[FFmpeg-devel] [PATCH] avcodec: add C xvid IDCT support

Michael Niedermayer michaelni at gmx.at
Mon Aug 11 05:18:32 CEST 2014


From: Pascal Massimino <pascal.massimino at gmail.com>

Thanks to Pascal Massimino and Michael Militzer for permission to use under LGPL
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
 libavcodec/Makefile      |    2 +-
 libavcodec/xvid_c_idct.c |  335 ++++++++++++++++++++++++++++++++++++++++++++++
 libavcodec/xvididct.c    |   60 +++++++++
 libavcodec/xvididct.h    |    2 +
 4 files changed, 398 insertions(+), 1 deletion(-)
 create mode 100644 libavcodec/xvid_c_idct.c

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 6873439..55b7b02 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -325,7 +325,7 @@ OBJS-$(CONFIG_MPEG1VIDEO_DECODER)      += mpeg12dec.o mpeg12.o mpeg12data.o
 OBJS-$(CONFIG_MPEG1VIDEO_ENCODER)      += mpeg12enc.o mpeg12.o
 OBJS-$(CONFIG_MPEG2VIDEO_DECODER)      += mpeg12dec.o mpeg12.o mpeg12data.o
 OBJS-$(CONFIG_MPEG2VIDEO_ENCODER)      += mpeg12enc.o mpeg12.o
-OBJS-$(CONFIG_MPEG4_DECODER)           += xvididct.o
+OBJS-$(CONFIG_MPEG4_DECODER)           += xvididct.o xvid_c_idct.o
 OBJS-$(CONFIG_MPL2_DECODER)            += mpl2dec.o ass.o
 OBJS-$(CONFIG_MSMPEG4V1_DECODER)       += msmpeg4dec.o msmpeg4.o msmpeg4data.o
 OBJS-$(CONFIG_MSMPEG4V2_DECODER)       += msmpeg4dec.o msmpeg4.o msmpeg4data.o
diff --git a/libavcodec/xvid_c_idct.c b/libavcodec/xvid_c_idct.c
new file mode 100644
index 0000000..b15fb8e
--- /dev/null
+++ b/libavcodec/xvid_c_idct.c
@@ -0,0 +1,335 @@
+/*****************************************************************************
+ *
+ *  XVID MPEG-4 VIDEO CODEC
+ *  - Inverse DCT  -
+ *
+ *  Copyright (C) 2006-2011 Xvid Solutions GmbH
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * $Id$
+ *
+ ****************************************************************************/
+
+/*
+ *  Authors: Skal
+ *
+ *  Walken IDCT
+ *  Alternative idct implementations for decoding compatibility
+ *
+ *  NOTE: this "C" version is not the original one,
+ *  but is modified to yield the same error profile
+ *  than the MMX version.
+ *
+ ************************************************************************/
+
+#include "xvididct.h"
+
+
+#define XVID_DSP_CLIP_255(x)   ( ((x)&~255) ? ((-(x)) >> (8*sizeof((x))-1))&0xff : (x) )
+
+#define ROW_SHIFT 11
+#define COL_SHIFT 6
+
+// #define FIX(x)   (int)((x) * (1<<ROW_SHIFT))
+#define Rnd0 65536 // 1<<(COL_SHIFT+ROW_SHIFT-1);
+#define Rnd1 3597  // FIX (1.75683487303);
+#define Rnd2 2260  // FIX (1.10355339059);
