mpc: provide 24 bit samples

Similar to libmad, libmpcdec provides samples with higher quality than
16 bit.  Send 24 bit samples to MPD, which allows MPD to apply
dithering just in case the output devices are only 16 bit capable.

1 files changed, 6 insertions, 7 deletions

diff --git a/src/decoder/mpc_plugin.c b/src/decoder/mpc_plugin.c
index 009828718..258947173 100644
--- a/src/decoder/mpc_plugin.c
+++ b/src/decoder/mpc_plugin.c
@@ -63,13 +63,13 @@ static mpc_int32_t mpc_getsize_cb(void *vdata)
 }
 
 /* this _looks_ performance-critical, don't de-inline -- eric */
-static inline int16_t convertSample(MPC_SAMPLE_FORMAT sample)
+static inline int32_t convertSample(MPC_SAMPLE_FORMAT sample)
 {
 	/* only doing 16-bit audio for now */
 	int32_t val;
 
 	enum {
-		bits = 16,
+		bits = 24,
 	};
 
 	const int clip_min = -1 << (bits - 1);
@@ -114,7 +114,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
 	char chunk[MPC_CHUNK_SIZE];
 	int chunkpos = 0;
 	long bitRate = 0;
-	int16_t *dest = (int16_t *) chunk;
+	int32_t *dest = (int32_t *) chunk;
 	unsigned long samplePos = 0;
 	mpc_uint32_t vbrUpdateAcc;
 	mpc_uint32_t vbrUpdateBits;
@@ -152,7 +152,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
 		return true;
 	}
 
-	audio_format.bits = 16;
+	audio_format.bits = 24;
 	audio_format.channels = info.channels;
 	audio_format.sample_rate = info.sample_freq;
 
@@ -170,7 +170,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
 			samplePos = decoder_seek_where(mpd_decoder) *
 				audio_format.sample_rate;
 			if (mpc_decoder_seek_sample(&decoder, samplePos)) {
-				dest = (int16_t *) chunk;
+				dest = (int32_t *)chunk;
 				chunkpos = 0;
 				decoder_command_finished(mpd_decoder);
 			} else
@@ -193,7 +193,6 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
 		ret *= 2;
 
 		for (i = 0; i < ret; i++) {
-			/* 16 bit audio again */
 			*dest++ = convertSample(sample_buffer[i]);
 			chunkpos += sizeof(*dest);
 
@@ -211,7 +210,7 @@ mpc_decode(struct decoder *mpd_decoder, struct input_stream *inStream)
 					     bitRate, replayGainInfo);
 
 				chunkpos = 0;
-				dest = (int16_t *) chunk;
+				dest = (int32_t *)chunk;
 				if (decoder_get_command(mpd_decoder) == DECODE_COMMAND_STOP) {
 					eof = true;
 					break;