svq3 decoder by anonymous

Originally committed as revision 1845 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 770 insertions, 0 deletions

diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c
new file mode 100644
index 0000000000..6d24a5c7da
--- /dev/null
+++ b/libavcodec/svq3.c
@@ -0,0 +1,770 @@
+/*
+ * Copyright (c) 2003 The FFmpeg Project.
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *
+ * How to use this decoder:
+ * SVQ3 data is transported within Apple Quicktime files. Quicktime files
+ * have stsd atoms to describe media trak properties. Sometimes the stsd
+ * atom contains information that the decoder must know in order to function
+ * properly. Such is the case with SVQ3. In order to get the best use out
+ * of this decoder, the calling app must make the video stsd atom available
+ * via the AVCodecContext's extradata[_size] field:
+ *
+ * AVCodecContext.extradata = pointer to stsd, first characters are expected
+ * to be 's', 't', 's', and 'd', NOT the atom length
+ * AVCodecContext.extradata_size = size of stsd atom memory buffer (which 
+ * will be the same as the stsd atom size field from the QT file, minus 4
+ * bytes since the length is missing.
+ *
+ */
+ 
+/**
+ * @file svq3.c
+ * svq3 decoder.
+ */
+
+static const uint8_t svq3_scan[16]={
+ 0+0*4, 1+0*4, 2+0*4, 2+1*4,
+ 2+2*4, 3+0*4, 3+1*4, 3+2*4,
+ 0+1*4, 0+2*4, 1+1*4, 1+2*4,
+ 0+3*4, 1+3*4, 2+3*4, 3+3*4,
+};
+
+static const uint8_t svq3_pred_0[25][2] = {
+  { 0, 0 },
+  { 1, 0 }, { 0, 1 },
+  { 0, 2 }, { 1, 1 }, { 2, 0 },
+  { 3, 0 }, { 2, 1 }, { 1, 2 }, { 0, 3 },
+  { 0, 4 }, { 1, 3 }, { 2, 2 }, { 3, 1 }, { 4, 0 },
+  { 4, 1 }, { 3, 2 }, { 2, 3 }, { 1, 4 },
+  { 2, 4 }, { 3, 3 }, { 4, 2 },
+  { 4, 3 }, { 3, 4 },
+  { 4, 4 }
+};
+
+static const int8_t svq3_pred_1[6][6][5] = {
+  { { 2,-1,-1,-1,-1 }, { 2, 1,-1,-1,-1 }, { 1, 2,-1,-1,-1 },
+    { 2, 1,-1,-1,-1 }, { 1, 2,-1,-1,-1 }, { 1, 2,-1,-1,-1 } },
+  { { 0, 2,-1,-1,-1 }, { 0, 2, 1, 4, 3 }, { 0, 1, 2, 4, 3 },
+    { 0, 2, 1, 4, 3 }, { 2, 0, 1, 3, 4 }, { 0, 4, 2, 1, 3 } },
+  { { 2, 0,-1,-1,-1 }, { 2, 1, 0, 4, 3 }, { 1, 2, 4, 0, 3 },
+    { 2, 1, 0, 4, 3 }, { 2, 1, 4, 3, 0 }, { 1, 2, 4, 0, 3 } },
+  { { 2, 0,-1,-1,-1 }, { 2, 0, 1, 4, 3 }, { 1, 2, 0, 4, 3 },
+    { 2, 1, 0, 4, 3 }, { 2, 1, 3, 4, 0 }, { 2, 4, 1, 0, 3 } },
+  { { 0, 2,-1,-1,-1 }, { 0, 2, 1, 3, 4 }, { 1, 2, 3, 0, 4 },
+    { 2, 0, 1, 3, 4 }, { 2, 1, 3, 0, 4 }, { 2, 0, 4, 3, 1 } },
+  { { 0, 2,-1,-1,-1 }, { 0, 2, 4, 1, 3 }, { 1, 4, 2, 0, 3 },
+    { 4, 2, 0, 1, 3 }, { 2, 0, 1, 4, 3 }, { 4, 2, 1, 0, 3 } },
+};
+
+static const struct { uint8_t run; uint8_t level; } svq3_dct_tables[2][16] = {
+  { { 0, 0 }, { 0, 1 }, { 1, 1 }, { 2, 1 }, { 0, 2 }, { 3, 1 }, { 4, 1 }, { 5, 1 },
+    { 0, 3 }, { 1, 2 }, { 2, 2 }, { 6, 1 }, { 7, 1 }, { 8, 1 }, { 9, 1 }, { 0, 4 } },
