indeo3.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * Intel Indeo 3 (IV31, IV32, etc.) video decoder for ffmpeg
 * written, produced, and directed by Alan Smithee
 *
 * 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
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"

#include "indeo3data.h"

typedef struct
{
  unsigned char *Ybuf;
  unsigned char *Ubuf;
  unsigned char *Vbuf;
  unsigned char *the_buf;
  unsigned int the_buf_size;
  unsigned short y_w, y_h;
  unsigned short uv_w, uv_h;
} YUVBufs;

typedef struct Indeo3DecodeContext {
    AVCodecContext *avctx;
    int width, height;
    AVFrame frame;

    YUVBufs iv_frame[2];
    YUVBufs *cur_frame;
    YUVBufs *ref_frame;

    unsigned char *ModPred;
    unsigned short *corrector_type;
} Indeo3DecodeContext;

static int corrector_type_0[24] = {
  195, 159, 133, 115, 101,  93,  87,  77,
  195, 159, 133, 115, 101,  93,  87,  77,
  128,  79,  79,  79,  79,  79,  79,  79
};

static int corrector_type_2[8] = { 9, 7, 6, 8, 5, 4, 3, 2 };

static void build_modpred(Indeo3DecodeContext *s)
{
  int i, j;

  s->ModPred = (unsigned char *) av_malloc (8 * 128);

  for (i=0; i < 128; ++i) {
    s->ModPred[i+0*128] = (i > 126) ? 254 : 2*((i + 1) - ((i + 1) % 2));
    s->ModPred[i+1*128] = (i == 7)  ?  20 : ((i == 119 || i == 120)
                                 ? 236 : 2*((i + 2) - ((i + 1) % 3)));
    s->ModPred[i+2*128] = (i > 125) ? 248 : 2*((i + 2) - ((i + 2) % 4));
    s->ModPred[i+3*128] =                        2*((i + 1) - ((i - 3) % 5));
    s->ModPred[i+4*128] = (i == 8)  ?  20 : 2*((i + 1) - ((i - 3) % 6));
    s->ModPred[i+5*128] =                        2*((i + 4) - ((i + 3) % 7));
    s->ModPred[i+6*128] = (i > 123) ? 240 : 2*((i + 4) - ((i + 4) % 8));
    s->ModPred[i+7*128] =                        2*((i + 5) - ((i + 4) % 9));
  }

  s->corrector_type = (unsigned short *) av_malloc (24 * 256 * sizeof(unsigned short));

  for (i=0; i < 24; ++i) {
    for (j=0; j < 256; ++j) {
      s->corrector_type[i*256+j] = (j < corrector_type_0[i])
                                ? 1 : ((j < 248 || (i == 16 && j == 248))
                                       ? 0 : corrector_type_2[j - 248]);
    }
  }
}

static void iv_Decode_Chunk(Indeo3DecodeContext *s, unsigned char *cur,
  unsigned char *ref, int width, int height, unsigned char *buf1,
  long fflags2, unsigned char *hdr,
  unsigned char *buf2, int min_width_160);

/* ---------------------------------------------------------------------- */
static void iv_alloc_frames(Indeo3DecodeContext *s)
{
  int luma_width, luma_height, luma_pixels, chroma_width, chroma_height,
      chroma_pixels, i;
  unsigned int bufsize;

  luma_width   = (s->width  + 3) & (~3);
  luma_height  = (s->height + 3) & (~3);

  s->iv_frame[0].y_w = s->iv_frame[0].y_h =
    s->iv_frame[0].the_buf_size = 0;
  s->iv_frame[1].y_w = s->iv_frame[1].y_h =
    s->iv_frame[1].the_buf_size = 0;
  s->iv_frame[1].the_buf = NULL;

  chroma_width  = ((luma_width >> 2) + 3) & (~3);
  chroma_height = ((luma_height>> 2) + 3) & (~3);
  luma_pixels = luma_width * luma_height;
  chroma_pixels = chroma_width * chroma_height;

  bufsize = luma_pixels * 2 + luma_width * 3 +
    (chroma_pixels + chroma_width) * 4;

  if((s->iv_frame[0].the_buf =
    (s->iv_frame[0].the_buf_size == 0 ? av_malloc(bufsize) :
      av_realloc(s->iv_frame[0].the_buf, bufsize))) == NULL)
    return;
  s->iv_frame[0].y_w = s->iv_frame[1].y_w = luma_width;
  s->iv_frame[0].y_h = s->iv_frame[1].y_h = luma_height;
  s->iv_frame[0].uv_w = s->iv_frame[1].uv_w = chroma_width;
  s->iv_frame[0].uv_h = s->iv_frame[1].uv_h = chroma_height;
  s->iv_frame[0].the_buf_size = bufsize;

