libmjpeg.c

这个库实现了录象功能

    free(compressor->rows[2]);
    }
  }


static void new_jpeg_objects(mjpeg_compressor *engine)
  {
  engine->jpeg_decompress.err = jpeg_std_error(&(engine->jpeg_error.pub));
  engine->jpeg_error.pub.error_exit = mjpeg_error_exit;
  /* Ideally the error handler would be set here but it must be called in a thread */
  jpeg_create_decompress(&(engine->jpeg_decompress));
  engine->jpeg_decompress.raw_data_out = TRUE;
  engine->jpeg_decompress.dct_method = JDCT_IFAST;
  }

static void delete_jpeg_objects(mjpeg_compressor *engine)
  {
  jpeg_destroy_decompress(&(engine->jpeg_decompress));
  }


// Make temp rows for compressor
static void get_mcu_rows(mjpeg_t *mjpeg, 
                         mjpeg_compressor *engine,
                         int start_row)
  {
  int i, j, scanline;
  for(i = 0; i < 3; i++)
    {
    for(j = 0; j < 16; j++)
      {
      if(i > 0 && j >= 8 && mjpeg->jpeg_color_model == BC_YUVJ420P) break;

      scanline = start_row;
      if(i > 0 && mjpeg->jpeg_color_model == BC_YUVJ420P) scanline /= 2;
      scanline += j;
      if(scanline >= engine->field_h) scanline = engine->field_h - 1;
      engine->mcu_rows[i][j] = engine->rows[i][scanline];
      }
    }
  }

/**********************************************************
 * Default huffman table generation: Ported from mjpegtools with
 * permission of the original author
 **********************************************************/

static void add_huff_table (j_decompress_ptr dinfo,
                            JHUFF_TBL **htblptr,
                            const UINT8 *bits, const UINT8 *val)
/* Define a Huffman table */
{
  int nsymbols, len;

  if (*htblptr == NULL)
    *htblptr = jpeg_alloc_huff_table((j_common_ptr) dinfo);

  /* Copy the number-of-symbols-of-each-code-length counts */
  memcpy((*htblptr)->bits, bits, sizeof((*htblptr)->bits));

  /* Validate the counts.  We do this here mainly so we can copy the right
   * number of symbols from the val[] array, without risking marching off
   * the end of memory.  jchuff.c will do a more thorough test later.
   */
  nsymbols = 0;
  for (len = 1; len <= 16; len++)
    nsymbols += bits[len];
  if (nsymbols < 1 || nsymbols > 256)
    //    mjpeg_error_exit1("jpegutils.c:  add_huff_table failed badly. ");
    lqt_log(NULL, LQT_LOG_ERROR, LOG_DOMAIN, "add_huff_table failed badly.\n");
  
  memcpy((*htblptr)->huffval, val, nsymbols * sizeof(UINT8));
}

static void std_huff_tables (j_decompress_ptr dinfo)
/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
/* IMPORTANT: these are only valid for 8-bit data precision! */
{
  static const UINT8 bits_dc_luminance[17] =
    { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
  static const UINT8 val_dc_luminance[] =
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  static const UINT8 bits_dc_chrominance[17] =
    { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
  static const UINT8 val_dc_chrominance[] =
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };

  static const UINT8 bits_ac_luminance[17] =
    { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
  static const UINT8 val_ac_luminance[] =
    { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
      0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
      0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
      0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
      0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
      0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
      0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
      0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
      0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
      0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
      0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
      0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
      0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
      0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
      0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
      0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
      0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
      0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
      0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
      0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };
  static const UINT8 bits_ac_chrominance[17] =
    { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
  static const UINT8 val_ac_chrominance[] =
    { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
      0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
      0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
      0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
      0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
      0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
      0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
      0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
      0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
      0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
      0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
      0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
      0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
      0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
      0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
      0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
      0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
      0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
      0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
      0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };

