yuv4mpeg.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

      if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
      break;
    default:
      /* possible error on unknown options */
      if (_y4mparam_allow_unknown_tags) {
	/* unknown tags ok:  store in xtag list and warn... */
	if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
	mp_msg(MSGT_DEMUX, MSGL_WARN, "Unknown stream tag encountered:  '%s'\n", token);
      } else {
	/* unknown tags are *not* ok */
	return Y4M_ERR_BADTAG;
      }
      break;
    }
  }
  /* Error checking... width and height must be known since we can't
   * parse without them
   */
  if( i->width == Y4M_UNKNOWN || i->height == Y4M_UNKNOWN )
	  return Y4M_ERR_HEADER;
  /* ta da!  done. */
  return Y4M_OK;
}



static int y4m_parse_frame_tags(char *s, y4m_frame_info_t *i)
{
  char *token, *value;
  char tag;
  int err;

  /* parse fields */
  for (token = strtok(s, Y4M_DELIM); 
       token != NULL; 
       token = strtok(NULL, Y4M_DELIM)) {
    if (token[0] == '\0') continue;   /* skip empty strings */
    tag = token[0];
    value = token + 1;
    switch (tag) {
    case 'X':  /* 'X' meta-tag */
      if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
      break;
    default:
      /* possible error on unknown options */
      if (_y4mparam_allow_unknown_tags) {
	/* unknown tags ok:  store in xtag list and warn... */
	if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
	mp_msg(MSGT_DEMUX, MSGL_WARN, "Unknown frame tag encountered:  '%s'\n", token);
      } else {
	/* unknown tags are *not* ok */
	return Y4M_ERR_BADTAG;
      }
      break;
    }
  }
  /* ta da!  done. */
  return Y4M_OK;
}





/*************************************************************************
 *
 * Read/Write stream header
 *
 *************************************************************************/


int y4m_read_stream_header(stream_t *s, y4m_stream_info_t *i)
{
   char line[Y4M_LINE_MAX];
   char *p;
   int n;
   int err;

   /* read the header line */
   for (n = 0, p = line; n < Y4M_LINE_MAX; n++, p++) {
     if (y4m_read(s, p, 1)) 
       return Y4M_ERR_SYSTEM;
     if (*p == '\n') {
       *p = '\0';           /* Replace linefeed by end of string */
       break;
     }
   }
   if (n >= Y4M_LINE_MAX)
      return Y4M_ERR_HEADER;
   /* look for keyword in header */
   if (strncmp(line, Y4M_MAGIC, strlen(Y4M_MAGIC)))
    return Y4M_ERR_MAGIC;
   if ((err = y4m_parse_stream_tags(line + strlen(Y4M_MAGIC), i)) != Y4M_OK)
     return err;

   i->framelength = (i->height * i->width) * 3 / 2;
   return Y4M_OK;
}


#if 0
int y4m_write_stream_header(int fd, y4m_stream_info_t *i)
{
  char s[Y4M_LINE_MAX+1];
  int n;
  int err;

  y4m_ratio_reduce(&(i->framerate));
  y4m_ratio_reduce(&(i->sampleaspect));
  n = snprintf(s, sizeof(s), "%s W%d H%d F%d:%d I%s A%d:%d",
	       Y4M_MAGIC,
	       i->width,
	       i->height,
	       i->framerate.n, i->framerate.d,
	       (i->interlace == Y4M_ILACE_NONE) ? "p" :
	       (i->interlace == Y4M_ILACE_TOP_FIRST) ? "t" :
	       (i->interlace == Y4M_ILACE_BOTTOM_FIRST) ? "b" : "?",
	       i->sampleaspect.n, i->sampleaspect.d);
  if ((n < 0) || (n > Y4M_LINE_MAX)) return Y4M_ERR_HEADER;
  if ((err = y4m_snprint_xtags(s + n, sizeof(s) - n - 1, &(i->x_tags))) 
      != Y4M_OK) 
    return err;
  /* non-zero on error */
  return (y4m_write(fd, s, strlen(s)) ? Y4M_ERR_SYSTEM : Y4M_OK);
}
#endif




/*************************************************************************
 *
 * Read/Write frame header
 *
 *************************************************************************/

int y4m_read_frame_header(stream_t *s, y4m_frame_info_t *i)
{
  char line[Y4M_LINE_MAX];
  char *p;
  int n;
  ssize_t remain;
  