+#define Rnd3 1203  // FIX (0.587788325588);
+#define Rnd4 0
+#define Rnd5 120   // FIX (0.058658283817);
+#define Rnd6 512   // FIX (0.25);
+#define Rnd7 512   // FIX (0.25);
+#undef FIX
+
+static const int Tab04[] = { 22725, 21407, 19266, 16384, 12873,  8867, 4520 };
+static const int Tab17[] = { 31521, 29692, 26722, 22725, 17855, 12299, 6270 };
+static const int Tab26[] = { 29692, 27969, 25172, 21407, 16819, 11585, 5906 };
+static const int Tab35[] = { 26722, 25172, 22654, 19266, 15137, 10426, 5315 };
+
+static int Idct_Row(short * In, const int * const Tab, int Rnd)
+{
+  const int C1 = Tab[0];
+  const int C2 = Tab[1];
+  const int C3 = Tab[2];
+  const int C4 = Tab[3];
+  const int C5 = Tab[4];
+  const int C6 = Tab[5];
+  const int C7 = Tab[6];
+
+  const int Right = In[5]|In[6]|In[7];
+  const int Left  = In[1]|In[2]|In[3];
+  if (!(Right | In[4]))
+  {
+    const int K = C4*In[0] + Rnd;
+    if (Left)
+    {
+      const int a0 = K + C2*In[2];
+      const int a1 = K + C6*In[2];
+      const int a2 = K - C6*In[2];
+      const int a3 = K - C2*In[2];
+
+      const int b0 = C1*In[1] + C3*In[3];
+      const int b1 = C3*In[1] - C7*In[3];
+      const int b2 = C5*In[1] - C1*In[3];
+      const int b3 = C7*In[1] - C5*In[3];
+
+      In[0] = (a0 + b0) >> ROW_SHIFT;
+      In[1] = (a1 + b1) >> ROW_SHIFT;
+      In[2] = (a2 + b2) >> ROW_SHIFT;
+      In[3] = (a3 + b3) >> ROW_SHIFT;
+      In[4] = (a3 - b3) >> ROW_SHIFT;
+      In[5] = (a2 - b2) >> ROW_SHIFT;
+      In[6] = (a1 - b1) >> ROW_SHIFT;
+      In[7] = (a0 - b0) >> ROW_SHIFT;
+    }
+    else
+    {
+      const int a0 = K >> ROW_SHIFT;
+      if (a0) {
+        In[0] = In[1] = In[2] = In[3] =
+        In[4] = In[5] = In[6] = In[7] = a0;
+      }
+      else return 0;
+    }
+  }
+  else if (!(Left|Right))
+  {
+    const int a0 = (Rnd + C4*(In[0]+In[4])) >> ROW_SHIFT;
+    const int a1 = (Rnd + C4*(In[0]-In[4])) >> ROW_SHIFT;
+
+    In[0] = a0;
+    In[3] = a0;
+    In[4] = a0;
+    In[7] = a0;
+    In[1] = a1;
+    In[2] = a1;
+    In[5] = a1;
+    In[6] = a1;
+  }
+  else
+  {
+    const int K = C4*In[0] + Rnd;
+    const int a0 = K + C2*In[2] + C4*In[4] + C6*In[6];
+    const int a1 = K + C6*In[2] - C4*In[4] - C2*In[6];
+    const int a2 = K - C6*In[2] - C4*In[4] + C2*In[6];
+    const int a3 = K - C2*In[2] + C4*In[4] - C6*In[6];
+
+    const int b0 = C1*In[1] + C3*In[3] + C5*In[5] + C7*In[7];
+    const int b1 = C3*In[1] - C7*In[3] - C1*In[5] - C5*In[7];
+    const int b2 = C5*In[1] - C1*In[3] + C7*In[5] + C3*In[7];
+    const int b3 = C7*In[1] - C5*In[3] + C3*In[5] - C1*In[7];
