wave_encoder: new encoder for streaming PCM wave files.

When using wave encoder with httpd audio output mpd can input this stream via http and audiofile decoder.
This for example opens simple way to configure lossless audio streaming port(like jack or pulseaudio does but without overhead).
Another possibility can be using it for gathering raw data for visualization plugins (If sync issue will be resolved)

1 files changed, 241 insertions, 0 deletions

diff --git a/src/encoder/wave_encoder.c b/src/encoder/wave_encoder.c
new file mode 100644
index 00000000..f06dea30
--- /dev/null
+++ b/src/encoder/wave_encoder.c
@@ -0,0 +1,241 @@
+/*
+ * Copyright (C) 2003-2009 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 "encoder_api.h"
+#include "encoder_plugin.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define MAX_BUFFER 32768
+
+struct wave_encoder {
+	struct encoder encoder;
+	unsigned bits;
+
+	uint8_t buffer[MAX_BUFFER];
+	size_t buffer_length;
+};
+
+struct wave_header {
+	uint32_t id_riff;
+	uint32_t riff_size;
+	uint32_t id_wave;
+	uint32_t id_fmt;
+	uint32_t fmt_size;
+	uint16_t format;
+	uint16_t channels;
+	uint32_t freq;
+	uint32_t byterate;
+	uint16_t blocksize;
+	uint16_t bits;
+	uint32_t id_data;
+	uint32_t data_size;
+};
+
+extern const struct encoder_plugin wave_encoder_plugin;
+
+static inline GQuark
+wave_encoder_quark(void)
+{
+	return g_quark_from_static_string("wave_encoder");
+}
+
+static void
+fill_wave_header(struct wave_header *header, int channels, int bits, 
+		int freq, int block_size)
+{
+	int data_size = 0x0FFFFFFF;
+
+	/* constants */
+	header->id_riff = GUINT32_TO_LE(0x46464952);
+	header->id_wave = GUINT32_TO_LE(0x45564157);
+	header->id_fmt = GUINT32_TO_LE(0x20746d66);
+	header->id_data = GUINT32_TO_LE(0x61746164);
+
+        /* wave format */
+	header->format = GUINT16_TO_LE(1);		// PCM_FORMAT
+	header->channels = GUINT16_TO_LE(channels);
+	header->bits = GUINT16_TO_LE(bits);
+	header->freq = GUINT32_TO_LE(freq);
+	header->blocksize = GUINT16_TO_LE(block_size);
+	header->byterate = GUINT32_TO_LE(freq * block_size);
+
+        /* chunk sizes (fake data length) */
+	header->fmt_size = GUINT32_TO_LE(16);
+	header->data_size = GUINT32_TO_LE(data_size);
+	header->riff_size = GUINT32_TO_LE(4 + (8 + 16) +
+					 (8 + data_size));
+}
+
+static struct encoder *
+wave_encoder_init(G_GNUC_UNUSED const struct config_param *param,
+		  G_GNUC_UNUSED GError **error)
+{
+	struct wave_encoder *encoder;
+
+	encoder = g_new(struct wave_encoder, 1);
+	encoder_struct_init(&encoder->encoder, &wave_encoder_plugin);
+
+	return &encoder->encoder;
+}
+
+static void
+wave_encoder_finish(struct encoder *_encoder)
+{
+	struct wave_encoder *encoder = (struct wave_encoder *)_encoder;
+
+	g_free(encoder);
+}
+
+static bool
+wave_encoder_open(struct encoder *_encoder,
+		  G_GNUC_UNUSED struct audio_format *audio_format,
+		  G_GNUC_UNUSED GError **error)
+{
+	struct wave_encoder *encoder = (struct wave_encoder *)_encoder;
+
+	encoder->bits = audio_format->bits;
+
