patch to split DSD decoder into separate decoders for DSF en DFF. Move common

functions to new dsdlib. Update user doc.

7 files changed, 568 insertions, 324 deletions

diff --git a/src/decoder/dsdiff_decoder_plugin.c b/src/decoder/dsdiff_decoder_plugin.c
index a7aa6017c..2c9ff3833 100644
--- a/src/decoder/dsdiff_decoder_plugin.c
+++ b/src/decoder/dsdiff_decoder_plugin.c
@@ -19,12 +19,11 @@
 
 /* \file
  *
- * This plugin decodes DSDIFF data (SACD) embedded in DFF and DSF files.
+ * This plugin decodes DSDIFF data (SACD) embedded in DFF files.
  * The DFF code was modeled after the specification found here:
  * http://www.sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
  *
- * The DSF code was created using the specification found here:
- * http://dsd-guide.com/sonys-dsf-file-format-spec
+ * All functions common to both DSD decoders have been moved to dsdlib
  */
 
 #include "config.h"
@@ -32,6 +31,8 @@
 #include "decoder_api.h"
 #include "audio_check.h"
 #include "util/bit_reverse.h"
+#include "tag_handler.h"
+#include "dsdlib.h"
 
 #include <unistd.h>
 #include <stdio.h> /* for SEEK_SET, SEEK_CUR */
@@ -39,74 +40,25 @@
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "dsdiff"
 
-struct dsdiff_id {
-	char value[4];
-};
-
 struct dsdiff_header {
-	struct dsdiff_id id;
+	struct dsdlib_id id;
 	uint32_t size_high, size_low;
-	struct dsdiff_id format;
+	struct dsdlib_id format;
 };
 
 struct dsdiff_chunk_header {
-	struct dsdiff_id id;
+	struct dsdlib_id id;
 	uint32_t size_high, size_low;
 };
 
 struct dsdiff_metadata {
 	unsigned sample_rate, channels;
-	bool fileisdff;
 	bool bitreverse;
 	uint64_t chunk_size;
 };
 
 static bool lsbitfirst;
 
-
-struct dsf_header {
-	/** DSF header id: "DSD " */
-	struct dsdiff_id id;
-	/** DSD chunk size, including id = 28 */
-	uint32_t size_low, size_high;
-	/** Total file size */
-	uint32_t fsize_low, fsize_high;
-	/** Pointer to id3v2 metadata, should be at the end of the file */
-	uint32_t pmeta_low, pmeta_high;
-};
-/** DSF file fmt chunk */
-struct dsf_fmt_chunk {
-
-	/** id: "fmt " */
-	struct dsdiff_id id;
-	/** fmt chunk size, including id, normally 52 */
-	uint32_t size_low, size_high;
-	/** Version of this format = 1 */
-	uint32_t version;
-	/** 0: DSD raw */
-	uint32_t formatid;
-	/** Channel Type, 1 = mono, 2 = stereo, 3 = 3 channels, etc */
-	uint32_t channeltype;
-	/** Channel number, 1 = mono, 2 = stereo, ... 6 = 6 channels */
-	uint32_t channelnum;
-	/** Sample frequency: 2822400, 5644800 */
-	uint32_t sample_freq;
-	/** Bits per sample 1 or 8 */
-	uint32_t bitssample;
-	/** Sample count per channel in bytes */
-	uint32_t scnt_low, scnt_high;
-	/** Block size per channel = 4096 */
-	uint32_t block_size;
-	/** Reserved, should be all zero */
-	uint32_t reserved;
-};
-
-struct dsf_data_chunk {
-	struct dsdiff_id id;
-	/** "data" chunk size, includes header (id+size) */
-	uint32_t size_low, size_high;
-};
-
 static bool
 dsdiff_init(const struct config_param *param)
 {
@@ -114,16 +66,6 @@ dsdiff_init(const struct config_param *param)
 	return true;
 }
 
-static bool
-dsdiff_id_equals(const struct dsdiff_id *id, const char *s)
-{
-	assert(id != NULL);
-	assert(s != NULL);
-	assert(strlen(s) == sizeof(id->value));
-
-	return memcmp(id->value, s, sizeof(id->value)) == 0;
-}
-
 /**
  * Read the "size" attribute from the specified header, converting it
  * to the host byte order if needed.
@@ -137,25 +79,17 @@ dsdiff_chunk_size(const struct dsdiff_chunk_header *header)
 }
 
 static bool
-dsdiff_read(struct decoder *decoder, struct input_stream *is,
-	    void *data, size_t length)
-{
-	size_t nbytes = decoder_read(decoder, is, data, length);
-	return nbytes == length;
-}
-
-static bool
 dsdiff_read_id(struct decoder *decoder, struct input_stream *is,
-	       struct dsdiff_id *id)
+	       struct dsdlib_id *id)
 {
-	return dsdiff_read(decoder, is, id, sizeof(*id));
+	return dsdlib_read(decoder, is, id, sizeof(*id));
 }
 
 static bool
 dsdiff_read_chunk_header(struct decoder *decoder, struct input_stream *is,
 			 struct dsdiff_chunk_header *header)
 {
-	return dsdiff_read(decoder, is, header, sizeof(*header));
+	return dsdlib_read(decoder, is, header, sizeof(*header));
 }
 
 static bool
@@ -172,65 +106,6 @@ dsdiff_read_payload(struct decoder *decoder, struct input_stream *is,
 }
 
