svq1.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

    dst = current;

    s->dsp.put_pixels_tab[1][((pmv[i]->y & 1) << 1) | (pmv[i]->x & 1)](dst,src,pitch,8);

    /* select next block */
    if (i & 1) {
      current  += 8*(pitch - 1);
      previous += 8*(pitch - 1);
    } else {
      current  += 8;
      previous += 8;
    }
  }

  return 0;
}

static int svq1_decode_delta_block (MpegEncContext *s, bit_buffer_t *bitbuf,
			uint8_t *current, uint8_t *previous, int pitch,
			svq1_pmv_t *motion, int x, int y) {
  uint32_t bit_cache;
  uint32_t block_type;
  int	   result = 0;

  /* get block type */
  bit_cache = get_bit_cache (bitbuf);

  bit_cache	>>= (32 - 3);
  block_type	  = svq1_block_type_table[bit_cache].value;
  skip_bits(bitbuf,svq1_block_type_table[bit_cache].length);

  /* reset motion vectors */
  if (block_type == SVQ1_BLOCK_SKIP || block_type == SVQ1_BLOCK_INTRA) {
    motion[0].x		  =
    motion[0].y		  =
    motion[(x / 8) + 2].x =
    motion[(x / 8) + 2].y =
    motion[(x / 8) + 3].x =
    motion[(x / 8) + 3].y = 0;
  }

  switch (block_type) {
  case SVQ1_BLOCK_SKIP:
    svq1_skip_block (current, previous, pitch, x, y);
    break;

  case SVQ1_BLOCK_INTER:
    result = svq1_motion_inter_block (s, bitbuf, current, previous, pitch, motion, x, y);

    if (result != 0)
    {
#ifdef DEBUG_SVQ1
    printf("Error in svq1_motion_inter_block %i\n",result);
#endif
      break;
    }
    result = svq1_decode_block_non_intra (bitbuf, current, pitch);
    break;

  case SVQ1_BLOCK_INTER_4V:
    result = svq1_motion_inter_4v_block (s, bitbuf, current, previous, pitch, motion, x, y);

    if (result != 0)
    {
#ifdef DEBUG_SVQ1
    printf("Error in svq1_motion_inter_4v_block %i\n",result);
#endif
      break;
    }
    result = svq1_decode_block_non_intra (bitbuf, current, pitch);
    break;

  case SVQ1_BLOCK_INTRA:
    result = svq1_decode_block_intra (bitbuf, current, pitch);
    break;
  }

  return result;
}

/* standard video sizes */
static struct { int width; int height; } svq1_frame_size_table[8] = {
  { 160, 120 }, { 128,  96 }, { 176, 144 }, { 352, 288 },
  { 704, 576 }, { 240, 180 }, { 320, 240 }, {  -1,  -1 }
};

static int svq1_decode_frame_header (bit_buffer_t *bitbuf,MpegEncContext *s) {
  int frame_size_code;

  /* unknown field */
  get_bits (bitbuf, 8);

  /* frame type */
  s->pict_type= get_bits (bitbuf, 2)+1;
  if(s->pict_type==4) 
      return -1;

  if (s->pict_type == I_TYPE) {

    /* unknown fields */
    if (s->f_code == 0x50 || s->f_code == 0x60) {
      get_bits (bitbuf, 16);
    }

    if ((s->f_code ^ 0x10) >= 0x50) {
      skip_bits(bitbuf,8*get_bits (bitbuf, 8));
    }

    get_bits (bitbuf, 2);
    get_bits (bitbuf, 2);
    get_bits (bitbuf, 1);

    /* load frame size */
    frame_size_code = get_bits (bitbuf, 3);

    if (frame_size_code == 7) {
      /* load width, height (12 bits each) */
      s->width = get_bits (bitbuf, 12);
      s->height = get_bits (bitbuf, 12);

      if (!s->width || !s->height)
        return -1;
    } else {
      /* get width, height from table */
      s->width = svq1_frame_size_table[frame_size_code].width;
      s->height = svq1_frame_size_table[frame_size_code].height;
    }
  }

