voc.c

linux下录音程序

	wlshort(ft, 0x1129);		/* checksum of version number */

	if (ft->info.size == BYTE)
	  ft->info.style = UNSIGNED;
	else
	  ft->info.style = SIGN2;
	if (ft->info.channels == -1)
		ft->info.channels = 1;
}

void vocwrite(ft, buf, len) 
ft_t ft;
LONG *buf, len;
{
	vs_t v = (vs_t) ft->priv;
	unsigned char uc;
	int sw;
	
	if (v->samples == 0) {
	  /* No silence packing yet. */
	  v->silent = 0;
	  blockstart(ft);
	}
	v->samples += len;
	while(len--) {
	  if (ft->info.size == BYTE) {
	    uc = RIGHT(*buf++, 24);
	    uc ^= 0x80;
	    putc(uc, ft->fp);
	  } else {
		sw = (int) RIGHT(*buf++, 16);
	    wlshort(ft,sw);
          }
	}
}

void vocstopwrite(ft) 
ft_t ft;
{
	blockstop(ft);
}

/* Voc-file handlers */

/* Read next block header, save info, leave position at start of data */
void
getblock(ft)
ft_t ft;
{
	vs_t v = (vs_t) ft->priv;
	unsigned char uc, block;
	ULONG sblen;
	LONG new_rate;
	int i;

	v->silent = 0;
	while (v->rest == 0) {
		if (feof(ft->fp))
			return;
		block = getc(ft->fp);
		if (block == VOC_TERM)
			return;
		if (feof(ft->fp))
			return;
		uc = getc(ft->fp);
		sblen = uc;
		uc = getc(ft->fp);
		sblen |= ((LONG) uc) << 8;
		uc = getc(ft->fp);
		sblen |= ((LONG) uc) << 16;
		switch(block) {
		case VOC_DATA: 
		        uc = getc(ft->fp);
			/* When DATA block preceeded by an EXTENDED     */
			/* block, the DATA blocks rate value is invalid */
		        if (!v->extended) {
			  if (uc == 0)
			    fail("File %s: Sample rate is zero?");
			  if ((v->rate != -1) && (uc != v->rate))
			    fail("File %s: sample rate codes differ: %d != %d",
				 ft->filename,v->rate, uc);
			  v->rate = uc;
			  ft->info.rate = 1000000.0/(256 - v->rate);
			  v->channels = 1;
			}
			uc = getc(ft->fp);
			if (uc != 0)
			  fail("File %s: only interpret 8-bit data!",
			       ft->filename);
			v->extended = 0;
			v->rest = sblen - 2;
			v->size = BYTE;
			return;
		case VOC_DATA_16:
			new_rate = rllong(ft);
			if (new_rate == 0)
			    fail("File %s: Sample rate is zero?",ft->filename);
			if ((v->rate != -1) && (new_rate != v->rate))
			    fail("File %s: sample rate codes differ: %d != %d",
				ft->filename, v->rate, new_rate);
			v->rate = new_rate;
			ft->info.rate = new_rate;
			uc = getc(ft->fp);
			switch (uc)
			{
			    case 8:	v->size = BYTE; break;
			    case 16:	v->size = WORD; break;
			    default:	fail("Don't understand size %d", uc);
			}
			v->channels = getc(ft->fp);
			getc(ft->fp);	/* unknown1 */
			getc(ft->fp);	/* notused */
			getc(ft->fp);	/* notused */
			getc(ft->fp);	/* notused */
			getc(ft->fp);	/* notused */
			getc(ft->fp);	/* notused */
			v->rest = sblen - 12;
			return;
		case VOC_CONT: 
			v->rest = sblen;
			return;
		case VOC_SILENCE: 
			{
			unsigned short period;

			period = rlshort(ft);
			uc = getc(ft->fp);
			if (uc == 0)
				fail("File %s: Silence sample rate is zero");
			/* 
			 * Some silence-packed files have gratuitously
			 * different sample rate codes in silence.
			 * Adjust period.
			 */
			if ((v->rate != -1) && (uc != v->rate))
				period = (period * (256 - uc))/(256 - v->rate);
			else
				v->rate = uc;
			v->rest = period;
			v->silent = 1;
			return;
			}
		case VOC_MARKER:
			uc = getc(ft->fp);
			uc = getc(ft->fp);
			/* Falling! Falling! */
		case VOC_TEXT:
			{
			int i;
			/* Could add to comment in SF? */
			for(i = 0; i < sblen; i++)
				getc(ft->fp);
			}
			continue;	/* get next block */
		case VOC_LOOP:
		case VOC_LOOPEND:
			report("File %s: skipping repeat loop");
			for(i = 0; i < sblen; i++)
				getc(ft->fp);
			break;
		case VOC_EXTENDED:
			/* An Extended block is followed by a data block */
			/* Set this byte so we know to use the rate      */
			/* value from the extended block and not the     */
			/* data block.					 */
			v->extended = 1;
			new_rate = rlshort(ft);
			if (new_rate == 0)
			   fail("File %s: Sample rate is zero?");
			if ((v->rate != -1) && (new_rate != v->rate))
			   fail("File %s: sample rate codes differ: %d != %d",
					ft->filename, v->rate, new_rate);
			v->rate = new_rate;
			uc = getc(ft->fp);
			if (uc != 0)
				fail("File %s: only interpret 8-bit data!",
					ft->filename);
			uc = getc(ft->fp);
			if (uc)
				ft->info.channels = 2;  /* Stereo */
			/* Needed number of channels before finishing
			   compute for rate */
			ft->info.rate = (256000000L/(65536L - v->rate))/ft->info.channels;
			/* An extended block must be followed by a data */
			/* block to be valid so loop back to top so it  */
			/* can be grabed.				*/
			continue;
		default:
			report("File %s: skipping unknown block code %d",
				ft->filename, block);
			for(i = 0; i < sblen; i++)
				getc(ft->fp);
		}
	}
}

