www.pudn.com > madlldlib-10b4_dll.zip > test.cpp

/**************************************************************************** 
 * test                                               (c) 2004 J. A. Robson 
 *  
 * test.cpp -- Primary example to using the madlldlib.dll interface 
 * 
 * This is an extremely simple example that defines a callback, handles a  
 * few command line parameters (i.e. file to convert, output format), and 
 * calls the DLL's main function CbMpegAudioDecoder() to process the MP3  
 * file. See the inline comments for details. For more details about  
 * CbMpegAudioDecoder, see comments in madlldlib.cpp. 
 * 
 * To compile, see 'Makefile' comments. 
 ****************************************************************************/ 
 
#include  
#include  
#include  
 
/* 
 * The callback function is used for reporting purposes and 
 * garnering information about the source MP3 file. This callback  
 * simply prints information to STDOUT, but it usually would be  
 * used to increment a counter, calculate a percentage, or advance 
 * a status bar. 
 */ 
void __stdcall mycb (unsigned long fcnt, unsigned long bcnt, struct mad_header *mhdr) { 
 
	/* 
	 * If this is the first iteration (frame count is one) 
	 * then print out the MP3 layer information. Using this logic 
	 * one can retrieve information about the MP3 file, such as  
	 * channels, layer, etc., that might be useful to the calling 
	 * code. 
	 */	 
	if (fcnt == 1) { 
		printf("frame:%d, tot. bytes:%d, layer:%d, mode:%d\n", 
				fcnt, 
				bcnt, 
				mhdr->layer,  
				mhdr->mode); 
	} 
	else { 
		printf("frame:%d, tot. bytes:%d\n",fcnt,bcnt); 
	} 
	 
} 
 
/*  
 * Program entry point 
 * note: argv error checking is minimal (to say the least)  
 */ 
void main(int argc, char *argv[]) { 
 
	 
	/* used for concatentating the appropriate  
	 * extension to output file */ 
	char *outf; 
	char *outfx; 
	outf=""; 
	outfx="."; 
	 
	/* status/error reporting */ 
	char statmsg[256]; 
	int status; 
	 
	/* if not the exact number of command  
	 * line parameters, quit */ 
	if (argc != 3) { 
		printf("usage: %s 'somefile.mp3' 'pcm|wav'\n", argv[0]); 
		return; 
	} 
 
	/* append suffix to output file (suffix is  
	 * either 'pcm' or 'wav') */ 
	strcat(outf, argv[1]); 
	strcat(outfx, argv[2]); 
	strcat(outf, outfx); 
 
	 
	/* call the decoding function with input file, 
	 * output file, and callback (defined above).  
	 * 
	 * Note on return values: CbMpegAudioDecoder()  
	 * returns 0 if successful, non-zero if it has  
	 * problems opening/reading the files passed.  
	 * libmad, the library concerned with the actual  
	 * MP3 decoding, passes detailed error information  
	 * specific to the MP3 conversion, which gets  
	 * set into the string statmsg.  
	 * (CbMpegAudioDecoder() returns a non-zero  
	 * status at this time as well.) So the upshot  
	 * of this is that both indicators handle  
	 * slightly overlapping but different events, 
	 * and are hence both useful. */ 
	 
	if (strcmp(argv[2], "pcm")==0) {		/* output raw PCM */ 
		status = CbMpegAudioDecoder(argv[1], outf, 0, statmsg, mycb); 
	} 
	else {									/* output as WAV */ 
		status = CbMpegAudioDecoder(argv[1], outf, 1, statmsg, mycb); 
	} 
 
 
	/* relay any errors */	 
	if (statmsg) 
		printf("%s", statmsg);		 
 
	return;	 
 
}