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add Advanced Decoding Interface

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You can now use WebPDecBuffer, WebPBitstreamFeatures and WebPDecoderOptions
to have better control over the decoding process (and the speed/quality tradeoff).

WebPDecoderOptions allow to:
 - turn fancy upsampler on/off
 - turn in-loop filter on/off
 - perform on-the-fly cropping
 - perform on the-fly rescale
(and more to come. Not all features are implemented yet).

On-the-fly cropping and scaling allow to save quite some memory
(as the decoding operation will now scale with the output's size, not
the input's one). It saves some CPU too (since for instance,
in-loop filtering is partially turned off where it doesn't matter,
and some YUV->RGB conversion operations are ommitted too).

The scaler uses summed area, so is mainly meant to be used for
downscaling (like: for generating thumbnails or previews).

Incremental decoding works with these new options.
More doc to come soon.

dwebp is now using the new decoding interface, with the new flags:
  -nofancy
  -nofilter
  -crop top left width height
  -scale width height

Change-Id: I08baf2fa291941686f4ef70a9cc2e4137874e85e
This commit is contained in:
Pascal Massimino
2011-06-20 00:45:15 -07:00
parent bd2f65f67c
commit d260310511
19 changed files with 2052 additions and 788 deletions
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52
src/dec/vp8.c
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@ -76,8 +76,12 @@ int VP8SetError(VP8Decoder* const dec,
//-----------------------------------------------------------------------------
int VP8GetInfo(const uint8_t* data, uint32_t chunk_size,
int *width, int *height) {
int VP8GetInfo(const uint8_t* data,
uint32_t data_size, uint32_t chunk_size,
int* width, int* height, int* has_alpha) {
if (data_size < 10) {
return 0; // not enough data
}
// check signature
if (data[3] != 0x9d || data[4] != 0x01 || data[5] != 0x2a) {
return 0; // Wrong signature.
@ -87,6 +91,14 @@ int VP8GetInfo(const uint8_t* data, uint32_t chunk_size,
const int w = ((data[7] << 8) | data[6]) & 0x3fff;
const int h = ((data[9] << 8) | data[8]) & 0x3fff;
if (has_alpha) {
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (data_size < 11) return 0;
*has_alpha = !!(data[10] & 0x80); // the colorspace_ bit
#else
*has_alpha = 0;
#endif
}
if (!key_frame) { // Not a keyframe.
return 0;
}
@ -254,7 +266,7 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
"null VP8Io passed to VP8GetHeaders()");
}
buf = (uint8_t *)io->data;
buf = (uint8_t*)io->data;
buf_size = io->data_size;
if (buf == NULL || buf_size <= 4) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
@ -329,8 +341,17 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
dec->mb_w_ = (pic_hdr->width_ + 15) >> 4;
dec->mb_h_ = (pic_hdr->height_ + 15) >> 4;
// Setup default output area (can be later modified during io->setup())
io->width = pic_hdr->width_;
io->height = pic_hdr->height_;
io->use_scaling = 0;
io->use_cropping = 0;
io->crop_top = 0;
io->crop_left = 0;
io->crop_right = io->width;
io->crop_bottom = io->height;
io->mb_w = io->width; // sanity check
io->mb_h = io->height; // ditto
VP8ResetProba(&dec->proba_);
ResetSegmentHeader(&dec->segment_hdr_);
@ -458,7 +479,7 @@ static const uint8_t kCat4[] = { 176, 155, 140, 135, 0 };
static const uint8_t kCat5[] = { 180, 157, 141, 134, 130, 0 };
static const uint8_t kCat6[] =
{ 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0 };
static const uint8_t * const kCat3456[] = { kCat3, kCat4, kCat5, kCat6 };
static const uint8_t* const kCat3456[] = { kCat3, kCat4, kCat5, kCat6 };
static const uint8_t kZigzag[16] = {
0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15
};
@ -662,11 +683,10 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) {
}
static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
for (dec->mb_y_ = 0; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
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_));
@ -681,9 +701,11 @@ 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)) {
return VP8SetError(dec, VP8_STATUS_USER_ABORT,
"Output aborted.");
return VP8SetError(dec, VP8_STATUS_USER_ABORT, "Output aborted.");
}
}
@ -722,22 +744,18 @@ int VP8Decode(VP8Decoder* const dec, VP8Io* const io) {
}
assert(dec->ready_);
// will allocate memory and prepare everything.
// Will allocate memory and prepare everything.
if (!VP8InitFrame(dec, io)) {
VP8Clear(dec);
return VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY,
"Allocation failed");
return 0;
}
if (io->setup && !io->setup(io)) {
// Finish setting up the decoding parameter
if (VP8FinishFrameSetup(dec, io) != VP8_STATUS_OK) {
VP8Clear(dec);
return VP8SetError(dec, VP8_STATUS_USER_ABORT,
"Frame setup failed");
return 0;
}
// Disable filtering per user request (_after_ setup() is called)
if (io->bypass_filtering) dec->filter_type_ = 0;
// Main decoding loop
{
const int ret = ParseFrame(dec, io);