text: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * 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.
   */
  
  #ifndef ANDROID_AUDIOTRACK_H
  #define ANDROID_AUDIOTRACK_H
  
  #include <stdint.h>
  #include <sys/types.h>
  
  #include <media/IAudioFlinger.h>
  #include <media/IAudioTrack.h>
  #include <media/AudioSystem.h>
  
  #include <utils/RefBase.h>
  #include <utils/Errors.h>
  #include <binder/IInterface.h>
  #include <binder/IMemory.h>
  #include <utils/threads.h>
  
  namespace android {
  
  // ----------------------------------------------------------------------------
  
  class audio_track_cblk_t;
  
  // ----------------------------------------------------------------------------
  
  class AudioTrack
  {
  public:
      enum channel_index {
          MONO   = 0,
          LEFT   = 0,
          RIGHT  = 1
      };
  
      /* Events used by AudioTrack callback function (audio_track_cblk_t).
       */
      enum event_type {
          EVENT_MORE_DATA = 0,        // Request to write more data to PCM buffer.
          EVENT_UNDERRUN = 1,         // PCM buffer underrun occured.
          EVENT_LOOP_END = 2,         // Sample loop end was reached; playback restarted from loop start if loop count was not 0.
          EVENT_MARKER = 3,           // Playback head is at the specified marker position (See setMarkerPosition()).
          EVENT_NEW_POS = 4,          // Playback head is at a new position (See setPositionUpdatePeriod()).
          EVENT_BUFFER_END = 5        // Playback head is at the end of the buffer.
      };
  
      /* Create Buffer on the stack and pass it to obtainBuffer()
       * and releaseBuffer().
       */
  
      class Buffer
      {
      public:
          enum {
              MUTE    = 0x00000001
          };
          uint32_t    flags;
          int         format;
          int         channelCount; // will be removed in the future, do not use
          size_t      frameCount;
          size_t      size;
          union {
              void*       raw;
              short*      i16;
              int8_t*     i8;
          };
      };
  
  
      /* As a convenience, if a callback is supplied, a handler thread
       * is automatically created with the appropriate priority. This thread
       * invokes the callback when a new buffer becomes availlable or an underrun condition occurs.
       * Parameters:
       *
       * event:   type of event notified (see enum AudioTrack::event_type).
       * user:    Pointer to context for use by the callback receiver.
       * info:    Pointer to optional parameter according to event type:
       *          - EVENT_MORE_DATA: pointer to AudioTrack::Buffer struct. The callback must not write
       *          more bytes than indicated by 'size' field and update 'size' if less bytes are
       *          written.
       *          - EVENT_UNDERRUN: unused.
       *          - EVENT_LOOP_END: pointer to an int indicating the number of loops remaining.
       *          - EVENT_MARKER: pointer to an uin32_t containing the marker position in frames.
       *          - EVENT_NEW_POS: pointer to an uin32_t containing the new position in frames.
       *          - EVENT_BUFFER_END: unused.
       */
  
      typedef void (*callback_t)(int event, void* user, void *info);
  
      /* Returns the minimum frame count required for the successful creation of
       * an AudioTrack object.
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - NO_INIT: audio server or audio hardware not initialized
       */
  
       static status_t getMinFrameCount(int* frameCount,
                                        int streamType      =-1,
                                        uint32_t sampleRate = 0);
  
      /* Constructs an uninitialized AudioTrack. No connection with
       * AudioFlinger takes place.
       */
                          AudioTrack();
  
      /* Creates an audio track and registers it with AudioFlinger.
       * Once created, the track needs to be started before it can be used.
       * Unspecified values are set to the audio hardware's current
       * values.
       *
       * Parameters:
       *
       * streamType:         Select the type of audio stream this track is attached to
       *                     (e.g. AUDIO_STREAM_MUSIC).
       * sampleRate:         Track sampling rate in Hz.
       * format:             Audio format (e.g AUDIO_FORMAT_PCM_16_BIT for signed
       *                     16 bits per sample).
       * channelMask:        Channel mask: see audio_channels_t.
       * frameCount:         Total size of track PCM buffer in frames. This defines the
       *                     latency of the track.
       * flags:              Reserved for future use.
       * cbf:                Callback function. If not null, this function is called periodically
       *                     to request new PCM data.
       * notificationFrames: The callback function is called each time notificationFrames PCM
       *                     frames have been comsumed from track input buffer.
       * user                Context for use by the callback receiver.
       */
  
                          AudioTrack( int streamType,
                                      uint32_t sampleRate  = 0,
                                      int format           = 0,
                                      int channelMask      = 0,
                                      int frameCount       = 0,
                                      uint32_t flags       = 0,
                                      callback_t cbf       = 0,
                                      void* user           = 0,
                                      int notificationFrames = 0,
                                      int sessionId = 0);
  
      /* Creates an audio track and registers it with AudioFlinger. With this constructor,
       * The PCM data to be rendered by AudioTrack is passed in a shared memory buffer
       * identified by the argument sharedBuffer. This prototype is for static buffer playback.
       * PCM data must be present into memory before the AudioTrack is started.
       * The Write() and Flush() methods are not supported in this case.
       * It is recommented to pass a callback function to be notified of playback end by an
       * EVENT_UNDERRUN event.
       */
  
