code: plan9front

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audio/mixfs: convert pcm for devices that are not 44.1kHz

--- a/sys/src/cmd/audio/mixfs/mixfs.c

+++ b/sys/src/cmd/audio/mixfs/mixfs.c

@@ -3,6 +3,7 @@

 #include <fcall.h>

 #include <thread.h>

 #include <9p.h>

+#include <pcm.h>

 enum {

 	NBUF = 8*1024,

@@ -9,7 +10,7 @@

 	NDELAY = 512,	/* ~11.6ms */

 	NQUANTA = 64,	/* ~1.45ms */

 	NCHAN = 2,

-	FREQ = 44100,

+	ABUF = NBUF*NCHAN*2,

 };

 #define MIN(a,b) ((a)<(b)?(a):(b))

@@ -44,6 +45,7 @@

 int	volume[2] = {100, 100};

 int	vol64k[2] = {65536, 65536};

+int	newrate;

 int

 s16(uchar *p)

@@ -76,6 +78,23 @@

 	qunlock(&devlock);

 }

+void

+updrate(void)

+{

+	static char svol[4*1024];

+	int n, rate;

+	char *s;

+

+	rate = pcmdescdef.rate;

+	if(volfd >= 0 && (n = pread(volfd, svol+1, sizeof(svol)-2, 0)) > 8){

+		svol[0] = '\n';

+		svol[1+n] = 0;

+		if((s = strstr(svol, "\nspeed ")) != nil && (n = strtol(s+6, &s, 10)) > 0)

+			rate = n;

+	}

+	newrate = rate;

+}

+

 int

 reopendevs(char *name)

 {

@@ -145,6 +164,7 @@

 		name = smprint("%.*svolume%s", (int)(p - name), name, p+5);

 		volfd = open(name, ORDWR);

 		free(name);

+		updrate();

 	}

 	return 0;

 }

@@ -205,15 +225,20 @@

 void

 audioproc(void *)

 {

-	static uchar buf[NBUF*NCHAN*2];

+	static uchar buf[ABUF];

+	static Pcmdesc desc;

 	int sweep, i, j, n, m, v;

 	ulong rp;

 	Stream *s;

-	uchar *p;

+	uchar *p, *bufconv;

+	Pcmconv	*conv;

 	threadsetname("audioproc");

-

+	desc = pcmdescdef;

+	conv = nil;

+	bufconv = nil;

 	sweep = 0;

+

 	for(;;){

 		m = NBUF;

 		for(s = streams; s < streams+nelem(streams); s++){

@@ -244,13 +269,13 @@

 			ms = 100;

 			if(audiofd >= 0){

-				if(sweep)

+				if(sweep){

 					closeaudiodev();

-				else {

+				} else {

 					/* attempt to sleep just shortly before buffer underrun */

 					ms = seek(audiofd, 0, 2);

 					ms *= 800;

-					ms /= FREQ*NCHAN*2;

+					ms /= desc.rate*NCHAN*2;

 				}

 				sweep = 1;

 			}

@@ -285,8 +310,27 @@

 		mixrp = rp;

 		unlock(&rplock);

+		if(desc.rate != newrate){

+			desc.rate = newrate;

+			free(bufconv);

+			bufconv = nil;

+			freepcmconv(conv);

+			if((conv = allocpcmconv(&pcmdescdef, &desc)) == nil ||

+			   (n = pcmratio(conv, ABUF)) < 0 ||

+			   (bufconv = malloc(n)) == nil){

+				fprint(2, "%s: %r\n", devaudio);

+				freepcmconv(conv);

+				conv = nil;

+			}

+		}

+

 		n = p - buf;

-		if(write(audiofd, buf, n) != n)

+		p = buf;

+		if(conv != nil){

+			n = pcmconv(conv, buf, bufconv, n);

+			p = bufconv;

+		}

+		if(write(audiofd, p, n) != n)

 			closeaudiodev();

 	}

 }

@@ -530,6 +574,7 @@

 	if(argc > 1)

 		usage();

+	newrate = pcmdescdef.rate;

 	reopendevs(argv[0]);

 	closeaudiodev();