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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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41
libavcodec/magicyuvenc.c
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@@ -40,7 +40,6 @@ typedef enum Prediction {
} Prediction; } Prediction;
typedef struct HuffEntry { typedef struct HuffEntry {
uint8_t sym;
uint8_t len; uint8_t len;
uint32_t code; uint32_t code;
} HuffEntry; } HuffEntry;
@@ -245,32 +244,18 @@ static av_cold int magy_encode_init(AVCodecContext *avctx)
return 0; 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; for (unsigned i = 32, nb_codes = 0; i > 0; i--) {
return (aa->len - bb->len) * 256 + aa->sym - bb->sym; 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
} }
static int huff_cmp_sym(const void *a, const void *b) for (unsigned i = 0; i < 256; i++) {
{ he[i].code = codes_count[he[i].len];
const HuffEntry *aa = a, *bb = b; codes_count[he[i].len]++;
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);
}
AV_QSORT(he, 256, HuffEntry, huff_cmp_sym);
} }
static void count_usage(uint8_t *src, int width, 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, static void magy_huffman_compute_bits(PTable *prob_table, HuffEntry *distincts,
uint16_t codes_counts[33],
int size, int max_length) int size, int max_length)
{ {
PackageMergerList list_a, list_b, *to = &list_a, *from = &list_b, *temp; 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++) { for (i = 0; i < size; i++) {
distincts[i].sym = i;
distincts[i].len = nbits[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) PutBitContext *pb, HuffEntry *he)
{ {
PTable counts[256] = { {0} }; PTable counts[256] = { {0} };
uint16_t codes_counts[33] = { 0 };
int i; int i;
count_usage(dst, width, height, counts); count_usage(dst, width, height, counts);
for (i = 0; i < 256; i++) { for (i = 0; i < 256; i++) {
counts[i].prob++; 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++) { for (i = 0; i < 256; i++) {
put_bits(pb, 1, 0); put_bits(pb, 1, 0);