audio_format: support packed 24 bit samples

Makefile.am

@@ -279,6 +279,7 @@ src_mpd_SOURCES = \
 	src/pcm_mix.c \
 	src/pcm_byteswap.c \
 	src/pcm_channels.c \
+	src/pcm_pack.c \
 	src/pcm_format.c \
 	src/pcm_resample.c \
 	src/pcm_resample_fallback.c \
@@ -888,6 +889,7 @@ test_run_filter_SOURCES = test/run_filter.c \
 	src/conf.c src/tokenizer.c src/utils.c \
 	src/pcm_volume.c src/pcm_convert.c src/pcm_byteswap.c \
 	src/pcm_format.c src/pcm_channels.c src/pcm_dither.c \
+	src/pcm_pack.c \
 	src/pcm_resample.c src/pcm_resample_fallback.c \
 	src/audio_check.c \
 	src/audio_format.c \
@@ -935,6 +937,7 @@ test_run_convert_SOURCES = test/run_convert.c \
 	src/audio_parser.c \
 	src/pcm_channels.c \
 	src/pcm_format.c \
+	src/pcm_pack.c \
 	src/pcm_dither.c \
 	src/pcm_byteswap.c \
 	src/pcm_resample.c \

NEWS

@@ -78,6 +78,7 @@ ver 0.16 (20??/??/??)
 * log: redirect stdout/stderr to /dev/null if syslog is used
 * set the close-on-exec flag on all file descriptors
 * pcm_volume, pcm_mix: implemented 32 bit support
+* support packed 24 bit samples
 * CUE sheet support
 * obey $(sysconfdir) for default mpd.conf location
 * build with large file support by default

doc/user.xml

@@ -313,6 +313,17 @@ cd mpd-version</programlisting>
                   <parameter>*:*:*</parameter> is equal to not having
                   a <varname>format</varname> specification.
                 </para>
+                <para>
+                  The following values are valid for
+                  <varname>bits</varname>: <varname>8</varname>
+                  (signed 8 bit integer samples),
+                  <varname>16</varname>, <varname>24</varname> (signed
+                  24 bit integer samples padded to 32 bit),
+                  <varname>24_3</varname> (signed 24 bit integer
+                  samples, no padding, 3 bytes per sample),
+                  <varname>32</varname> (signed 32 bit integer
+                  samples).
+                </para>
               </entry>
             </row>
             <row>

src/audio_format.c

@@ -41,6 +41,9 @@ sample_format_to_string(enum sample_format format)
 	case SAMPLE_FORMAT_S16:
 		return "16";
 
+	case SAMPLE_FORMAT_S24:
+		return "24_3";
+
 	case SAMPLE_FORMAT_S24_P32:
 		return "24";
 

src/audio_format.h

@@ -29,6 +29,11 @@ enum sample_format {
 	SAMPLE_FORMAT_S8,
 	SAMPLE_FORMAT_S16,
 
+	/**
+	 * Signed 24 bit integer samples, without padding.
+	 */
+	SAMPLE_FORMAT_S24,
+
 	/**
 	 * Signed 24 bit integer samples, packed in 32 bit integers
 	 * (the most significant byte is filled with the sign bit).
@@ -156,6 +161,7 @@ audio_valid_sample_format(enum sample_format format)
 	switch (format) {
 	case SAMPLE_FORMAT_S8:
 	case SAMPLE_FORMAT_S16:
+	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_S24_P32:
 	case SAMPLE_FORMAT_S32:
 		return true;
@@ -235,6 +241,9 @@ static inline unsigned audio_format_sample_size(const struct audio_format *af)
 	case SAMPLE_FORMAT_S16:
 		return 2;
 
+	case SAMPLE_FORMAT_S24:
+		return 3;
+
 	case SAMPLE_FORMAT_S24_P32:
 	case SAMPLE_FORMAT_S32:
 		return 4;

src/audio_parser.c

@@ -28,6 +28,7 @@
 #include "audio_check.h"
 
