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avcodec/mpeg4videoenc: Remove no-output code

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While it offers modest speedups compared to the ordinary code,
removing it completely offers even bigger speedups; and given
that these speedups also exist in the ordinary mode, they are
even more important. The no-output code has a 7.8% performance
improvement (based on benchmarking mpeg4_encode_mb()), yet
removing the no-output code resulted in a 9.4% improvement.

Furthermore, the no-output code was broken for the majority of
its existence (until 9207dc3b0d)
and no one complained, so it is likely not used at all.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2025-05-18 18:33:55 +02:00
parent 2a59cb0c82
commit f7bd2a5af8
1 changed files with 0 additions and 76 deletions
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76
libavcodec/mpeg4videoenc.c
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@ -292,14 +292,6 @@ static inline void mpeg4_encode_dc(PutBitContext *s, int level, int n)
}
}
static inline int mpeg4_get_dc_length(int level, int n)
{
if (n < 4)
return uni_DCtab_lum_len[level + 256];
else
return uni_DCtab_chrom_len[level + 256];
}
/**
* Encode an 8x8 block.
* @param n block index (0-3 are luma, 4-5 are chroma)
@ -365,60 +357,6 @@ static inline void mpeg4_encode_block(const MPVEncContext *const s,
}
}
static int mpeg4_get_block_length(MPVEncContext *const s,
const int16_t *block, int n,
int intra_dc, const uint8_t *scan_table)
{
int i, last_non_zero;
const uint8_t *len_tab;
const int last_index = s->c.block_last_index[n];
int len = 0;
if (s->c.mb_intra) { // Note gcc (3.2.1 at least) will optimize this away
/* MPEG-4 based DC predictor */
len += mpeg4_get_dc_length(intra_dc, n);
if (last_index < 1)
return len;
i = 1;
len_tab = uni_mpeg4_intra_rl_len;
} else {
if (last_index < 0)
return 0;
i = 0;
len_tab = uni_mpeg4_inter_rl_len;
}
/* AC coefs */
last_non_zero = i - 1;
for (; i < last_index; i++) {
int level = block[scan_table[i]];
if (level) {
int run = i - last_non_zero - 1;
level += 64;
if ((level & (~127)) == 0) {
const int index = UNI_MPEG4_ENC_INDEX(0, run, level);
len += len_tab[index];
} else { // ESC3
len += 7 + 2 + 1 + 6 + 1 + 12 + 1;
}
last_non_zero = i;
}
}
/* if (i <= last_index) */ {
int level = block[scan_table[i]];
int run = i - last_non_zero - 1;
level += 64;
if ((level & (~127)) == 0) {
const int index = UNI_MPEG4_ENC_INDEX(1, run, level);
len += len_tab[index];
} else { // ESC3
len += 7 + 2 + 1 + 6 + 1 + 12 + 1;
}
}
return len;
}
static inline void mpeg4_encode_blocks(MPVEncContext *const s,
const int16_t block[6][64],
const int intra_dc[6],
@ -429,30 +367,16 @@ static inline void mpeg4_encode_blocks(MPVEncContext *const s,
int i;
if (scan_table) {
if (s->c.avctx->flags2 & AV_CODEC_FLAG2_NO_OUTPUT) {
for (i = 0; i < 6; i++)
skip_put_bits(&s->pb,
mpeg4_get_block_length(s, block[i], i,
intra_dc[i], scan_table[i]));
} else {
/* encode each block */
for (i = 0; i < 6; i++)
mpeg4_encode_block(s, block[i], i,
intra_dc[i], scan_table[i], dc_pb, ac_pb);
}
} else {
if (s->c.avctx->flags2 & AV_CODEC_FLAG2_NO_OUTPUT) {
for (i = 0; i < 6; i++)
skip_put_bits(&s->pb,
mpeg4_get_block_length(s, block[i], i, 0,
s->c.intra_scantable.permutated));
} else {
/* encode each block */
for (i = 0; i < 6; i++)
mpeg4_encode_block(s, block[i], i, 0,
s->c.intra_scantable.permutated, dc_pb, ac_pb);
}
}
}
static inline int get_b_cbp(MPVEncContext *const s, int16_t block[6][64],