code: plan9front

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audio/mixfs: resample based on audio dev output format, not just the rate

This is pleminary work of replacing "speed" with "fmtout"/"fmtin"
through the entire system.
Switching between output devices with different PCM formats
back and forth now works as expected.

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

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

@@ -4,6 +4,7 @@

 #include <thread.h>

 #include <9p.h>

 #include <pcm.h>

+#pragma varargck type "!" Pcmdesc

 enum {

 	NBUF = 8*1024,

@@ -45,8 +46,11 @@

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

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

-int	newrate;

+Pcmdesc	fmt;

+Lock	fmtlock;

+int	fmtchanged;

+

 int

 s16(uchar *p)

 {

@@ -79,20 +83,36 @@

 }

 void

-updrate(void)

+updfmt(void)

 {

 	static char svol[4*1024];

-	int n, rate;

-	char *s;

+	char *s, *e;

+	int n, ok;

-	rate = pcmdescdef.rate;

+	ok = 0;

 	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;

+		if((s = strstr(svol, "\nfmtout ")) != nil && (e = strchr(s+12, '\n')) != nil){

+			*e = 0;

+			lock(&fmtlock);

+			ok = fmtchanged = mkpcmdesc(s+8, &fmt) == 0;

+			unlock(&fmtlock);

+		}

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

+			lock(&fmtlock);

+			fmt = pcmdescdef;

+			fmt.rate = n;

+			ok = fmtchanged = fmt.rate > 0;

+			unlock(&fmtlock);

+		}

 	}

-	newrate = rate;

+	if(!ok){

+		lock(&fmtlock);

+		fmt = pcmdescdef;

+		fmtchanged = 1;

+		unlock(&fmtlock);

+	}

 }

 int

@@ -164,7 +184,7 @@

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

 		volfd = open(name, ORDWR);

 		free(name);

-		updrate();

+		updfmt();

 	}

 	return 0;

 }

@@ -222,12 +242,22 @@

 	f->aux = nil;

 }

+int

+eqfmt(Pcmdesc *a, Pcmdesc *b)

+{

+	return

+		a->rate == b->rate

+		&& a->bits == b->bits

+		&& a->channels == b->channels

+		&& a->framesz == b->framesz

+		&& a->fmt == b->fmt;

+}

+

 void

 audioproc(void *)

 {

 	static uchar buf[ABUF];

-	static Pcmdesc desc;

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

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

 	ulong rp;

 	Stream *s;

 	uchar *p, *bufconv;

@@ -234,10 +264,10 @@

 	Pcmconv	*conv;

 	threadsetname("audioproc");

-	desc = pcmdescdef;

 	conv = nil;

 	bufconv = nil;

 	sweep = 0;

+	rate = fmt.rate;

 	for(;;){

 		m = NBUF;

@@ -275,7 +305,7 @@

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

 					ms = seek(audiofd, 0, 2);

 					ms *= 800;

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

+					ms /= rate*NCHAN*2;

 				}

 				sweep = 1;

 			}

@@ -310,12 +340,15 @@

 		mixrp = rp;

 		unlock(&rplock);

-		if(desc.rate != newrate){

-			desc.rate = newrate;

+		lock(&fmtlock);

+		if(fmtchanged){

+			fmtchanged = 0;

 			free(bufconv);

 			bufconv = nil;

 			freepcmconv(conv);

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

+			conv = nil;

+			if(!eqfmt(&fmt, &pcmdescdef))

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

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

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

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

@@ -322,7 +355,9 @@

 				freepcmconv(conv);

 				conv = nil;

 			}

+			rate = fmt.rate;

 		}

+		unlock(&fmtlock);

 		n = p - buf;

 		p = buf;

@@ -340,6 +375,7 @@

 {

 	Srv *srv;

 	int i, j, n, m, v;

+	char *f, *e;

 	Stream *s;

 	uchar *p;

@@ -346,11 +382,23 @@

 	if(r->fid->file->aux == &volfd){

 		static char svol[4096];

 		if(r->ifcall.offset == 0){

-			m = snprint(svol, sizeof(svol), "dev %s\nmix %d %d\n",

+			m = snprint(svol, sizeof(svol), "dev %s\nmix %d %d\nfmtout %!\nspeed %d\n",

 				devaudio?devaudio:"",

-				volume[0], volume[1]);

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

+				volume[0], volume[1],

+				pcmdescdef,

+				pcmdescdef.rate);

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

 				svol[m+n] = 0;

+				/* device's fmtout and speed are removed */

+				if((f = strstr(svol+m-1, "\nfmtout ")) != nil && (e = strchr(f+8, '\n')) != nil){

+					n -= e-f;

+					memmove(f, e, n+1);

+				}

+				if((f = strstr(svol+m-1, "\nspeed ")) != nil && (e = strchr(f+7, '\n')) != nil){

+					n -= e-f;

+					memmove(f, e, n+1);

+				}

+			}

 		}

 		readstr(r, svol);

 		respond(r, nil);

@@ -574,7 +622,7 @@

 	if(argc > 1)

 		usage();

-	newrate = pcmdescdef.rate;

+	fmtinstall('!', pcmdescfmt);

 	reopendevs(argv[0]);

 	closeaudiodev();