 /**
- * Skip the #input_stream to the specified offset.
- */
-static bool
-dsdiff_skip_to(struct decoder *decoder, struct input_stream *is,
-	       goffset offset)
-{
-	if (is->seekable)
-		return input_stream_seek(is, offset, SEEK_SET, NULL);
-
-	if (is->offset > offset)
-		return false;
-
-	char buffer[8192];
-	while (is->offset < offset) {
-		size_t length = sizeof(buffer);
-		if (offset - is->offset < (goffset)length)
-			length = offset - is->offset;
-
-		size_t nbytes = decoder_read(decoder, is, buffer, length);
-		if (nbytes == 0)
-			return false;
-	}
-
-	assert(is->offset == offset);
-	return true;
-}
-
-/**
- * Skip some bytes from the #input_stream.
- */
-static bool
-dsdiff_skip(struct decoder *decoder, struct input_stream *is,
-	    goffset delta)
-{
-	assert(delta >= 0);
-
-	if (delta == 0)
-		return true;
-
-	if (is->seekable)
-		return input_stream_seek(is, delta, SEEK_CUR, NULL);
-
-	char buffer[8192];
-	while (delta > 0) {
-		size_t length = sizeof(buffer);
-		if ((goffset)length > delta)
-			length = delta;
-
-		size_t nbytes = decoder_read(decoder, is, buffer, length);
-		if (nbytes == 0)
-			return false;
-
-		delta -= nbytes;
-	}
-
-	return true;
-}
-
-/**
  * Read and parse a "SND" chunk inside "PROP".
  */
 static bool
@@ -248,7 +123,7 @@ dsdiff_read_prop_snd(struct decoder *decoder, struct input_stream *is,
 		if (chunk_end_offset > end_offset)
 			return false;
 
-		if (dsdiff_id_equals(&header.id, "FS  ")) {
+		if (dsdlib_id_equals(&header.id, "FS  ")) {
 			uint32_t sample_rate;
 			if (!dsdiff_read_payload(decoder, is, &header,
 						 &sample_rate,
@@ -256,31 +131,31 @@ dsdiff_read_prop_snd(struct decoder *decoder, struct input_stream *is,
 				return false;
 
 			metadata->sample_rate = GUINT32_FROM_BE(sample_rate);
-		} else if (dsdiff_id_equals(&header.id, "CHNL")) {
+		} else if (dsdlib_id_equals(&header.id, "CHNL")) {
 			uint16_t channels;
 			if (dsdiff_chunk_size(&header) < sizeof(channels) ||
-			    !dsdiff_read(decoder, is,
+			    !dsdlib_read(decoder, is,
 					 &channels, sizeof(channels)) ||
-			    !dsdiff_skip_to(decoder, is, chunk_end_offset))
+			    !dsdlib_skip_to(decoder, is, chunk_end_offset))
 				return false;
 
 			metadata->channels = GUINT16_FROM_BE(channels);
-		} else if (dsdiff_id_equals(&header.id, "CMPR")) {
-			struct dsdiff_id type;
+		} else if (dsdlib_id_equals(&header.id, "CMPR")) {
+			struct dsdlib_id type;
 			if (dsdiff_chunk_size(&header) < sizeof(type) ||
-			    !dsdiff_read(decoder, is,
+			    !dsdlib_read(decoder, is,
 					 &type, sizeof(type)) ||
-			    !dsdiff_skip_to(decoder, is, chunk_end_offset))
+			    !dsdlib_skip_to(decoder, is, chunk_end_offset))
 				return false;
 
-			if (!dsdiff_id_equals(&type, "DSD "))
+			if (!dsdlib_id_equals(&type, "DSD "))
 				/* only uncompressed DSD audio data
 				   is implemented */
 				return false;
 		} else {
 			/* ignore unknown chunk */
 
-			if (!dsdiff_skip_to(decoder, is, chunk_end_offset))
+			if (!dsdlib_skip_to(decoder, is, chunk_end_offset))
 				return false;
 		}
 	}
@@ -299,16 +174,16 @@ dsdiff_read_prop(struct decoder *decoder, struct input_stream *is,
 	uint64_t prop_size = dsdiff_chunk_size(prop_header);
 	goffset end_offset = is->offset + prop_size;
 
-	struct dsdiff_id prop_id;
+	struct dsdlib_id prop_id;
 	if (prop_size < sizeof(prop_id) ||
 	    !dsdiff_read_id(decoder, is, &prop_id))
 		return false;
 
