audio_format: support packed 24 bit samples

1 files changed, 48 insertions, 0 deletions

diff --git a/src/pcm_convert.c b/src/pcm_convert.c
index 06e4d05a2..5fe89b53a 100644
--- a/src/pcm_convert.c
+++ b/src/pcm_convert.c
@@ -22,6 +22,7 @@
 #include "pcm_channels.h"
 #include "pcm_format.h"
 #include "pcm_byteswap.h"
+#include "pcm_pack.h"
 #include "audio_format.h"
 
 #include <assert.h>
@@ -40,6 +41,7 @@ void pcm_convert_init(struct pcm_convert_state *state)
 	pcm_dither_24_init(&state->dither);
 
 	pcm_buffer_init(&state->format_buffer);
+	pcm_buffer_init(&state->pack_buffer);
 	pcm_buffer_init(&state->channels_buffer);
 	pcm_buffer_init(&state->byteswap_buffer);
 }
@@ -49,6 +51,7 @@ void pcm_convert_deinit(struct pcm_convert_state *state)
 	pcm_resample_deinit(&state->resample);
 
 	pcm_buffer_deinit(&state->format_buffer);
+	pcm_buffer_deinit(&state->pack_buffer);
 	pcm_buffer_deinit(&state->channels_buffer);
 	pcm_buffer_deinit(&state->byteswap_buffer);
 }
@@ -164,6 +167,45 @@ pcm_convert_24(struct pcm_convert_state *state,
 	return buf;
 }
 
+/**
+ * Convert to 24 bit packed samples (aka S24_3LE / S24_3BE).
+ */
+static const void *
+pcm_convert_24_packed(struct pcm_convert_state *state,
+		      const struct audio_format *src_format,
+		      const void *src_buffer, size_t src_size,
+		      const struct audio_format *dest_format,
+		      size_t *dest_size_r,
+		      GError **error_r)
+{
+	assert(dest_format->format == SAMPLE_FORMAT_S24);
+
+	/* use the normal 24 bit conversion first */
+
+	struct audio_format audio_format;
+	audio_format_init(&audio_format, dest_format->sample_rate,
+			  SAMPLE_FORMAT_S24_P32, dest_format->channels);
+
+	const int32_t *buffer;
+	size_t buffer_size;
+
+	buffer = pcm_convert_24(state, src_format, src_buffer, src_size,
+				&audio_format, &buffer_size, error_r);
+	if (buffer == NULL)
+		return NULL;
+
+	/* now convert to packed 24 bit */
+
+	unsigned num_samples = buffer_size / 4;
+	size_t dest_size = num_samples * 3;
+
+	uint8_t *dest = pcm_buffer_get(&state->pack_buffer, dest_size);
+	pcm_pack_24(dest, buffer, num_samples, dest_format->reverse_endian);
+
+	*dest_size_r = dest_size;
+	return dest;
+}
+
 static const int32_t *
 pcm_convert_32(struct pcm_convert_state *state,
 	       const struct audio_format *src_format,
@@ -234,6 +276,12 @@ pcm_convert(struct pcm_convert_state *state,
 				      dest_format, dest_size_r,
 				      error_r);
 
+	case SAMPLE_FORMAT_S24:
+		return pcm_convert_24_packed(state,
+					     src_format, src, src_size,
+					     dest_format, dest_size_r,
+					     error_r);
+
 	case SAMPLE_FORMAT_S24_P32:
 		return pcm_convert_24(state,
 				      src_format, src, src_size,