audio_format: basic support for DSD-over-USB

src/audio_format.c

@@ -77,6 +77,9 @@ sample_format_to_string(enum sample_format format)
 
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
 		return "dsdl";
+
+	case SAMPLE_FORMAT_DSD_OVER_USB:
+		return "dsdusb";
 	}
 
 	/* unreachable */

src/audio_format.h

@@ -61,6 +61,13 @@ enum sample_format {
 	 * comes first.
 	 */
 	SAMPLE_FORMAT_DSD_LSBFIRST,
+
+	/**
+	 * DSD packed in 24 bit samples (no padding), according to the
+	 * dCS suggested standard:
+	 * http://www.dcsltd.co.uk/page/assets/DSDoverUSB.pdf
+	 */
+	SAMPLE_FORMAT_DSD_OVER_USB,
 };
 
 static const unsigned MAX_CHANNELS = 8;
@@ -189,6 +196,7 @@ audio_valid_sample_format(enum sample_format format)
 	case SAMPLE_FORMAT_FLOAT:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		return true;
 
 	case SAMPLE_FORMAT_UNDEFINED:
@@ -258,6 +266,7 @@ sample_format_size(enum sample_format format)
 		return 2;
 
 	case SAMPLE_FORMAT_S24:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		return 3;
 
 	case SAMPLE_FORMAT_S24_P32:

src/audio_parser.c

@@ -87,6 +87,12 @@ parse_sample_format(const char *src, bool mask,
 		return true;
 	}
 
+	if (memcmp(src, "dsdusb", 6) == 0) {
+		*sample_format_r = SAMPLE_FORMAT_DSD_OVER_USB;
+		*endptr_r = src + 6;
+		return true;
+	}
+
 	if (memcmp(src, "dsd", 3) == 0) {
 		if (src[3] == 'l') {
 			*sample_format_r = SAMPLE_FORMAT_DSD_LSBFIRST;

src/decoder/flac_pcm.c

@@ -105,6 +105,7 @@ flac_convert(void *dest,
 	case SAMPLE_FORMAT_FLOAT:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 	case SAMPLE_FORMAT_UNDEFINED:
 		/* unreachable */
 		assert(false);

src/output/alsa_output_plugin.c

@@ -196,6 +196,7 @@ get_bitformat(enum sample_format sample_format)
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		return SND_PCM_FORMAT_UNKNOWN;
 
 	case SAMPLE_FORMAT_S8:

src/output/oss_output_plugin.c

@@ -398,6 +398,7 @@ sample_format_to_oss(enum sample_format format)
 	case SAMPLE_FORMAT_FLOAT:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		return AFMT_QUERY;
 
 	case SAMPLE_FORMAT_S8:

src/pcm_byteswap.c

@@ -70,6 +70,7 @@ pcm_byteswap(struct pcm_buffer *buffer, enum sample_format format,
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_FLOAT:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		/* not implemented */
 		return NULL;
 

src/pcm_convert.c

@@ -82,6 +82,7 @@ pcm_convert_channels(struct pcm_buffer *buffer, enum sample_format format,
 	case SAMPLE_FORMAT_FLOAT:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		g_set_error(error_r, pcm_convert_quark(), 0,
 			    "Channel conversion not implemented for format '%s'",
 			    sample_format_to_string(format));

src/pcm_format.c

@@ -149,6 +149,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		break;
 
 	case SAMPLE_FORMAT_S8:
@@ -269,6 +270,7 @@ pcm_convert_to_24(struct pcm_buffer *buffer,
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		break;
 
 	case SAMPLE_FORMAT_S8:
@@ -395,6 +397,7 @@ pcm_convert_to_32(struct pcm_buffer *buffer,
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		break;
 
 	case SAMPLE_FORMAT_S8:
@@ -532,6 +535,7 @@ pcm_convert_to_float(struct pcm_buffer *buffer,
 	case SAMPLE_FORMAT_UNDEFINED:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		break;
 
 	case SAMPLE_FORMAT_S8:

src/pcm_mix.c

@@ -122,6 +122,7 @@ pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
 	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		/* not implemented */
 		return false;
 
@@ -233,6 +234,7 @@ pcm_add(void *buffer1, const void *buffer2, size_t size,
 	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		/* not implemented */
 		return false;
 

src/pcm_volume.c

@@ -161,6 +161,7 @@ pcm_volume(void *buffer, size_t length,
 	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_DSD:
 	case SAMPLE_FORMAT_DSD_LSBFIRST:
+	case SAMPLE_FORMAT_DSD_OVER_USB:
 		/* not implemented */
 		return false;