const dec) {
VP8MB* const left = dec->mb_info_ - 1;
left->nz_ = 0;
left->dc_nz_ = 0;
memset(dec->intra_l_, B_DC_PRED, sizeof(dec->intra_l_));
dec->filter_row_ =
(dec->filter_type_ > 0) &&
(dec->mb_y_ >= dec->tl_mb_y_) && (dec->mb_y_ <= dec->br_mb_y_);
}
static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
for (dec->mb_y_ = 0; dec->mb_y_ < dec->br_mb_y_; ++dec->mb_y_) {
VP8MB* const left = dec->mb_info_ - 1;
VP8BitReader* const token_br =
&dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
left->nz_ = 0;
left->dc_nz_ = 0;
memset(dec->intra_l_, B_DC_PRED, sizeof(dec->intra_l_));
VP8InitScanline(dec);
for (dec->mb_x_ = 0; dec->mb_x_ < dec->mb_w_; dec->mb_x_++) {
if (!VP8DecodeMB(dec, token_br)) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
@ -701,13 +708,13 @@ static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
// Store data and save block's filtering params
VP8StoreBlock(dec);
}
if (dec->filter_type_ > 0) {
VP8FilterRow(dec);
}
if (!VP8FinishRow(dec, io)) {
if (!VP8ProcessRow(dec, io)) {
return VP8SetError(dec, VP8_STATUS_USER_ABORT, "Output aborted.");
}
}
if (dec->use_threads_ && !WebPWorkerSync(&dec->worker_)) {
return 0;
}
// Finish
#ifndef ONLY_KEYFRAME_CODE
@ -729,6 +736,7 @@ static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
// Main entry point
int VP8Decode(VP8Decoder* const dec, VP8Io* const io) {
int ok = 0;
if (dec == NULL) {
return 0;
}
@ -744,30 +752,24 @@ int VP8Decode(VP8Decoder* const dec, VP8Io* const io) {
}
assert(dec->ready_);
// Will allocate memory and prepare everything.
if (!VP8InitFrame(dec, io)) {
VP8Clear(dec);
return 0;
// Finish setting up the decoding parameter. Will call io->setup().
ok = (VP8EnterCritical(dec, io) == VP8_STATUS_OK);
if (ok) { // good to go.
// Will allocate memory and prepare everything.
if (ok) ok = VP8InitFrame(dec, io);
// Main decoding loop
if (ok) ok = ParseFrame(dec, io);
// Exit.
ok &= VP8ExitCritical(dec, io);
}
// Finish setting up the decoding parameter
if (VP8FinishFrameSetup(dec, io) != VP8_STATUS_OK) {
if (!ok) {
VP8Clear(dec);
return 0;
}
// Main decoding loop
{
const int ret = ParseFrame(dec, io);
if (io->teardown) {
io->teardown(io);
}
if (!ret) {
VP8Clear(dec);
return 0;
}
}
dec->ready_ = 0;
return 1;
}
@ -776,6 +778,9 @@ void VP8Clear(VP8Decoder* const dec) {
if (dec == NULL) {
return;
}
if (dec->use_threads_) {
WebPWorkerEnd(&dec->worker_);
}
if (dec->mem_) {
free(dec->mem_);
}