-	if (dsdiff_id_equals(&prop_id, "SND "))
+	if (dsdlib_id_equals(&prop_id, "SND "))
 		return dsdiff_read_prop_snd(decoder, is, metadata, end_offset);
 	else
 		/* ignore unknown PROP chunk */
-		return dsdiff_skip_to(decoder, is, end_offset);
+		return dsdlib_skip_to(decoder, is, end_offset);
 }
 
 /**
@@ -322,9 +197,9 @@ dsdiff_read_metadata(struct decoder *decoder, struct input_stream *is,
 		     struct dsdiff_chunk_header *chunk_header)
 {
 	struct dsdiff_header header;
-	if (!dsdiff_read(decoder, is, &header, sizeof(header)) ||
-	    !dsdiff_id_equals(&header.id, "FRM8") ||
-	    !dsdiff_id_equals(&header.format, "DSD "))
+	if (!dsdlib_read(decoder, is, &header, sizeof(header)) ||
+	    !dsdlib_id_equals(&header.id, "FRM8") ||
+	    !dsdlib_id_equals(&header.format, "DSD "))
 		return false;
 
 	while (true) {
@@ -332,13 +207,14 @@ dsdiff_read_metadata(struct decoder *decoder, struct input_stream *is,
 					      chunk_header))
 			return false;
 
-		if (dsdiff_id_equals(&chunk_header->id, "PROP")) {
+		if (dsdlib_id_equals(&chunk_header->id, "PROP")) {
 			if (!dsdiff_read_prop(decoder, is, metadata,
 					      chunk_header))
 					return false;
-		} else if (dsdiff_id_equals(&chunk_header->id, "DSD ")) {
-			/* done with metadata, mark as DFF */
-			metadata->fileisdff = true;
+		} else if (dsdlib_id_equals(&chunk_header->id, "DSD ")) {
+			uint64_t chunk_size;
+			chunk_size = dsdiff_chunk_size(chunk_header);
+			metadata->chunk_size = chunk_size;
 			return true;
 		} else {
 			/* ignore unknown chunk */
@@ -346,89 +222,12 @@ dsdiff_read_metadata(struct decoder *decoder, struct input_stream *is,
 			chunk_size = dsdiff_chunk_size(chunk_header);
 			goffset chunk_end_offset = is->offset + chunk_size;
 
-			if (!dsdiff_skip_to(decoder, is,
-					    chunk_end_offset))
+			if (!dsdlib_skip_to(decoder, is, chunk_end_offset))
 				return false;
 		}
 	}
 }
 
-/**
- * Read and parse all needed metadata chunks for DSF files.
- */
-static bool
-dsf_read_metadata(struct decoder *decoder, struct input_stream *is,
-		  struct dsdiff_metadata *metadata)
-{
-	/* Reset to beginning of the stream */
-	if (!dsdiff_skip_to(decoder, is, 0))
-		return false;
-
-	uint64_t chunk_size;
-	struct dsf_header dsf_header;
-	if (!dsdiff_read(decoder, is, &dsf_header, sizeof(dsf_header)) ||
-	    !dsdiff_id_equals(&dsf_header.id, "DSD "))
-		return false;
-
-	chunk_size = (((uint64_t)GUINT32_FROM_LE(dsf_header.size_high)) << 32) |
-		((uint64_t)GUINT32_FROM_LE(dsf_header.size_low));
-
-	if (sizeof(dsf_header) != chunk_size)
-		return false;
-
-	/* Read the 'fmt ' chunk of the DSF file */
-	struct dsf_fmt_chunk dsf_fmt_chunk;
-	if (!dsdiff_read(decoder, is, &dsf_fmt_chunk, sizeof(dsf_fmt_chunk)) ||
-	    !dsdiff_id_equals(&dsf_fmt_chunk.id, "fmt "))
-		return false;
-
-	uint64_t fmt_chunk_size;
-	fmt_chunk_size = (((uint64_t)GUINT32_FROM_LE(dsf_fmt_chunk.size_high)) << 32) |
-		((uint64_t)GUINT32_FROM_LE(dsf_fmt_chunk.size_low));
-
-	if (fmt_chunk_size != sizeof(dsf_fmt_chunk))
-		return false;
-
-	uint32_t samplefreq = (uint32_t)GUINT32_FROM_LE(dsf_fmt_chunk.sample_freq);
-
-	/* For now, only support version 1 of the standard, DSD raw stereo
-	   files with a sample freq of 2822400 Hz */
-
-	if (dsf_fmt_chunk.version != 1 || dsf_fmt_chunk.formatid != 0
-	    || dsf_fmt_chunk.channeltype != 2
-	    || dsf_fmt_chunk.channelnum != 2
-	    || samplefreq != 2822400)
-		return false;
-
-	uint32_t chblksize = (uint32_t)GUINT32_FROM_LE(dsf_fmt_chunk.block_size);
-	/* According to the spec block size should always be 4096 */
-	if (chblksize != 4096)
-		return false;
-
-	/* Read the 'data' chunk of the DSF file */
-	struct dsf_data_chunk data_chunk;
-	if (!dsdiff_read(decoder, is, &data_chunk, sizeof(data_chunk)) ||
-	    !dsdiff_id_equals(&data_chunk.id, "data"))
-		return false;
-
-	/* Data size of DSF files are padded to multiple of 4096,
-	   we use the actual data size as chunk size */
-
-	uint64_t data_size;
-	data_size = (((uint64_t)GUINT32_FROM_LE(data_chunk.size_high)) << 32) |
-		((uint64_t)GUINT32_FROM_LE(data_chunk.size_low));
-	data_size -= sizeof(data_chunk);
-
-	metadata->chunk_size = data_size;
-	metadata->channels = (unsigned) dsf_fmt_chunk.channelnum;
-	metadata->sample_rate = samplefreq;
-
-	/* Check bits per sample format, determine if bitreverse is needed */
-	metadata->bitreverse = dsf_fmt_chunk.bitssample == 1 ?  true : false;
-	metadata->fileisdff = false;
-	return true;
-}
-
 static void
 bit_reverse_buffer(uint8_t *p, uint8_t *end)
 {
@@ -437,46 +236,15 @@ bit_reverse_buffer(uint8_t *p, uint8_t *end)
 }
 