 #include <assert.h>
+#include <string.h>
 #include <stdlib.h>
 
 /**
@@ -97,7 +98,11 @@ parse_sample_format(const char *src, bool mask,
 		break;
 
 	case 24:
-		sample_format = SAMPLE_FORMAT_S24_P32;
+		if (memcmp(endptr, "_3", 2) == 0) {
+			sample_format = SAMPLE_FORMAT_S24;
+			endptr += 2;
+		} else
+			sample_format = SAMPLE_FORMAT_S24_P32;
 		break;
 
 	case 32:

src/decoder/flac_pcm.c

@@ -101,6 +101,7 @@ flac_convert(void *dest,
 			       position, end);
 		break;
 
+	case SAMPLE_FORMAT_S24:
 	case SAMPLE_FORMAT_UNDEFINED:
 		/* unreachable */
 		assert(false);

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,

src/pcm_convert.h

@@ -39,6 +39,9 @@ struct pcm_convert_state {
 	/** the buffer for converting the sample format */
 	struct pcm_buffer format_buffer;
 
+	/** the buffer for converting to/from packed samples */
+	struct pcm_buffer pack_buffer;
+
 	/** the buffer for converting the channel count */
 	struct pcm_buffer channels_buffer;
 

src/pcm_format.c

@@ -21,6 +21,7 @@
 #include "pcm_format.h"
 #include "pcm_dither.h"
 #include "pcm_buffer.h"
+#include "pcm_pack.h"
 
 static void
 pcm_convert_8_to_16(int16_t *out, const int8_t *in,
@@ -48,6 +49,15 @@ pcm_convert_32_to_16(struct pcm_dither *dither,
 	pcm_dither_32_to_16(dither, out, in, num_samples);
 }
 
+static int32_t *
+pcm_convert_24_to_24p32(struct pcm_buffer *buffer, const uint8_t *src,
+			unsigned num_samples)
+{
+	int32_t *dest = pcm_buffer_get(buffer, num_samples * 4);
+	pcm_unpack_24(dest, src, num_samples, false);
+	return dest;
+}
+
 const int16_t *
 pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
 		  enum sample_format src_format, const void *src,
@@ -55,6 +65,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
 {
 	unsigned num_samples;
 	int16_t *dest;
+	int32_t *dest32;
 
 	switch (src_format) {
 	case SAMPLE_FORMAT_UNDEFINED:
@@ -74,6 +85,19 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
 		*dest_size_r = src_size;
 		return src;
 
+	case SAMPLE_FORMAT_S24:
+		/* convert to S24_P32 first */
+		num_samples = src_size / 3;
+
+		dest32 = pcm_convert_24_to_24p32(buffer, src, num_samples);
+		dest = (int16_t *)dest32;
+
+		/* convert to 16 bit in-place */
+		*dest_size_r = num_samples * sizeof(*dest);
+		pcm_convert_24_to_16(dither, dest, dest32,
+				     num_samples);
+		return dest;
+
 	case SAMPLE_FORMAT_S24_P32:
 		num_samples = src_size / 4;
 		*dest_size_r = num_samples * sizeof(*dest);
@@ -158,6 +182,12 @@ pcm_convert_to_24(struct pcm_buffer *buffer,
 				     num_samples);
 		return dest;
 
+	case SAMPLE_FORMAT_S24:
+		num_samples = src_size / 3;
+		*dest_size_r = num_samples * sizeof(*dest);
+
+		return pcm_convert_24_to_24p32(buffer, src, num_samples);
+
 	case SAMPLE_FORMAT_S24_P32:
 		*dest_size_r = src_size;
 		return src;
@@ -235,6 +265,17 @@ pcm_convert_to_32(struct pcm_buffer *buffer,
 				     num_samples);
 		return dest;
 