  /* unknown fields */
  if (get_bits (bitbuf, 1) == 1) {
    get_bits (bitbuf, 1);
    get_bits (bitbuf, 1);

    if (get_bits (bitbuf, 2) != 0)
      return -1;
  }

  if (get_bits (bitbuf, 1) == 1) {
    get_bits (bitbuf, 1);
    get_bits (bitbuf, 4);
    get_bits (bitbuf, 1);
    get_bits (bitbuf, 2);

    while (get_bits (bitbuf, 1) == 1) {
      get_bits (bitbuf, 8);
    }
  }
  
  return 0;
}

static int svq1_decode_frame(AVCodecContext *avctx, 
                             void *data, int *data_size,
                             UINT8 *buf, int buf_size)
{
  MpegEncContext *s=avctx->priv_data;
  uint8_t      *current, *previous;
  int		result, i, x, y, width, height;
  AVPicture *pict = data; 

  /* initialize bit buffer */
  init_get_bits(&s->gb,buf,buf_size);

  /* decode frame header */
  s->f_code = get_bits (&s->gb, 22);

  if ((s->f_code & ~0x70) || !(s->f_code & 0x60))
    return -1;

  /* swap some header bytes (why?) */
  if (s->f_code != 0x20) {
    uint32_t *src = (uint32_t *) (buf + 4);

    for (i=0; i < 4; i++) {
      src[i] = ((src[i] << 16) | (src[i] >> 16)) ^ src[7 - i];
    }
  }

  result = svq1_decode_frame_header (&s->gb, s);
  
  if(MPV_frame_start(s, avctx) < 0)
      return -1;

  if (result != 0)
  {
#ifdef DEBUG_SVQ1
    printf("Error in svq1_decode_frame_header %i\n",result);
#endif
    return result;
  }
  
  if(avctx->hurry_up && s->pict_type==B_TYPE) return buf_size;

  /* decode y, u and v components */
  for (i=0; i < 3; i++) {
    int linesize;
    if (i == 0) {
      width  = (s->width+15)&~15;
      height = (s->height+15)&~15;
      linesize= s->linesize;
    } else {
      if(s->flags&CODEC_FLAG_GRAY) break;
      width  = (s->width/4+15)&~15;
      height = (s->height/4+15)&~15;
      linesize= s->uvlinesize;
    }

    current  = s->current_picture[i];

    if(s->pict_type==B_TYPE){
        previous = s->next_picture[i];
    }else{
        previous = s->last_picture[i];
    }

    if (s->pict_type == I_TYPE) {
      /* keyframe */
      for (y=0; y < height; y+=16) {
	for (x=0; x < width; x+=16) {
	  result = svq1_decode_block_intra (&s->gb, &current[x], linesize);
	  if (result != 0)
	  {
#ifdef DEBUG_SVQ1
	    printf("Error in svq1_decode_block %i (keyframe)\n",result);
#endif
	    return result;
	  }
	}
	current += 16*linesize;
      }
    } else {
      svq1_pmv_t pmv[width/8+3];
      /* delta frame */
      memset (pmv, 0, ((width / 8) + 3) * sizeof(svq1_pmv_t));

      for (y=0; y < height; y+=16) {
	for (x=0; x < width; x+=16) {
	  result = svq1_decode_delta_block (s, &s->gb, &current[x], previous,
					    linesize, pmv, x, y);
	  if (result != 0)
	  {
#ifdef DEBUG_SVQ1
    printf("Error in svq1_decode_delta_block %i\n",result);
#endif
	    return result;
	  }
	}

	pmv[0].x =
	pmv[0].y = 0;

	current += 16*linesize;
      }
    }

    pict->data[i] = s->current_picture[i];
    pict->linesize[i] = linesize;
  }

  *data_size=sizeof(AVPicture);
  return buf_size;
}

static int svq1_decode_init(AVCodecContext *avctx)
{
    MpegEncContext *s = avctx->priv_data;

    s->avctx = avctx;
    s->width = (avctx->width+3)&~3;
    s->height = (avctx->height+3)&~3;
    s->codec_id= avctx->codec->id;
    avctx->mbskip_table= s->mbskip_table;
    avctx->pix_fmt = PIX_FMT_YUV410P;
    avctx->has_b_frames= s->has_b_frames=1; // not true, but DP frames and these behave like unidirectional b frames
    s->flags= avctx->flags;
    if (MPV_common_init(s) < 0) return -1;
    return 0;
}

static int svq1_decode_end(AVCodecContext *avctx)
{
    MpegEncContext *s = avctx->priv_data;

    MPV_common_end(s);
    return 0;
}

AVCodec svq1_decoder = {
    "svq1",
    CODEC_TYPE_VIDEO,
    CODEC_ID_SVQ1,
    sizeof(MpegEncContext),
    svq1_decode_init,
    NULL,
    svq1_decode_end,
    svq1_decode_frame,
    CODEC_CAP_DR1,
};