  add_huff_table(dinfo, &dinfo->dc_huff_tbl_ptrs[0],
                 bits_dc_luminance, val_dc_luminance);
  add_huff_table(dinfo, &dinfo->ac_huff_tbl_ptrs[0],
                 bits_ac_luminance, val_ac_luminance);
  add_huff_table(dinfo, &dinfo->dc_huff_tbl_ptrs[1],
                 bits_dc_chrominance, val_dc_chrominance);
  add_huff_table(dinfo, &dinfo->ac_huff_tbl_ptrs[1],
                 bits_ac_chrominance, val_ac_chrominance);
}

static void guarantee_huff_tables(j_decompress_ptr dinfo)
{
  if ( (dinfo->dc_huff_tbl_ptrs[0] == NULL) &&
       (dinfo->dc_huff_tbl_ptrs[1] == NULL) &&
       (dinfo->ac_huff_tbl_ptrs[0] == NULL) &&
       (dinfo->ac_huff_tbl_ptrs[1] == NULL) ) {
  //    mjpeg_debug( "Generating standard Huffman tables for this frame.");
    std_huff_tables(dinfo);
  }
}


static void decompress_field(mjpeg_compressor *engine, int field)
  {
  mjpeg_t *mjpeg = engine->mjpeg;
  long buffer_offset = field * mjpeg->input_field2;
  unsigned char *buffer = mjpeg->input_data + buffer_offset;
  long buffer_size;


  if(mjpeg->fields > 1)
    {
    if(field)
      buffer_size = mjpeg->input_size - buffer_offset;
    else
      buffer_size = mjpeg->input_field2;
    }
  else
    buffer_size = mjpeg->input_size;
  
  mjpeg->error = 0;
#if 1 
  if(setjmp(engine->jpeg_error.setjmp_buffer))
    {
    /* If we get here, the JPEG code has signaled an error. */
    delete_jpeg_objects(engine);
    new_jpeg_objects(engine);
    mjpeg->error = 1;
    goto finish;
    }
#endif
  jpeg_buffer_src(&engine->jpeg_decompress, 
                  buffer, 
                  buffer_size);
  jpeg_read_header(&engine->jpeg_decompress, TRUE);
  guarantee_huff_tables(&engine->jpeg_decompress);


  
  // Reset by jpeg_read_header
  engine->jpeg_decompress.raw_data_out = TRUE;
  jpeg_start_decompress(&engine->jpeg_decompress);

  // Generate colormodel from jpeg sampling
  if(engine->jpeg_decompress.comp_info[0].v_samp_factor == 2 &&
     engine->jpeg_decompress.comp_info[0].h_samp_factor == 2)
    {
    mjpeg->jpeg_color_model = BC_YUVJ420P;
    mjpeg->coded_w_uv = mjpeg->coded_w / 2;
    }
  else if(engine->jpeg_decompress.comp_info[0].v_samp_factor == 1 &&
          engine->jpeg_decompress.comp_info[0].h_samp_factor == 2)
    {
    mjpeg->jpeg_color_model = BC_YUVJ422P;
    mjpeg->coded_w_uv = mjpeg->coded_w / 2;
    }
  else
    {
    mjpeg->jpeg_color_model = BC_YUVJ444P;
    mjpeg->coded_w_uv = mjpeg->coded_w;
    }
  // Must be here because the color model isn't known until now
  allocate_temps(mjpeg);
  get_rows(mjpeg, engine, field);

  while(engine->jpeg_decompress.output_scanline < engine->jpeg_decompress.output_height)
    {
    get_mcu_rows(mjpeg, engine, engine->jpeg_decompress.output_scanline);
    jpeg_read_raw_data(&engine->jpeg_decompress, 
                       engine->mcu_rows, 
                       engine->field_h);
    }
  jpeg_finish_decompress(&engine->jpeg_decompress);


  finish:
  ;
  }

static void compress_field(mjpeg_compressor *engine, int field)
  {
  mjpeg_t *mjpeg = engine->mjpeg;

  get_rows(engine->mjpeg, engine, field);
  reset_buffer(&engine->output_buffer, &engine->output_size, &engine->output_allocated);
  jpeg_buffer_dest(&engine->jpeg_compress, engine);


  engine->jpeg_compress.raw_data_in = TRUE;
  jpeg_start_compress(&engine->jpeg_compress, TRUE);