+	case SAMPLE_FORMAT_S24:
+		/* convert to S24_P32 first */
+		num_samples = src_size / 3;
+
+		dest = pcm_convert_24_to_24p32(buffer, src, num_samples);
+
+		/* convert to 32 bit in-place */
+		*dest_size_r = num_samples * sizeof(*dest);
+		pcm_convert_24_to_32(dest, dest, num_samples);
+		return dest;
+
 	case SAMPLE_FORMAT_S24_P32:
 		num_samples = src_size / 4;
 		*dest_size_r = num_samples * sizeof(*dest);

src/pcm_pack.c

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2003-2010 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "pcm_pack.h"
+
+#include <glib.h>
+
+static void
+pack_sample(uint8_t *dest, const int32_t *src0, bool reverse_endian)
+{
+	const uint8_t *src = (const uint8_t *)src0;
+
+	if ((G_BYTE_ORDER == G_BIG_ENDIAN) != reverse_endian)
+		++src;
+
+	*dest++ = *src++;
+	*dest++ = *src++;
+	*dest++ = *src++;
+}
+
+void
+pcm_pack_24(uint8_t *dest, const int32_t *src, unsigned num_samples,
+	    bool reverse_endian)
+{
+	/* duplicate loop to help the compiler's optimizer (constant
+	   parameter to the pack_sample() inline function) */
+
+	if (G_LIKELY(!reverse_endian)) {
+		while (num_samples-- > 0) {
+			pack_sample(dest, src++, false);
+			dest += 3;
+		}
+	} else {
+		while (num_samples-- > 0) {
+			pack_sample(dest, src++, true);
+			dest += 3;
+		}
+	}
+}
+
+static void
+unpack_sample(int32_t *dest0, const uint8_t *src, bool reverse_endian)
+{
+	uint8_t *dest = (uint8_t *)dest0;
+
+	if ((G_BYTE_ORDER == G_BIG_ENDIAN) != reverse_endian)
+		/* extend the sign bit to the most fourth byte */
+		*dest++ = *src & 0x80 ? 0xff : 0x00;
+
+	*dest++ = *src++;
+	*dest++ = *src++;
+	*dest++ = *src;
+
+	if ((G_BYTE_ORDER == G_LITTLE_ENDIAN) != reverse_endian)
+		/* extend the sign bit to the most fourth byte */
+		*dest++ = *src & 0x80 ? 0xff : 0x00;
+}
+
+void
+pcm_unpack_24(int32_t *dest, const uint8_t *src, unsigned num_samples,
+	      bool reverse_endian)
+{
+	/* duplicate loop to help the compiler's optimizer (constant
+	   parameter to the unpack_sample() inline function) */
+
+	if (G_LIKELY(!reverse_endian)) {
+		while (num_samples-- > 0) {
+			unpack_sample(dest++, src, false);
+			src += 3;
+		}
+	} else {
+		while (num_samples-- > 0) {
+			unpack_sample(dest++, src, true);
+			src += 3;
+		}
+	}
+}

src/pcm_pack.h

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2003-2010 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/** \file
+ *
+ * Library for working with packed 24 bit samples.
+ */
+
+#ifndef PCM_PACK_H
+#define PCM_PACK_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * Converts padded 24 bit samples (4 bytes per sample) to packed 24
+ * bit samples (3 bytes per sample).
+ *
+ * This function can be used to convert a buffer in-place.
+ *
+ * @param dest the destination buffer (array of triples)
+ * @param src the source buffer
+ * @param num_samples the number of samples to convert
+ * @param reverse_endian is src and dest in non-host byte order?
+ */
+void
+pcm_pack_24(uint8_t *dest, const int32_t *src, unsigned num_samples,
+	    bool reverse_endian);
+
+/**
+ * Converts packed 24 bit samples (3 bytes per sample) to padded 24
+ * bit samples (4 bytes per sample).
+ *
+ * @param dest the destination buffer
+ * @param src the source buffer (array of triples)
+ * @param num_samples the number of samples to convert
+ * @param reverse_endian is src and dest in non-host byte order?
+ */
+void
+pcm_unpack_24(int32_t *dest, const uint8_t *src, unsigned num_samples,
+	      bool reverse_endian);
+
+#endif