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

/**************************************************************************** 
 * armslen                                            (c) 2004 J. A. Robson 
 *  
 * Creates a named pipe '\\.\pipe\madArmsLen', and once a client process  
 * (i.e. armslen_test.cpp) accesses the pipe, begins converting the given 
 * file from  MP3 using madlldlib (and thus libmad), and passes the encoding 
 * information as a formatted stream to the pipe. The formatting is simple-- 
 * a comma-delimited string with name/value pairs: 
 * 
 * 		fc			Frame count 
 * 		tb			Total bytes converted 
 * 		(MP3 related): 
 * 		lyr			MP3 layer 
 * 		md			Mode 
 * 		mdx			Mode extension 
 * 		emp			Emphasis 
 *		br			Bitrate	 
 *		sr			Samplerate 
 * 
 * The client application can access the pipe, read and parse out the above  
 * data, and then use it to update status indicators. 
 *  
 * This is provided as a simple example in case you do not want to include  
 * madlldlib as a DLL, but still need to update a display in your  
 * application. To test this example, armslen_test.cpp must also be compiled. 
 * After compilation, first run armslen.exe, then, in a different console, 
 * run armslen_test.exe. 
 ****************************************************************************/ 
 
#include  
#include  
#include  
#include  
#include  
 
 
char *pipe_srv = "\\\\.\\pipe\\madArmsLen"; 
HANDLE ha; 
int twentyfour = 24; 
unsigned long pbuffsz = 256+twentyfour; 
bool tf; 
 
 
 
/* 
 * 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) { 
 
	char pmsg[256]; 
	unsigned long bamt = 0; 
	 
	/* 
	 * 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) { 
		 
 
		sprintf(pmsg, "fc=%d,tb=%d,lyr=%d,md=%d,mdx=%d,emp=%d,br=%d,sr=%d", 
				fcnt, 
				bcnt, 
				mhdr->layer,  
				mhdr->mode, 
				mhdr->mode_extension, 
				mhdr->emphasis, 
				mhdr->bitrate, 
				mhdr->samplerate); 
 
 
		if (WriteFile(ha, &pmsg, 256, &bamt, NULL) == 0) { 
		 
			printf("WriteFile failed: err=%d\n", GetLastError()); 
			return;		 
		 
		} 
 
 
	} 
	else { 
		 
		sprintf(pmsg, "fc=%d,tb=%d", fcnt, bcnt); 
 
		if (WriteFile(ha, &pmsg, 256, &bamt, NULL) == 0) { 
		 
			printf("WriteFile failed: err=%d\n", GetLastError()); 
			return;		 
		 
		}		 
 
 
	} 
	 
} 
 
/*  
 * Program entry point 
 * note: argv error checking is minimal (to say the least)  
 */ 
int main(int argc, char *argv[]) { 
 
 
	/* status/error reporting */ 
	char statmsg[256]; 
	int status; 
	 
	 
	/* if not the exact number of command  
	 * line parameters, quit */ 
	if (argc != 4) { 
		printf("usage: %s 'input.mp3' 'output file' 'pcm|wav'\n", argv[0]); 
		return 1; 
	} 
 
	 
	 
	/* Create named pipe server (for 
	 * write only) */ 
	 
	ha = CreateNamedPipe(pipe_srv, 
        PIPE_ACCESS_OUTBOUND, 
        PIPE_TYPE_BYTE, 
        2,              // two connections 
        pbuffsz,              // input buffer size 
        pbuffsz,              // output buffer size 
        INFINITE,       // timeout 
        NULL);          // security 
 
 
 
	if (ha == INVALID_HANDLE_VALUE)  
	{ 
    	printf("CreateNamedPipe() FAILED: err=%d\n",  
				GetLastError()); 
		return 1; 
		 
  	} 
	 
	 
	/* Do not execute conversion until 
	 * client has attached */ 
	 
	printf("Pipe %s waiting for client...\n", pipe_srv);	 
	tf = ConnectNamedPipe(ha, NULL); 
 
	 
	/* 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[3], "pcm")==0) {		/* output raw PCM */ 
		status = CbMpegAudioDecoder(argv[1], argv[2], 0, statmsg, mycb); 
	} 
	else {									/* output as WAV */ 
		status = CbMpegAudioDecoder(argv[1], argv[2], 1, statmsg, mycb); 
	} 
 
 
	/* relay any errors */	 
	if (statmsg) 
		printf("%s", statmsg);		 
 
	return 0;	 
 
}