src/ALAC/ALACEncoder.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:		ALACEncoder.h
*/

#pragma once

#include <stdint.h>

#include "ALACAudioTypes.h"


struct BitBuffer ;

class ALACEncoder
{
	public :
		ALACEncoder () ;
		virtual ~ALACEncoder () ;

		virtual int32_t	Encode (AudioFormatDescription theInputFormat, AudioFormatDescription theOutputFormat,
								unsigned char * theReadBuffer, unsigned char * theWriteBuffer, int32_t * ioNumBytes) ;
		virtual int32_t	Finish () ;

		void			SetFastMode (bool fast) { mFastMode = fast ; } ;

		// this must be called *before* InitializeEncoder ()
		void			SetFrameSize (uint32_t frameSize) { mFrameSize = frameSize ; } ;

		void			GetConfig (ALACSpecificConfig & config) ;
		uint32_t		GetMagicCookieSize (uint32_t inNumChannels) ;
		void			GetMagicCookie (void * config, uint32_t * ioSize) ;

		virtual int32_t	InitializeEncoder (AudioFormatDescription theOutputFormat) ;

	protected :
		virtual void	GetSourceFormat (const AudioFormatDescription * source, AudioFormatDescription * output) ;

		int32_t			EncodeStereo (struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples) ;
		int32_t			EncodeStereoFast (struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples) ;
		int32_t			EncodeStereoEscape (struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t numSamples) ;
		int32_t			EncodeMono (struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples) ;


		// ALAC encoder parameters
		int16_t			mBitDepth ;
		bool			mFastMode ;

		// encoding state
		int16_t			mLastMixRes [kALACMaxChannels] ;

		// encoding buffers
		int32_t *		mMixBufferU ;
		int32_t *		mMixBufferV ;
		int32_t *		mPredictorU ;
		int32_t *		mPredictorV ;
		uint16_t *		mShiftBufferUV ;

		uint8_t *		mWorkBuffer ;

		// per-channel coefficients buffers
		int16_t			mCoefsU [kALACMaxChannels][kALACMaxSearches][kALACMaxCoefs] ;
		int16_t			mCoefsV [kALACMaxChannels][kALACMaxSearches][kALACMaxCoefs] ;

		// encoding statistics
		uint32_t		mTotalBytesGenerated ;
		uint32_t		mAvgBitRate ;
		uint32_t		mMaxFrameBytes ;
		uint32_t		mFrameSize ;
		uint32_t		mMaxOutputBytes ;
		uint32_t		mNumChannels ;
		uint32_t		mOutputSampleRate ;
} ;