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Merge "Tune Lossless encoder"

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pascal massimino 2012-10-30 18:27:14 -07:00 committed by Gerrit Code Review
commit 6c66dde80f
1 changed files with 48 additions and 16 deletions
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64
src/enc/backward_references.c
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@ -141,9 +141,25 @@ static void HashChainInsert(HashChain* const p,
p->hash_to_first_index_[hash_code] = pos;
}
static void GetParamsForHashChainFindCopy(int quality, int xsize,
int* window_size, int* iter_pos,
int* iter_limit) {
const int iter_mult = (quality < 27) ? 1 : 1 + ((quality - 27) >> 4);
// Limit the backward-ref window size for lower qualities.
const int max_window_size = (quality > 50) ? WINDOW_SIZE
: (quality > 25) ? (xsize << 8)
: (xsize << 4);
assert(xsize > 0);
*window_size = (max_window_size > WINDOW_SIZE) ? WINDOW_SIZE
: max_window_size;
*iter_pos = 5 + (quality >> 3);
*iter_limit = -quality * iter_mult;
}
static int HashChainFindCopy(const HashChain* const p,
int quality, int index, int xsize,
int index, int xsize,
const uint32_t* const argb, int maxlen,
int window_size, int iter_pos, int iter_limit,
int* const distance_ptr,
int* const length_ptr) {
const uint64_t hash_code = GetPixPairHash64(&argb[index]);
@ -152,10 +168,7 @@ static int HashChainFindCopy(const HashChain* const p,
int best_length = 0;
int best_distance = 0;
const uint32_t* const argb_start = argb + index;
const int iter_min_mult = (quality < 36) ? 1 : 1 + ((quality - 36) >> 3);
const int iter_min = -quality * iter_min_mult;
int iter_cnt = 10 + (quality >> 2);
const int min_pos = (index > WINDOW_SIZE) ? index - WINDOW_SIZE : 0;
const int min_pos = (index > window_size) ? index - window_size : 0;
int pos;
assert(xsize > 0);
@ -164,12 +177,12 @@ static int HashChainFindCopy(const HashChain* const p,
pos = p->chain_[pos]) {
int64_t val;
int curr_length;
if (iter_cnt < 0) {
if (iter_cnt < iter_min || best_val >= 0xff0000) {
if (iter_pos < 0) {
if (iter_pos < iter_limit || best_val >= 0xff0000) {
break;
}
}
--iter_cnt;
--iter_pos;
if (best_length != 0 &&
argb[pos + best_length - 1] != argb_start[best_length - 1]) {
continue;
@ -257,6 +270,9 @@ static int BackwardReferencesHashChain(int xsize, int ysize,
const int pix_count = xsize * ysize;
HashChain* const hash_chain = (HashChain*)malloc(sizeof(*hash_chain));
VP8LColorCache hashers;
int window_size = WINDOW_SIZE;
int iter_pos = 1;
int iter_limit = -1;
if (hash_chain == NULL) return 0;
if (use_color_cache) {
@ -267,6 +283,8 @@ static int BackwardReferencesHashChain(int xsize, int ysize,
if (!HashChainInit(hash_chain, pix_count)) goto Error;
refs->size = 0;
GetParamsForHashChainFindCopy(quality, xsize, &window_size, &iter_pos,
&iter_limit);
for (i = 0; i < pix_count; ) {
// Alternative#1: Code the pixels starting at 'i' using backward reference.
int offset = 0;
@ -276,7 +294,8 @@ static int BackwardReferencesHashChain(int xsize, int ysize,
if (maxlen > MAX_LENGTH) {
maxlen = MAX_LENGTH;
}
HashChainFindCopy(hash_chain, quality, i, xsize, argb, maxlen,
HashChainFindCopy(hash_chain, i, xsize, argb, maxlen,
window_size, iter_pos, iter_limit,
&offset, &len);
}
if (len >= MIN_LENGTH) {
@ -291,8 +310,9 @@ static int BackwardReferencesHashChain(int xsize, int ysize,
if (maxlen > MAX_LENGTH) {
maxlen = MAX_LENGTH;
}
HashChainFindCopy(hash_chain, quality,
i + 1, xsize, argb, maxlen, &offset2, &len2);
HashChainFindCopy(hash_chain, i + 1, xsize, argb, maxlen,
window_size, iter_pos, iter_limit,
&offset2, &len2);
if (len2 > len + 1) {
const uint32_t pixel = argb[i];
// Alternative#2 is a better match. So push pixel at 'i' as literal.
@ -465,6 +485,9 @@ static int BackwardReferencesHashChainDistanceOnly(
VP8LColorCache hashers;
const double mul0 = (recursive_cost_model != 0) ? 1.0 : 0.68;
const double mul1 = (recursive_cost_model != 0) ? 1.0 : 0.82;
int window_size = WINDOW_SIZE;
int iter_pos = 1;
int iter_limit = -1;
if (cost == NULL || cost_model == NULL || hash_chain == NULL) goto Error;
@ -485,6 +508,8 @@ static int BackwardReferencesHashChainDistanceOnly(
// We loop one pixel at a time, but store all currently best points to
// non-processed locations from this point.
dist_array[0] = 0;
GetParamsForHashChainFindCopy(quality, xsize, &window_size, &iter_pos,
&iter_limit);
for (i = 0; i < pix_count; ++i) {
double prev_cost = 0.0;
int shortmax;
@ -499,7 +524,8 @@ static int BackwardReferencesHashChainDistanceOnly(
if (maxlen > pix_count - i) {
maxlen = pix_count - i;
}
HashChainFindCopy(hash_chain, quality, i, xsize, argb, maxlen,
HashChainFindCopy(hash_chain, i, xsize, argb, maxlen,
window_size, iter_pos, iter_limit,
&offset, &len);
}
if (len >= MIN_LENGTH) {
@ -612,6 +638,9 @@ static int BackwardReferencesHashChainFollowChosenPath(
int ix;
int ok = 0;
int cc_init = 0;
int window_size = WINDOW_SIZE;
int iter_pos = 1;
int iter_limit = -1;
HashChain* hash_chain = (HashChain*)malloc(sizeof(*hash_chain));
VP8LColorCache hashers;
@ -624,13 +653,16 @@ static int BackwardReferencesHashChainFollowChosenPath(
}
refs->size = 0;
GetParamsForHashChainFindCopy(quality, xsize, &window_size, &iter_pos,
&iter_limit);
for (ix = 0; ix < chosen_path_size; ++ix, ++size) {
int offset = 0;
int len = 0;
int maxlen = chosen_path[ix];
if (maxlen != 1) {
HashChainFindCopy(hash_chain, quality,
i, xsize, argb, maxlen, &offset, &len);
HashChainFindCopy(hash_chain, i, xsize, argb, maxlen,
window_size, iter_pos, iter_limit,
&offset, &len);
assert(len == maxlen);
refs->refs[size] = PixOrCopyCreateCopy(offset, len);
if (use_color_cache) {
@ -762,8 +794,8 @@ int VP8LGetBackwardReferences(int width, int height,
// Choose appropriate backward reference.
if (lz77_is_useful) {
// TraceBackwards is costly. Don't execute it at lower quality (q <= 25).
const int try_lz77_trace_backwards = (quality > 25);
// TraceBackwards is costly. Don't execute it at lower quality (q <= 10).
const int try_lz77_trace_backwards = (quality > 10);
*best = refs_lz77; // default guess: lz77 is better
VP8LClearBackwardRefs(&refs_rle);
if (try_lz77_trace_backwards) {