encoder: introducing flac encoder plugin

1 files changed, 296 insertions, 0 deletions

diff --git a/src/encoder/flac_encoder.c b/src/encoder/flac_encoder.c
new file mode 100644
index 00000000..ab7dc0c3
--- /dev/null
+++ b/src/encoder/flac_encoder.c
@@ -0,0 +1,296 @@
+/*
+ * 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 "config.h"
+#include "encoder_api.h"
+#include "encoder_plugin.h"
+#include "audio_format.h"
+#include "pcm_buffer.h"
+
+#include <assert.h>
+#include <string.h>
+
+#include <FLAC/stream_encoder.h>
+
+struct flac_encoder {
+	struct encoder encoder;
+
+	struct audio_format audio_format;
+	unsigned compression;
+
+	FLAC__StreamEncoder *fse;
+
+	struct pcm_buffer expand_buffer;
+
+	struct pcm_buffer buffer;
+	size_t buffer_length;
+};
+
+extern const struct encoder_plugin flac_encoder_plugin;
+
+static inline GQuark
+flac_encoder_quark(void)
+{
+	return g_quark_from_static_string("flac_encoder");
+}
+
+static bool
+flac_encoder_configure(struct flac_encoder *encoder,
+		const struct config_param *param, G_GNUC_UNUSED GError **error)
+{
+	encoder->compression = config_get_block_unsigned(param, 
+						"compression", 5);
+
+	return true;
+}
+
+static struct encoder *
+flac_encoder_init(const struct config_param *param, GError **error)
+{
+	struct flac_encoder *encoder;
+
+	encoder = g_new(struct flac_encoder, 1);
+	encoder_struct_init(&encoder->encoder, &flac_encoder_plugin);
+
+	/* load configuration from "param" */
+	if (!flac_encoder_configure(encoder, param, error)) {
+		/* configuration has failed, roll back and return error */
+		g_free(encoder);
+		return NULL;
+	}
+
+	return &encoder->encoder;
+}
+
+static void
+flac_encoder_finish(struct encoder *_encoder)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+
+	/* the real libFLAC cleanup was already performed by
+	   flac_encoder_close(), so no real work here */
+	g_free(encoder);
+}
+
+static bool
+flac_encoder_setup(struct flac_encoder *encoder, GError **error)
+{
+	if ( !FLAC__stream_encoder_set_compression_level(encoder->fse,
+					encoder->compression)) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "error setting flac compression to %d",
+			    encoder->compression);
+		return false;
+	}
+	if ( !FLAC__stream_encoder_set_channels(encoder->fse,
+					encoder->audio_format.channels)) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "error setting flac channels num to %d",
+			    encoder->audio_format.channels);
+		return false;
+	}
+	if ( !FLAC__stream_encoder_set_bits_per_sample(encoder->fse,
+					encoder->audio_format.bits)) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "error setting flac bit format to %d",
+			    encoder->audio_format.bits);
+		return false;
+	}
+	if ( !FLAC__stream_encoder_set_sample_rate(encoder->fse,
+					encoder->audio_format.sample_rate)) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "error setting flac sample rate to %d",
+			    encoder->audio_format.sample_rate);
+		return false;
+	}
+	return true;
+}
+
+static FLAC__StreamEncoderWriteStatus
+flac_write_callback(G_GNUC_UNUSED const FLAC__StreamEncoder *fse,
+	const FLAC__byte data[], size_t bytes, G_GNUC_UNUSED unsigned samples,
+	G_GNUC_UNUSED unsigned current_frame, void *client_data)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *) client_data;
+
+	char *buffer = pcm_buffer_get(&encoder->buffer, encoder->buffer_length + bytes);
+
+	//transfer data to buffer
+	memcpy( buffer + encoder->buffer_length, data, bytes);
+	encoder->buffer_length += bytes;
+
+	return FLAC__STREAM_ENCODER_WRITE_STATUS_OK;
+}
+
+static bool
+flac_encoder_open(struct encoder *_encoder, struct audio_format *audio_format,
+		     GError **error)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+	FLAC__StreamEncoderInitStatus init_status;
+