 /**
- * DSF data is build up of alternating 4096 blocks of DSD samples for left and
- * right. Convert the buffer holding 1 block of 4096 DSD left samples and 1
- * block of 4096 DSD right samples to 8k of samples in normal PCM left/right
- * order.
- */
-static void
-dsf_to_pcm_order(uint8_t *dest, uint8_t *scratch, size_t nrbytes)
-{
-	for (unsigned i = 0, j = 0; i < (unsigned)nrbytes; i += 2) {
-		scratch[i] = *(dest+j);
-		j++;
-	}
-
-	for (unsigned i = 1, j = 0; i < (unsigned) nrbytes; i += 2) {
-		scratch[i] = *(dest+4096+j);
-		j++;
-	}
-
-	for (unsigned i = 0; i < (unsigned)nrbytes; i++) {
-		*dest = scratch[i];
-		dest++;
-	}
-}
-
-/**
  * Decode one "DSD" chunk.
  */
 static bool
 dsdiff_decode_chunk(struct decoder *decoder, struct input_stream *is,
 		    unsigned channels,
-		    uint64_t chunk_size,
-		    bool fileisdff,
-		    bool bitreverse)
+		    uint64_t chunk_size)
 {
 	uint8_t buffer[8192];
 
-	/* Scratch buffer for DSF samples to convert to the needed
-	   normal Left/Right regime of samples */
-	uint8_t dsf_scratch_buffer[8192];
-
 	const size_t sample_size = sizeof(buffer[0]);
 	const size_t frame_size = channels * sample_size;
 	const unsigned buffer_frames = sizeof(buffer) / frame_size;
@@ -499,12 +267,9 @@ dsdiff_decode_chunk(struct decoder *decoder, struct input_stream *is,
 
 		chunk_size -= nbytes;
 
-		if (lsbitfirst || bitreverse)
+		if (lsbitfirst)
 			bit_reverse_buffer(buffer, buffer + nbytes);
 
-		if (!fileisdff)
-			dsf_to_pcm_order(buffer, dsf_scratch_buffer, nbytes);
-
 		enum decoder_command cmd =
 			decoder_data(decoder, is, buffer, nbytes, 0);
 		switch (cmd) {
@@ -516,13 +281,13 @@ dsdiff_decode_chunk(struct decoder *decoder, struct input_stream *is,
 			return false;
 
 		case DECODE_COMMAND_SEEK:
-			/* not implemented yet */
+
+			/* Not implemented yet */
 			decoder_seek_error(decoder);
 			break;
 		}
 	}
-
-	return dsdiff_skip(decoder, is, chunk_size);
+	return dsdlib_skip(decoder, is, chunk_size);
 }
 
 static void
@@ -534,13 +299,9 @@ dsdiff_stream_decode(struct decoder *decoder, struct input_stream *is)
 	};
 
 	struct dsdiff_chunk_header chunk_header;
-	/* First see if it is is a DFF file */
+	/* check if it is is a proper DFF file */
 	if (!dsdiff_read_metadata(decoder, is, &metadata, &chunk_header))
-	{
-		/* It was not a DFF file, now check if it is a DSF file */
-		if (!dsf_read_metadata(decoder, is, &metadata))
-			return;
-	}
+		return;
 
 	GError *error = NULL;
 	struct audio_format audio_format;
@@ -555,47 +316,28 @@ dsdiff_stream_decode(struct decoder *decoder, struct input_stream *is)
 	/* success: file was recognized */
 	decoder_initialized(decoder, &audio_format, false, -1);
 
