read_mp3.c

linux下的rtp的实例源代码

/* * 
 *  $Id: read_MP3.c 133 2005-05-09 17:35:14Z federico $
 *  
 *  This file is part of Fenice
 *
 *  Fenice -- Open Media Server
 *
 *  Copyright (C) 2004 by
 *  	
 *	- Giampaolo Mancini	<[e-mail]>
 *	- Francesco Varano	<[e-mail]>
 *	- Marco Penno		<[e-mail]>
 *	- Federico Ridolfo	<[e-mail]>
 *	- Eugenio Menegatti 	<[e-mail]>
 *	- Stefano Cau
 *	- Giuliano Emma
 *	- Stefano Oldrini
 * 
 *  Fenice is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Fenice 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Fenice; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *  
 * */

#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <fenice/types.h>
#include <fenice/utils.h>
#include <fenice/mediainfo.h>
#include <fenice/mp3.h>

int read_MP3(media_entry *me,uint8 *data,uint32 *data_size,double *mtime, int *recallme, uint8 *marker)
{
        // char thefile[255];
	int ret;
	unsigned char *buff = me->buff_data;
        int N=0, res;

	*marker=0;
	*recallme=0;
        if (!(me->flags & ME_FD)) {
		if ( (ret=mediaopen(me)) < 0 )
			return ret;
		//me->prev_mstart_offset=0;	
		/* TODO support Id3 TAG v2, this doesn't work*/
		//if ((me->description.flags & MED_ID3) && (me->description).msource!=live)
		//	lseek(me->fd,(me->description.tag_dim)+10,SEEK_SET);
        }

	
	
        if(me->play_offset!=-1/*me->prev_mstart_offset*/ && (me->description).msource!=live){                 //random access 
                N=(float)me->description.bitrate/8 * me->play_offset/1000;
        	/*me->prev_mstart_offset=*/me->play_offset=-1; 						// pkt_len is pkt lenght in milliseconds,
		lseek(me->fd,N,SEEK_SET);
	}		                                                                		

	if ((read(me->fd,&(buff[me->buff_size]),4)) != 4 ){
		return ERR_EOF;
	}
	me->buff_size = 0;
	if ((buff[0]==0xff) && ((buff[1] & 0xe0)==0xe0)) {
		N = (int)(me->description.frame_len * (float)me->description.bitrate / (float)me->description.sample_rate / 8);
		if (buff[2] & 0x02) N++;
	} 
	else {
		// Sync not found, not Mpeg-1/2
		// id3 TAG v1 is suppressed, id3 TAG v2 is not supported and
		//fprintf(stderr,"ERROR: Sync not found, not Mpeg-1/2\n");
		N = (int)(me->description.frame_len * (float)me->description.bitrate / (float)me->description.sample_rate / 8);
		//return ERR_EOF;
	}
        *data_size = N + 4; // 4 bytes are needed for mp3 in RTP encapsulation
        data[0]=0;
        data[1]=0;
        data[2]=0;
        data[3]=0;
        // These first 4 bytes are for mp3 in RTP encapsulation
	
        data[4]=buff[0];
        data[5]=buff[1];
        data[6]=buff[2];
        data[7]=buff[3];
		
       if (( res = read ( me->fd, &(data[8]) ,N-4 ) ) < (N-4)) {
                if ((res <= 0)){ 
			return ERR_EOF;
		}
                else *data_size = res + 8;
        }
	
        return ERR_NOERROR;
}