+  { { 0, 0 }, { 0, 1 }, { 1, 1 }, { 0, 2 }, { 2, 1 }, { 0, 3 }, { 0, 4 }, { 0, 5 },
+    { 3, 1 }, { 4, 1 }, { 1, 2 }, { 1, 3 }, { 0, 6 }, { 0, 7 }, { 0, 8 }, { 0, 9 } }
+};
+
+static const uint32_t svq3_dequant_coeff[32] = {
+   3881,  4351,  4890,  5481,  6154,  6914,  7761,  8718,
+   9781, 10987, 12339, 13828, 15523, 17435, 19561, 21873,
+  24552, 27656, 30847, 34870, 38807, 43747, 49103, 54683,
+  61694, 68745, 77615, 89113,100253,109366,126635,141533
+};
+
+
+static void svq3_luma_dc_dequant_idct_c(DCTELEM *block, int qp){
+    const int qmul= svq3_dequant_coeff[qp];
+#define stride 16
+    int i;
+    int temp[16];
+    static const int x_offset[4]={0, 1*stride, 4* stride,  5*stride};
+    static const int y_offset[4]={0, 2*stride, 8* stride, 10*stride};
+
+    for(i=0; i<4; i++){
+        const int offset= y_offset[i];
+        const int z0= 13*(block[offset+stride*0] +    block[offset+stride*4]);
+        const int z1= 13*(block[offset+stride*0] -    block[offset+stride*4]);
+        const int z2=  7* block[offset+stride*1] - 17*block[offset+stride*5];
+        const int z3= 17* block[offset+stride*1] +  7*block[offset+stride*5];
+
+        temp[4*i+0]= z0+z3;
+        temp[4*i+1]= z1+z2;
+        temp[4*i+2]= z1-z2;
+        temp[4*i+3]= z0-z3;
+    }
+
+    for(i=0; i<4; i++){
+        const int offset= x_offset[i];
+        const int z0= 13*(temp[4*0+i] +    temp[4*2+i]);
+        const int z1= 13*(temp[4*0+i] -    temp[4*2+i]);
+        const int z2=  7* temp[4*1+i] - 17*temp[4*3+i];
+        const int z3= 17* temp[4*1+i] +  7*temp[4*3+i];
+
+        block[stride*0 +offset]= ((z0 + z3)*qmul + 0x80000)>>20;
+        block[stride*2 +offset]= ((z1 + z2)*qmul + 0x80000)>>20;
+        block[stride*8 +offset]= ((z1 - z2)*qmul + 0x80000)>>20;
+        block[stride*10+offset]= ((z0 - z3)*qmul + 0x80000)>>20;
+    }
+}
+#undef stride
+
+static void svq3_add_idct_c (uint8_t *dst, DCTELEM *block, int stride, int qp, int dc){
+    const int qmul= svq3_dequant_coeff[qp];
+    int i;
+    uint8_t *cm = cropTbl + MAX_NEG_CROP;
+
+    if (dc) {
+        dc = 13*13*((dc == 1) ? 1538*block[0] : ((qmul*(block[0] >> 3)) / 2));
+        block[0] = 0;
+    }
+
+    for (i=0; i < 4; i++) {
+        const int z0= 13*(block[0 + 4*i] +    block[2 + 4*i]);
+        const int z1= 13*(block[0 + 4*i] -    block[2 + 4*i]);
+        const int z2=  7* block[1 + 4*i] - 17*block[3 + 4*i];
+        const int z3= 17* block[1 + 4*i] +  7*block[3 + 4*i];
+
+        block[0 + 4*i]= z0 + z3;
+        block[1 + 4*i]= z1 + z2;
+        block[2 + 4*i]= z1 - z2;
+        block[3 + 4*i]= z0 - z3;
+    }
+
+    for (i=0; i < 4; i++) {
+        const int z0= 13*(block[i + 4*0] +    block[i + 4*2]);
+        const int z1= 13*(block[i + 4*0] -    block[i + 4*2]);
+        const int z2=  7* block[i + 4*1] - 17*block[i + 4*3];