-	if (!metadata.fileisdff) {
-		uint64_t chunk_size = metadata.chunk_size;
-		if (!dsdiff_decode_chunk(decoder, is,
-					 metadata.channels,
-					 chunk_size,
-					 metadata.fileisdff,
-					 metadata.bitreverse))
-			return;
+	/* every iteration of the following loop decodes one "DSD"
+	   chunk from a DFF file */
 
-	} else {
-
-		/* every iteration of the following loop decodes one "DSD"
-		   chunk from a DFF file */
-
-		while (true) {
-
-			uint64_t chunk_size = dsdiff_chunk_size(&chunk_header);
-
-			if (dsdiff_id_equals(&chunk_header.id, "DSD ")) {
-				if (!dsdiff_decode_chunk(decoder, is,
-							 metadata.channels,
-							 chunk_size,
-							 metadata.fileisdff,
-						/* Set bitreverse to
-						   false for DFF files */
-							false))
-					break;
-			} else {
-				/* ignore other chunks */
+	while (true) {
+		uint64_t chunk_size = dsdiff_chunk_size(&chunk_header);
 
-				if (!dsdiff_skip(decoder, is, chunk_size))
+		if (dsdlib_id_equals(&chunk_header.id, "DSD ")) {
+			if (!dsdiff_decode_chunk(decoder, is,
+						 metadata.channels,
+						 chunk_size))
 					break;
-			}
-
-			/* read next chunk header; the first one was read by
-			   dsdiff_read_metadata() */
-
-			if (!dsdiff_read_chunk_header(decoder,
-						      is, &chunk_header))
+		} else {
+			/* ignore other chunks */
+			if (!dsdlib_skip(decoder, is, chunk_size))
 				break;
 		}
+
+		/* read next chunk header; the first one was read by
+		   dsdiff_read_metadata() */
+		if (!dsdiff_read_chunk_header(decoder,
+					      is, &chunk_header))
+			break;
 	}
 }
 
@@ -612,11 +354,7 @@ dsdiff_scan_stream(struct input_stream *is,
 	struct dsdiff_chunk_header chunk_header;
 	/* First check for DFF metadata */
 	if (!dsdiff_read_metadata(NULL, is, &metadata, &chunk_header))
-	{
-		/* It was not an DFF file, now check for DSF metadata */
-		if (!dsf_read_metadata(NULL, is, &metadata))
-			return false;
-	}
+		return false;
 
 	struct audio_format audio_format;
 	if (!audio_format_init_checked(&audio_format, metadata.sample_rate / 8,
@@ -625,19 +363,16 @@ dsdiff_scan_stream(struct input_stream *is,
 		/* refuse to parse files which we cannot play anyway */
 		return false;
 
-	/* no total time estimate, no tags implemented yet */
 	return true;
 }
 
 static const char *const dsdiff_suffixes[] = {
 	"dff",
-	"dsf",
 	NULL
 };
 
 static const char *const dsdiff_mime_types[] = {
 	"application/x-dff",
-	"application/x-dsf",
 	NULL
 };
 