+
+    In[0] = (a0 + b0) >> ROW_SHIFT;
+    In[1] = (a1 + b1) >> ROW_SHIFT;
+    In[2] = (a2 + b2) >> ROW_SHIFT;
+    In[3] = (a3 + b3) >> ROW_SHIFT;
+    In[4] = (a3 - b3) >> ROW_SHIFT;
+    In[5] = (a2 - b2) >> ROW_SHIFT;
+    In[6] = (a1 - b1) >> ROW_SHIFT;
+    In[7] = (a0 - b0) >> ROW_SHIFT;
+  }
+  return 1;
+}
+
+#define Tan1  0x32ec
+#define Tan2  0x6a0a
+#define Tan3  0xab0e
+#define Sqrt2 0x5a82
+
+#define MULT(c,x, n)  ( ((c) * (x)) >> (n) )
+// 12b version => #define MULT(c,x, n)  ( (((c)>>3) * (x)) >> ((n)-3) )
+// 12b zero-testing version:
+
+#define BUTF(a, b, tmp) \
+  (tmp) = (a)+(b);      \
+  (b)   = (a)-(b);      \
+  (a)   = (tmp)
+
+#define LOAD_BUTF(m1, m2, a, b, tmp, S) \
+  (m1) = (S)[(a)] + (S)[(b)];           \
+  (m2) = (S)[(a)] - (S)[(b)]
+
+static void Idct_Col_8(short * const In)
+{
+  int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
+
+    // odd
+
+  mm4 = (int)In[7*8];
+  mm5 = (int)In[5*8];
+  mm6 = (int)In[3*8];
+  mm7 = (int)In[1*8];
+
+  mm0 = MULT(Tan1, mm4, 16) + mm7;
+  mm1 = MULT(Tan1, mm7, 16) - mm4;
+  mm2 = MULT(Tan3, mm5, 16) + mm6;
+  mm3 = MULT(Tan3, mm6, 16) - mm5;
+
+  mm7 = mm0 + mm2;
+  mm4 = mm1 - mm3;
+  mm0 = mm0 - mm2;
+  mm1 = mm1 + mm3;
+  mm6 = mm0 + mm1;
+  mm5 = mm0 - mm1;
+  mm5 = 2*MULT(Sqrt2, mm5, 16);  // 2*sqrt2
+  mm6 = 2*MULT(Sqrt2, mm6, 16);  // Watch out: precision loss but done to match
+                                 // the pmulhw used in mmx/sse versions
+
+    // even
+
+  mm1 = (int)In[2*8];
+  mm2 = (int)In[6*8];
+  mm3 = MULT(Tan2,mm2, 16) + mm1;
+  mm2 = MULT(Tan2,mm1, 16) - mm2;
+
+  LOAD_BUTF(mm0, mm1, 0*8, 4*8, Spill, In);
+
+  BUTF(mm0, mm3, Spill);
+  BUTF(mm0, mm7, Spill);
+  In[8*0] = (int16_t) (mm0 >> COL_SHIFT);
+  In[8*7] = (int16_t) (mm7 >> COL_SHIFT);
+  BUTF(mm3, mm4, mm0);
+  In[8*3] = (int16_t) (mm3 >> COL_SHIFT);
+  In[8*4] = (int16_t) (mm4 >> COL_SHIFT);
+
+  BUTF(mm1, mm2, mm0);
+  BUTF(mm1, mm6, mm0);
+  In[8*1] = (int16_t) (mm1 >> COL_SHIFT);
+  In[8*6] = (int16_t) (mm6 >> COL_SHIFT);
+  BUTF(mm2, mm5, mm0);
+  In[8*2] = (int16_t) (mm2 >> COL_SHIFT);
+  In[8*5] = (int16_t) (mm5 >> COL_SHIFT);
+}
+
+static void Idct_Col_4(short * const In)
+{
+  int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
+
+    // odd
+
+  mm0 = (int)In[1*8];
+  mm2 = (int)In[3*8];
+
+  mm1 = MULT(Tan1, mm0, 16);
+  mm3 = MULT(Tan3, mm2, 16);
+
+  mm7 = mm0 + mm2;
+  mm4 = mm1 - mm3;
+  mm0 = mm0 - mm2;
+  mm1 = mm1 + mm3;
+  mm6 = mm0 + mm1;
+  mm5 = mm0 - mm1;
+  mm6 = 2*MULT(Sqrt2, mm6, 16);  // 2*sqrt2
