ALACAudioTypes.h

/*
 * Copyright (c) 2011 Apple Inc. All rights reserved.
 *
 * @APPLE_APACHE_LICENSE_HEADER_START@
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * @APPLE_APACHE_LICENSE_HEADER_END@
 */

/*
	File:		ALACAudioTypes.h
*/

#ifndef ALACAUDIOTYPES_H
#define ALACAUDIOTYPES_H

#if PRAGMA_ONCE
#pragma once
#endif

#ifdef __cplusplus
extern "C" {
#endif

#if PRAGMA_STRUCT_ALIGN
    #pragma options align=mac68k
#elif PRAGMA_STRUCT_PACKPUSH
    #pragma pack(push, 2)
#elif PRAGMA_STRUCT_PACK
    #pragma pack(2)
#endif

#include <stdint.h>

#if defined(__ppc__)
#define TARGET_RT_BIG_ENDIAN 1
#elif defined(__ppc64__)
#define TARGET_RT_BIG_ENDIAN 1
#endif

#define kChannelAtomSize 12
    
enum 
{
    kALAC_UnimplementedError   = -4,
    kALAC_FileNotFoundError    = -43,
    kALAC_ParamError           = -50,
    kALAC_MemFullError         = -108
};

enum
{
    kALACFormatAppleLossless = 'alac',
    kALACFormatLinearPCM = 'lpcm'
};

enum
{
    kALACMaxChannels	= 8,
    kALACMaxEscapeHeaderBytes = 8,
    kALACMaxSearches	= 16,
    kALACMaxCoefs		= 16,
    kALACDefaultFramesPerPacket = 4096
};

typedef uint32_t ALACChannelLayoutTag;

enum
{
    kALACFormatFlagIsFloat                     = (1 << 0),     // 0x1
    kALACFormatFlagIsBigEndian                 = (1 << 1),     // 0x2
    kALACFormatFlagIsSignedInteger             = (1 << 2),     // 0x4
    kALACFormatFlagIsPacked                    = (1 << 3),     // 0x8
    kALACFormatFlagIsAlignedHigh               = (1 << 4),     // 0x10
};

enum
{
#if TARGET_RT_BIG_ENDIAN
    kALACFormatFlagsNativeEndian       = kALACFormatFlagIsBigEndian
#else
    kALACFormatFlagsNativeEndian       = 0
#endif
};

// this is required to be an IEEE 64bit float
typedef double alac_float64_t;

// These are the Channel Layout Tags used in the Channel Layout Info portion of the ALAC magic cookie
enum
{
    kALACChannelLayoutTag_Mono          = (100<<16) | 1,    // C
    kALACChannelLayoutTag_Stereo        = (101<<16) | 2,	// L R
    kALACChannelLayoutTag_MPEG_3_0_B    = (113<<16) | 3,	// C L R
    kALACChannelLayoutTag_MPEG_4_0_B    = (116<<16) | 4,	// C L R Cs
    kALACChannelLayoutTag_MPEG_5_0_D    = (120<<16) | 5,    // C L R Ls Rs
    kALACChannelLayoutTag_MPEG_5_1_D    = (124<<16) | 6,	// C L R Ls Rs LFE
    kALACChannelLayoutTag_AAC_6_1       = (142<<16) | 7,	// C L R Ls Rs Cs LFE
    kALACChannelLayoutTag_MPEG_7_1_B	= (127<<16) | 8     // C Lc Rc L R Ls Rs LFE    (doc: IS-13818-7 MPEG2-AAC)
};

// ALAC currently only utilizes these channels layouts. There is a one for one correspondance between a
// given number of channels and one of these layout tags
static const ALACChannelLayoutTag	ALACChannelLayoutTags[kALACMaxChannels] =
{
    kALACChannelLayoutTag_Mono,         // C
    kALACChannelLayoutTag_Stereo,		// L R
    kALACChannelLayoutTag_MPEG_3_0_B,	// C L R
    kALACChannelLayoutTag_MPEG_4_0_B,	// C L R Cs
    kALACChannelLayoutTag_MPEG_5_0_D,	// C L R Ls Rs
    kALACChannelLayoutTag_MPEG_5_1_D,	// C L R Ls Rs LFE
    kALACChannelLayoutTag_AAC_6_1,		// C L R Ls Rs Cs LFE
    kALACChannelLayoutTag_MPEG_7_1_B	// C Lc Rc L R Ls Rs LFE    (doc: IS-13818-7 MPEG2-AAC)
};

// AudioChannelLayout from CoreAudioTypes.h. We never need the AudioChannelDescription so we remove it
struct ALACAudioChannelLayout
{
    ALACChannelLayoutTag          mChannelLayoutTag;
    uint32_t                      mChannelBitmap;
    uint32_t                      mNumberChannelDescriptions;
};
typedef struct ALACAudioChannelLayout ALACAudioChannelLayout;

struct AudioFormatDescription
{
    alac_float64_t mSampleRate;
    uint32_t  mFormatID;
    uint32_t  mFormatFlags;
    uint32_t  mBytesPerPacket;
    uint32_t  mFramesPerPacket;
    uint32_t  mBytesPerFrame;
    uint32_t  mChannelsPerFrame;
    uint32_t  mBitsPerChannel;
    uint32_t  mReserved;
};
typedef struct AudioFormatDescription  AudioFormatDescription;

/* Lossless Definitions */

enum
{
	kALACCodecFormat		= 'alac',
	kALACVersion			= 0,
	kALACCompatibleVersion	= kALACVersion,
	kALACDefaultFrameSize	= 4096
};

// note: this struct is wrapped in an 'alac' atom in the sample description extension area
// note: in QT movies, it will be further wrapped in a 'wave' atom surrounded by 'frma' and 'term' atoms
typedef struct ALACSpecificConfig
{
	uint32_t				frameLength;
	uint8_t					compatibleVersion;
	uint8_t					bitDepth;							// max 32
	uint8_t					pb;									// 0 <= pb <= 255
	uint8_t					mb;
	uint8_t					kb;
	uint8_t					numChannels;
	uint16_t				maxRun;
	uint32_t				maxFrameBytes;
	uint32_t				avgBitRate;
	uint32_t				sampleRate;

} ALACSpecificConfig;


// The AudioChannelLayout atom type is not exposed yet so define it here
enum
{
	AudioChannelLayoutAID = 'chan'
};

#if PRAGMA_STRUCT_ALIGN
    #pragma options align=reset
#elif PRAGMA_STRUCT_PACKPUSH
    #pragma pack(pop)
#elif PRAGMA_STRUCT_PACK
    #pragma pack()
#endif

#ifdef __cplusplus
}
#endif

#endif	/* ALACAUDIOTYPES_H */