diff --git a/src/decoder/dsdiff_decoder_plugin.h b/src/decoder/dsdiff_decoder_plugin.h
index 34e1438de..452f9050b 100644
--- a/src/decoder/dsdiff_decoder_plugin.h
+++ b/src/decoder/dsdiff_decoder_plugin.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2003-2011 The Music Player Daemon Project
+ * Copyright (C) 2003-2012 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
diff --git a/src/decoder/dsdlib.c b/src/decoder/dsdlib.c
new file mode 100644
index 000000000..3df9497c4
--- /dev/null
+++ b/src/decoder/dsdlib.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2012 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
+ *
+ * This file contains functions used by the DSF and DSDIFF decoders.
+ *
+ */
+
+#include "config.h"
+#include "dsf_decoder_plugin.h"
+#include "decoder_api.h"
+#include "util/bit_reverse.h"
+#include "dsdlib.h"
+#include "dsdiff_decoder_plugin.h"
+
+#include <unistd.h>
+#include <stdio.h> /* for SEEK_SET, SEEK_CUR */
+
+bool
+dsdlib_id_equals(const struct dsdlib_id *id, const char *s)
+{
+	assert(id != NULL);
+	assert(s != NULL);
+	assert(strlen(s) == sizeof(id->value));
+
+	return memcmp(id->value, s, sizeof(id->value)) == 0;
+}
+
+bool
+dsdlib_read(struct decoder *decoder, struct input_stream *is,
+	    void *data, size_t length)
+{
+	size_t nbytes = decoder_read(decoder, is, data, length);
+	return nbytes == length;
+}
+
+/**
+ * Skip the #input_stream to the specified offset.
+ */
+bool
+dsdlib_skip_to(struct decoder *decoder, struct input_stream *is,
+	       goffset offset)
+{
+	if (is->seekable)
+		return input_stream_seek(is, offset, SEEK_SET, NULL);
+
+	if (is->offset > offset)
+		return false;
+
+	char buffer[8192];
+	while (is->offset < offset) {
+		size_t length = sizeof(buffer);
+		if (offset - is->offset < (goffset)length)
+			length = offset - is->offset;
+
+		size_t nbytes = decoder_read(decoder, is, buffer, length);
+		if (nbytes == 0)
+			return false;
+	}
+
+	assert(is->offset == offset);
+	return true;
+}
+
+/**
+ * Skip some bytes from the #input_stream.
+ */
+bool
+dsdlib_skip(struct decoder *decoder, struct input_stream *is,
+	    goffset delta)
+{
+	assert(delta >= 0);
+
+	if (delta == 0)
+		return true;
+
+	if (is->seekable)
+		return input_stream_seek(is, delta, SEEK_CUR, NULL);
+
+	char buffer[8192];
+	while (delta > 0) {
+		size_t length = sizeof(buffer);
+		if ((goffset)length > delta)
+			length = delta;
+
+		size_t nbytes = decoder_read(decoder, is, buffer, length);
+		if (nbytes == 0)
+			return false;
+
+		delta -= nbytes;
+	}
+
+	return true;
+}
+
diff --git a/src/decoder/dsdlib.h b/src/decoder/dsdlib.h
new file mode 100644
index 000000000..d9675f5fe
--- /dev/null
+++ b/src/decoder/dsdlib.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef MPD_DECODER_DSDLIB_H
+#define MPD_DECODER_DSDLIB_H
+
+struct dsdlib_id {
+	char value[4];
+};
+
+bool
+dsdlib_id_equals(const struct dsdlib_id *id, const char *s);
+
+bool
+dsdlib_read(struct decoder *decoder, struct input_stream *is,
+	    void *data, size_t length);
+
+bool
+dsdlib_skip_to(struct decoder *decoder, struct input_stream *is,
+	       goffset offset);
+
+bool
+dsdlib_skip(struct decoder *decoder, struct input_stream *is,
+	    goffset delta);
+
+#endif
diff --git a/src/decoder/dsf_decoder_plugin.c b/src/decoder/dsf_decoder_plugin.c
new file mode 100644
index 000000000..b66ed75e9
--- /dev/null
+++ b/src/decoder/dsf_decoder_plugin.c
@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2012 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
+ *
+ * This plugin decodes DSDIFF data (SACD) embedded in DSF files.
+ *
+ * The DSF code was created using the specification found here:
+ * http://dsd-guide.com/sonys-dsf-file-format-spec
+ *
+ * All functions common to both DSD decoders have been moved to dsdlib
+ */
+
+#include "config.h"
+#include "dsf_decoder_plugin.h"
+#include "decoder_api.h"
+#include "audio_check.h"
+#include "util/bit_reverse.h"
+#include "dsdlib.h"
+
+#include <unistd.h>
+#include <stdio.h> /* for SEEK_SET, SEEK_CUR */
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "dsf"
+
+struct dsf_metadata {
+	unsigned sample_rate, channels;
+	bool bitreverse;
+	uint64_t chunk_size;
+};
+
+struct dsf_header {
+	/** DSF header id: "DSD " */
+	struct dsdlib_id id;
+	/** DSD chunk size, including id = 28 */
+	uint32_t size_low, size_high;
+	/** total file size */
