dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-01-26 22:52:55 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

parse one row of intra modes altogether

Browse Source 
(instead of per-macroblock)

speed unchanged.
simplified the context-saving for incremental decoding

Change-Id: I301be581bab581ff68de14c4ffe5bc0ec63f34be
This commit is contained in:
skal 2014-01-28 21:40:40 +01:00
parent a2f608f9e0
commit bbc23ff34c
4 changed files with 55 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
src/dec/idec.c
View File

@ -72,15 +72,14 @@ struct WebPIDecoder {
MemBuffer mem_; // input memory buffer.
WebPDecBuffer output_; // output buffer (when no external one is supplied)
size_t chunk_size_; // Compressed VP8/VP8L size extracted from Header.
int last_mb_y_; // last row reached for intra-mode decoding
};
// MB context to restore in case VP8DecodeMB() fails
typedef struct {
VP8MB left_;
VP8MB info_;
uint8_t intra_t_[4];
uint8_t intra_l_[4];
VP8BitReader br_;
VP8BitReader token_br_;
} MBContext;
@ -264,30 +263,16 @@ static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br,
MBContext* const context) {
const VP8BitReader* const br = &dec->br_;
const VP8MB* const left = dec->mb_info_ - 1;
const VP8MB* const info = dec->mb_info_ + dec->mb_x_;
context->left_ = *left;
context->info_ = *info;
context->br_ = *br;
context->left_ = dec->mb_info_[-1];
context->info_ = dec->mb_info_[dec->mb_x_];
context->token_br_ = *token_br;
memcpy(context->intra_t_, dec->intra_t_ + 4 * dec->mb_x_, 4);
memcpy(context->intra_l_, dec->intra_l_, 4);
}
static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
VP8BitReader* const token_br) {
VP8BitReader* const br = &dec->br_;
VP8MB* const left = dec->mb_info_ - 1;
VP8MB* const info = dec->mb_info_ + dec->mb_x_;
*left = context->left_;
*info = context->info_;
*br = context->br_;
dec->mb_info_[-1] = context->left_;
dec->mb_info_[dec->mb_x_] = context->info_;
*token_br = context->token_br_;
memcpy(dec->intra_t_ + 4 * dec->mb_x_, context->intra_t_, 4);
memcpy(dec->intra_l_, context->intra_l_, 4);
}
//------------------------------------------------------------------------------
@ -459,16 +444,26 @@ static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
assert(dec->ready_);
for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
VP8BitReader* token_br = &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
if (idec->last_mb_y_ != dec->mb_y_) {
if (!VP8ParseIntraModeRow(&dec->br_, dec)) {
// note: normally, error shouldn't occur since we already have the whole
// partition0 available here in DecodeRemaining(). Reaching EOF while
// reading intra modes really means a BITSTREAM_ERROR.
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
idec->last_mb_y_ = dec->mb_y_;
}
for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) {
VP8BitReader* const token_br =
&dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
MBContext context;
SaveContext(dec, token_br, &context);
if (!VP8DecodeMB(dec, token_br)) {
RestoreContext(&context, dec, token_br);
// We shouldn't fail when MAX_MB data was available
if (dec->num_parts_ == 1 && MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
RestoreContext(&context, dec, token_br);
return VP8_STATUS_SUSPENDED;
}
// Release buffer only if there is only one partition
@ -585,6 +580,8 @@ WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
idec->state_ = STATE_WEBP_HEADER;
idec->chunk_size_ = 0;
idec->last_mb_y_ = -1;
InitMemBuffer(&idec->mem_);
WebPInitDecBuffer(&idec->output_);
VP8InitIo(&idec->io_);

27
src/dec/tree.c
View File

@ -278,10 +278,23 @@ void VP8ResetProba(VP8Proba* const proba) {
// proba->bands_[][] is initialized later
}
void VP8ParseIntraMode(VP8BitReader* const br, VP8Decoder* const dec) {
uint8_t* const top = dec->intra_t_ + 4 * dec->mb_x_;
static void ParseIntraMode(VP8BitReader* const br,
VP8Decoder* const dec, int mb_x) {
uint8_t* const top = dec->intra_t_ + 4 * mb_x;
uint8_t* const left = dec->intra_l_;
VP8MBData* const block = dec->mb_data_ + dec->mb_x_;
VP8MBData* const block = dec->mb_data_ + mb_x;
// Note: we don't save segment map (yet), as we don't expect
// to decode more than 1 keyframe.
if (dec->segment_hdr_.update_map_) {
// Hardcoded tree parsing
block->segment_ = !VP8GetBit(br, dec->proba_.segments_[0])
? VP8GetBit(br, dec->proba_.segments_[1])
: 2 + VP8GetBit(br, dec->proba_.segments_[2]);
} else {
block->segment_ = 0; // default for intra
}
if (dec->use_skip_proba_) block->skip_ = VP8GetBit(br, dec->skip_p_);
block->is_i4x4_ = !VP8GetBit(br, 145); // decide for B_PRED first
if (!block->is_i4x4_) {
@ -332,6 +345,14 @@ void VP8ParseIntraMode(VP8BitReader* const br, VP8Decoder* const dec) {
: VP8GetBit(br, 183) ? TM_PRED : H_PRED;
}
int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec) {
int mb_x;
for (mb_x = 0; mb_x < dec->mb_w_; ++mb_x) {
ParseIntraMode(br, dec, mb_x);
}
return !dec->br_.eof_;
}
//------------------------------------------------------------------------------
// Paragraph 13