  while(engine->jpeg_compress.next_scanline < engine->jpeg_compress.image_height)
    {
    get_mcu_rows(mjpeg, engine, engine->jpeg_compress.next_scanline);

    jpeg_write_raw_data(&engine->jpeg_compress, 
			engine->mcu_rows, 
			engine->field_h);
    }
  jpeg_finish_compress(&engine->jpeg_compress);
  }



static void delete_temps(mjpeg_t *mjpeg)
  {
  if(mjpeg->temp_data)
    {
    free(mjpeg->temp_data);
    free(mjpeg->temp_rows[0]);
    free(mjpeg->temp_rows[1]);
    free(mjpeg->temp_rows[2]);
    }
  }

static mjpeg_compressor* mjpeg_new_decompressor(mjpeg_t *mjpeg)
  {
  mjpeg_compressor *result = lqt_bufalloc(sizeof(mjpeg_compressor));

  result->mjpeg = mjpeg;
  new_jpeg_objects(result);
  result->field_h = mjpeg->coded_h / mjpeg->fields;

  result->mcu_rows[0] = lqt_bufalloc(16 * sizeof(unsigned char*));
  result->mcu_rows[1] = lqt_bufalloc(16 * sizeof(unsigned char*));
  result->mcu_rows[2] = lqt_bufalloc(16 * sizeof(unsigned char*));

  return result;
  }

static void mjpeg_delete_decompressor(mjpeg_compressor *engine)
  {
  /*
   * Must honor the locking protocol to avoid a race condition with
   * the child going into the cond_wait state for more input
   */

  jpeg_destroy_decompress(&(engine->jpeg_decompress));
  delete_rows(engine);
  free(engine->mcu_rows[0]);
  free(engine->mcu_rows[1]);
  free(engine->mcu_rows[2]);
  free(engine);
  }

static mjpeg_compressor* mjpeg_new_compressor(mjpeg_t *mjpeg)
  {
  mjpeg_compressor *result = lqt_bufalloc(sizeof(mjpeg_compressor));

  result->field_h = mjpeg->coded_h / mjpeg->fields;
  result->mjpeg = mjpeg;
  result->jpeg_compress.err = jpeg_std_error(&(result->jpeg_error.pub));
  jpeg_create_compress(&(result->jpeg_compress));
  result->jpeg_compress.image_width = mjpeg->coded_w;
  result->jpeg_compress.image_height = result->field_h;
  result->jpeg_compress.input_components = 3;
  result->jpeg_compress.in_color_space = JCS_RGB;
  jpeg_set_defaults(&(result->jpeg_compress));
  result->jpeg_compress.input_components = 3;
  result->jpeg_compress.in_color_space = JCS_RGB;
  jpeg_set_quality(&(result->jpeg_compress), mjpeg->quality, 0);

  if(mjpeg->use_float) 
    result->jpeg_compress.dct_method = JDCT_FLOAT;
  else
    result->jpeg_compress.dct_method = JDCT_IFAST;
  //		result->jpeg_compress.dct_method = JDCT_ISLOW;

  /* Fix sampling */
  switch(mjpeg->fields)
    {
    case 1:
      mjpeg->jpeg_color_model = BC_YUVJ420P;
      result->jpeg_compress.comp_info[0].h_samp_factor = 2;
      result->jpeg_compress.comp_info[0].v_samp_factor = 2;
      result->jpeg_compress.comp_info[1].h_samp_factor = 1;
      result->jpeg_compress.comp_info[1].v_samp_factor = 1;
      result->jpeg_compress.comp_info[2].h_samp_factor = 1;
      result->jpeg_compress.comp_info[2].v_samp_factor = 1;
      break;
    case 2:
      mjpeg->jpeg_color_model = BC_YUVJ422P;
      result->jpeg_compress.comp_info[0].h_samp_factor = 2;
      result->jpeg_compress.comp_info[0].v_samp_factor = 1;
      result->jpeg_compress.comp_info[1].h_samp_factor = 1;
      result->jpeg_compress.comp_info[1].v_samp_factor = 1;
      result->jpeg_compress.comp_info[2].h_samp_factor = 1;
      result->jpeg_compress.comp_info[2].v_samp_factor = 1;
      break;
    }
  allocate_temps(mjpeg);

