cog/Plugins/Opus/Opus/OpusDecoder.m

//
//  OpusDecoder.m
//  Opus
//
//  Created by Christopher Snowhill on 10/4/13.
//  Copyright 2013 __NoWork, Inc__. All rights reserved.
//

#import "Plugin.h"

#import "OpusDecoder.h"

#import "Logging.h"

@implementation OpusFile

static const int MAXCHANNELS = 8;
static const int chmap[MAXCHANNELS][MAXCHANNELS] = {
	{
	0,
	}, // mono
	{
	0,
	1,
	}, // l, r
	{
	0,
	2,
	1,
	}, // l, c, r -> l, r, c
	{
	0,
	1,
	2,
	3,
	}, // l, r, bl, br
	{
	0,
	2,
	1,
	3,
	4,
	}, // l, c, r, bl, br -> l, r, c, bl, br
	{ 0, 2, 1, 5, 3, 4 }, // l, c, r, bl, br, lfe -> l, r, c, lfe, bl, br
	{ 0, 2, 1, 6, 5, 3, 4 }, // l, c, r, sl, sr, bc, lfe -> l, r, c, lfe, bc, sl, sr
	{ 0, 2, 1, 7, 5, 6, 3, 4 } // l, c, r, sl, sr, bl, br, lfe -> l, r, c, lfe, bl, br, sl, sr
};

int sourceRead(void *_stream, unsigned char *_ptr, int _nbytes) {
	id source = (__bridge id)_stream;

	return (int)[source read:_ptr amount:_nbytes];
}

int sourceSeek(void *_stream, opus_int64 _offset, int _whence) {
	id source = (__bridge id)_stream;
	return ([source seek:_offset whence:_whence] ? 0 : -1);
}

int sourceClose(void *_stream) {
	return 0;
}

opus_int64 sourceTell(void *_stream) {
	id source = (__bridge id)_stream;

	return [source tell];
}

- (id)init {
	self = [super init];
	if(self) {
		opusRef = NULL;
	}
	return self;
}

- (BOOL)open:(id<CogSource>)s {
	source = s;

	OpusFileCallbacks callbacks = {
		.read = sourceRead,
		.seek = sourceSeek,
		.close = sourceClose,
		.tell = sourceTell
	};

	int error;
	opusRef = op_open_callbacks((__bridge void *)source, &callbacks, NULL, 0, &error);

	if(!opusRef) {
		DLog(@"FAILED TO OPEN OPUS FILE");
		return NO;
	}

	currentSection = lastSection = op_current_link(opusRef);

	bitrate = (op_bitrate(opusRef, currentSection) / 1000.0);
	channels = op_channel_count(opusRef, currentSection);

	seekable = op_seekable(opusRef);

	totalFrames = op_pcm_total(opusRef, -1);

	NSString *gainMode = [[NSUserDefaults standardUserDefaults] stringForKey:@"volumeScaling"];
	BOOL isAlbum = [gainMode hasPrefix:@"albumGain"];
	BOOL isTrack = [gainMode hasPrefix:@"trackGain"];

	if(isAlbum || isTrack) {
		op_set_gain_offset(opusRef, isAlbum ? OP_HEADER_GAIN : OP_TRACK_GAIN, 0);
	} else {
		op_set_gain_offset(opusRef, OP_ABSOLUTE_GAIN, 0);
	}

	[self willChangeValueForKey:@"properties"];
	[self didChangeValueForKey:@"properties"];

	return YES;
}

- (int)readAudio:(void *)buf frames:(UInt32)frames {
	int numread;
	int total = 0;

	if(currentSection != lastSection) {
		bitrate = (op_bitrate(opusRef, currentSection) / 1000.0);
		channels = op_channel_count(opusRef, currentSection);

		[self willChangeValueForKey:@"properties"];
		[self didChangeValueForKey:@"properties"];
	}

	int size = frames * channels;

	do {
		float *out = ((float *)buf) + total;
		float tempbuf[512 * channels];
		lastSection = currentSection;
		int toread = size - total;
		if(toread > 512) toread = 512;
		numread = op_read_float(opusRef, (channels < MAXCHANNELS) ? tempbuf : out, toread, NULL);
		if(numread > 0 && channels <= MAXCHANNELS) {
			for(int i = 0; i < numread; ++i) {
				for(int j = 0; j < channels; ++j) {
					out[i * channels + j] = tempbuf[i * channels + chmap[channels - 1][j]];
				}
			}
		}
		currentSection = op_current_link(opusRef);
		if(numread > 0) {
			total += numread * channels;
		}

		if(currentSection != lastSection) {
			break;
		}

	} while(total != size && numread != 0);

	return total / channels;
}

- (void)close {
	op_free(opusRef);
	opusRef = NULL;
}

- (void)dealloc {
	[self close];
}

- (long)seek:(long)frame {
	op_pcm_seek(opusRef, frame);

	return frame;
}

- (NSDictionary *)properties {
	return @{@"channels": [NSNumber numberWithInt:channels],
			 @"bitsPerSample": [NSNumber numberWithInt:32],
			 @"floatingPoint": [NSNumber numberWithBool:YES],
			 @"sampleRate": [NSNumber numberWithFloat:48000],
			 @"totalFrames": [NSNumber numberWithDouble:totalFrames],
			 @"bitrate": [NSNumber numberWithInt:bitrate],
			 @"seekable": [NSNumber numberWithBool:([source seekable] && seekable)],
			 @"codec": @"Opus",
			 @"endian": @"host",
			 @"encoding": @"lossy"};
}

+ (NSArray *)fileTypes {
	return @[@"opus", @"ogg"];
}

+ (NSArray *)mimeTypes {
	return @[@"audio/x-opus+ogg", @"application/ogg"];
}

+ (float)priority {
	return 1.0;
}

+ (NSArray *)fileTypeAssociations {
	return @[
		@[@"Opus Audio File", @"ogg.icns", @"opus"],
		@[@"Ogg Audio File", @"ogg.icns", @"ogg"]
	];
}

@end