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mpeg12dec: Refactor mpeg1_decode_block_intra()

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Reduce variable scope, improve variable name, drop pointless ff_dlog(),
merge variable declaration and initialization, whitespace cosmetics.
This commit is contained in:
Diego Biurrun 2016-02-06 18:02:47 +01:00
parent cdbaa43604
commit 249827f736
1 changed files with 18 additions and 11 deletions
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27
libavcodec/mpeg12dec.c
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@ -139,30 +139,33 @@ static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
} while (0)
static inline int mpeg1_decode_block_intra(MpegEncContext *s,
int16_t *block, int n)
int16_t *block, int index)
{
int level, dc, diff, i, j, run;
int component;
int dc, diff, i = 0, component;
RLTable *rl = &ff_rl_mpeg1;
uint8_t *const scantable = s->intra_scantable.permutated;
const uint16_t *quant_matrix = s->intra_matrix;
const int qscale = s->qscale;
/* DC coefficient */
component = (n <= 3 ? 0 : n - 4 + 1);
component = index <= 3 ? 0 : index - 4 + 1;
diff = decode_dc(&s->gb, component);
if (diff >= 0xffff)
return AVERROR_INVALIDDATA;
dc = s->last_dc[component];
dc += diff;
s->last_dc[component] = dc;
block[0] = dc * quant_matrix[0];
ff_dlog(s->avctx, "dc=%d diff=%d\n", dc, diff);
i = 0;
{
OPEN_READER(re, &s->gb);
/* now quantify & encode AC coefficients */
for (;;) {
while (1) {
int level, run, j;
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0],
TEX_VLC_BITS, 2, 0);
@ -173,6 +176,7 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s,
i += run;
if (i > MAX_INDEX)
break;
j = scantable[i];
level = (level * qscale * quant_matrix[j]) >> 4;
level = (level - 1) | 1;
@ -186,6 +190,7 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s,
UPDATE_CACHE(re, &s->gb);
level = SHOW_SBITS(re, &s->gb, 8);
SKIP_BITS(re, &s->gb, 8);
if (level == -128) {
level = SHOW_UBITS(re, &s->gb, 8) - 256;
LAST_SKIP_BITS(re, &s->gb, 8);
@ -193,9 +198,11 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s,
level = SHOW_UBITS(re, &s->gb, 8);
LAST_SKIP_BITS(re, &s->gb, 8);
}
i += run;
if (i > MAX_INDEX)
break;
j = scantable[i];
if (level < 0) {
level = -level;
@ -215,13 +222,13 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s,
check_scantable_index(s, i);
s->block_last_index[n] = i;
s->block_last_index[index] = i;
return 0;
}
int ff_mpeg1_decode_block_intra(MpegEncContext *s, int16_t *block, int n)
int ff_mpeg1_decode_block_intra(MpegEncContext *s, int16_t *block, int index)
{
return mpeg1_decode_block_intra(s, block, n);
return mpeg1_decode_block_intra(s, block, index);
}
static inline int mpeg1_decode_block_inter(MpegEncContext *s,