1 /* 2 * Copyright (c) 2011 Apple Inc. All rights reserved. 3 * 4 * @APPLE_APACHE_LICENSE_HEADER_START@ 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 * 18 * @APPLE_APACHE_LICENSE_HEADER_END@ 19 */ 20 21 /* 22 File: ALACEncoder.h 23 */ 24 25 #pragma once 26 27 #include <stdint.h> 28 29 #include "ALACAudioTypes.h" 30 31 32 struct BitBuffer; 33 34 class ALACEncoder 35 { 36 public: 37 ALACEncoder(); 38 virtual ~ALACEncoder(); 39 40 virtual int32_t Encode(AudioFormatDescription theInputFormat, AudioFormatDescription theOutputFormat, 41 unsigned char * theReadBuffer, unsigned char * theWriteBuffer, int32_t * ioNumBytes); 42 virtual int32_t Finish( ); 43 SetFastMode(bool fast)44 void SetFastMode( bool fast ) { mFastMode = fast; }; 45 46 // this must be called *before* InitializeEncoder() SetFrameSize(uint32_t frameSize)47 void SetFrameSize( uint32_t frameSize ) { mFrameSize = frameSize; }; 48 49 void GetConfig( ALACSpecificConfig & config ); 50 uint32_t GetMagicCookieSize(uint32_t inNumChannels); 51 void GetMagicCookie( void * config, uint32_t * ioSize ); 52 53 virtual int32_t InitializeEncoder(AudioFormatDescription theOutputFormat); 54 55 protected: 56 virtual void GetSourceFormat( const AudioFormatDescription * source, AudioFormatDescription * output ); 57 58 int32_t EncodeStereo( struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples ); 59 int32_t EncodeStereoFast( struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples ); 60 int32_t EncodeStereoEscape( struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t numSamples ); 61 int32_t EncodeMono( struct BitBuffer * bitstream, void * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples ); 62 63 64 // ALAC encoder parameters 65 int16_t mBitDepth; 66 bool mFastMode; 67 68 // encoding state 69 int16_t mLastMixRes[kALACMaxChannels]; 70 71 // encoding buffers 72 int32_t * mMixBufferU; 73 int32_t * mMixBufferV; 74 int32_t * mPredictorU; 75 int32_t * mPredictorV; 76 uint16_t * mShiftBufferUV; 77 78 uint8_t * mWorkBuffer; 79 80 // per-channel coefficients buffers 81 int16_t mCoefsU[kALACMaxChannels][kALACMaxSearches][kALACMaxCoefs]; 82 int16_t mCoefsV[kALACMaxChannels][kALACMaxSearches][kALACMaxCoefs]; 83 84 // encoding statistics 85 uint32_t mTotalBytesGenerated; 86 uint32_t mAvgBitRate; 87 uint32_t mMaxFrameBytes; 88 uint32_t mFrameSize; 89 uint32_t mMaxOutputBytes; 90 uint32_t mNumChannels; 91 uint32_t mOutputSampleRate; 92 }; 93