+        const int z3= 17* block[i + 4*1] +  7*block[i + 4*3];
+        const int rr= (dc + 0x80000);
+
+        dst[i + stride*0]= cm[ dst[i + stride*0] + (((z0 + z3)*qmul + rr) >> 20) ];
+        dst[i + stride*1]= cm[ dst[i + stride*1] + (((z1 + z2)*qmul + rr) >> 20) ];
+        dst[i + stride*2]= cm[ dst[i + stride*2] + (((z1 - z2)*qmul + rr) >> 20) ];
+        dst[i + stride*3]= cm[ dst[i + stride*3] + (((z0 - z3)*qmul + rr) >> 20) ];
+    }
+}
+
+static void pred4x4_down_left_svq3_c(uint8_t *src, uint8_t *topright, int stride){
+    LOAD_TOP_EDGE    
+    LOAD_LEFT_EDGE    
+    const __attribute__((unused)) int unu0= t0;
+    const __attribute__((unused)) int unu1= l0;
+
+    src[0+0*stride]=(l1 + t1)>>1;
+    src[1+0*stride]=
+    src[0+1*stride]=(l2 + t2)>>1;
+    src[2+0*stride]=
+    src[1+1*stride]=
+    src[0+2*stride]=
+    src[3+0*stride]=
+    src[2+1*stride]=
+    src[1+2*stride]=
+    src[0+3*stride]=
+    src[3+1*stride]=
+    src[2+2*stride]=
+    src[1+3*stride]=
+    src[3+2*stride]=
+    src[2+3*stride]=
+    src[3+3*stride]=(l3 + t3)>>1;
+};
+
+static void pred16x16_plane_svq3_c(uint8_t *src, int stride){
+    pred16x16_plane_compat_c(src, stride, 1);
+}
+
+static inline int svq3_decode_block (GetBitContext *gb, DCTELEM *block,
+				     int index, const int type) {
+
+  static const uint8_t *const scan_patterns[4] =
+  { luma_dc_zigzag_scan, zigzag_scan, svq3_scan, chroma_dc_scan };
+
+  int run, level, sign, vlc, limit;
+  const int intra = (3 * type) >> 2;
+  const uint8_t *const scan = scan_patterns[type];
+
+  for (limit=(16 >> intra); index < 16; index=limit, limit+=8) {
+    for (; (vlc = svq3_get_ue_golomb (gb)) != 0; index++) {
+
+      if (vlc == INVALID_VLC)
+	return -1;
+
+      sign = (vlc & 0x1) - 1;
+      vlc  = (vlc + 1) >> 1;
+
+      if (type == 3) {
+	if (vlc < 3) {
+	  run   = 0;
+	  level = vlc;
+	} else if (vlc < 4) {
+	  run   = 1;
+	  level = 1;
+	} else {
+	  run   = (vlc & 0x3);
+	  level = ((vlc + 9) >> 2) - run;
+	}
+      } else {
+	if (vlc < 16) {
+	  run   = svq3_dct_tables[intra][vlc].run;
+	  level = svq3_dct_tables[intra][vlc].level;
+	} else if (intra) {
+	  run   = (vlc & 0x7);
+	  level = (vlc >> 3) + ((run == 0) ? 8 : ((run < 2) ? 2 : ((run < 5) ? 0 : -1)));
+	} else {
+	  run   = (vlc & 0xF);
+	  level = (vlc >> 4) + ((run == 0) ? 4 : ((run < 3) ? 2 : ((run < 10) ? 1 : 0)));
+	}
+      }
+
+      if ((index += run) >= limit)
+	return -1;
+
+      block[scan[index]] = (level ^ sign) - sign;
+    }
+
+    if (type != 2) {
+      break;
+    }
+  }
+
+  return 0;
+}
+
+static void sixpel_mc_put (MpegEncContext *s,
+			   uint8_t *src, uint8_t *dst, int stride,
+			   int dxy, int width, int height) {
+  int i, j;
+
+  switch (dxy) {
+  case 6*0+0:
+    for (i=0; i < height; i++) {
