ppmtoy4m.c

Motion JPEG编解码器源代码

			       uint8_t *buffers[], 
			       uint8_t *buffers2[], 
			       uint8_t *rowbuffer,
			       int width, int height, int bgr)
{
  int x, y;
  uint8_t *pixels;
  uint8_t *R = buffers[0];
  uint8_t *G = buffers[1];
  uint8_t *B = buffers[2];
  uint8_t *R2 = buffers2[0];
  uint8_t *G2 = buffers2[1];
  uint8_t *B2 = buffers2[2];

  mjpeg_debug("read into two buffers, %dx%d", width, height);
  height /= 2;
  for (y = 0; y < height; y++) {
    pixels = rowbuffer;
    if (y4m_read(fd, pixels, width * 3))
      mjpeg_error_exit1("read error A  y=%d", y);
    if (bgr) {
      for (x = 0; x < width; x++) {
	*(B++) = *(pixels++);
	*(G++) = *(pixels++);
	*(R++) = *(pixels++);
      }
    } else {
      for (x = 0; x < width; x++) {
	*(R++) = *(pixels++);
	*(G++) = *(pixels++);
	*(B++) = *(pixels++);
      }
    }
    pixels = rowbuffer;
    if (y4m_read(fd, pixels, width * 3))
      mjpeg_error_exit1("read error B  y=%d", y);
    if (bgr) {
      for (x = 0; x < width; x++) {
	*(B2++) = *(pixels++);
	*(G2++) = *(pixels++);
	*(R2++) = *(pixels++);
      }
    } else {
      for (x = 0; x < width; x++) {
	*(R2++) = *(pixels++);
	*(G2++) = *(pixels++);
	*(B2++) = *(pixels++);
      }
    }
  }
}



static
void read_ppm_into_one_buffer(int fd,
			      uint8_t *buffers[],
			      uint8_t *rowbuffer,
			      int width, int height, int bgr) 
{
  int x, y;
  uint8_t *pixels;
  uint8_t *R = buffers[0];
  uint8_t *G = buffers[1];
  uint8_t *B = buffers[2];

  for (y = 0; y < height; y++) {
    pixels = rowbuffer;
    y4m_read(fd, pixels, width * 3);
    if (bgr) {
      for (x = 0; x < width; x++) {
	*(B++) = *(pixels++);
	*(G++) = *(pixels++);
	*(R++) = *(pixels++);
      }
    } else {
      for (x = 0; x < width; x++) {
	*(R++) = *(pixels++);
	*(G++) = *(pixels++);
	*(B++) = *(pixels++);
      }
    }
  }
}


/* 
 * read one whole frame
 * if field-sequential interlaced, this requires reading two PPM images
 *
 * if interlaced, fields are written into separate buffers
 *
 * ppm.width/height refer to image dimensions
 */

static
int read_ppm_frame(int fd, ppm_info_t *ppm,
		   uint8_t *buffers[], uint8_t *buffers2[],
		   int ilace, int ileave, int bgr)
{
  int width, height;
  static uint8_t *rowbuffer = NULL;
  int err;

  err = read_ppm_header(fd, &width, &height);
  if (err > 0) return 1;  /* EOF */
  if (err < 0) return -1; /* error */
  mjpeg_debug("Got PPM header:  %dx%d", width, height);

  if (ppm->width == 0) {
    /* first time */
    mjpeg_debug("Initializing PPM read_frame");
    ppm->width = width;
    ppm->height = height;
    rowbuffer = malloc(width * 3 * sizeof(rowbuffer[0]));
  } else {
    /* make sure everything matches */
    if ( (ppm->width != width) ||
	 (ppm->height != height) )
      mjpeg_error_exit1("One of these frames is not like the others!");
  }
  if (buffers[0] == NULL) 
    alloc_buffers(buffers, width, height);
  if ((buffers2[0] == NULL) && (ilace != Y4M_ILACE_NONE))
    alloc_buffers(buffers2, width, height);

