Shine encoding plugin

This encoding plugin features a fixed-point mp3 encoder,
with faster encoding on architectures without a FPU.

Right now the encoder is limited to stereo and 16 bit depth.
The bitrate and sample rate can be modified in audio_output.

audio_output {
        type            "httpd"
        name            "My shine stream"
        encoder         "shine"
        port            "8000"
        format          "44100:16:2"
        bitrate         "320"  # default: 128
}

src/encoder/ShineEncoderPlugin.cxx

@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2003-2014 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 "ShineEncoderPlugin.hxx"
+#include "config.h"
+#include "EncoderAPI.hxx"
+#include "AudioFormat.hxx"
+#include "ConfigError.hxx"
+#include "util/Manual.hxx"
+#include "util/NumberParser.hxx"
+#include "util/DynamicFifoBuffer.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+extern "C"
+{
+#include <shine/layer3.h>
+}
+
+static constexpr size_t BUFFER_INIT_SIZE = 8192;
+static constexpr unsigned CHANNELS = 2;
+
+struct ShineEncoder {
+	Encoder encoder;
+
+	AudioFormat audio_format;
+
+	shine_t shine;
+
+	shine_config_t config;
+
+	uint16_t frame_size;
+	int16_t buffer[SHINE_MAX_SAMPLES * CHANNELS];
+	int16_t channels[CHANNELS][SHINE_MAX_SAMPLES];
+	int16_t *stereo[CHANNELS];
+
+	Manual<DynamicFifoBuffer<int16_t>> input_buffer;
+	size_t input_size;
+
+	Manual<DynamicFifoBuffer<uint8_t>> output_buffer;
+
+	ShineEncoder()
+		:encoder(shine_encoder_plugin),
+		 stereo { channels[0], channels[1] },
+		 input_size(0) {}
+
+	bool Configure(const config_param &param, Error &error);
+
+	bool Setup(Error &error);
+
+	bool WriteChunks(bool flush, Error &error);
+};
+
+static constexpr Domain shine_encoder_domain("shine_encoder");
+
+inline bool
+ShineEncoder::Configure(const config_param &param,
+			 gcc_unused Error &error)
+{
+	shine_set_config_mpeg_defaults(&config.mpeg);
+	config.mpeg.bitr = param.GetBlockValue("bitrate", 128);
+
+	return true;
+}
+
+static Encoder *
+shine_encoder_init(const config_param &param, Error &error)
+{
+	ShineEncoder *encoder = new ShineEncoder();
+
+	/* load configuration from "param" */
+	if (!encoder->Configure(param, error)) {
+		/* configuration has failed, roll back and return error */
+		delete encoder;
+		return nullptr;
+	}
+
+	return &encoder->encoder;
+}
+
+static void
+shine_encoder_finish(Encoder *_encoder)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+
+	delete encoder;
+}
+
+inline bool
+ShineEncoder::Setup(Error &error)
+{
+	input_size = 0;
+	config.mpeg.mode = audio_format.channels == 2 ? STEREO : MONO;
+	config.wave.samplerate = audio_format.sample_rate;
+	config.wave.channels = audio_format.channels == 2 ? PCM_STEREO : PCM_MONO;
+
+	if (shine_check_config(config.wave.samplerate, config.mpeg.bitr) < 0) {
+		error.Format(config_domain,
+			     "error configuring shine. samplerate %d and bitrate %d configuration not supported.",
+			     config.wave.samplerate,
+			     config.mpeg.bitr);
+
+		return false;
+	}
+
+	shine = shine_initialise(&config);
+
+	if (!shine) {
+		error.Format(config_domain,
+			     "error initializing shine.");
+
+		return false;
+	}
+
+	frame_size = shine_samples_per_pass(shine);
+
+	return true;
+}
+
+static bool
+shine_encoder_open(Encoder *_encoder, AudioFormat &audio_format, Error &error)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+
+	audio_format.format = SampleFormat::S16;
+	audio_format.channels = CHANNELS;
+	encoder->audio_format = audio_format;
+
+	if (!encoder->Setup(error))
+		return false;
+
+	encoder->input_buffer.Construct(BUFFER_INIT_SIZE);
+	encoder->output_buffer.Construct(BUFFER_INIT_SIZE);
+
+	return true;
+}
+
+static void
+shine_encoder_close(Encoder *_encoder)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+
+	shine_close(encoder->shine);
+	encoder->input_buffer.Destruct();
+	encoder->output_buffer.Destruct();
+}
+
+bool
+ShineEncoder::WriteChunks(bool flush, gcc_unused Error &error)
+{
+	const size_t chunk_size = frame_size * audio_format.channels;
+
+	/*
+	 * shine requires data in specific sizes, therefore we need to
+	 * buffer the received data and encode in chunks.
+	 */
+	while (input_size >= chunk_size || (flush && input_size > 0)) {
+		long written;
+
+		const size_t read = input_buffer->Read(buffer, chunk_size);
+		input_size -= read;
+
+		/* de-interleave data */
+		for (size_t i = 0; i < read / audio_format.channels; i++) {
+			channels[0][i] = buffer[i * audio_format.channels];
+			channels[1][i] = buffer[i * audio_format.channels + 1];
+		}
+
+		if (flush) {
+			/* fill remaining with 0s */
+			for (size_t i = read / audio_format.channels; i < frame_size; i++) {
+				channels[0][i] = channels[1][i] = 0;
+			}
+		}
+
+		const uint8_t *out = shine_encode_buffer(shine, stereo, &written);
+
+		if (written > 0)
+			output_buffer->Append((const uint8_t *)out, written);
+	}
+
+	return true;
+}
+
+static bool
+shine_encoder_write(Encoder *_encoder,
+		    const void *_data, size_t length,
+		    gcc_unused Error &error)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+	const int16_t *data = (const int16_t*)_data;
+
+	encoder->input_buffer->Append(data, length / sizeof(*data));
+	encoder->input_size += length / sizeof(*data);
+
+	return encoder->WriteChunks(false, error);
+}
+
+static bool
+shine_encoder_flush(Encoder *_encoder, gcc_unused Error &error)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+	long written;
+
+	encoder->WriteChunks(true, error);
+	const uint8_t *data = shine_flush(encoder->shine, &written);
+
+	if (written > 0)
+		encoder->output_buffer->Append(data, written);
+
+	return true;
+}
+
+static size_t
+shine_encoder_read(Encoder *_encoder, void *dest, size_t length)
+{
+	ShineEncoder *encoder = (ShineEncoder *)_encoder;
+
+	return encoder->output_buffer->Read((uint8_t *)dest, length);
+}
+
+static const char *
+shine_encoder_get_mime_type(gcc_unused Encoder *_encoder)
+{
+	return "audio/mpeg";
+}
+
+const EncoderPlugin shine_encoder_plugin = {
+	"shine",
+	shine_encoder_init,
+	shine_encoder_finish,
+	shine_encoder_open,
+	shine_encoder_close,
+	shine_encoder_flush,
+	shine_encoder_flush,
+	nullptr,
+	nullptr,
+	shine_encoder_write,
+	shine_encoder_read,
+	shine_encoder_get_mime_type,
+};

src/encoder/ShineEncoderPlugin.hxx

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2003-2014 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_ENCODER_SHINE_HXX
+#define MPD_ENCODER_SHINE_HXX
+
+extern const struct EncoderPlugin shine_encoder_plugin;
+
+#endif