diff --git a/src/minimodem.c b/src/minimodem.c
index 43b4f1f..5acaf69 100644
--- a/src/minimodem.c
+++ b/src/minimodem.c
@@ -520,6 +520,7 @@ main( int argc, char*argv[] )
 	    tx_interactive = 0;
 #if USE_SNDFILE
 	    sa_out = simpleaudio_open_stream_sndfile(SA_STREAM_PLAYBACK,
+					SA_SAMPLE_FORMAT_FLOAT,
 					sample_rate, nchannels,
 					filename);
 #endif
@@ -529,6 +530,7 @@ main( int argc, char*argv[] )
 
 	if ( ! sa_out )
 	    sa_out = simpleaudio_open_system_audio(SA_STREAM_PLAYBACK,
+					SA_SAMPLE_FORMAT_FLOAT,
 					sample_rate, nchannels,
 					program_name, "output audio");
 	if ( ! sa_out )
@@ -552,6 +554,7 @@ main( int argc, char*argv[] )
     if ( filename ) {
 #if USE_SNDFILE
 	sa = simpleaudio_open_stream_sndfile(SA_STREAM_RECORD,
+				SA_SAMPLE_FORMAT_FLOAT,
 				sample_rate, nchannels,
 				filename);
 #endif
@@ -561,6 +564,7 @@ main( int argc, char*argv[] )
 
     if ( ! sa )
 	sa = simpleaudio_open_system_audio(SA_STREAM_RECORD,
+				SA_SAMPLE_FORMAT_FLOAT,
 				sample_rate, nchannels,
 				program_name, "input audio");
     if ( !sa )
diff --git a/src/simpleaudio-alsa.c b/src/simpleaudio-alsa.c
index b6e68df..b2d1e25 100644
--- a/src/simpleaudio-alsa.c
+++ b/src/simpleaudio-alsa.c
@@ -105,6 +105,7 @@ static const struct simpleaudio_backend simpleaudio_backend_alsa = {
 simpleaudio *
 simpleaudio_open_stream_alsa(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name )
 {
@@ -120,6 +121,8 @@ simpleaudio_open_stream_alsa(
 	return NULL;
     }
 
+    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+
     /* set up ALSA hardware params */
     error = snd_pcm_set_params(pcm,
 		SND_PCM_FORMAT_FLOAT,
@@ -160,6 +163,7 @@ simpleaudio_open_stream_alsa(
 	snd_pcm_close(pcm);
         return NULL;
     }
+    sa->format = sa_sample_format;
     sa->rate = rate;
     sa->channels = channels;
     sa->samplesize = sizeof(float);
diff --git a/src/simpleaudio-pulse.c b/src/simpleaudio-pulse.c
index 932ea38..47741af 100644
--- a/src/simpleaudio-pulse.c
+++ b/src/simpleaudio-pulse.c
@@ -89,6 +89,7 @@ static const struct simpleaudio_backend simpleaudio_backend_pulse = {
 simpleaudio *
 simpleaudio_open_stream_pulseaudio(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name )
 {
@@ -97,6 +98,8 @@ simpleaudio_open_stream_pulseaudio(
     // FIXME - use source for something
     // just take the default pulseaudio source for now
 
+    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+
     /* The sample type to use */
     pa_sample_spec ss = {
         .format = PA_SAMPLE_FLOAT32,
@@ -134,6 +137,7 @@ simpleaudio_open_stream_pulseaudio(
 	pa_simple_free(s);
         return NULL;
     }
+    sa->format = sa_sample_format;
     sa->rate = ss.rate;
     sa->channels = ss.channels;
     sa->samplesize = sizeof(float);
diff --git a/src/simpleaudio-sndfile.c b/src/simpleaudio-sndfile.c
index 232d567..94abfb2 100644
--- a/src/simpleaudio-sndfile.c
+++ b/src/simpleaudio-sndfile.c
@@ -135,9 +135,12 @@ sndfile_format_from_path( const char *path )
 simpleaudio *
 simpleaudio_open_stream_sndfile(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *path )
 {
+    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+
     /* setting for SA_STREAM_PLAYBACK (file write) */
     SF_INFO sfinfo = {
 	.format = 0,
@@ -165,6 +168,7 @@ simpleaudio_open_stream_sndfile(
 	sf_close(s);
         return NULL;
     }
+    sa->format = sa_sample_format;
     sa->rate = sfinfo.samplerate;
     sa->channels = sfinfo.channels;
     sa->samplesize = sizeof(float);
diff --git a/src/simpleaudio.c b/src/simpleaudio.c
index a12c4fc..4a86fa0 100644
--- a/src/simpleaudio.c
+++ b/src/simpleaudio.c
@@ -21,6 +21,12 @@
 #include "simpleaudio_internal.h"
 #include "malloc.h"
 
+sa_sample_format_t
+simpleaudio_get_format( simpleaudio *sa )
+{
+    return sa->format;
+}
+
 unsigned int
 simpleaudio_get_rate( simpleaudio *sa )
 {
diff --git a/src/simpleaudio.h b/src/simpleaudio.h
index 4ac4ef8..f922ba9 100644
--- a/src/simpleaudio.h
+++ b/src/simpleaudio.h
@@ -31,26 +31,36 @@ typedef struct simpleaudio simpleaudio;
  *
  */
 
+/* sa_stream_direction */
 enum {
     SA_STREAM_PLAYBACK,
     SA_STREAM_RECORD,
 };
 
+/* sa_stream_format */
+typedef enum {
+    SA_SAMPLE_FORMAT_S16,
+    SA_SAMPLE_FORMAT_FLOAT,
+} sa_sample_format_t;
+
 simpleaudio *
 simpleaudio_open_stream_pulseaudio(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name );
 
 simpleaudio *
 simpleaudio_open_stream_alsa(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name );
 
 simpleaudio *
 simpleaudio_open_stream_sndfile(
 		int sa_stream_direction,
+		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *path );
 
@@ -67,6 +77,9 @@ simpleaudio_get_channels( simpleaudio *sa );
 unsigned int
 simpleaudio_get_framesize( simpleaudio *sa );
 
+sa_sample_format_t
+simpleaudio_get_format( simpleaudio *sa );
+
 unsigned int
 simpleaudio_get_samplesize( simpleaudio *sa );
 
diff --git a/src/simpleaudio_internal.h b/src/simpleaudio_internal.h
index fbdac00..688c908 100644
--- a/src/simpleaudio_internal.h
+++ b/src/simpleaudio_internal.h
@@ -33,6 +33,7 @@ typedef struct simpleaudio_backend simpleaudio_backend;
 
 struct simpleaudio {
 	const struct simpleaudio_backend	*backend;
+	sa_sample_format_t	format;
 	unsigned int	rate;
 	unsigned int	channels;
 	void *		backend_handle;