  mjpeg_debug("Reading rows");

  if ((ilace != Y4M_ILACE_NONE) && (ileave)) {
    /* Interlaced and Interleaved:
       --> read image and deinterleave fields at same time */
    if (ilace == Y4M_ILACE_TOP_FIRST) {
      /* 1st buff arg == top field == temporally first == "buffers" */
      read_ppm_into_two_buffers(fd, buffers, buffers2,
				rowbuffer, width, height, bgr);
    } else {
      /* bottom-field-first */
      /* 1st buff art == top field == temporally second == "buffers2" */
      read_ppm_into_two_buffers(fd, buffers2, buffers,
				rowbuffer, width, height, bgr);
    }      
  } else if ((ilace == Y4M_ILACE_NONE) || (!ileave)) {
    /* Not Interlaced, or Not Interleaved:
       --> read image into first buffer... */
    read_ppm_into_one_buffer(fd, buffers, rowbuffer, width, height, bgr);
    if ((ilace != Y4M_ILACE_NONE) && (!ileave)) {
      /* ...Actually Interlaced:
	 --> read the second image/field into second buffer */
      err = read_ppm_header(fd, &width, &height);
      if (err > 0) return 1;  /* EOF */
      if (err < 0) return -1; /* error */
      mjpeg_debug("Got PPM header:  %dx%d", width, height);
      
      /* make sure everything matches */
      if ( (ppm->width != width) ||
	   (ppm->height != height) )
	mjpeg_error_exit1("One of these frames is not like the others!");
      read_ppm_into_one_buffer(fd, buffers2, rowbuffer, width, height, bgr);
    }
  }
  return 0;
}



static
void setup_output_stream(int fdout, cl_info_t *cl,
			 y4m_stream_info_t *sinfo, ppm_info_t *ppm,
			 int *field_height) 
{
  int err;
  int x_alignment = y4m_chroma_ss_x_ratio(cl->ss_mode).d;
  int y_alignment = y4m_chroma_ss_y_ratio(cl->ss_mode).d;
    
  if (cl->interlace != Y4M_ILACE_NONE) 
    y_alignment *= 2;

  if ((ppm->width % x_alignment) != 0) {
    mjpeg_error_exit1("PPM width (%d) is not a multiple of %d!",
		      ppm->width, x_alignment);
  }
  if ((ppm->height % y_alignment) != 0) {
    mjpeg_error_exit1("PPM height (%d) is not a multiple of %d!",
		      ppm->height, y_alignment);
  }

  y4m_si_set_width(sinfo, ppm->width);
  if (cl->interlace == Y4M_ILACE_NONE) {
    y4m_si_set_height(sinfo, ppm->height);
    *field_height = ppm->height;
  } else if (cl->interleave) {
    y4m_si_set_height(sinfo, ppm->height);
    *field_height = ppm->height / 2;
  } else {
    y4m_si_set_height(sinfo, ppm->height * 2);
    *field_height = ppm->height;
  }
  y4m_si_set_sampleaspect(sinfo, cl->aspect);
  y4m_si_set_interlace(sinfo, cl->interlace);
  y4m_si_set_framerate(sinfo, cl->framerate);
  y4m_si_set_chroma(sinfo, cl->ss_mode);

  if ((err = y4m_write_stream_header(fdout, sinfo)) != Y4M_OK)
    mjpeg_error_exit1("Write header failed:  %s", y4m_strerr(err));

  mjpeg_info("Output Stream parameters:");
  y4m_log_stream_info(LOG_INFO, "  ", sinfo);
}




int main(int argc, char **argv)
{
  cl_info_t cl;
  y4m_stream_info_t sinfo;
  y4m_frame_info_t finfo;
  uint8_t *buffers[Y4M_MAX_NUM_PLANES];  /* R'G'B' or Y'CbCr */
  uint8_t *buffers2[Y4M_MAX_NUM_PLANES]; /* R'G'B' or Y'CbCr */
  ppm_info_t ppm;
  int field_height;

  int fdout = 1;
  int err, i, count, repeating_last;

  y4m_accept_extensions(1);
  y4m_init_stream_info(&sinfo);
  y4m_init_frame_info(&finfo);

  parse_args(&cl, argc, argv);

  ppm.width = 0;
  ppm.height = 0;
  for (i = 0; i < 3; i++) {
    buffers[i] = NULL;
    buffers2[i] = NULL;
  }