  result->mcu_rows[0] = lqt_bufalloc(16 * sizeof(unsigned char*));
  result->mcu_rows[1] = lqt_bufalloc(16 * sizeof(unsigned char*));
  result->mcu_rows[2] = lqt_bufalloc(16 * sizeof(unsigned char*));

  return result;
  }

static void mjpeg_delete_compressor(mjpeg_compressor *engine)
  {
  /*
   * Must honor the locking protocol to avoid a race condition with 
   * the child going into the cond_wait state for more input 
   */

  jpeg_destroy((j_common_ptr)&(engine->jpeg_compress));
  if(engine->output_buffer) free(engine->output_buffer);
  delete_rows(engine);
  free(engine->mcu_rows[0]);
  free(engine->mcu_rows[1]);
  free(engine->mcu_rows[2]);
  free(engine);
  }

unsigned char* mjpeg_output_buffer(mjpeg_t *mjpeg)
  {
  return mjpeg->output_data;
  }

long mjpeg_output_field2(mjpeg_t *mjpeg)
  {
  return mjpeg->output_field2;
  }

long mjpeg_output_size(mjpeg_t *mjpeg)
  {
  return mjpeg->output_size;
  }

int mjpeg_compress(mjpeg_t *mjpeg, 
                   unsigned char **row_pointers)
  {
  uint8_t * cpy_rows[3];
  int i;

  /* Reset output buffer */
  reset_buffer(&mjpeg->output_data, 
               &mjpeg->output_size, 
               &mjpeg->output_allocated);

  /* Create compression engines as needed */
  if(!mjpeg->compressor)
    {
    mjpeg->compressor = mjpeg_new_compressor(mjpeg);
    }
  
  // Copy to buffer first

  cpy_rows[0] = mjpeg->temp_rows[0][0];
  cpy_rows[1] = mjpeg->temp_rows[1][0];
  cpy_rows[2] = mjpeg->temp_rows[2][0];
  
  lqt_rows_copy(cpy_rows,
                row_pointers, mjpeg->output_w, mjpeg->output_h, mjpeg->rowspan, mjpeg->rowspan_uv,
                mjpeg->coded_w, mjpeg->coded_w_uv, mjpeg->jpeg_color_model);
  
  
  /* Start the compressors on the image fields */

  for(i = 0; i < mjpeg->fields; i++)
    {
    compress_field(mjpeg->compressor, i);
    append_buffer(&mjpeg->output_data, 
                  &mjpeg->output_size, 
                  &mjpeg->output_allocated,
                  mjpeg->compressor->output_buffer, 
                  mjpeg->compressor->output_size);
    if(i == 0) mjpeg->output_field2 = mjpeg->output_size;
    }	

  return 0;
  }


int mjpeg_decompress(mjpeg_t *mjpeg, 
                     unsigned char *buffer, 
                     long buffer_len,
                     long input_field2)
  {
  int i;

  if(buffer_len == 0) return 1;
  if(input_field2 == 0 && mjpeg->fields > 1) return 1;

    
  /* Create decompression engines as needed */
  if(!mjpeg->decompressor)
    {
    mjpeg->decompressor = mjpeg_new_decompressor(mjpeg);
    }
  
  /* Arm YUV buffers */
  //	mjpeg->y_argument = y_plane;
  //	mjpeg->u_argument = u_plane;
  //	mjpeg->v_argument = v_plane;
  mjpeg->input_data = buffer;
  mjpeg->input_size = buffer_len;
  mjpeg->input_field2 = input_field2;
  //	mjpeg->color_model = color_model;

  /* Start decompressors */

  for(i = 0; i < mjpeg->fields; i++)
    {
    decompress_field(mjpeg->decompressor, i);
    }
  return 0;
  }

void mjpeg_get_frame(mjpeg_t * mjpeg, uint8_t ** row_pointers)
  {