  /* This is more clever than read_stream_header...
     Try to read "FRAME\n" all at once, and don't try to parse
     if nothing else is there...
  */
  remain = y4m_read(s, line, sizeof(Y4M_FRAME_MAGIC));
  if (remain != 0)
  {
	  /* A clean EOF should end exactly at a frame-boundary */
	  if( remain == sizeof(Y4M_FRAME_MAGIC) )
		  return Y4M_ERR_EOF;
	  else
		  return Y4M_ERR_SYSTEM;
  }
  if (strncmp(line, Y4M_FRAME_MAGIC, sizeof(Y4M_FRAME_MAGIC)-1))
    return Y4M_ERR_MAGIC;
  if (line[sizeof(Y4M_FRAME_MAGIC)-1] == '\n')
    return Y4M_OK; /* done -- no tags:  that was the end-of-line. */

  if (line[sizeof(Y4M_FRAME_MAGIC)-1] != Y4M_DELIM[0]) {
    return Y4M_ERR_MAGIC; /* wasn't a space -- what was it? */
  }

  /* proceed to get the tags... (overwrite the magic) */
  for (n = 0, p = line; n < Y4M_LINE_MAX; n++, p++) {
    if (y4m_read(s, p, 1))
      return Y4M_ERR_SYSTEM;
    if (*p == '\n') {
      *p = '\0';           /* Replace linefeed by end of string */
      break;
    }
  }
  if (n >= Y4M_LINE_MAX) return Y4M_ERR_HEADER;
  /* non-zero on error */
  return y4m_parse_frame_tags(line, i);
}


#if 0
int y4m_write_frame_header(int fd, y4m_frame_info_t *i)
{
  char s[Y4M_LINE_MAX+1];
  int n;
  int err;
  
  n = snprintf(s, sizeof(s), "%s", Y4M_FRAME_MAGIC);
  if ((n < 0) || (n > Y4M_LINE_MAX)) return Y4M_ERR_HEADER;
  if ((err = y4m_snprint_xtags(s + n, sizeof(s) - n - 1, &(i->x_tags))) 
      != Y4M_OK) 
    return err;
  /* non-zero on error */
  return (y4m_write(fd, s, strlen(s)) ? Y4M_ERR_SYSTEM : Y4M_OK);
}
#endif



/*************************************************************************
 *
 * Read/Write entire frame
 *
 *************************************************************************/

int y4m_read_frame(stream_t *s, y4m_stream_info_t *si, 
		   y4m_frame_info_t *fi, unsigned char *yuv[3])
{
  int err;
  int w = si->width;
  int h = si->height;
  
  /* Read frame header */
  if ((err = y4m_read_frame_header(s, fi)) != Y4M_OK) return err;
  /* Read luminance scanlines */
  if (y4m_read(s, yuv[0], w*h)) return Y4M_ERR_SYSTEM;
  /* Read chrominance scanlines */
  if (y4m_read(s, yuv[1], w*h/4)) return Y4M_ERR_SYSTEM;
  if (y4m_read(s, yuv[2], w*h/4)) return Y4M_ERR_SYSTEM;

  return Y4M_OK;
}



#if 0
int y4m_write_frame(int fd, y4m_stream_info_t *si, 
		    y4m_frame_info_t *fi, unsigned char *yuv[3])
{
  int err;
  int w = si->width;
  int h = si->height;

  /* Write frame header */
  if ((err = y4m_write_frame_header(fd, fi)) != Y4M_OK) return err;
  /* Write luminance,chrominance scanlines */
  if (y4m_write(fd, yuv[0], w*h) ||
      y4m_write(fd, yuv[1], w*h/4) ||
      y4m_write(fd, yuv[2], w*h/4))
    return Y4M_ERR_SYSTEM;
  return Y4M_OK;
}
#endif


/*************************************************************************
 *
 * Read/Write entire frame, (de)interleaved (to)from two separate fields
 *
 *************************************************************************/

#if 0
int y4m_read_fields(int fd, y4m_stream_info_t *si, y4m_frame_info_t *fi,
                    unsigned char *upper_field[3], 
                    unsigned char *lower_field[3])
{
  int i, y, err;
  int width = si->width;
  int height = si->height;
  
