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* simplified indexing

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* ignoring error from msmpeg4_decode_block

Originally committed as revision 307 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Zdenek Kabelac 2002-02-18 09:34:54 +00:00
parent af8793ae75
commit 38d171ebbe
1 changed files with 22 additions and 19 deletions
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41
libavcodec/msmpeg4.c
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@ -410,20 +410,22 @@ void msmpeg4_dc_scale(MpegEncContext * s)
static int msmpeg4_pred_dc(MpegEncContext * s, int n,
INT16 **dc_val_ptr, int *dir_ptr)
{
int a, b, c, x, y, wrap, pred, scale;
int a, b, c, xy, wrap, pred, scale;
INT16 *dc_val;
/* find prediction */
if (n < 4) {
x = 2 * s->mb_x + 1 + (n & 1);
y = 2 * s->mb_y + 1 + ((n & 2) >> 1);
wrap = s->mb_width * 2 + 2;
xy = 2 * s->mb_y + 1 + ((n & 2) >> 1);
xy *= wrap;
xy += 2 * s->mb_x + 1 + (n & 1);
dc_val = s->dc_val[0];
scale = s->y_dc_scale;
} else {
x = s->mb_x + 1;
y = s->mb_y + 1;
wrap = s->mb_width + 2;
xy = s->mb_y + 1;
xy *= wrap;
xy += s->mb_x + 1;
dc_val = s->dc_val[n - 4 + 1];
scale = s->c_dc_scale;
}
@ -431,9 +433,9 @@ static int msmpeg4_pred_dc(MpegEncContext * s, int n,
/* B C
* A X
*/
a = dc_val[(x - 1) + (y) * wrap];
b = dc_val[(x - 1) + (y - 1) * wrap];
c = dc_val[(x) + (y - 1) * wrap];
a = dc_val[xy - 1];
b = dc_val[xy - 1 - wrap];
c = dc_val[xy - wrap];
/* XXX: the following solution consumes divisions, but it does not
necessitate to modify mpegvideo.c. The problem comes from the
@ -484,7 +486,7 @@ static int msmpeg4_pred_dc(MpegEncContext * s, int n,
}
/* update predictor */
*dc_val_ptr = &dc_val[(x) + (y) * wrap];
*dc_val_ptr = &dc_val[xy];
return pred;
}
@ -776,7 +778,7 @@ int msmpeg4_decode_ext_header(MpegEncContext * s, int buf_size)
return 0;
}
void memsetw(short *tab, int val, int n)
static inline void memsetw(short *tab, int val, int n)
{
int i;
for(i=0;i<n;i++)
@ -787,7 +789,6 @@ int msmpeg4_decode_mb(MpegEncContext *s,
DCTELEM block[6][64])
{
int cbp, code, i;
int pred, val;
UINT8 *coded_val;
/* special slice handling */
@ -840,10 +841,8 @@ int msmpeg4_decode_mb(MpegEncContext *s,
code = get_vlc(&s->gb, &mb_non_intra_vlc);
if (code < 0)
return -1;
if (code & 0x40)
s->mb_intra = 0;
else
s->mb_intra = 1;
//s->mb_intra = (code & 0x40) ? 0 : 1;
s->mb_intra = (~code & 0x40) >> 6;
cbp = code & 0x3f;
} else {
@ -855,9 +854,9 @@ int msmpeg4_decode_mb(MpegEncContext *s,
/* predict coded block pattern */
cbp = 0;
for(i=0;i<6;i++) {
val = ((code >> (5 - i)) & 1);
int val = ((code >> (5 - i)) & 1);
if (i < 4) {
pred = coded_block_pred(s, i, &coded_val);
int pred = coded_block_pred(s, i, &coded_val);
val = val ^ pred;
*coded_val = val;
}
@ -882,7 +881,10 @@ int msmpeg4_decode_mb(MpegEncContext *s,
for (i = 0; i < 6; i++) {
if (msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1) < 0)
return -1;
{
fprintf(stderr,"\nIgnoring error while decoding block: %d x %d (%d)\n", s->mb_x, s->mb_y, i);
// return -1;
}
}
return 0;
}
@ -953,7 +955,8 @@ static int msmpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
run = get_bits(&s->gb, 6);
level = get_bits(&s->gb, 8);
level = (level << 24) >> 24; /* sign extend */
if(level>0) level= level * qmul + qadd;
//level = level * qmul + (level>0) * qadd - (level<=0) * qadd ;
if (level>0) level= level * qmul + qadd;
else level= level * qmul - qadd;
} else {
/* second escape */