+      memcpy (dst, src, width);
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*0+2:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (683*(2*src[j] + src[j+1] + 1)) >> 11;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*0+3:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (src[j] + src[j+1] + 1) >> 1;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*0+4:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (683*(src[j] + 2*src[j+1] + 1)) >> 11;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*2+0:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (683*(2*src[j] + src[j+stride] + 1)) >> 11;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*2+2:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (2731*(4*src[j] + 3*src[j+1] + 3*src[j+stride] + 2*src[j+stride+1] + 6)) >> 15;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*2+4:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (2731*(3*src[j] + 4*src[j+1] + 2*src[j+stride] + 3*src[j+stride+1] + 6)) >> 15;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*3+0:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (src[j] + src[j+stride]+1) >> 1;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*3+3:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (src[j] + src[j+1] + src[j+stride] + src[j+stride+1] + 2) >> 2;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*4+0:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (683*(src[j] + 2*src[j+stride] + 1)) >> 11;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*4+2:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (2731*(3*src[j] + 2*src[j+1] + 4*src[j+stride] + 3*src[j+stride+1] + 6)) >> 15;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  case 6*4+4:
+    for (i=0; i < height; i++) {
+      for (j=0; j < width; j++) {
+	dst[j] = (2731*(2*src[j] + 3*src[j+1] + 3*src[j+stride] + 4*src[j+stride+1] + 6)) >> 15;
+      }
+      src += stride;
+      dst += stride;
+    }
+    break;
+  }
+}
+
+static inline void svq3_mc_dir_part (MpegEncContext *s, int x, int y,
+				     int width, int height, int mx, int my) {
+  uint8_t *src, *dest;
+  int i, emu = 0;
+  const int sx = ((unsigned) (mx + 0x7FFFFFFE)) % 6;
+  const int sy = ((unsigned) (my + 0x7FFFFFFE)) % 6;
+  const int dxy= 6*sy + sx;
+
+  /* decode and clip motion vector to frame border (+16) */
+  mx = x + (mx - sx) / 6;
+  my = y + (my - sy) / 6;
+
+  if (mx < 0 || mx >= (s->width  - width  - 1) ||
+      my < 0 || my >= (s->height - height - 1)) {
+
+    if ((s->flags & CODEC_FLAG_EMU_EDGE)) {
+      emu = 1;
+    }
+
+    mx = clip (mx, -16, (s->width  - width  + 15));
+    my = clip (my, -16, (s->height - height + 15));
+  }
+
+  /* form component predictions */
+  dest = s->current_picture.data[0] + x + y*s->linesize;
+  src  = s->last_picture.data[0] + mx + my*s->linesize;
