src/lib/alac/codec/ALACEncoder.h

   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
  44                 void                            SetFastMode( bool fast ) { mFastMode = fast; };
  45
  46                 // this must be called *before* InitializeEncoder()
  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 };