  s->iv_frame[0].Ybuf = s->iv_frame[0].the_buf + luma_width;
  i = luma_pixels + luma_width * 2;
  s->iv_frame[1].Ybuf = s->iv_frame[0].the_buf + i;
  i += (luma_pixels + luma_width);
  s->iv_frame[0].Ubuf = s->iv_frame[0].the_buf + i;
  i += (chroma_pixels + chroma_width);
  s->iv_frame[1].Ubuf = s->iv_frame[0].the_buf + i;
  i += (chroma_pixels + chroma_width);
  s->iv_frame[0].Vbuf = s->iv_frame[0].the_buf + i;
  i += (chroma_pixels + chroma_width);
  s->iv_frame[1].Vbuf = s->iv_frame[0].the_buf + i;

  for(i = 1; i <= luma_width; i++)
    s->iv_frame[0].Ybuf[-i] = s->iv_frame[1].Ybuf[-i] =
      s->iv_frame[0].Ubuf[-i] = 0x80;

  for(i = 1; i <= chroma_width; i++) {
    s->iv_frame[1].Ubuf[-i] = 0x80;
    s->iv_frame[0].Vbuf[-i] = 0x80;
    s->iv_frame[1].Vbuf[-i] = 0x80;
    s->iv_frame[1].Vbuf[chroma_pixels+i-1] = 0x80;
  }
}

/* ---------------------------------------------------------------------- */
static void iv_free_func(Indeo3DecodeContext *s)
{
  int i;

  for(i = 0 ; i < 2 ; i++) {
    if(s->iv_frame[i].the_buf != NULL)
      av_free(s->iv_frame[i].the_buf);
    s->iv_frame[i].Ybuf = s->iv_frame[i].Ubuf =
      s->iv_frame[i].Vbuf = NULL;
    s->iv_frame[i].the_buf = NULL;
    s->iv_frame[i].the_buf_size = 0;
    s->iv_frame[i].y_w = s->iv_frame[i].y_h = 0;
    s->iv_frame[i].uv_w = s->iv_frame[i].uv_h = 0;
  }

  av_free(s->ModPred);
  av_free(s->corrector_type);
}

/* ---------------------------------------------------------------------- */
static unsigned long iv_decode_frame(Indeo3DecodeContext *s,
                                     unsigned char *buf, int buf_size)
{
  unsigned int hdr_width, hdr_height,
    chroma_width, chroma_height;
  unsigned long fflags1, fflags2, fflags3, offs1, offs2, offs3, offs;
  unsigned char *hdr_pos, *buf_pos;

  buf_pos = buf;
  buf_pos += 18;

  fflags1 = le2me_16(*(uint16_t *)buf_pos);
  buf_pos += 2;
  fflags3 = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;
  fflags2 = *buf_pos++;
  buf_pos += 3;
  hdr_height = le2me_16(*(uint16_t *)buf_pos);
  buf_pos += 2;
  hdr_width = le2me_16(*(uint16_t *)buf_pos);

  if(avcodec_check_dimensions(NULL, hdr_width, hdr_height))
      return -1;

  buf_pos += 2;
  chroma_height = ((hdr_height >> 2) + 3) & 0x7ffc;
  chroma_width = ((hdr_width >> 2) + 3) & 0x7ffc;
  offs1 = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;
  offs2 = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;
  offs3 = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 8;
  hdr_pos = buf_pos;
  if(fflags3 == 0x80) return 4;

  if(fflags1 & 0x200) {
    s->cur_frame = s->iv_frame + 1;
    s->ref_frame = s->iv_frame;
  } else {
    s->cur_frame = s->iv_frame;
    s->ref_frame = s->iv_frame + 1;
  }

  buf_pos = buf + 16 + offs1;
  offs = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;

  iv_Decode_Chunk(s, s->cur_frame->Ybuf, s->ref_frame->Ybuf, hdr_width,
    hdr_height, buf_pos + offs * 2, fflags2, hdr_pos, buf_pos,
    FFMIN(hdr_width, 160));

  if (!(s->avctx->flags & CODEC_FLAG_GRAY))
  {

  buf_pos = buf + 16 + offs2;
  offs = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;

  iv_Decode_Chunk(s, s->cur_frame->Vbuf, s->ref_frame->Vbuf, chroma_width,
    chroma_height, buf_pos + offs * 2, fflags2, hdr_pos, buf_pos,
    FFMIN(chroma_width, 40));

  buf_pos = buf + 16 + offs3;
  offs = le2me_32(*(uint32_t *)buf_pos);
  buf_pos += 4;

  iv_Decode_Chunk(s, s->cur_frame->Ubuf, s->ref_frame->Ubuf, chroma_width,
    chroma_height, buf_pos + offs * 2, fflags2, hdr_pos, buf_pos,
    FFMIN(chroma_width, 40));