+
+  if (emu) {
+    ff_emulated_edge_mc (s, src, s->linesize, (width + 1), (height + 1),
+			 mx, my, s->width, s->height);
+    src = s->edge_emu_buffer;
+  }
+  sixpel_mc_put (s, src, dest, s->linesize, dxy, width, height);
+
+  if (!(s->flags & CODEC_FLAG_GRAY)) {
+    mx	   = (mx + (mx < (int) x)) >> 1;
+    my	   = (my + (my < (int) y)) >> 1;
+    width  = (width  >> 1);
+    height = (height >> 1);
+
+    for (i=1; i < 3; i++) {
+      dest = s->current_picture.data[i] + (x >> 1) + (y >> 1)*s->uvlinesize;
+      src  = s->last_picture.data[i] + mx + my*s->uvlinesize;
+
+      if (emu) {
+	ff_emulated_edge_mc (s, src, s->uvlinesize, (width + 1), (height + 1),
+			     mx, my, (s->width >> 1), (s->height >> 1));
+	src = s->edge_emu_buffer;
+      }
+      sixpel_mc_put (s, src, dest, s->uvlinesize, dxy, width, height);
+    }
+  }
+}
+
+static int svq3_decode_mb (H264Context *h, unsigned int mb_type) {
+  int cbp, dir, mode, mx, my, dx, dy, x, y, part_width, part_height;
+  int i, j, k, l, m;
+  uint32_t vlc;
+  int8_t *top, *left;
+  MpegEncContext *const s = (MpegEncContext *) h;
+  const int mb_xy = s->mb_x + s->mb_y*s->mb_stride;
+  const int b_xy = 4*s->mb_x + 4*s->mb_y*h->b_stride;
+
+  h->top_samples_available	= (s->mb_y == 0) ? 0x33FF : 0xFFFF;
+  h->left_samples_available	= (s->mb_x == 0) ? 0x5F5F : 0xFFFF;
+  h->topright_samples_available	= 0xFFFF;
+
+  if (mb_type == 0) {		/* SKIP */
+    svq3_mc_dir_part (s, 16*s->mb_x, 16*s->mb_y, 16, 16, 0, 0);
+
+    cbp = 0;
+    mb_type = MB_TYPE_SKIP;
+  } else if (mb_type < 8) {	/* INTER */
+    if (h->thirdpel_flag && h->halfpel_flag == !get_bits (&s->gb, 1)) {
+      mode = 3;	/* thirdpel */
+    } else if (h->halfpel_flag && h->thirdpel_flag == !get_bits (&s->gb, 1)) {
+      mode = 2;	/* halfpel */
+    } else {
+      mode = 1;	/* fullpel */
+    }
+
+    /* fill caches */
+    memset (h->ref_cache[0], PART_NOT_AVAILABLE, 8*5*sizeof(int8_t));
+
+    if (s->mb_x > 0) {
+      for (i=0; i < 4; i++) {
+	*(uint32_t *) h->mv_cache[0][scan8[0] - 1 + i*8] = *(uint32_t *) s->current_picture.motion_val[0][b_xy - 1 + i*h->b_stride];
+	h->ref_cache[0][scan8[0] - 1 + i*8] = 1;
+      }
+    } else {
+      for (i=0; i < 4; i++) {
+	*(uint32_t *) h->mv_cache[0][scan8[0] - 1 + i*8] = 0;
+	h->ref_cache[0][scan8[0] - 1 + i*8] = 1;
+      }
+    }
+    if (s->mb_y > 0) {
+      memcpy (h->mv_cache[0][scan8[0] - 1*8], s->current_picture.motion_val[0][b_xy - h->b_stride], 4*2*sizeof(int16_t));
+      memset (&h->ref_cache[0][scan8[0] - 1*8], 1, 4);
+
+      if (s->mb_x < (s->mb_width - 1)) {
+	*(uint32_t *) h->mv_cache[0][scan8[0] + 4 - 1*8] = *(uint32_t *) s->current_picture.motion_val[0][b_xy - h->b_stride + 4];
+	h->ref_cache[0][scan8[0] + 4 - 1*8] = 1;
+      }
+      if (s->mb_x > 0) {