+  mm5 = 2*MULT(Sqrt2, mm5, 16);
+
+    // even
+
+  mm0 = mm1 = (int)In[0*8];
+  mm3 = (int)In[2*8];
+  mm2 = MULT(Tan2,mm3, 16);
+
+  BUTF(mm0, mm3, Spill);
+  BUTF(mm0, mm7, Spill);
+  In[8*0] = (int16_t) (mm0 >> COL_SHIFT);
+  In[8*7] = (int16_t) (mm7 >> COL_SHIFT);
+  BUTF(mm3, mm4, mm0);
+  In[8*3] = (int16_t) (mm3 >> COL_SHIFT);
+  In[8*4] = (int16_t) (mm4 >> COL_SHIFT);
+
+  BUTF(mm1, mm2, mm0);
+  BUTF(mm1, mm6, mm0);
+  In[8*1] = (int16_t) (mm1 >> COL_SHIFT);
+  In[8*6] = (int16_t) (mm6 >> COL_SHIFT);
+  BUTF(mm2, mm5, mm0);
+  In[8*2] = (int16_t) (mm2 >> COL_SHIFT);
+  In[8*5] = (int16_t) (mm5 >> COL_SHIFT);
+}
+
+static void Idct_Col_3(short * const In)
+{
+  int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
+
+    // odd
+
+  mm7 = (int)In[1*8];
+  mm4 = MULT(Tan1, mm7, 16);
+
+  mm6 = mm7 + mm4;
+  mm5 = mm7 - mm4;
+  mm6 = 2*MULT(Sqrt2, mm6, 16);  // 2*sqrt2
+  mm5 = 2*MULT(Sqrt2, mm5, 16);
+
+    // even
+
+  mm0 = mm1 = (int)In[0*8];
+  mm3 = (int)In[2*8];
+  mm2 = MULT(Tan2,mm3, 16);
+
+  BUTF(mm0, mm3, Spill);
+  BUTF(mm0, mm7, Spill);
+  In[8*0] = (int16_t) (mm0 >> COL_SHIFT);
+  In[8*7] = (int16_t) (mm7 >> COL_SHIFT);
+  BUTF(mm3, mm4, mm0);
+  In[8*3] = (int16_t) (mm3 >> COL_SHIFT);
+  In[8*4] = (int16_t) (mm4 >> COL_SHIFT);
+
+  BUTF(mm1, mm2, mm0);
+  BUTF(mm1, mm6, mm0);
+  In[8*1] = (int16_t) (mm1 >> COL_SHIFT);
+  In[8*6] = (int16_t) (mm6 >> COL_SHIFT);
+  BUTF(mm2, mm5, mm0);
+  In[8*2] = (int16_t) (mm2 >> COL_SHIFT);
+  In[8*5] = (int16_t) (mm5 >> COL_SHIFT);
+}
+
+#undef Tan1
+#undef Tan2
+#undef Tan3
+#undef Sqrt2
+
+#undef ROW_SHIFT
+#undef COL_SHIFT
+
+//////////////////////////////////////////////////////////
+
+void ff_idct_xvid(int16_t *const In)
+{
+  int i, Rows = 0x07;
+
+  Idct_Row(In + 0*8, Tab04, Rnd0);
+  Idct_Row(In + 1*8, Tab17, Rnd1);
+  Idct_Row(In + 2*8, Tab26, Rnd2);
+  if (Idct_Row(In + 3*8, Tab35, Rnd3)) Rows |= 0x08;
+  if (Idct_Row(In + 4*8, Tab04, Rnd4)) Rows |= 0x10;
+  if (Idct_Row(In + 5*8, Tab35, Rnd5)) Rows |= 0x20;
+  if (Idct_Row(In + 6*8, Tab26, Rnd6)) Rows |= 0x40;
+  if (Idct_Row(In + 7*8, Tab17, Rnd7)) Rows |= 0x80;
+
+  if (Rows&0xf0) {
+    for(i=0; i<8; i++)
+      Idct_Col_8(In + i);
+  }
+  else if (Rows&0x08) {
+    for(i=0; i<8; i++)
+      Idct_Col_4(In + i);
+  }
+  else {
+    for(i=0; i<8; i++)
+      Idct_Col_3(In + i);
+  }
+}
diff --git a/libavcodec/xvididct.c b/libavcodec/xvididct.c
index 8645af4..9b07518 100644
--- a/libavcodec/xvididct.c
+++ b/libavcodec/xvididct.c
@@ -22,6 +22,59 @@
 #include "idctdsp.h"
 #include "xvididct.h"
 
