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avcodec/magicyuvenc: Avoid sorting Huffman table unnecessarily

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Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-09-28 15:11:52 +02:00
parent dc3f177b8f
commit 17b003a9e2
1 changed files with 15 additions and 28 deletions
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43
libavcodec/magicyuvenc.c
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@ -40,7 +40,6 @@ typedef enum Prediction {
} Prediction;
typedef struct HuffEntry {
uint8_t sym;
uint8_t len;
uint32_t code;
} HuffEntry;
@ -245,32 +244,18 @@ static av_cold int magy_encode_init(AVCodecContext *avctx)
return 0;
}
static int magy_huff_cmp_len(const void *a, const void *b)
static void calculate_codes(HuffEntry *he, uint16_t codes_count[33])
{
const HuffEntry *aa = a, *bb = b;
return (aa->len - bb->len) * 256 + aa->sym - bb->sym;
}
static int huff_cmp_sym(const void *a, const void *b)
{
const HuffEntry *aa = a, *bb = b;
return bb->sym - aa->sym;
}
static void calculate_codes(HuffEntry *he)
{
uint32_t code;
int i;
AV_QSORT(he, 256, HuffEntry, magy_huff_cmp_len);
code = 1;
for (i = 255; i >= 0; i--) {
he[i].code = code >> (32 - he[i].len);
code += 0x80000000u >> (he[i].len - 1);
for (unsigned i = 32, nb_codes = 0; i > 0; i--) {
uint16_t curr = codes_count[i]; // # of leafs of length i
codes_count[i] = nb_codes / 2; // # of non-leaf nodes on level i
nb_codes = codes_count[i] + curr; // # of nodes on level i
}
AV_QSORT(he, 256, HuffEntry, huff_cmp_sym);
for (unsigned i = 0; i < 256; i++) {
he[i].code = codes_count[he[i].len];
codes_count[he[i].len]++;
}
}
static void count_usage(uint8_t *src, int width,
@ -301,6 +286,7 @@ static int compare_by_prob(const void *a, const void *b)
}
static void magy_huffman_compute_bits(PTable *prob_table, HuffEntry *distincts,
uint16_t codes_counts[33],
int size, int max_length)
{
PackageMergerList list_a, list_b, *to = &list_a, *from = &list_b, *temp;
@ -356,8 +342,8 @@ static void magy_huffman_compute_bits(PTable *prob_table, HuffEntry *distincts,
}
for (i = 0; i < size; i++) {
distincts[i].sym = i;
distincts[i].len = nbits[i];
codes_counts[nbits[i]]++;
}
}
@ -366,18 +352,19 @@ static int encode_table(AVCodecContext *avctx, uint8_t *dst,
PutBitContext *pb, HuffEntry *he)
{
PTable counts[256] = { {0} };
uint16_t codes_counts[33] = { 0 };
int i;
count_usage(dst, width, height, counts);
for (i = 0; i < 256; i++) {
counts[i].prob++;
counts[i].value = 255 - i;
counts[i].value = i;
}
magy_huffman_compute_bits(counts, he, 256, 12);
magy_huffman_compute_bits(counts, he, codes_counts, 256, 12);
calculate_codes(he);
calculate_codes(he, codes_counts);
for (i = 0; i < 256; i++) {
put_bits(pb, 1, 0);