diff --git a/src/pcm/pcm_meter.c b/src/pcm/pcm_meter.c
index 8fc5c15d..df8c612a 100644
--- a/src/pcm/pcm_meter.c
+++ b/src/pcm/pcm_meter.c
@@ -1005,6 +1005,7 @@ typedef struct _snd_pcm_scope_s16 {
 	snd_pcm_uframes_t old;
 	int16_t *buf;
 	snd_pcm_channel_area_t *buf_areas;
+	int silent;
 } snd_pcm_scope_s16_t;
 
 static int s16_enable(snd_pcm_scope_t *scope)
@@ -1043,7 +1044,20 @@ static int s16_enable(snd_pcm_scope_t *scope)
 		idx = snd_pcm_linear_convert_index(spcm->format, SND_PCM_FORMAT_S16);
 		break;
 	default:
-		return -EINVAL;
+		/* No S16 conversion exists for this format - DSD, the 3-byte
+		 * packed formats, float. Leaving the scope disabled is worse
+		 * than useless: scopes that depend on it, including our own
+		 * level scope, call snd_pcm_scope_s16_get_channel_buffer()
+		 * from their update callback and that assert()s on the buffer
+		 * this function never allocated, killing the application.
+		 * Hand out a silent buffer instead, so a scope reads zero on a
+		 * format it cannot see rather than aborting the process.
+		 */
+		snd_error(PCM, "s16 scope: no S16 conversion for format %s, scopes will read silence",
+			  snd_pcm_format_name(spcm->format));
+		s16->silent = 1;
+		idx = 0;
+		break;
 	}
 	s16->index = idx;
 	if (spcm->format == SND_PCM_FORMAT_IMA_ADPCM) {
@@ -1051,7 +1065,10 @@ static int s16_enable(snd_pcm_scope_t *scope)
 		if (!s16->adpcm_states)
 			return -ENOMEM;
 	}
-	s16->buf = malloc(meter->buf_size * 2 * spcm->channels);
+	/* calloc, not malloc: when s16->silent is set nothing ever writes to
+	 * this buffer and scopes must read silence, not uninitialised memory.
+	 */
+	s16->buf = calloc(meter->buf_size * 2 * spcm->channels, 1);
 	if (!s16->buf) {
 		free(s16->adpcm_states);
 		return -ENOMEM;
@@ -1103,6 +1120,11 @@ static void s16_update(snd_pcm_scope_t *scope)
 	snd_pcm_t *spcm = meter->gen.slave;
 	snd_pcm_sframes_t size;
 	snd_pcm_uframes_t offset;
+	if (s16->silent) {
+		/* Nothing to convert; the buffer stays zero. */
+		s16->old = meter->now;
+		return;
+	}
 	size = meter->now - s16->old;
 	if (size < 0)
 		size += spcm->boundary;