+static void put_pixels_clamped_c(const int16_t *block, uint8_t *av_restrict pixels,
+                                 int line_size)
+{
+    int i;
+
+    /* read the pixels */
+    for (i = 0; i < 8; i++) {
+        pixels[0] = av_clip_uint8(block[0]);
+        pixels[1] = av_clip_uint8(block[1]);
+        pixels[2] = av_clip_uint8(block[2]);
+        pixels[3] = av_clip_uint8(block[3]);
+        pixels[4] = av_clip_uint8(block[4]);
+        pixels[5] = av_clip_uint8(block[5]);
+        pixels[6] = av_clip_uint8(block[6]);
+        pixels[7] = av_clip_uint8(block[7]);
+
+        pixels += line_size;
+        block  += 8;
+    }
+}
+
+static void add_pixels_clamped_c(const int16_t *block, uint8_t *av_restrict pixels,
+                                 int line_size)
+{
+    int i;
+
+    /* read the pixels */
+    for (i = 0; i < 8; i++) {
+        pixels[0] = av_clip_uint8(pixels[0] + block[0]);
+        pixels[1] = av_clip_uint8(pixels[1] + block[1]);
+        pixels[2] = av_clip_uint8(pixels[2] + block[2]);
+        pixels[3] = av_clip_uint8(pixels[3] + block[3]);
+        pixels[4] = av_clip_uint8(pixels[4] + block[4]);
+        pixels[5] = av_clip_uint8(pixels[5] + block[5]);
+        pixels[6] = av_clip_uint8(pixels[6] + block[6]);
+        pixels[7] = av_clip_uint8(pixels[7] + block[7]);
+        pixels   += line_size;
+        block    += 8;
+    }
+}
+
+static void idct_xvid_put(uint8_t *dest, int line_size, int16_t *block)
+{
+    ff_idct_xvid(block);
+    put_pixels_clamped_c(block, dest, line_size);
+}
+
+static void idct_xvid_add(uint8_t *dest, int line_size, int16_t *block)
+{
+    ff_idct_xvid(block);
+    add_pixels_clamped_c(block, dest, line_size);
+}
+
 av_cold void ff_xvididct_init(IDCTDSPContext *c, AVCodecContext *avctx)
 {
     const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8;
@@ -31,6 +84,13 @@ av_cold void ff_xvididct_init(IDCTDSPContext *c, AVCodecContext *avctx)
           avctx->idct_algo == FF_IDCT_XVID))
         return;
 
+    if (avctx->idct_algo == FF_IDCT_XVID) {
+        c->idct_put  = idct_xvid_put;
+        c->idct_add  = idct_xvid_add;
+        c->idct      = ff_idct_xvid;
+        c->perm_type = FF_IDCT_PERM_NONE;
+    }
+
     if (ARCH_X86)
         ff_xvididct_init_x86(c);
 
diff --git a/libavcodec/xvididct.h b/libavcodec/xvididct.h
index 6678329..1b95cb7 100644
--- a/libavcodec/xvididct.h
+++ b/libavcodec/xvididct.h
@@ -26,4 +26,6 @@ void ff_xvididct_init(IDCTDSPContext *c, AVCodecContext *avctx);
 
 void ff_xvididct_init_x86(IDCTDSPContext *c);
 
+void ff_idct_xvid(int16_t *const In);
+
 #endif /* AVCODEC_XVIDIDCT_H */
-- 
1.7.9.5



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