encoder/twolame: new encoder plugin based on libtwolame

This encoder plugin is a replacement for the LAME encoder plugin for
those who prefer a "free" (non-patent encumbered) encoder library.
Most of the plugin source code is copied from the LAME encoder plugin,
since the LAME and TwoLAME APIs are nearly the same.

1 files changed, 299 insertions, 0 deletions

diff --git a/src/encoder/twolame_encoder.c b/src/encoder/twolame_encoder.c
new file mode 100644
index 00000000..5a8a82d8
--- /dev/null
+++ b/src/encoder/twolame_encoder.c
@@ -0,0 +1,299 @@
+/*
+ * 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 "audio_format.h"
+
+#include <twolame.h>
+#include <assert.h>
+#include <string.h>
+
+struct twolame_encoder {
+	struct encoder encoder;
+
+	struct audio_format audio_format;
+	float quality;
+	int bitrate;
+
+	twolame_options *options;
+
+	unsigned char buffer[32768];
+	size_t buffer_length;
+
+	/**
+	 * Call libtwolame's flush function when the buffer is empty?
+	 */
+	bool flush;
+};
+
+extern const struct encoder_plugin twolame_encoder_plugin;
+
+static inline GQuark
+twolame_encoder_quark(void)
+{
+	return g_quark_from_static_string("twolame_encoder");
+}
+
+static bool
+twolame_encoder_configure(struct twolame_encoder *encoder,
+			  const struct config_param *param, GError **error)
+{
+	const char *value;
+	char *endptr;
+
+	value = config_get_block_string(param, "quality", NULL);
+	if (value != NULL) {
+		/* a quality was configured (VBR) */
+
+		encoder->quality = g_ascii_strtod(value, &endptr);
+
+		if (*endptr != '\0' || encoder->quality < -1.0 ||
+		    encoder->quality > 10.0) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "quality \"%s\" is not a number in the "
+				    "range -1 to 10, line %i",
+				    value, param->line);
+			return false;
+		}
+
+		if (config_get_block_string(param, "bitrate", NULL) != NULL) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "quality and bitrate are "
+				    "both defined (line %i)",
+				    param->line);
+			return false;
+		}
+	} else {
+		/* a bit rate was configured */
+
+		value = config_get_block_string(param, "bitrate", NULL);
+		if (value == NULL) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "neither bitrate nor quality defined "
+				    "at line %i",
+				    param->line);
+			return false;
+		}
+
+		encoder->quality = -2.0;
+		encoder->bitrate = g_ascii_strtoll(value, &endptr, 10);
+
+		if (*endptr != '\0' || encoder->bitrate <= 0) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "bitrate at line %i should be a positive integer",
+				    param->line);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static struct encoder *
+twolame_encoder_init(const struct config_param *param, GError **error)
+{
+	struct twolame_encoder *encoder;
+
+	g_debug("libtwolame version %s", get_twolame_version());
+
+	encoder = g_new(struct twolame_encoder, 1);
+	encoder_struct_init(&encoder->encoder, &twolame_encoder_plugin);
+
+	/* load configuration from "param" */
+	if (!twolame_encoder_configure(encoder, param, error)) {
+		/* configuration has failed, roll back and return error */
+		g_free(encoder);
+		return NULL;
+	}
+
+	return &encoder->encoder;
+}
+
+static void
+twolame_encoder_finish(struct encoder *_encoder)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+
+	/* the real libtwolame cleanup was already performed by
+	   twolame_encoder_close(), so no real work here */
+	g_free(encoder);
+}
+
+static bool
+twolame_encoder_setup(struct twolame_encoder *encoder, GError **error)
+{
+	if (encoder->quality >= -1.0) {
+		/* a quality was configured (VBR) */
+