+	*(uint32_t *) h->mv_cache[0][scan8[0] - 1 - 1*8] = *(uint32_t *) s->current_picture.motion_val[0][b_xy - h->b_stride - 1];
+	h->ref_cache[0][scan8[0] - 1 - 1*8] = 1;
+      }
+    }
+
+    /* decode motion vector(s) and form prediction(s) */
+    part_width  = ((mb_type & 5) == 5) ? 4 : 8 << (mb_type & 1);
+    part_height = 16 >> ((unsigned) mb_type / 3);
+
+    for (i=0; i < 16; i+=part_height) {
+      for (j=0; j < 16; j+=part_width) {
+	x = 16*s->mb_x + j;
+	y = 16*s->mb_y + i;
+	k = ((j>>2)&1) + ((i>>1)&2) + ((j>>1)&4) + (i&8);
+
+	pred_motion (h, k, (part_width >> 2), 0, 1, &mx, &my);
+
+	/* clip motion vector prediction to frame border */
+	mx = clip (mx, -6*x, 6*(s->width  - part_width  - x));
+	my = clip (my, -6*y, 6*(s->height - part_height - y));
+
+	/* get motion vector differential */
+	dy = svq3_get_se_golomb (&s->gb);
+	dx = svq3_get_se_golomb (&s->gb);
+
+	if (dx == INVALID_VLC || dy == INVALID_VLC) {
+	  return -1;
+	}
+
+	/* compute motion vector */
+	if (mode == 3) {
+	  mx = ((mx + 1) & ~0x1) + 2*dx;
+	  my = ((my + 1) & ~0x1) + 2*dy;
+	} else if (mode == 2) {
+	  mx = (mx + 1) - ((unsigned) (0x7FFFFFFF + mx) % 3) + 3*dx;
+	  my = (my + 1) - ((unsigned) (0x7FFFFFFF + my) % 3) + 3*dy;
+	} else if (mode == 1) {
+	  mx = (mx + 3) - ((unsigned) (0x7FFFFFFB + mx) % 6) + 6*dx;
+	  my = (my + 3) - ((unsigned) (0x7FFFFFFB + my) % 6) + 6*dy;
+	}
+
+	/* update mv_cache */
+	for (l=0; l < part_height; l+=4) {
+	  for (m=0; m < part_width; m+=4) {
+	    k = scan8[0] + ((m + j) >> 2) + ((l + i) << 1);
+	    h->mv_cache [0][k][0] = mx;
+	    h->mv_cache [0][k][1] = my;
+	    h->ref_cache[0][k] = 1;
+	  }
+	}
+
+	svq3_mc_dir_part (s, x, y, part_width, part_height, mx, my);
+      }
+    }
+
+    for (i=0; i < 4; i++) {
+      memcpy (s->current_picture.motion_val[0][b_xy + i*h->b_stride], h->mv_cache[0][scan8[0] + 8*i], 4*2*sizeof(int16_t));
+    }
+
+    if ((vlc = svq3_get_ue_golomb (&s->gb)) >= 48)
+      return -1;
+
+    cbp = golomb_to_inter_cbp[vlc];
+    mb_type = MB_TYPE_16x16;
+  } else if (mb_type == 8) {	/* INTRA4x4 */
+    memset (h->intra4x4_pred_mode_cache, -1, 8*5*sizeof(int8_t));
+
+    if (s->mb_x > 0) {
+      for (i=0; i < 4; i++) {
+	h->intra4x4_pred_mode_cache[scan8[0] - 1 + i*8] = h->intra4x4_pred_mode[mb_xy - 1][i];
+      }
+    }
+    if (s->mb_y > 0) {
+      h->intra4x4_pred_mode_cache[4+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][4];
+      h->intra4x4_pred_mode_cache[5+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][5];
+      h->intra4x4_pred_mode_cache[6+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][6];
+      h->intra4x4_pred_mode_cache[7+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][3];
+    }
+
+    /* decode prediction codes for luma blocks */
+    for (i=0; i < 16; i+=2) {
+      vlc = svq3_get_ue_golomb (&s->gb);