+	uint32_t fsize_low, fsize_high;
+	/** pointer to id3v2 metadata, should be at the end of the file */
+	uint32_t pmeta_low, pmeta_high;
+};
+/** DSF file fmt chunk */
+struct dsf_fmt_chunk {
+
+	/** id: "fmt " */
+	struct dsdlib_id id;
+	/** fmt chunk size, including id, normally 52 */
+	uint32_t size_low, size_high;
+	/** version of this format = 1 */
+	uint32_t version;
+	/** 0: DSD raw */
+	uint32_t formatid;
+	/** channel type, 1 = mono, 2 = stereo, 3 = 3 channels, etc */
+	uint32_t channeltype;
+	/** Channel number, 1 = mono, 2 = stereo, ... 6 = 6 channels */
+	uint32_t channelnum;
+	/** sample frequency: 2822400, 5644800 */
+	uint32_t sample_freq;
+	/** bits per sample 1 or 8 */
+	uint32_t bitssample;
+	/** Sample count per channel in bytes */
+	uint32_t scnt_low, scnt_high;
+	/** block size per channel = 4096 */
+	uint32_t block_size;
+	/** reserved, should be all zero */
+	uint32_t reserved;
+};
+
+struct dsf_data_chunk {
+	struct dsdlib_id id;
+	/** "data" chunk size, includes header (id+size) */
+	uint32_t size_low, size_high;
+};
+
+/**
+ * Read and parse all needed metadata chunks for DSF files.
+ */
+static bool
+dsf_read_metadata(struct decoder *decoder, struct input_stream *is,
+		  struct dsf_metadata *metadata)
+{
+	uint64_t chunk_size;
+	struct dsf_header dsf_header;
+	if (!dsdlib_read(decoder, is, &dsf_header, sizeof(dsf_header)) ||
+	    !dsdlib_id_equals(&dsf_header.id, "DSD "))
+		return false;
+
+	chunk_size = (((uint64_t)GUINT32_FROM_LE(dsf_header.size_high)) << 32) |
+		((uint64_t)GUINT32_FROM_LE(dsf_header.size_low));
+
+	if (sizeof(dsf_header) != chunk_size)
+		return false;
+
+	/* read the 'fmt ' chunk of the DSF file */
+	struct dsf_fmt_chunk dsf_fmt_chunk;
+	if (!dsdlib_read(decoder, is, &dsf_fmt_chunk, sizeof(dsf_fmt_chunk)) ||
+	    !dsdlib_id_equals(&dsf_fmt_chunk.id, "fmt "))
+		return false;
+
+	uint64_t fmt_chunk_size;
+	fmt_chunk_size = (((uint64_t)GUINT32_FROM_LE(dsf_fmt_chunk.size_high)) << 32) |
+			  ((uint64_t)GUINT32_FROM_LE(dsf_fmt_chunk.size_low));
+
+	if (fmt_chunk_size != sizeof(dsf_fmt_chunk))
+		return false;
+
+	uint32_t samplefreq = (uint32_t)GUINT32_FROM_LE(dsf_fmt_chunk.sample_freq);
+
+	/* for now, only support version 1 of the standard, DSD raw stereo
+	   files with a sample freq of 2822400 Hz */
+
+	if (dsf_fmt_chunk.version != 1 || dsf_fmt_chunk.formatid != 0
+	    || dsf_fmt_chunk.channeltype != 2
+	    || dsf_fmt_chunk.channelnum != 2
+	    || samplefreq != 2822400)
+		return false;
+
+	uint32_t chblksize = (uint32_t)GUINT32_FROM_LE(dsf_fmt_chunk.block_size);
+	/* according to the spec block size should always be 4096 */
+	if (chblksize != 4096)
+		return false;
+
+	/* read the 'data' chunk of the DSF file */
+	struct dsf_data_chunk data_chunk;
+	if (!dsdlib_read(decoder, is, &data_chunk, sizeof(data_chunk)) ||
+	    !dsdlib_id_equals(&data_chunk.id, "data"))
+		return false;
+
+	/* data size of DSF files are padded to multiple of 4096,
+	   we use the actual data size as chunk size */
+
+	uint64_t data_size;
+	data_size = (((uint64_t)GUINT32_FROM_LE(data_chunk.size_high)) << 32) |
+		((uint64_t)GUINT32_FROM_LE(data_chunk.size_low));
+	data_size -= sizeof(data_chunk);
+
+	metadata->chunk_size = data_size;
+	metadata->channels = (unsigned) dsf_fmt_chunk.channelnum;
+	metadata->sample_rate = samplefreq;
+
+	/* check bits per sample format, determine if bitreverse is needed */
+	metadata->bitreverse = dsf_fmt_chunk.bitssample == 1;
+	return true;
+}
+
+static void
+bit_reverse_buffer(uint8_t *p, uint8_t *end)
+{
+	for (; p < end; ++p)
+		*p = bit_reverse(*p);
+}
+
+/**
+ * DSF data is build up of alternating 4096 blocks of DSD samples for left and
+ * right. Convert the buffer holding 1 block of 4096 DSD left samples and 1
+ * block of 4096 DSD right samples to 8k of samples in normal PCM left/right
+ * order.
+ */
+static void
+dsf_to_pcm_order(uint8_t *dest, uint8_t *scratch, size_t nrbytes)
+{
+	for (unsigned i = 0, j = 0; i < (unsigned)nrbytes; i += 2) {
+		scratch[i] = *(dest+j);
+		j++;
+	}
+
+	for (unsigned i = 1, j = 0; i < (unsigned) nrbytes; i += 2) {
+		scratch[i] = *(dest+4096+j);
+		j++;
+	}
+
+	for (unsigned i = 0; i < (unsigned)nrbytes; i++) {
+		*dest = scratch[i];
+		dest++;
+	}
+}
+
+/**
+ * Decode one complete DSF 'data' chunk i.e. a complete song
+ */
+static bool