+		if (0 != twolame_set_VBR(encoder->options, true)) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "error setting twolame VBR mode");
+			return false;
+		}
+		if (0 != twolame_set_VBR_q(encoder->options, encoder->quality)) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "error setting twolame VBR quality");
+			return false;
+		}
+	} else {
+		/* a bit rate was configured */
+
+		if (0 != twolame_set_brate(encoder->options, encoder->bitrate)) {
+			g_set_error(error, twolame_encoder_quark(), 0,
+				    "error setting twolame bitrate");
+			return false;
+		}
+	}
+
+	if (0 != twolame_set_num_channels(encoder->options,
+					  encoder->audio_format.channels)) {
+		g_set_error(error, twolame_encoder_quark(), 0,
+			    "error setting twolame num channels");
+		return false;
+	}
+
+	if (0 != twolame_set_in_samplerate(encoder->options,
+					   encoder->audio_format.sample_rate)) {
+		g_set_error(error, twolame_encoder_quark(), 0,
+			    "error setting twolame sample rate");
+		return false;
+	}
+
+	if (0 > twolame_init_params(encoder->options)) {
+		g_set_error(error, twolame_encoder_quark(), 0,
+			    "error initializing twolame params");
+		return false;
+	}
+
+	return true;
+}
+
+static bool
+twolame_encoder_open(struct encoder *_encoder, struct audio_format *audio_format,
+		     GError **error)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+
+	audio_format->bits = 16;
+	audio_format->channels = 2;
+
+	encoder->audio_format = *audio_format;
+
+	encoder->options = twolame_init();
+	if (encoder->options == NULL) {
+		g_set_error(error, twolame_encoder_quark(), 0,
+			    "twolame_init() failed");
+		return false;
+	}
+
+	if (!twolame_encoder_setup(encoder, error)) {
+		twolame_close(&encoder->options);
+		return false;
+	}
+
+	encoder->buffer_length = 0;
+	encoder->flush = false;
+
+	return true;
+}
+
+static void
+twolame_encoder_close(struct encoder *_encoder)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+
+	twolame_close(&encoder->options);
+}
+
+static bool
+twolame_encoder_flush(struct encoder *_encoder, G_GNUC_UNUSED GError **error)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+
+	encoder->flush = true;
+	return true;
+}
+
+static bool
+twolame_encoder_write(struct encoder *_encoder,
+		      const void *data, size_t length,
+		      G_GNUC_UNUSED GError **error)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+	unsigned num_frames;
+	const int16_t *src = (const int16_t*)data;
+	int bytes_out;
+
+	assert(encoder->buffer_length == 0);
+
+	num_frames =
+		length / audio_format_frame_size(&encoder->audio_format);
+
+	bytes_out = twolame_encode_buffer_interleaved(encoder->options,
+						      src, num_frames,
+						      encoder->buffer,
+						      sizeof(encoder->buffer));
+	if (bytes_out < 0) {
+		g_set_error(error, twolame_encoder_quark(), 0,
+			    "twolame encoder failed");
+		return false;
+	}
+
+	encoder->buffer_length = (size_t)bytes_out;
+	return true;
+}
+
+static size_t
+twolame_encoder_read(struct encoder *_encoder, void *dest, size_t length)
+{
+	struct twolame_encoder *encoder = (struct twolame_encoder *)_encoder;
+
+	if (encoder->buffer_length == 0 && encoder->flush) {
+		int ret = twolame_encode_flush(encoder->options,
+					       encoder->buffer,
+					       sizeof(encoder->buffer));
+		if (ret > 0)
+			encoder->buffer_length = (size_t)ret;
+
+		encoder->flush = false;
+	}
+
+	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 twolame_encoder_plugin = {
+	.name = "twolame",
+	.init = twolame_encoder_init,
+	.finish = twolame_encoder_finish,
+	.open = twolame_encoder_open,
+	.close = twolame_encoder_close,
+	.flush = twolame_encoder_flush,
+	.write = twolame_encoder_write,
+	.read = twolame_encoder_read,
+};