mpd/src/encoder/plugins/VorbisEncoderPlugin.cxx

/*
 * Copyright 2003-2017 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 "VorbisEncoderPlugin.hxx"
#include "OggEncoder.hxx"
#include "lib/xiph/VorbisComment.hxx"
#include "AudioFormat.hxx"
#include "config/ConfigError.hxx"
#include "util/StringUtil.hxx"
#include "util/NumberParser.hxx"
#include "util/RuntimeError.hxx"

#include <vorbis/vorbisenc.h>

class VorbisEncoder final : public OggEncoder {
	AudioFormat audio_format;

	vorbis_dsp_state vd;
	vorbis_block vb;
	vorbis_info vi;

public:
	VorbisEncoder(float quality, int bitrate, AudioFormat &_audio_format);

	virtual ~VorbisEncoder() {
		vorbis_block_clear(&vb);
		vorbis_dsp_clear(&vd);
		vorbis_info_clear(&vi);
	}

	/* virtual methods from class Encoder */
	void End() override {
		PreTag();
	}

	void PreTag() override;
	void SendTag(const Tag &tag) override;

	void Write(const void *data, size_t length) override;

private:
	void HeaderOut(vorbis_comment &vc);
	void SendHeader();
	void BlockOut();
};

class PreparedVorbisEncoder final : public PreparedEncoder {
	float quality = 3;
	int bitrate;

public:
	PreparedVorbisEncoder(const ConfigBlock &block);

	/* virtual methods from class PreparedEncoder */
	Encoder *Open(AudioFormat &audio_format) override;

	const char *GetMimeType() const override {
		return "audio/ogg";
	}
};

PreparedVorbisEncoder::PreparedVorbisEncoder(const ConfigBlock &block)
{
	const char *value = block.GetBlockValue("quality");
	if (value != nullptr) {
		/* a quality was configured (VBR) */

		char *endptr;
		quality = ParseDouble(value, &endptr);

		if (*endptr != '\0' || quality < -1.0 || quality > 10.0)
			throw FormatRuntimeError("quality \"%s\" is not a number in the "
						 "range -1 to 10",
						 value);

		if (block.GetBlockValue("bitrate") != nullptr)
			throw std::runtime_error("quality and bitrate are both defined");
	} else {
		/* a bit rate was configured */

		value = block.GetBlockValue("bitrate");
		if (value == nullptr)
			return;

		quality = -2.0;

		char *endptr;
		bitrate = ParseInt(value, &endptr);
		if (*endptr != '\0' || bitrate <= 0)
			throw std::runtime_error("bitrate should be a positive integer");
	}
}

static PreparedEncoder *
vorbis_encoder_init(const ConfigBlock &block)
{
	return new PreparedVorbisEncoder(block);
}

VorbisEncoder::VorbisEncoder(float quality, int bitrate,
			     AudioFormat &_audio_format)
	:OggEncoder(true)
{
	vorbis_info_init(&vi);

	_audio_format.format = SampleFormat::FLOAT;
	audio_format = _audio_format;

	if (quality >= -1.0) {
		/* a quality was configured (VBR) */

		if (0 != vorbis_encode_init_vbr(&vi,
						audio_format.channels,
						audio_format.sample_rate,
						quality * 0.1)) {
			vorbis_info_clear(&vi);
			throw std::runtime_error("error initializing vorbis vbr");
		}
	} else {
		/* a bit rate was configured */

		if (0 != vorbis_encode_init(&vi,
					    audio_format.channels,
					    audio_format.sample_rate, -1.0,
					    bitrate * 1000, -1.0)) {
			vorbis_info_clear(&vi);
			throw std::runtime_error("error initializing vorbis encoder");
		}
	}

	vorbis_analysis_init(&vd, &vi);
	vorbis_block_init(&vd, &vb);

	SendHeader();
}

void
VorbisEncoder::HeaderOut(vorbis_comment &vc)
{
	ogg_packet packet, comments, codebooks;

	vorbis_analysis_headerout(&vd, &vc,
				  &packet, &comments, &codebooks);

	stream.PacketIn(packet);
	stream.PacketIn(comments);
	stream.PacketIn(codebooks);
}

void
VorbisEncoder::SendHeader()
{
	VorbisComment vc;
	HeaderOut(vc);
}

Encoder *
PreparedVorbisEncoder::Open(AudioFormat &audio_format)
{
	return new VorbisEncoder(quality, bitrate, audio_format);
}

void
VorbisEncoder::BlockOut()
{
	while (vorbis_analysis_blockout(&vd, &vb) == 1) {
		vorbis_analysis(&vb, nullptr);
		vorbis_bitrate_addblock(&vb);

		ogg_packet packet;
		while (vorbis_bitrate_flushpacket(&vd, &packet))
			stream.PacketIn(packet);
	}
}

void
VorbisEncoder::PreTag()
{
	vorbis_analysis_wrote(&vd, 0);
	BlockOut();

	/* reinitialize vorbis_dsp_state and vorbis_block to reset the
	   end-of-stream marker */
	vorbis_block_clear(&vb);
	vorbis_dsp_clear(&vd);
	vorbis_analysis_init(&vd, &vi);
	vorbis_block_init(&vd, &vb);

	Flush();
}

static void
copy_tag_to_vorbis_comment(VorbisComment &vc, const Tag &tag)
{
	for (const auto &item : tag) {
		char name[64];
		ToUpperASCII(name, tag_item_names[item.type], sizeof(name));
		vc.AddTag(name, item.value);
	}
}

void
VorbisEncoder::SendTag(const Tag &tag)
{
	/* write the vorbis_comment object */

	VorbisComment comment;
	copy_tag_to_vorbis_comment(comment, tag);

	/* reset ogg_stream_state and begin a new stream */

	stream.Reinitialize(GenerateOggSerial());

	/* send that vorbis_comment to the ogg_stream_state */

	HeaderOut(comment);
}

static void
interleaved_to_vorbis_buffer(float **dest, const float *src,
			     unsigned num_frames, unsigned num_channels)
{
	for (unsigned i = 0; i < num_frames; i++)
		for (unsigned j = 0; j < num_channels; j++)
			dest[j][i] = *src++;
}

void
VorbisEncoder::Write(const void *data, size_t length)
{
	unsigned num_frames = length / audio_format.GetFrameSize();

	/* this is for only 16-bit audio */

	interleaved_to_vorbis_buffer(vorbis_analysis_buffer(&vd, num_frames),
				     (const float *)data,
				     num_frames,
				     audio_format.channels);

	vorbis_analysis_wrote(&vd, num_frames);
	BlockOut();
}

const EncoderPlugin vorbis_encoder_plugin = {
	"vorbis",
	vorbis_encoder_init,
};