213     struct TrackBase {  struct
214         TrackBase()  in TrackBase()  function
219         virtual ~TrackBase() {}  in ~TrackBase()  argument
221         virtual uint32_t getOutputChannelCount() { return channelCount; }  in getOutputChannelCount()
222         virtual uint32_t getMixerChannelCount() { return mMixerChannelCount; }  in getMixerChannelCount()
224         bool        needsRamp() { return (volumeInc[0] | volumeInc[1] | auxInc) != 0; }  in needsRamp()
226         bool        doesResample() const { return mResampler.get() != nullptr; }  in doesResample()
228         void        resetResampler() { if (mResampler.get() != nullptr) mResampler->reset(); }  in resetResampler()
230         size_t      getUnreleasedFrames() const { return mResampler.get() != nullptr ?  in getUnreleasedFrames()
233         bool        useStereoVolume() const { return channelMask == AUDIO_CHANNEL_OUT_STEREO  in useStereoVolume()
245         uint32_t    needs;
248         union {
253         int32_t     prevVolume[MAX_NUM_VOLUMES];
254         int32_t     volumeInc[MAX_NUM_VOLUMES];
255         int32_t     auxInc;
256         int32_t     prevAuxLevel;
257         int16_t     auxLevel;       // 0 <= auxLevel <= MAX_GAIN_INT, but signed for mul performance
259         uint16_t    frameCount;
261         uint8_t     channelCount;   // 1 or 2, redundant with (needs & NEEDS_CHANNEL_COUNT__MASK)
262         uint8_t     unused_padding; // formerly format, was always 16
263         uint16_t    enabled;        // actually bool
264         audio_channel_mask_t channelMask;
267         AudioBufferProvider*                bufferProvider;
269         mutable AudioBufferProvider::Buffer buffer; // 8 bytes
271         hook_t      hook;
272         const void  *mIn;             // current location in buffer
274         std::unique_ptr<AudioResampler> mResampler;
275         uint32_t    sampleRate;
276         int32_t*    mainBuffer;
277         int32_t*    auxBuffer;
278         int32_t*    teeBuffer;
280         int32_t     sessionId;
282         audio_format_t mMixerFormat;     // output mix format: AUDIO_FORMAT_PCM_(FLOAT|16_BIT)
283         audio_format_t mFormat;          // input track format
284         audio_format_t mMixerInFormat;   // mix internal format AUDIO_FORMAT_PCM_(FLOAT|16_BIT)
287         float          mVolume[MAX_NUM_VOLUMES];     // floating point set volume
288         float          mPrevVolume[MAX_NUM_VOLUMES]; // floating point previous volume
289         float          mVolumeInc[MAX_NUM_VOLUMES];  // floating point volume increment
291         float          mAuxLevel;                     // floating point set aux level
292         float          mPrevAuxLevel;                 // floating point prev aux level
293         float          mAuxInc;                       // floating point aux increment
295         audio_channel_mask_t mMixerChannelMask;
296         uint32_t             mMixerChannelCount;
298         int32_t        mTeeBufferFrameCount;
300         uint32_t       mInputFrameSize; // The track input frame size, used for tee buffer
303         inline bool isVolumeMuted() const {  in isVolumeMuted()