+
+      if (vlc >= 25)
+	return -1;
+
+      left    = &h->intra4x4_pred_mode_cache[scan8[i] - 1];
+      top     = &h->intra4x4_pred_mode_cache[scan8[i] - 8];
+
+      left[1] = svq3_pred_1[top[0] + 1][left[0] + 1][svq3_pred_0[vlc][0]];
+      left[2] = svq3_pred_1[top[1] + 1][left[1] + 1][svq3_pred_0[vlc][1]];
+
+      if (left[1] == -1 || left[2] == -1)
+	return -1;
+    }
+
+    write_back_intra_pred_mode (h);
+    check_intra4x4_pred_mode (h);
+
+    if ((vlc = svq3_get_ue_golomb (&s->gb)) >= 48)
+      return -1;
+
+    cbp = golomb_to_intra4x4_cbp[vlc];
+    mb_type = MB_TYPE_INTRA4x4;
+  } else {			/* INTRA16x16 */
+    dir = i_mb_type_info[mb_type - 8].pred_mode;
+    dir = (dir >> 1) ^ 3*(dir & 1) ^ 1;
+
+    if ((h->intra16x16_pred_mode = check_intra_pred_mode (h, dir)) == -1)
+      return -1;
+
+    cbp = i_mb_type_info[mb_type - 8].cbp;
+    mb_type = MB_TYPE_INTRA16x16;
+  }
+
+  if (!IS_INTER(mb_type) && s->pict_type != I_TYPE) {
+    for (i=0; i < 4; i++) {
+      memset (s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));
+    }
+  }
+  if (!IS_INTRA4x4(mb_type)) {
+    memset (h->intra4x4_pred_mode[mb_xy], DC_PRED, 8);
+  }
+  if (!IS_SKIP(mb_type)) {
+    memset (h->mb, 0, 24*16*sizeof(DCTELEM));
+    memset (h->non_zero_count_cache, 0, 8*6*sizeof(uint8_t));
+  }
+
+  if (IS_INTRA16x16(mb_type) || (s->pict_type != I_TYPE && s->adaptive_quant && cbp)) {
+    s->qscale += svq3_get_se_golomb (&s->gb);
+
+    if (s->qscale > 31)
+      return -1;
+  }
+  if (IS_INTRA16x16(mb_type)) {
+    if (svq3_decode_block (&s->gb, h->mb, 0, 0))
+      return -1;
+  }
+
+  if (!IS_SKIP(mb_type) && cbp) {
+    l = IS_INTRA16x16(mb_type) ? 1 : 0;
+    m = ((s->qscale < 24 && IS_INTRA4x4(mb_type)) ? 2 : 1);
+
+    for (i=0; i < 4; i++) {
+      if ((cbp & (1 << i))) {
+	for (j=0; j < 4; j++) {
+	  k = l ? ((j&1) + 2*(i&1) + 2*(j&2) + 4*(i&2)) : (4*i + j);
+	  h->non_zero_count_cache[ scan8[k] ] = 1;
+
+	  if (svq3_decode_block (&s->gb, &h->mb[16*k], l, m))
+	    return -1;
+	}
+      }
+    }
+
+    if ((cbp & 0x30)) {
+      for (i=0; i < 2; ++i) {
+	if (svq3_decode_block (&s->gb, &h->mb[16*(16 + 4*i)], 0, 3))
+	  return -1;
+      }
+
+      if ((cbp & 0x20)) {
+	for (i=0; i < 8; i++) {
+	  h->non_zero_count_cache[ scan8[16+i] ] = 1;
+
+	  if (svq3_decode_block (&s->gb, &h->mb[16*(16 + i)], 1, 1))
+	    return -1;
+	}
+      }
+    }
+  }
+
+  s->current_picture.mb_type[mb_xy] = mb_type;
+
+  if (IS_INTRA(mb_type)) {
+    h->chroma_pred_mode = check_intra_pred_mode (h, DC_PRED8x8);
+  }
+
+  return 0;
+}
+
+static int svq3_decode_frame (AVCodecContext *avctx,
+			      void *data, int *data_size,
+			      uint8_t *buf, int buf_size) {
+  MpegEncContext *const s = avctx->priv_data;
+  H264Context *const h = avctx->priv_data;
+  int i;
+