/* Start an output block. */
void blockstart(ft)
ft_t ft;
{
	vs_t v = (vs_t) ft->priv;

	v->blockseek = ftell(ft->fp);
	if (v->silent) {
		putc(VOC_SILENCE, ft->fp);	/* Silence block code */
		putc(0, ft->fp);		/* Period length */
		putc(0, ft->fp);		/* Period length */
		putc((int) v->rate, ft->fp);		/* Rate code */
	} else {
	  if (ft->info.size == BYTE) {
	    /* 8-bit sample section.  By always setting the correct     */
	    /* rate value in the DATA block (even when its preceeded    */
	    /* by an EXTENDED block) old software can still play stereo */
	    /* files in mono by just skipping over the EXTENDED block.  */
	    /* Prehaps the rate should be doubled though to make up for */
	    /* double amount of samples for a given time????            */
	    if (ft->info.channels > 1) {
	      putc(VOC_EXTENDED, ft->fp);	/* Voice Extended block code */
	      putc(4, ft->fp);                /* block length = 4 */
	      putc(0, ft->fp);                /* block length = 4 */
	      putc(0, ft->fp);                /* block length = 4 */
		  v->rate = 65536L - (256000000.0/(2*(float)ft->info.rate));
	      wlshort(ft,v->rate);	/* Rate code */
	      putc(0, ft->fp);                /* File is not packed */
	      putc(1, ft->fp);                /* samples are in stereo */
	    }
	    putc(VOC_DATA, ft->fp);		/* Voice Data block code */
	    putc(0, ft->fp);		/* block length (for now) */
	    putc(0, ft->fp);		/* block length (for now) */
	    putc(0, ft->fp);		/* block length (for now) */
	    v->rate = 256 - (1000000.0/(float)ft->info.rate);
	    putc((int) v->rate, ft->fp);/* Rate code */
	    putc(0, ft->fp);		/* 8-bit raw data */
	} else {
	    putc(VOC_DATA_16, ft->fp);		/* Voice Data block code */
	    putc(0, ft->fp);		/* block length (for now) */
	    putc(0, ft->fp);		/* block length (for now) */
	    putc(0, ft->fp);		/* block length (for now) */
	    v->rate = ft->info.rate;
	    wllong(ft, v->rate);	/* Rate code */
	    putc(16, ft->fp);		/* Sample Size */
	    putc(ft->info.channels, ft->fp);	/* Sample Size */
	    putc(0, ft->fp);		/* Unknown */
	    putc(0, ft->fp);		/* Unused */
	    putc(0, ft->fp);		/* Unused */
	    putc(0, ft->fp);		/* Unused */
	    putc(0, ft->fp);		/* Unused */
	    putc(0, ft->fp);		/* Unused */
	  }
	}
}

/* End the current data or silence block. */
void blockstop(ft) 
ft_t ft;
{
	vs_t v = (vs_t) ft->priv;
	LONG datum;

	putc(0, ft->fp);			/* End of file block code */
	fseek(ft->fp, v->blockseek, 0);		/* seek back to block length */
	fseek(ft->fp, 1, 1);			/* seek forward one */
	if (v->silent) {
		datum = (v->samples) & 0xff;
		putc((int)datum, ft->fp);       /* low byte of length */
		datum = (v->samples >> 8) & 0xff;
		putc((int)datum, ft->fp);  /* high byte of length */
	} else {
	  if (ft->info.size == BYTE) {
	    if (ft->info.channels > 1) {
	      fseek(ft->fp, 8, 1); /* forward 7 + 1 for new block header */
	    }
	  }
	        v->samples += 2;		/* adjustment: SBDK pp. 3-5 */
		datum = (v->samples) & 0xff;
		putc((int)datum, ft->fp);       /* low byte of length */
		datum = (v->samples >> 8) & 0xff;
		putc((int)datum, ft->fp);  /* middle byte of length */
		datum = (v->samples >> 16) & 0xff;
		putc((int)datum, ft->fp); /* high byte of length */
	}
}