+	/* create PCM wave header in initial buffer */
+	fill_wave_header((struct wave_header *) encoder->buffer, 
+			audio_format->channels,
+			audio_format->bits,
+			audio_format->sample_rate,
+			(audio_format->bits / 8) * audio_format->channels );
+
+	encoder->buffer_length = sizeof(struct wave_header);
+	return true;
+}
+
+static inline size_t
+pcm16_to_wave(void *dst, const void *src, size_t length)
+{
+	uint32_t scnt;
+	const uint16_t *src16 = (const uint16_t *) src;
+	uint16_t *dst16 = (uint16_t *) dst;
+
+	for(scnt = length >> 1; scnt>0; scnt--){
+		*dst16++ = GUINT16_TO_LE(*src16++);
+	}
+	return length;
+}
+
+static inline size_t
+pcm32_to_wave(void *dst, const void *src, size_t length)
+{
+	uint32_t scnt;
+	const uint32_t *src32 = (const uint32_t *) src;
+	uint32_t *dst32 = (uint32_t *) dst;
+
+	for(scnt = length >> 2; scnt>0; scnt--){
+		*dst32++ = GUINT32_TO_LE(*src32++);
+	}
+	return length;
+}
+
+static inline size_t
+pcm24_to_wave(void *dst, const void *src, size_t length)
+{
+	uint32_t scnt, value;
+	const uint32_t *src32 = (const uint32_t *) src;
+	uint8_t *dst8  = (uint8_t *) dst;
+
+	for(scnt = length >> 2; scnt>0; scnt--){
+		value = *src32++;
+		*dst8++ = (value) & 0xFF;
+		*dst8++ = (value >> 8) & 0xFF;
+		*dst8++ = (value >> 16) & 0xFF;
+	}
+	//correct buffer length
+	length = dst8 - ((uint8_t *)dst);
+	return length;
+}
+
+static bool
+wave_encoder_write(struct encoder *_encoder,
+		   const void *src, size_t length,
+		   G_GNUC_UNUSED GError **error)
+{
+	struct wave_encoder *encoder = (struct wave_encoder *)_encoder;
+	void *dst;
+
+	assert(length + encoder->buffer_length < MAX_BUFFER);
+
+	dst = encoder->buffer + encoder->buffer_length;
+
+#if (G_BYTE_ORDER == G_LITTLE_ENDIAN)
+	switch (encoder->bits) {
+	case 8:
+	case 16:
+	case 32:// optimized cases
+		memcpy(dst, src, length);
+		break;
+	case 24:
+		length = pcm24_to_wave(dst, src, length);
+		break;
+	}
+#elif (G_BYTE_ORDER == G_BIG_ENDIAN)
+	switch (encoder->bits) {
+	case 8:
+		memcpy(dst, src, length);
+		break;
+	case 16:
+		length = pcm16_to_wave(dst, src, length);
+		break;
+	case 24:
+		length = pcm24_to_wave(dst, src, length);
+		break;
+	case 32:
+		length = pcm32_to_wave(dst, src, length);
+		break;
+	}
+#else
+#error G_BYTE_ORDER set to G_PDP_ENDIAN is not supported by wave_encoder
+#endif
+
+	encoder->buffer_length += length;
+	return true;
+}
+
+static size_t
+wave_encoder_read(struct encoder *_encoder, void *dest, size_t length)
+{
+	struct wave_encoder *encoder = (struct wave_encoder *)_encoder;
+
+	if (length > encoder->buffer_length)
+		length = encoder->buffer_length;
+
+	memcpy(dest, encoder->buffer, length);
+
+	encoder->buffer_length -= length;
+	memmove(encoder->buffer, encoder->buffer + length,
+		encoder->buffer_length);
+
+	return length;
+}
+
+const struct encoder_plugin wave_encoder_plugin = {
+	.name = "wave",
+	.init = wave_encoder_init,
+	.finish = wave_encoder_finish,
+	.open = wave_encoder_open,
+	.write = wave_encoder_write,
+	.read = wave_encoder_read,
+};