FFmpeg
mpegvideo_altivec.c
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1 /*
2  * Copyright (c) 2002 Dieter Shirley
3  *
4  * dct_unquantize_h263_altivec:
5  * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include <stdlib.h>
25 #include <stdio.h>
26 
27 #include "config.h"
28 
29 #include "libavutil/attributes.h"
30 #include "libavutil/cpu.h"
31 #include "libavutil/mem_internal.h"
32 #include "libavutil/ppc/cpu.h"
34 
35 #include "libavcodec/mpegvideo.h"
36 
37 #if HAVE_ALTIVEC
38 
39 /* AltiVec version of dct_unquantize_h263
40  this code assumes `block' is 16 bytes-aligned */
41 static void dct_unquantize_h263_altivec(MpegEncContext *s,
42  int16_t *block, int n, int qscale)
43 {
44  int i, level, qmul, qadd;
45  int nCoeffs;
46 
47  qadd = (qscale - 1) | 1;
48  qmul = qscale << 1;
49 
50  if (s->mb_intra) {
51  if (!s->h263_aic) {
52  if (n < 4)
53  block[0] = block[0] * s->y_dc_scale;
54  else
55  block[0] = block[0] * s->c_dc_scale;
56  }else
57  qadd = 0;
58  i = 1;
59  nCoeffs= 63; //does not always use zigzag table
60  } else {
61  i = 0;
62  av_assert2(s->block_last_index[n]>=0);
63  nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ];
64  }
65 
66  {
67  register const vector signed short vczero = (const vector signed short)vec_splat_s16(0);
68  DECLARE_ALIGNED(16, short, qmul8) = qmul;
69  DECLARE_ALIGNED(16, short, qadd8) = qadd;
70  register vector signed short blockv, qmulv, qaddv, nqaddv, temp1;
71  register vector bool short blockv_null, blockv_neg;
72  register short backup_0 = block[0];
73  register int j = 0;
74 
75  qmulv = vec_splat((vec_s16)vec_lde(0, &qmul8), 0);
76  qaddv = vec_splat((vec_s16)vec_lde(0, &qadd8), 0);
77  nqaddv = vec_sub(vczero, qaddv);
78 
79  // vectorize all the 16 bytes-aligned blocks
80  // of 8 elements
81  for(; (j + 7) <= nCoeffs ; j+=8) {
82  blockv = vec_ld(j << 1, block);
83  blockv_neg = vec_cmplt(blockv, vczero);
84  blockv_null = vec_cmpeq(blockv, vczero);
85  // choose between +qadd or -qadd as the third operand
86  temp1 = vec_sel(qaddv, nqaddv, blockv_neg);
87  // multiply & add (block{i,i+7} * qmul [+-] qadd)
88  temp1 = vec_mladd(blockv, qmulv, temp1);
89  // put 0 where block[{i,i+7} used to have 0
90  blockv = vec_sel(temp1, blockv, blockv_null);
91  vec_st(blockv, j << 1, block);
92  }
93 
94  // if nCoeffs isn't a multiple of 8, finish the job
95  // using good old scalar units.
96  // (we could do it using a truncated vector,
97  // but I'm not sure it's worth the hassle)
98  for(; j <= nCoeffs ; j++) {
99  level = block[j];
100  if (level) {
101  if (level < 0) {
102  level = level * qmul - qadd;
103  } else {
104  level = level * qmul + qadd;
105  }
106  block[j] = level;
107  }
108  }
109 
110  if (i == 1) {
111  // cheat. this avoid special-casing the first iteration
112  block[0] = backup_0;
113  }
114  }
115 }
116 
117 #endif /* HAVE_ALTIVEC */
118 
120 {
121 #if HAVE_ALTIVEC
123  return;
124 
125  if ((s->avctx->dct_algo == FF_DCT_AUTO) ||
126  (s->avctx->dct_algo == FF_DCT_ALTIVEC)) {
127  s->dct_unquantize_h263_intra = dct_unquantize_h263_altivec;
128  s->dct_unquantize_h263_inter = dct_unquantize_h263_altivec;
129  }
130 #endif /* HAVE_ALTIVEC */
131 }
int dct_algo
DCT algorithm, see FF_DCT_* below.
Definition: avcodec.h:1701
void(* dct_unquantize_h263_inter)(struct MpegEncContext *s, int16_t *block, int n, int qscale)
Definition: mpegvideo.h:534
uint8_t raster_end[64]
Definition: idctdsp.h:34
mpegvideo header.
int h263_aic
Advanced INTRA Coding (AIC)
Definition: mpegvideo.h:87
Macro definitions for various function/variable attributes.
The exact code depends on how similar the blocks are and how related they are to the block
#define av_cold
Definition: attributes.h:88
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
av_cold void ff_mpv_common_init_ppc(MpegEncContext *s)
#define DECLARE_ALIGNED(n, t, v)
Declare a variable that is aligned in memory.
Definition: mem.h:117
#define vec_s16
Definition: util_altivec.h:37
#define PPC_ALTIVEC(flags)
Definition: cpu.h:25
#define FF_DCT_ALTIVEC
Definition: avcodec.h:1706
#define s(width, name)
Definition: cbs_vp9.c:257
int block_last_index[12]
last non zero coefficient in block
Definition: mpegvideo.h:86
ScanTable intra_scantable
Definition: mpegvideo.h:91
void(* dct_unquantize_h263_intra)(struct MpegEncContext *s, int16_t *block, int n, int qscale)
Definition: mpegvideo.h:532
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:95
Contains misc utility macros and inline functions.
uint8_t level
Definition: svq3.c:206
MpegEncContext.
Definition: mpegvideo.h:81
struct AVCodecContext * avctx
Definition: mpegvideo.h:98
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option keep it simple and lowercase description are short
#define FF_DCT_AUTO
Definition: avcodec.h:1702
int i
Definition: input.c:407