+dsf_decode_chunk(struct decoder *decoder, struct input_stream *is,
+		    unsigned channels,
+		    uint64_t chunk_size,
+		    bool bitreverse)
+{
+	uint8_t buffer[8192];
+
+	/* scratch buffer for DSF samples to convert to the needed
+	   normal left/right regime of samples */
+	uint8_t dsf_scratch_buffer[8192];
+
+	const size_t sample_size = sizeof(buffer[0]);
+	const size_t frame_size = channels * sample_size;
+	const unsigned buffer_frames = sizeof(buffer) / frame_size;
+	const unsigned buffer_samples = buffer_frames * frame_size;
+	const size_t buffer_size = buffer_samples * sample_size;
+
+	while (chunk_size > 0) {
+		/* see how much aligned data from the remaining chunk
+		   fits into the local buffer */
+		unsigned now_frames = buffer_frames;
+		size_t now_size = buffer_size;
+		if (chunk_size < (uint64_t)now_size) {
+			now_frames = (unsigned)chunk_size / frame_size;
+			now_size = now_frames * frame_size;
+		}
+
+		size_t nbytes = decoder_read(decoder, is, buffer, now_size);
+		if (nbytes != now_size)
+			return false;
+
+		chunk_size -= nbytes;
+
+		if (bitreverse)
+			bit_reverse_buffer(buffer, buffer + nbytes);
+
+		dsf_to_pcm_order(buffer, dsf_scratch_buffer, nbytes);
+
+		enum decoder_command cmd =
+			decoder_data(decoder, is, buffer, nbytes, 0);
+		switch (cmd) {
+		case DECODE_COMMAND_NONE:
+			break;
+
+		case DECODE_COMMAND_START:
+		case DECODE_COMMAND_STOP:
+			return false;
+
+		case DECODE_COMMAND_SEEK:
+
+			/* not implemented yet */
+			decoder_seek_error(decoder);
+			break;
+			}
+	}
+	return dsdlib_skip(decoder, is, chunk_size);
+}
+
+static void
+dsf_stream_decode(struct decoder *decoder, struct input_stream *is)
+{
+	struct dsf_metadata metadata = {
+		.sample_rate = 0,
+		.channels = 0,
+	};
+
+	/* check if it is a proper DSF file */
+	if (!dsf_read_metadata(decoder, is, &metadata))
+		return;
+
+	GError *error = NULL;
+	struct audio_format audio_format;
+	if (!audio_format_init_checked(&audio_format, metadata.sample_rate / 8,
+				       SAMPLE_FORMAT_DSD,
+				       metadata.channels, &error)) {
+		g_warning("%s", error->message);
+		g_error_free(error);
+		return;
+	}
+
+	/* success: file was recognized */
+	decoder_initialized(decoder, &audio_format, false, -1);
+
+	if (!dsf_decode_chunk(decoder, is, metadata.channels,
+			      metadata.chunk_size,
+			      metadata.bitreverse))
+		return;
+}
+
+static bool
+dsf_scan_stream(struct input_stream *is,
+		   G_GNUC_UNUSED const struct tag_handler *handler,
+		   G_GNUC_UNUSED void *handler_ctx)
+{
+	struct dsf_metadata metadata = {
+		.sample_rate = 0,
+		.channels = 0,
+	};
+
+	/* check DSF metadata */
+	if (!dsf_read_metadata(NULL, is, &metadata))
+		return false;
+
+	struct audio_format audio_format;
+	if (!audio_format_init_checked(&audio_format, metadata.sample_rate / 8,
+				       SAMPLE_FORMAT_DSD,
+				       metadata.channels, NULL))
+		/* refuse to parse files which we cannot play anyway */
+		return false;
+
+	return true;
+}
+
+static const char *const dsf_suffixes[] = {
+	"dsf",
+	NULL
+};
+
+static const char *const dsf_mime_types[] = {
+	"application/x-dsf",
+	NULL
+};
+
+const struct decoder_plugin dsf_decoder_plugin = {
+	.name = "dsf",
+	.stream_decode = dsf_stream_decode,
+	.scan_stream = dsf_scan_stream,
+	.suffixes = dsf_suffixes,
+	.mime_types = dsf_mime_types,
+};
diff --git a/src/decoder/dsf_decoder_plugin.h b/src/decoder/dsf_decoder_plugin.h
new file mode 100644
index 000000000..401d3fed7
--- /dev/null
+++ b/src/decoder/dsf_decoder_plugin.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef MPD_DECODER_DSF_H
+#define MPD_DECODER_DSF_H
+
+extern const struct decoder_plugin dsf_decoder_plugin;
+
+#endif
diff --git a/src/decoder_list.c b/src/decoder_list.c
index e9e29c691..177b632ad 100644
--- a/src/decoder_list.c
+++ b/src/decoder_list.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2003-2011 The Music Player Daemon Project
+ * Copyright (C) 2003-2012 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -25,6 +25,7 @@
 #include "mpd_error.h"
 #include "decoder/pcm_decoder_plugin.h"
 #include "decoder/dsdiff_decoder_plugin.h"
+#include "decoder/dsf_decoder_plugin.h"
 
 #include <glib.h>
 
@@ -72,6 +73,7 @@ const struct decoder_plugin *const decoder_plugins[] = {
 	&audiofile_decoder_plugin,
 #endif
 	&dsdiff_decoder_plugin,
+	&dsf_decoder_plugin,
 #ifdef HAVE_FAAD
 	&faad_decoder_plugin,
 #endif