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authorFalk Hüffner <mellum@users.sourceforge.net>2002-07-03 03:01:06 +0000
committerFalk Hüffner <mellum@users.sourceforge.net>2002-07-03 03:01:06 +0000
commite0580f8c688f0dcb87f2bf71b08f477ba583e8dd (patch)
tree009a07b3b0233a93a398f212ba94e984a5712685 /libavcodec/alpha/mpegvideo_alpha.c
parentdde3f77dbc30a6564ca8ad373b7517f282983bdb (diff)
downloadffmpeg-e0580f8c688f0dcb87f2bf71b08f477ba583e8dd.tar.gz
Update and activate dct_unquantize_h263_mvi. Thanks to Måns Rullgård
for some improvements. Originally committed as revision 714 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/alpha/mpegvideo_alpha.c')
-rw-r--r--libavcodec/alpha/mpegvideo_alpha.c105
1 files changed, 53 insertions, 52 deletions
diff --git a/libavcodec/alpha/mpegvideo_alpha.c b/libavcodec/alpha/mpegvideo_alpha.c
index eb1997eee7..443857e571 100644
--- a/libavcodec/alpha/mpegvideo_alpha.c
+++ b/libavcodec/alpha/mpegvideo_alpha.c
@@ -23,69 +23,70 @@
extern UINT8 zigzag_end[64];
-static void dct_unquantize_h263_axp(MpegEncContext *s,
- DCTELEM *block, int n, int qscale)
+static void dct_unquantize_h263_mvi(MpegEncContext *s, DCTELEM *block,
+ int n, int qscale)
{
- int i, level;
- UINT64 qmul, qadd;
+ int i, n_coeffs;
+ uint64_t qmul, qadd;
+ uint64_t correction;
+ DCTELEM *orig_block = block;
+ DCTELEM block0;
ASM_ACCEPT_MVI;
-
+
if (s->mb_intra) {
- if (n < 4)
- block[0] = block[0] * s->y_dc_scale;
- else
- block[0] = block[0] * s->c_dc_scale;
- /* Catch up to aligned point. */
- qmul = s->qscale << 1;
- qadd = (s->qscale - 1) | 1;
- for (i = 1; i < 4; ++i) {
- level = block[i];
- if (level) {
- if (level < 0) {
- level = level * qmul - qadd;
- } else {
- level = level * qmul + qadd;
- }
- block[i] = level;
- }
- }
- block += 4;
- i = 60 / 4;
+ if (!s->h263_aic) {
+ if (n < 4)
+ block0 = block[0] * s->y_dc_scale;
+ else
+ block0 = block[0] * s->c_dc_scale;
+ }
+ n_coeffs = 64; // does not always use zigzag table
} else {
- i = zigzag_end[s->block_last_index[n]] / 4;
+ n_coeffs = zigzag_end[s->block_last_index[n]];
}
- qmul = s->qscale << 1;
+
+ qmul = qscale << 1;
qadd = WORD_VEC((qscale - 1) | 1);
- do {
- UINT64 levels, negmask, zeromask, corr;
- levels = ldq(block);
- if (levels == 0)
- continue;
- zeromask = cmpbge(0, levels);
- zeromask &= zeromask >> 1;
- /* Negate all negative words. */
- negmask = maxsw4(levels, WORD_VEC(0xffff)); /* negative -> ffff (-1) */
- negmask = minsw4(negmask, 0); /* positive -> 0000 (0) */
- corr = negmask & WORD_VEC(0x0001); /* twos-complement correction */
- levels ^= negmask;
- levels += corr;
-
- levels = levels * qmul;
- levels += zap(qadd, zeromask);
-
- /* Re-negate negative words. */
- levels -= corr;
- levels ^= negmask;
-
- stq(levels, block);
- } while (block += 4, --i);
+ /* This mask kills spill from negative subwords to the next subword. */
+ correction = WORD_VEC((qmul - 1) + 1); /* multiplication / addition */
+
+ for(i = 0; i < n_coeffs; block += 4, i += 4) {
+ uint64_t levels, negmask, zeros, add;
+
+ levels = ldq(block);
+ if (levels == 0)
+ continue;
+
+ negmask = maxsw4(levels, -1); /* negative -> ffff (-1) */
+ negmask = minsw4(negmask, 0); /* positive -> 0000 (0) */
+
+ zeros = cmpbge(0, levels);
+ zeros &= zeros >> 1;
+ /* zeros |= zeros << 1 is not needed since qadd <= 255, so
+ zapping the lower byte suffices. */
+
+ levels *= qmul;
+ levels -= correction & (negmask << 16);
+
+ /* Negate qadd for negative levels. */
+ add = qadd ^ negmask;
+ add += WORD_VEC(0x0001) & negmask;
+ /* Set qadd to 0 for levels == 0. */
+ add = zap(add, zeros);
+
+ levels += add;
+
+ stq(levels, block);
+ }
+
+ if (s->mb_intra && !s->h263_aic)
+ orig_block[0] = block0;
}
void MPV_common_init_axp(MpegEncContext *s)
{
if (amask(AMASK_MVI) == 0) {
- if (s->out_format == FMT_H263)
- s->dct_unquantize = dct_unquantize_h263_axp;
+ s->dct_unquantize_h263 = dct_unquantize_h263_mvi;
}
}