  /* Read first PPM frame/field-pair, to get dimensions */
  if (read_ppm_frame(cl.fdin, &ppm, buffers, buffers2, 
		     cl.interlace, cl.interleave, cl.bgr))
    mjpeg_error_exit1("Failed to read first frame.");

  /* Setup streaminfo and write output header */
  setup_output_stream(fdout, &cl, &sinfo, &ppm, &field_height);

  /* Loop 'framecount' times, or possibly forever... */
  for (count = 0, repeating_last = 0;
       (count < (cl.offset + cl.framecount)) || (cl.framecount == 0);
       count++) {

    if (repeating_last) goto WRITE_FRAME;

    /* Read PPM frame/field */
    /* ...but skip reading very first frame, already read prior to loop */
    if (count > 0) {
      err = read_ppm_frame(cl.fdin, &ppm, buffers, buffers2, 
			   cl.interlace, cl.interleave, cl.bgr);
      if (err == 1) {
	/* clean input EOF */
	if (cl.repeatlast) {
	  repeating_last = 1;
	  goto WRITE_FRAME;
	} else if (cl.framecount != 0) {
	  mjpeg_error_exit1("Input frame shortfall (only %d converted).",
			    count - cl.offset);
	} else {
	  break;  /* input is exhausted; we are done!  time to go home! */
	}
      } else if (err)
	mjpeg_error_exit1("Error reading ppm frame");
    }
    
    /* ...skip transforms if we are just going to skip this frame anyway.
       BUT, if 'cl.repeatlast' is on, we must process/buffer every frame,
       because we don't know when we will see the last one. */
    if ((count >= cl.offset) || (cl.repeatlast)) {
      /* Transform colorspace, then subsample (in place) */
      convert_RGB_to_YCbCr(buffers, ppm.width * field_height);
      chroma_subsample(cl.ss_mode, buffers, ppm.width, field_height);
      if (cl.interlace != Y4M_ILACE_NONE) {
	convert_RGB_to_YCbCr(buffers2, ppm.width * field_height);
	chroma_subsample(cl.ss_mode, buffers2, ppm.width, field_height);
      }
    }

  WRITE_FRAME:
    /* Write converted frame to output */
    if (count >= cl.offset) {
      switch (cl.interlace) {
      case Y4M_ILACE_NONE:
	if ((err = y4m_write_frame(fdout, &sinfo, &finfo, buffers)) != Y4M_OK)
	  mjpeg_error_exit1("Write frame failed: %s", y4m_strerr(err));
	break;
      case Y4M_ILACE_TOP_FIRST:
	if ((err = y4m_write_fields(fdout, &sinfo, &finfo, buffers, buffers2))
	    != Y4M_OK)
	  mjpeg_error_exit1("Write fields failed: %s", y4m_strerr(err));
	break;
      case Y4M_ILACE_BOTTOM_FIRST:
	if ((err = y4m_write_fields(fdout, &sinfo, &finfo, buffers2, buffers))
	    != Y4M_OK)
	  mjpeg_error_exit1("Write fields failed: %s", y4m_strerr(err));
	break;
      default:
	mjpeg_error_exit1("Unknown ilace type!   %d", cl.interlace);
	break;
      }
    }
  } 


  for (i = 0; i < 3; i++) {
    free(buffers[i]);
    free(buffers2[i]);
  }
  y4m_fini_stream_info(&sinfo);
  y4m_fini_frame_info(&finfo);

  mjpeg_debug("Done.");
  return 0;
}