  /* Read frame header */
  if ((err = y4m_read_frame_header(fd, fi)) != Y4M_OK) return err;
  /* Read Y', Cb, and Cr planes */
  for (i = 0; i < 3; i++) {
    unsigned char *srctop = upper_field[i];
    unsigned char *srcbot = lower_field[i];
    /* alternately write one line from each */
    for (y = 0; y < height; y += 2) {
      if (y4m_read(fd, srctop, width)) return Y4M_ERR_SYSTEM;
      srctop += width;
      if (y4m_read(fd, srcbot, width)) return Y4M_ERR_SYSTEM;
      srcbot += width;
    }
    /* for chroma, width/height are half as big */
    if (i == 0) {
      width /= 2;
      height /= 2;
    }
  }
  return Y4M_OK;
}



int y4m_write_fields(int fd, y4m_stream_info_t *si, y4m_frame_info_t *fi,
                     unsigned char *upper_field[3], 
                     unsigned char *lower_field[3])
{
  int i, y, err;
  int width = si->width;
  int height = si->height;

  /* Write frame header */
  if ((err = y4m_write_frame_header(fd, fi)) != Y4M_OK) return err;
  /* Write Y', Cb, and Cr planes */
  for (i = 0; i < 3; i++) {
    unsigned char *srctop = upper_field[i];
    unsigned char *srcbot = lower_field[i];
    /* alternately write one line from each */
    for (y = 0; y < height; y += 2) {
      if (y4m_write(fd, srctop, width)) return Y4M_ERR_SYSTEM;
      srctop += width;
      if (y4m_write(fd, srcbot, width)) return Y4M_ERR_SYSTEM;
      srcbot += width;
    }
    /* for chroma, width/height are half as big */
    if (i == 0) {
      width /= 2;
      height /= 2;
    }
  }
  return Y4M_OK;
}
#endif


/*************************************************************************
 *
 * Handy logging of stream info
 *
 *************************************************************************/

void y4m_log_stream_info(const char *prefix, y4m_stream_info_t *i)
{
  char s[256];

  snprintf(s, sizeof(s), "  frame size:  ");
  if (i->width == Y4M_UNKNOWN)
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "(?)x");
  else
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "%dx", i->width);
  if (i->height == Y4M_UNKNOWN)
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "(?) pixels ");
  else
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "%d pixels ", i->height);
  if (i->framelength == Y4M_UNKNOWN)
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "(? bytes)");
  else
    snprintf(s+strlen(s), sizeof(s)-strlen(s), "(%d bytes)", i->framelength);
  mp_msg(MSGT_DEMUX, MSGL_V, "%s%s\n", prefix, s);
  if ((i->framerate.n == 0) && (i->framerate.d == 0))
    mp_msg(MSGT_DEMUX, MSGL_V, "%s  frame rate:  ??? fps\n", prefix);
  else
    mp_msg(MSGT_DEMUX, MSGL_V, "%s  frame rate:  %d/%d fps (~%f)\n", prefix,
	      i->framerate.n, i->framerate.d, 
	      (double) i->framerate.n / (double) i->framerate.d);
  mp_msg(MSGT_DEMUX, MSGL_V, "%s   interlace:  %s\n", prefix,
	  (i->interlace == Y4M_ILACE_NONE) ? "none/progressive" :
	  (i->interlace == Y4M_ILACE_TOP_FIRST) ? "top-field-first" :
	  (i->interlace == Y4M_ILACE_BOTTOM_FIRST) ? "bottom-field-first" :
	  "anyone's guess");
  if ((i->sampleaspect.n == 0) && (i->sampleaspect.d == 0))
    mp_msg(MSGT_DEMUX, MSGL_V, "%ssample aspect ratio:  ?:?\n", prefix);
  else
    mp_msg(MSGT_DEMUX, MSGL_V, "%ssample aspect ratio:  %d:%d\n", prefix,
	      i->sampleaspect.n, i->sampleaspect.d);
}


/*************************************************************************
 *
 * Convert error code to string
 *
 *************************************************************************/

const char *y4m_strerr(int err)
{
  switch (err) {
  case Y4M_OK:          return "no error";
  case Y4M_ERR_RANGE:   return "parameter out of range";
  case Y4M_ERR_SYSTEM:  return "stream ended unexpectedly (failed read/write)";
  case Y4M_ERR_HEADER:  return "bad stream or frame header";
  case Y4M_ERR_BADTAG:  return "unknown header tag";
  case Y4M_ERR_MAGIC:   return "bad header magic";
  case Y4M_ERR_XXTAGS:  return "too many xtags";
  case Y4M_ERR_EOF:     return "end-of-file";
  default: 
    return "unknown error code";
  }
}