yuv4mpeg.h

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.

 *    the structures; don't touch the structure directly.  (Ok, so there
 *    is no really convenient C syntax to prevent you from doing this,
 *    but we are all responsible programmers here, so just don't do it!)
 *
 ************************************************************************/

/* initialize a stream_info structure */
void y4m_init_stream_info(y4m_stream_info_t *i);

/* finalize a stream_info structure */
void y4m_fini_stream_info(y4m_stream_info_t *i);

/* make one stream_info into a copy of another */
void y4m_copy_stream_info(y4m_stream_info_t *dest, y4m_stream_info_t *src);

/* access or set stream_info fields */
void y4m_si_set_width(y4m_stream_info_t *si, int width);
int y4m_si_get_width(y4m_stream_info_t *si);
void y4m_si_set_height(y4m_stream_info_t *si, int height);
int y4m_si_get_height(y4m_stream_info_t *si);
void y4m_si_set_interlace(y4m_stream_info_t *si, int interlace);
int y4m_si_get_interlace(y4m_stream_info_t *si);
void y4m_si_set_framerate(y4m_stream_info_t *si, y4m_ratio_t framerate);
y4m_ratio_t y4m_si_get_framerate(y4m_stream_info_t *si);
void y4m_si_set_sampleaspect(y4m_stream_info_t *si, y4m_ratio_t sar);
y4m_ratio_t y4m_si_get_sampleaspect(y4m_stream_info_t *si);
int y4m_si_get_framelength(y4m_stream_info_t *si);

/* access stream_info xtag_list */
y4m_xtag_list_t *y4m_si_xtags(y4m_stream_info_t *si);


/* initialize a frame_info structure */
void y4m_init_frame_info(y4m_frame_info_t *i);

/* finalize a frame_info structure */
void y4m_fini_frame_info(y4m_frame_info_t *i);

/* make one frame_info into a copy of another */
void y4m_copy_frame_info(y4m_frame_info_t *dest, y4m_frame_info_t *src);

/* access frame_info xtag_list */
y4m_xtag_list_t *y4m_fi_xtags(y4m_frame_info_t *fi);



/************************************************************************
 *  blocking read and write functions
 *
 *  o guaranteed to transfer entire payload (or fail)
 *  o return values:
 *                         0 (zero)   complete success
 *          -(# of remaining bytes)   error (and errno left set)
 *          +(# of remaining bytes)   EOF (for y4m_read only)
 *
 ************************************************************************/

/* read len bytes from fd into buf */
ssize_t y4m_read(stream_t *s, char *buf, size_t len);

#if 0
/* write len bytes from fd into buf */
ssize_t y4m_write(int fd, char *buf, size_t len);
#endif


/************************************************************************
 *  stream header processing functions
 *  
 *  o return values:
 *                   Y4M_OK - success
 *                Y4M_ERR_* - error (see y4m_strerr() for descriptions)
 *
 ************************************************************************/

/* parse a string of stream header tags */
int y4m_parse_stream_tags(char *s, y4m_stream_info_t *i);

/* read a stream header from file descriptor fd */
int y4m_read_stream_header(stream_t *s, y4m_stream_info_t *i);

#if 0
/* write a stream header to file descriptor fd */
int y4m_write_stream_header(int fd,  y4m_stream_info_t *i);
#endif


/************************************************************************
 *  frame processing functions
 *  
 *  o return values:
 *                   Y4M_OK - success
 *                Y4M_ERR_* - error (see y4m_strerr() for descriptions)
 *
 ************************************************************************/

/* read a frame header from file descriptor fd */
int y4m_read_frame_header(stream_t *s, y4m_frame_info_t *i);

#if 0
/* write a frame header to file descriptor fd */
int y4m_write_frame_header(int fd, y4m_frame_info_t *i);
#endif

/* read a complete frame (header + data)
   o yuv[3] points to three buffers, one each for Y, U, V planes */
int y4m_read_frame(stream_t *s, y4m_stream_info_t *si, 
		   y4m_frame_info_t *fi, unsigned char *yuv[3]);

#if 0
/* write a complete frame (header + data)
   o yuv[3] points to three buffers, one each for Y, U, V planes */
int y4m_write_frame(int fd, y4m_stream_info_t *si, 
		    y4m_frame_info_t *fi, unsigned char *yuv[3]);
#endif

#if 0
/* read a complete frame (header + data), but de-interleave fields
    into two separate buffers
   o upper_field[3] same as yuv[3] above, but for upper field
   o lower_field[3] same as yuv[3] above, but for lower field
*/
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]);

/* write a complete frame (header + data), but interleave fields
    from two separate buffers
   o upper_field[3] same as yuv[3] above, but for upper field
   o lower_field[3] same as yuv[3] above, but for lower field
*/
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]);

#endif

/************************************************************************
 *  miscellaneous functions
 ************************************************************************/

/* convenient dump of stream header info via mjpeg_log facility
 *  - each logged/printed line is prefixed by 'prefix'
 */
void y4m_log_stream_info(const char *prefix, y4m_stream_info_t *i);

/* convert a Y4M_ERR_* error code into mildly explanatory string */
const char *y4m_strerr(int err);

/* set 'allow_unknown_tag' flag for library...
    o yn = 0 :  unknown header tags will produce a parsing error
    o yn = 1 :  unknown header tags/values will produce a warning, but
                 are otherwise passed along via the xtags list
    o yn = -1:  don't change, just return current setting

   return value:  previous setting of flag
*/
int y4m_allow_unknown_tags(int yn);


#ifdef __cplusplus
}
#endif

/************************************************************************
 ************************************************************************

  Description of the (new!, forever?) YUV4MPEG2 stream format:

  STREAM consists of
    o one '\n' terminated STREAM-HEADER
    o unlimited number of FRAMEs

  FRAME consists of
    o one '\n' terminated FRAME-HEADER
    o "length" octets of planar YCrCb 4:2:0 image data
        (if frame is interlaced, then the two fields are interleaved)


  STREAM-HEADER consists of
     o string "YUV4MPEG2 "  (note the space after the '2')
     o unlimited number of ' ' separated TAGGED-FIELDs
     o '\n' line terminator

  FRAME-HEADER consists of
     o string "FRAME "  (note the space after the 'E')
     o unlimited number of ' ' separated TAGGED-FIELDs
     o '\n' line terminator


  TAGGED-FIELD consists of
     o single ascii character tag
     o VALUE (which does not contain whitespace)

  VALUE consists of
     o integer (base 10 ascii representation)
  or o RATIO
  or o single ascii character
  or o generic ascii string

  RATIO consists of
     o numerator (integer)
     o ':' (a colon)
     o denominator (integer)


  The currently supported tags for the STREAM-HEADER:
     W - [integer] frame width, pixels, should be > 0
     H - [integer] frame height, pixels, should be > 0
     I - [char] interlacing:  p - progressive (none)
                            t - top-field-first
                            b - bottom-field-first
		            ? - unknown
     F - [ratio] frame-rate, 0:0 == unknown
     A - [ratio] sample (pixel) aspect ratio, 0:0 == unknown
     X - [character string] 'metadata' (unparsed, but passed around)

  The currently supported tags for the FRAME-HEADER:
     X - character string 'metadata' (unparsed, but passed around)

 ************************************************************************
 ************************************************************************/

#endif /* __YUV4MPEG_H__ */