  }

  return 8;
}

typedef struct {
  long xpos;
  long ypos;
  long width;
  long height;
  long split_flag;
  long split_direction;
  long usl7;
} ustr_t;

/* ---------------------------------------------------------------------- */

#define LV1_CHECK(buf1,rle_v3,lv1,lp2)  \
  if((lv1 & 0x80) != 0) {   \
    if(rle_v3 != 0)         \
      rle_v3 = 0;           \
    else {                  \
      rle_v3 = 1;           \
      buf1 -= 2;            \
    }                       \
  }                         \
  lp2 = 4;


#define RLE_V3_CHECK(buf1,rle_v1,rle_v2,rle_v3)  \
  if(rle_v3 == 0) {         \
    rle_v2 = *buf1;         \
    rle_v1 = 1;             \
    if(rle_v2 > 32) {       \
      rle_v2 -= 32;         \
      rle_v1 = 0;           \
    }                       \
    rle_v3 = 1;             \
  }                         \
  buf1--;


#define LP2_CHECK(buf1,rle_v3,lp2)  \
  if(lp2 == 0 && rle_v3 != 0)     \
    rle_v3 = 0;           \
  else {                  \
    buf1--;               \
    rle_v3 = 1;           \
  }


#define RLE_V2_CHECK(buf1,rle_v2, rle_v3,lp2) \
  rle_v2--;             \
  if(rle_v2 == 0) {     \
    rle_v3 = 0;         \
    buf1 += 2;          \
  }                     \
  lp2 = 4;

static void iv_Decode_Chunk(Indeo3DecodeContext *s,
  unsigned char *cur, unsigned char *ref, int width, int height,
  unsigned char *buf1, long fflags2, unsigned char *hdr,
  unsigned char *buf2, int min_width_160)
{
  unsigned char bit_buf;
  unsigned long bit_pos, lv, lv1, lv2;
  long *width_tbl, width_tbl_arr[10];
  signed char *ref_vectors;
  unsigned char *cur_frm_pos, *ref_frm_pos, *cp, *cp2;
  uint32_t *cur_lp, *ref_lp;
  const uint32_t *correction_lp[2], *correctionloworder_lp[2], *correctionhighorder_lp[2];
  unsigned short *correction_type_sp[2];
  ustr_t strip_tbl[20], *strip;
  int i, j, k, lp1, lp2, flag1, cmd, blks_width, blks_height, region_160_width,
    rle_v1, rle_v2, rle_v3;
  unsigned short res;

  bit_buf = 0;
  ref_vectors = NULL;

  width_tbl = width_tbl_arr + 1;
  i = (width < 0 ? width + 3 : width)/4;
  for(j = -1; j < 8; j++)
    width_tbl[j] = i * j;

  strip = strip_tbl;

  for(region_160_width = 0; region_160_width < (width - min_width_160); region_160_width += min_width_160);

  strip->ypos = strip->xpos = 0;
  for(strip->width = min_width_160; width > strip->width; strip->width *= 2);
  strip->height = height;
  strip->split_direction = 0;
  strip->split_flag = 0;
  strip->usl7 = 0;

  bit_pos = 0;

  rle_v1 = rle_v2 = rle_v3 = 0;

  while(strip >= strip_tbl) {
    if(bit_pos <= 0) {
      bit_pos = 8;
      bit_buf = *buf1++;
    }

    bit_pos -= 2;
    cmd = (bit_buf >> bit_pos) & 0x03;

    if(cmd == 0) {
      strip++;
      memcpy(strip, strip-1, sizeof(ustr_t));
      strip->split_flag = 1;
      strip->split_direction = 0;
      strip->height = (strip->height > 8 ? ((strip->height+8)>>4)<<3 : 4);
      continue;
    } else if(cmd == 1) {
      strip++;
      memcpy(strip, strip-1, sizeof(ustr_t));
      strip->split_flag = 1;
      strip->split_direction = 1;
      strip->width = (strip->width > 8 ? ((strip->width+8)>>4)<<3 : 4);
      continue;
    } else if(cmd == 2) {
      if(strip->usl7 == 0) {
        strip->usl7 = 1;
        ref_vectors = NULL;
        continue;
      }
    } else if(cmd == 3) {
      if(strip->usl7 == 0) {
        strip->usl7 = 1;
        ref_vectors = (signed char*)buf2 + (*buf1 * 2);
        buf1++;
        continue;