27
src/dec/vp8.c
View File

@ -317,7 +317,6 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
VP8ResetProba(&dec->proba_);
ResetSegmentHeader(&dec->segment_hdr_);
dec->segment_ = 0; // default for intra
}
// Check if we have all the partition #0 available, and initialize dec->br_
@ -479,8 +478,8 @@ static int ParseResiduals(VP8Decoder* const dec,
VP8MB* const mb, VP8BitReader* const token_br) {
VP8BandProbas (* const bands)[NUM_BANDS] = dec->proba_.bands_;
const VP8BandProbas* ac_proba;
const VP8QuantMatrix* const q = &dec->dqm_[dec->segment_];
VP8MBData* const block = dec->mb_data_ + dec->mb_x_;
const VP8QuantMatrix* const q = &dec->dqm_[block->segment_];
int16_t* dst = block->coeffs_;
VP8MB* const left_mb = dec->mb_info_ - 1;
uint8_t tnz, lnz;
@ -570,26 +569,10 @@ static int ParseResiduals(VP8Decoder* const dec,
// Main loop
int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) {
VP8BitReader* const br = &dec->br_;
VP8MB* const left = dec->mb_info_ - 1;
VP8MB* const mb = dec->mb_info_ + dec->mb_x_;
VP8MBData* const block = dec->mb_data_ + dec->mb_x_;
int skip;
// Note: we don't save segment map (yet), as we don't expect
// to decode more than 1 keyframe.
if (dec->segment_hdr_.update_map_) {
// Hardcoded tree parsing
dec->segment_ = !VP8GetBit(br, dec->proba_.segments_[0]) ?
VP8GetBit(br, dec->proba_.segments_[1]) :
2 + VP8GetBit(br, dec->proba_.segments_[2]);
}
skip = dec->use_skip_proba_ ? VP8GetBit(br, dec->skip_p_) : 0;
VP8ParseIntraMode(br, dec);
if (br->eof_) {
return 0;
}
int skip = dec->use_skip_proba_ ? block->skip_ : 0;
if (!skip) {
skip = ParseResiduals(dec, mb, token_br);
@ -604,7 +587,7 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) {
if (dec->filter_type_ > 0) { // store filter info
VP8FInfo* const finfo = dec->f_info_ + dec->mb_x_;
*finfo = dec->fstrengths_[dec->segment_][block->is_i4x4_];
*finfo = dec->fstrengths_[block->segment_][block->is_i4x4_];
finfo->f_inner_ |= !skip;
}
@ -624,6 +607,10 @@ static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
// Parse bitstream for this row.
VP8BitReader* const token_br =
&dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
if (!VP8ParseIntraModeRow(&dec->br_, dec)) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
"Premature end-of-partition0 encountered.");
}
for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) {
if (!VP8DecodeMB(dec, token_br)) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,

6
src/dec/vp8i.h
View File

@ -195,6 +195,8 @@ typedef struct {
uint32_t non_zero_y_;
uint32_t non_zero_uv_;
uint8_t dither_; // local dithering strength (deduced from non_zero_*)
uint8_t skip_;
uint8_t segment_;
} VP8MBData;
// Persistent information needed by the parallel processing
@ -265,7 +267,6 @@ struct VP8Decoder {
uint8_t* intra_t_; // top intra modes values: 4 * mb_w_
uint8_t intra_l_[4]; // left intra modes values
uint8_t segment_; // segment of the currently parsed block
VP8TopSamples* yuv_t_; // top y/u/v samples
VP8MB* mb_info_; // contextual macroblock info (mb_w_ + 1)
@ -313,7 +314,8 @@ int VP8SetError(VP8Decoder* const dec,
// in tree.c
void VP8ResetProba(VP8Proba* const proba);
void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec);
void VP8ParseIntraMode(VP8BitReader* const br, VP8Decoder* const dec);
// parses one row of intra mode data in partition 0, returns !eof
int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec);
// in quant.c
void VP8ParseQuant(VP8Decoder* const dec);