+	encoder->audio_format = *audio_format;
+
+	/* FIXME: flac should support 32bit as well */
+	if (audio_format->bits > 24)
+		audio_format->bits = 24;
+
+	/* allocate the encoder */
+	encoder->fse = FLAC__stream_encoder_new();
+	if (encoder->fse == NULL) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "flac_new() failed");
+		return false;
+	}
+
+	if (!flac_encoder_setup(encoder, error)) {
+		FLAC__stream_encoder_delete(encoder->fse);
+		return false;
+	}
+
+	encoder->buffer_length = 0;
+	pcm_buffer_init(&encoder->buffer);
+	pcm_buffer_init(&encoder->expand_buffer);
+
+	/* this immediatelly outputs data throught callback */
+
+	init_status = FLAC__stream_encoder_init_stream(encoder->fse,
+			    flac_write_callback,
+			    NULL, NULL, NULL, encoder);
+
+	if(init_status != FLAC__STREAM_ENCODER_INIT_STATUS_OK) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "failed to initialize encoder: %s\n", 
+			    FLAC__StreamEncoderInitStatusString[init_status]);
+		FLAC__stream_encoder_delete(encoder->fse);
+		return false;
+	}
+
+	return true;
+}
+
+static void
+flac_encoder_close(struct encoder *_encoder)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+
+	FLAC__stream_encoder_delete(encoder->fse);
+
+	pcm_buffer_deinit(&encoder->buffer);
+	pcm_buffer_deinit(&encoder->expand_buffer);
+}
+
+static bool
+flac_encoder_flush(struct encoder *_encoder, G_GNUC_UNUSED GError **error)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+
+	return FLAC__stream_encoder_finish(encoder->fse);
+}
+
+static inline void
+pcm8_to_flac(int32_t *out, const int8_t *in, unsigned num_samples)
+{
+	while (num_samples > 0) {
+		*out++ = *in++;
+		--num_samples;
+	}
+}
+
+static inline void
+pcm16_to_flac(int32_t *out, const int16_t *in, unsigned num_samples)
+{
+	while (num_samples > 0) {
+		*out++ = *in++;
+		--num_samples;
+	}
+}
+
+static bool
+flac_encoder_write(struct encoder *_encoder,
+		      const void *data, size_t length,
+		      G_GNUC_UNUSED GError **error)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+	unsigned num_frames, num_samples;
+	void *exbuffer;
+	const void *buffer = NULL;
+
+	/* format conversion */
+
+	num_frames = length / audio_format_frame_size(&encoder->audio_format);
+	num_samples = num_frames * encoder->audio_format.channels;
+
+	switch (encoder->audio_format.bits) {
+	case 8:
+		exbuffer = pcm_buffer_get(&encoder->expand_buffer, length*4);
+		pcm8_to_flac(exbuffer, data, num_samples);
+		buffer = exbuffer;
+		break;
+	case 16:
+		exbuffer = pcm_buffer_get(&encoder->expand_buffer, length*2);
+		pcm16_to_flac(exbuffer, data, num_samples);
+		buffer = exbuffer;
+		break;
+	case 24:
+	case 32: /* nothing need to be done
+		  * format is the same for both mpd and libFLAC */
+		buffer = data;
+		break;
+	}
+
+	/* feed samples to encoder */
+
+	if (!FLAC__stream_encoder_process_interleaved(encoder->fse, buffer,
+							num_frames)) {
+		g_set_error(error, flac_encoder_quark(), 0,
+			    "flac encoder process failed");
+		return false;
+	}
+
+	return true;
+}
+
+static size_t
+flac_encoder_read(struct encoder *_encoder, void *dest, size_t length)
+{
+	struct flac_encoder *encoder = (struct flac_encoder *)_encoder;
+	char *buffer = pcm_buffer_get(&encoder->buffer, encoder->buffer_length);
+
+	if (length > encoder->buffer_length)
+		length = encoder->buffer_length;
+
+	memcpy(dest, buffer, length);
+
+	encoder->buffer_length -= length;
+	memmove(buffer, buffer + length, encoder->buffer_length);
+
+	return length;
+}
+
+const struct encoder_plugin flac_encoder_plugin = {
+	.name = "flac",
+	.init = flac_encoder_init,
+	.finish = flac_encoder_finish,
+	.open = flac_encoder_open,
+	.close = flac_encoder_close,
+	.flush = flac_encoder_flush,
+	.write = flac_encoder_write,
+	.read = flac_encoder_read,
+};