sndiod: Use resampling algorithm from aucat

sndiod doesn't use partial blocks as aucat, but having the same
algorithm makes code review and testing easier.

3 files changed, 107 insertions, 19 deletions

diff --git a/usr.bin/sndiod/dev.c b/usr.bin/sndiod/dev.c
index c3d32509311..ec9452d941f 100644
--- a/usr.bin/sndiod/dev.c
+++ b/usr.bin/sndiod/dev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dev.c,v 1.111 2024/04/22 10:57:36 ratchov Exp $	*/
+/*	$OpenBSD: dev.c,v 1.112 2024/04/22 11:01:02 ratchov Exp $	*/
 /*
  * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -517,7 +517,8 @@ dev_mix_badd(struct dev *d, struct slot *s)
 	}
 
 	if (s->mix.resampbuf) {
-		resamp_do(&s->mix.resamp, in, s->mix.resampbuf, s->round);
+		resamp_do(&s->mix.resamp,
+		    in, s->mix.resampbuf, s->round, d->round);
 		in = s->mix.resampbuf;
 	}
 
@@ -654,7 +655,7 @@ dev_sub_bcopy(struct dev *d, struct slot *s)
 
 	if (s->sub.resampbuf) {
 		resamp_do(&s->sub.resamp,
-		    s->sub.resampbuf, resamp_out, d->round);
+		    s->sub.resampbuf, resamp_out, d->round, s->round);
 	}
 
 	if (s->sub.encbuf)
diff --git a/usr.bin/sndiod/dsp.c b/usr.bin/sndiod/dsp.c
index 6c963f14d79..57085b8dbbc 100644
--- a/usr.bin/sndiod/dsp.c
+++ b/usr.bin/sndiod/dsp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dsp.c,v 1.18 2021/07/05 08:29:59 ratchov Exp $	*/
+/*	$OpenBSD: dsp.c,v 1.19 2024/04/22 11:01:02 ratchov Exp $	*/
 /*
  * Copyright (c) 2008-2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -269,30 +269,50 @@ aparams_native(struct aparams *par)
 }
 
 /*
- * resample the given number of frames
+ * Return the number of input and output frame that would be consumed
+ * by resamp_do(p, *icnt, *ocnt).
  */
 void
-resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
+resamp_getcnt(struct resamp *p, int *icnt, int *ocnt)
+{
+	long long idiff, odiff;
+	int cdiff;
+
+	cdiff = p->oblksz - p->diff;
+	idiff = (long long)*icnt * p->oblksz;
+	odiff = (long long)*ocnt * p->iblksz;
+	if (odiff - idiff >= cdiff)
+		*ocnt = (idiff + cdiff + p->iblksz - 1) / p->iblksz;
+	else
+		*icnt = (odiff + p->diff) / p->oblksz;
+}
+
+/*
+ * Resample the given number of frames. The number of output frames
+ * must match the corresponding number of input frames. Either always
+ * use icnt and ocnt such that:
+ *
+ *	 icnt * oblksz = ocnt * iblksz
+ *
+ * or use resamp_getcnt() to calculate the proper numbers.
+ */
+void
+resamp_do(struct resamp *p, adata_t *in, adata_t *out, int icnt, int ocnt)
 {
 	unsigned int nch;
 	adata_t *idata;
 	unsigned int oblksz;
+	unsigned int ifr;
 	int s, ds, diff;
 	adata_t *odata;
 	unsigned int iblksz;
+	unsigned int ofr;
 	unsigned int c;
 	int64_t f[NCHAN_MAX];
 	adata_t *ctxbuf, *ctx;
 	unsigned int ctx_start;
 	int q, qi, qf, n;
 
-#ifdef DEBUG
-	if (todo % p->iblksz != 0) {
-		log_puts("resamp_do: partial blocks not supported\n");
-		panic();
-	}
-#endif
-
 	/*
 	 * Partially copy structures into local variables, to avoid
 	 * unnecessary indirections; this also allows the compiler to
@@ -300,16 +320,32 @@ resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 	 */
 	idata = in;
 	odata = out;
-	diff = p->oblksz;
+	diff = p->diff;
 	iblksz = p->iblksz;
 	oblksz = p->oblksz;
 	ctxbuf = p->ctx;
 	ctx_start = p->ctx_start;
 	nch = p->nch;
+	ifr = icnt;
+	ofr = ocnt;
 