+  s->flags = avctx->flags;
+
+  if (!s->context_initialized) {
+    s->width = (avctx->width + 15) & ~15;
+    s->height = (avctx->height + 15) & ~15;
+    h->b_stride = (s->width >> 2);
+    h->pred4x4[DIAG_DOWN_LEFT_PRED] = pred4x4_down_left_svq3_c;
+    h->pred16x16[PLANE_PRED8x8] = pred16x16_plane_svq3_c;
+    h->halfpel_flag = 1;
+    h->thirdpel_flag = 1;
+    h->chroma_qp = 4;
+
+    if (MPV_common_init (s) < 0)
+      return -1;
+
+    alloc_tables (h);
+  }
+  if (avctx->extradata && avctx->extradata_size >= 115
+      && !memcmp (avctx->extradata, "stsd", 4)) {
+
+    uint8_t *stsd = (uint8_t *) avctx->extradata + 114;
+
+    if ((*stsd >> 5) != 7 || avctx->extradata_size >= 118) {
+
+      if ((*stsd >> 5) == 7) {
+	stsd += 3;	/* skip width, height (12 bits each) */
+      }
+
+      h->halfpel_flag = (*stsd >> 4) & 1;
+      h->thirdpel_flag = (*stsd >> 3) & 1;
+    }
+  }
+
+  if ((buf[0] & 0x9F) != 1) {
+    /* TODO: what? */
+    fprintf (stderr, "unsupported header (%02X)\n", buf[0]);
+    return -1;
+  } else {
+    int length = (buf[0] >> 5) & 3;
+    int offset = 0;
+
+    for (i=0; i < length; i++) {
+      offset = (offset << 8) | buf[i + 1];
+    }
+
+    if (buf_size < (offset + length + 1) || length == 0)
+      return -1;
+
+    memcpy (&buf[2], &buf[offset + 2], (length - 1));
+  }
+
+  init_get_bits (&s->gb, &buf[2], 8*(buf_size - 2));
+
+  if ((i = svq3_get_ue_golomb (&s->gb)) == INVALID_VLC || i >= 3)
+    return -1;
+
+  s->pict_type = golomb_to_pict_type[i];
+
+  /* unknown fields */
+  get_bits (&s->gb, 1);
+  get_bits (&s->gb, 8);
+
+  s->qscale = get_bits (&s->gb, 5);
+  s->adaptive_quant = get_bits (&s->gb, 1);
+
+  /* unknown fields */
+  get_bits (&s->gb, 1);
+  get_bits (&s->gb, 1);
+  get_bits (&s->gb, 2);
+
+  while (get_bits (&s->gb, 1)) {
+    get_bits (&s->gb, 8);
+  }
+
+  /* B-frames are not supported */
+  if (s->pict_type == B_TYPE/* && avctx->hurry_up*/)
+    return buf_size;
+
+  frame_start (h);
+
+  for (s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) {
+    for (s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) {
+      int mb_type = svq3_get_ue_golomb (&s->gb);
+
+      if (s->pict_type == I_TYPE) {
+	mb_type += 8;
+      }
+      if (mb_type > 32 || svq3_decode_mb (h, mb_type)) {
+	fprintf (stderr, "error while decoding MB %d %d\n", s->mb_x, s->mb_y);
+	return -1;
+      }
+
+      if (mb_type != 0) {
+	hl_decode_mb (h);
+      }
+    }
+  }
+
+  *(AVFrame *) data = *(AVFrame *) &s->current_picture;
+  *data_size = sizeof(AVFrame);
+
+  MPV_frame_end(s);
+  
+  return buf_size;
+}
+
+
+AVCodec svq3_decoder = {
+    "svq3",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_SVQ3,
+    sizeof(H264Context),
+    decode_init,
+    NULL,
+    decode_end,
+    svq3_decode_frame,
+    CODEC_CAP_DR1,
+};