mpd/src/decoder/pcm_decoder_plugin.c

/*
 * Copyright (C) 2003-2011 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 "decoder/pcm_decoder_plugin.h"
#include "decoder_api.h"

#include <glib.h>
#include <unistd.h>
#include <stdio.h> /* for SEEK_SET */

#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "pcm"

static void
pcm_stream_decode(struct decoder *decoder, struct input_stream *is)
{
	static const struct audio_format host_audio_format = {
		.sample_rate = 44100,
		.format = SAMPLE_FORMAT_S16,
		.channels = 2,
	};

	static const struct audio_format reverse_audio_format = {
		.sample_rate = 44100,
		.format = SAMPLE_FORMAT_S16,
		.channels = 2,
		.reverse_endian = true,
	};

	const struct audio_format *audio_format =
		(is->mime == NULL ||
		 strcmp(is->mime, "audio/x-mpd-cdda-pcm-reverse") != 0)
		? &host_audio_format
		: &reverse_audio_format;

	GError *error = NULL;
	enum decoder_command cmd;

	double time_to_size = audio_format_time_to_size(audio_format);

	float total_time = -1;
	if (is->size >= 0)
		total_time = is->size / time_to_size;

	decoder_initialized(decoder, audio_format, is->seekable, total_time);

	do {
		char buffer[4096];

		size_t nbytes = decoder_read(decoder, is,
					     buffer, sizeof(buffer));

		if (nbytes == 0 && input_stream_lock_eof(is))
			break;

		cmd = nbytes > 0
			? decoder_data(decoder, is,
				       buffer, nbytes, 0)
			: decoder_get_command(decoder);
		if (cmd == DECODE_COMMAND_SEEK) {
			goffset offset = (goffset)(time_to_size *
						   decoder_seek_where(decoder));
			if (input_stream_lock_seek(is, offset, SEEK_SET,
						   &error)) {
				decoder_command_finished(decoder);
			} else {
				g_warning("seeking failed: %s", error->message);
				g_error_free(error);
				decoder_seek_error(decoder);
			}

			cmd = DECODE_COMMAND_NONE;
		}
	} while (cmd == DECODE_COMMAND_NONE);
}

static const char *const pcm_mime_types[] = {
	/* for streams obtained by the cdio_paranoia input plugin */
	"audio/x-mpd-cdda-pcm",

	/* same as above, but with reverse byte order */
	"audio/x-mpd-cdda-pcm-reverse",

	NULL
};

const struct decoder_plugin pcm_decoder_plugin = {
	.name = "pcm",
	.stream_decode = pcm_stream_decode,
	.mime_types = pcm_mime_types,
};