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mpeg124: use sign_extend() function 

Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2011-10-09 23:16:07 +01:00
parent 633ddb8519
commit aa498fef0d
3 changed files with 6 additions and 10 deletions
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5
libavcodec/ituh263dec.c
View File

@ -271,7 +271,7 @@ int ff_h263_resync(MpegEncContext *s){
int h263_decode_motion(MpegEncContext * s, int pred, int f_code) int h263_decode_motion(MpegEncContext * s, int pred, int f_code)
{ {
int code, val, sign, shift, l; int code, val, sign, shift;
code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2); code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
if (code == 0) if (code == 0)
@ -293,8 +293,7 @@ int h263_decode_motion(MpegEncContext * s, int pred, int f_code)
/* modulo decoding */ /* modulo decoding */
if (!s->h263_long_vectors) { if (!s->h263_long_vectors) {
l = INT_BIT - 5 - f_code; val = sign_extend(val, 5 + f_code);
val = (val<<l)>>l;
} else { } else {
/* horrible h263 long vector mode */ /* horrible h263 long vector mode */
if (pred < -31 && val < -63) if (pred < -31 && val < -63)

5
libavcodec/ituh263enc.c
View File

@ -657,7 +657,7 @@ void h263_encode_mb(MpegEncContext * s,
void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code) void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
{ {
int range, l, bit_size, sign, code, bits; int range, bit_size, sign, code, bits;
if (val == 0) { if (val == 0) {
/* zero vector */ /* zero vector */
@ -667,8 +667,7 @@ void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
bit_size = f_code - 1; bit_size = f_code - 1;
range = 1 << bit_size; range = 1 << bit_size;
/* modulo encoding */ /* modulo encoding */
l= INT_BIT - 6 - bit_size; val = sign_extend(val, 6 + bit_size);
val = (val<<l)>>l;
sign = val>>31; sign = val>>31;
val= (val^sign)-sign; val= (val^sign)-sign;
sign&=1; sign&=1;

6
libavcodec/mpeg12.c
View File

@ -54,7 +54,7 @@ static VLC mv_vlc;
/* as H.263, but only 17 codes */ /* as H.263, but only 17 codes */
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred) static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
{ {
int code, sign, val, l, shift; int code, sign, val, shift;
code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2); code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
if (code == 0) { if (code == 0) {
@ -77,9 +77,7 @@ static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
val += pred; val += pred;
/* modulo decoding */ /* modulo decoding */
l = INT_BIT - 5 - shift; return sign_extend(val, 5 + shift);
val = (val << l) >> l;
return val;
} }
static inline int mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n) static inline int mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n)