+	/*
+	 * Start conversion.
+	 */
+#ifdef DEBUG
+	if (log_level >= 4) {
+		log_puts("resamp: copying ");
+		log_puti(ifr);
+		log_puts(" -> ");
+		log_putu(ofr);
+		log_puts(" frames, diff = ");
+		log_puti(diff);
+		log_puts("\n");
+	}
+#endif
 	for (;;) {
 		if (diff >= oblksz) {
-			if (todo == 0)
+			if (ifr == 0)
 				break;
 			ctx_start = (ctx_start - 1) & (RESAMP_NCTX - 1);
 			ctx = ctxbuf + ctx_start;
@@ -318,8 +354,10 @@ resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 				ctx += RESAMP_NCTX;
 			}
 			diff -= oblksz;
-			todo--;
+			ifr--;
 		} else {
+			if (ofr == 0)
+				break;
 
 			for (c = 0; c < nch; c++)
 				f[c] = 0;
@@ -361,11 +399,40 @@ resamp_do(struct resamp *p, adata_t *in, adata_t *out, int todo)
 #endif
 				*odata++ = s;
 			}
+
 			diff += iblksz;
+			ofr--;
 		}
 	}
-
+	p->diff = diff;
 	p->ctx_start = ctx_start;
+#ifdef DEBUG
+	if (ifr != 0) {
+		log_puts("resamp_do: ");
+		log_puti(ifr);
+		log_puts(": too many input frames\n");
+		panic();
+	}
+	if (ofr != 0) {
+		log_puts("resamp_do: ");
+		log_puti(ofr);
+		log_puts(": too many output frames\n");
+		panic();
+	}
+#endif
+}
+
+static unsigned int
+uint_gcd(unsigned int a, unsigned int b)
+{
+	unsigned int r;
+
+	while (b > 0) {
+		r = a % b;
+		a = b;
+		b = r;
+	}
+	return a;
 }
 
 /*
@@ -375,8 +442,26 @@ void
 resamp_init(struct resamp *p, unsigned int iblksz,
     unsigned int oblksz, int nch)
 {
+	unsigned int g;
+
+	/*
+	 * reduce iblksz/oblksz fraction
+	 */
+	g = uint_gcd(iblksz, oblksz);
+	iblksz /= g;
+	oblksz /= g;
+
+	/*
+	 * ensure weird rates don't cause integer overflow
+	 */
+	while (iblksz > ADATA_UNIT || oblksz > ADATA_UNIT) {
+		iblksz >>= 1;
+		oblksz >>= 1;
+	}
+
 	p->iblksz = iblksz;
 	p->oblksz = oblksz;
+	p->diff = 0;
 	p->nch = nch;
 	p->ctx_start = 0;
 	memset(p->ctx, 0, sizeof(p->ctx));
diff --git a/usr.bin/sndiod/dsp.h b/usr.bin/sndiod/dsp.h
index 71ff518c52e..69e1b7a63ba 100644
--- a/usr.bin/sndiod/dsp.h
+++ b/usr.bin/sndiod/dsp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dsp.h,v 1.12 2022/12/26 19:16:03 jmc Exp $	*/
+/*	$OpenBSD: dsp.h,v 1.13 2024/04/22 11:01:02 ratchov Exp $	*/
 /*
  * Copyright (c) 2012 Alexandre Ratchov <alex@caoua.org>
  *
@@ -85,6 +85,7 @@ struct resamp {
 	adata_t ctx[NCHAN_MAX * RESAMP_NCTX];
 	int filt_cutoff, filt_step;
 	unsigned int iblksz, oblksz;
+	int diff;
 	int nch;
 };
 
@@ -115,7 +116,8 @@ int aparams_strtoenc(struct aparams *, char *);
 int aparams_enctostr(struct aparams *, char *);
 int aparams_native(struct aparams *);
 
-void resamp_do(struct resamp *, adata_t *, adata_t *, int);
+void resamp_getcnt(struct resamp *, int *, int *);
+void resamp_do(struct resamp *, adata_t *, adata_t *, int, int);
 void resamp_init(struct resamp *, unsigned int, unsigned int, int);
 void enc_do(struct conv *, unsigned char *, unsigned char *, int);
 void enc_sil_do(struct conv *, unsigned char *, int);