                          AudioTrack( int streamType,
                                      uint32_t sampleRate = 0,
                                      int format          = 0,
                                      int channelMask     = 0,
                                      const sp<IMemory>& sharedBuffer = 0,
                                      uint32_t flags      = 0,
                                      callback_t cbf      = 0,
                                      void* user          = 0,
                                      int notificationFrames = 0,
                                      int sessionId = 0);
  
      /* Terminates the AudioTrack and unregisters it from AudioFlinger.
       * Also destroys all resources assotiated with the AudioTrack.
       */
                          ~AudioTrack();
  
  
      /* Initialize an uninitialized AudioTrack.
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful intialization
       *  - INVALID_OPERATION: AudioTrack is already intitialized
       *  - BAD_VALUE: invalid parameter (channels, format, sampleRate...)
       *  - NO_INIT: audio server or audio hardware not initialized
       * */
              status_t    set(int streamType      =-1,
                              uint32_t sampleRate = 0,
                              int format          = 0,
                              int channelMask     = 0,
                              int frameCount      = 0,
                              uint32_t flags      = 0,
                              callback_t cbf      = 0,
                              void* user          = 0,
                              int notificationFrames = 0,
                              const sp<IMemory>& sharedBuffer = 0,
                              bool threadCanCallJava = false,
                              int sessionId = 0);
  
  
      /* Result of constructing the AudioTrack. This must be checked
       * before using any AudioTrack API (except for set()), using
       * an uninitialized AudioTrack produces undefined results.
       * See set() method above for possible return codes.
       */
              status_t    initCheck() const;
  
      /* Returns this track's latency in milliseconds.
       * This includes the latency due to AudioTrack buffer size, AudioMixer (if any)
       * and audio hardware driver.
       */
              uint32_t     latency() const;
  
      /* getters, see constructor */
  
              int         streamType() const;
              int         format() const;
              int         channelCount() const;
              uint32_t    frameCount() const;
              int         frameSize() const;
              sp<IMemory>& sharedBuffer();
  
  
      /* After it's created the track is not active. Call start() to
       * make it active. If set, the callback will start being called.
       */
              void        start();
  
      /* Stop a track. If set, the callback will cease being called and
       * obtainBuffer returns STOPPED. Note that obtainBuffer() still works
       * and will fill up buffers until the pool is exhausted.
       */
              void        stop();
              bool        stopped() const;
  
      /* flush a stopped track. All pending buffers are discarded.
       * This function has no effect if the track is not stoped.
       */
              void        flush();
  
      /* Pause a track. If set, the callback will cease being called and
       * obtainBuffer returns STOPPED. Note that obtainBuffer() still works
       * and will fill up buffers until the pool is exhausted.
       */
              void        pause();
  
      /* mute or unmutes this track.
       * While mutted, the callback, if set, is still called.
       */
              void        mute(bool);
              bool        muted() const;
  
  
      /* set volume for this track, mostly used for games' sound effects
       * left and right volumes. Levels must be <= 1.0.
       */
              status_t    setVolume(float left, float right);
              void        getVolume(float* left, float* right);
  
      /* set the send level for this track. An auxiliary effect should be attached
       * to the track with attachEffect(). Level must be <= 1.0.
       */
              status_t    setAuxEffectSendLevel(float level);
              void        getAuxEffectSendLevel(float* level);
  
      /* set sample rate for this track, mostly used for games' sound effects
       */
              status_t    setSampleRate(int sampleRate);
              uint32_t    getSampleRate();
  
      /* Enables looping and sets the start and end points of looping.
       *
       * Parameters:
       *
       * loopStart:   loop start expressed as the number of PCM frames played since AudioTrack start.
       * loopEnd:     loop end expressed as the number of PCM frames played since AudioTrack start.
       * loopCount:   number of loops to execute. Calling setLoop() with loopCount == 0 cancels any pending or
       *          active loop. loopCount = -1 means infinite looping.
       *
       * For proper operation the following condition must be respected:
       *          (loopEnd-loopStart) <= framecount()
       */
              status_t    setLoop(uint32_t loopStart, uint32_t loopEnd, int loopCount);
              status_t    getLoop(uint32_t *loopStart, uint32_t *loopEnd, int *loopCount);
  
  
      /* Sets marker position. When playback reaches the number of frames specified, a callback with event 
       * type EVENT_MARKER is called. Calling setMarkerPosition with marker == 0 cancels marker notification 
       * callback. 
       * If the AudioTrack has been opened with no callback function associated, the operation will fail.
       *
       * Parameters:
       *
       * marker:   marker position expressed in frames.
       *
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - INVALID_OPERATION: the AudioTrack has no callback installed.
       */
              status_t    setMarkerPosition(uint32_t marker);
              status_t    getMarkerPosition(uint32_t *marker);
  
  
      /* Sets position update period. Every time the number of frames specified has been played, 
       * a callback with event type EVENT_NEW_POS is called. 
       * Calling setPositionUpdatePeriod with updatePeriod == 0 cancels new position notification 
       * callback. 
       * If the AudioTrack has been opened with no callback function associated, the operation will fail.
       *
       * Parameters:
       *
       * updatePeriod:  position update notification period expressed in frames.
       *
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - INVALID_OPERATION: the AudioTrack has no callback installed.
       */
              status_t    setPositionUpdatePeriod(uint32_t updatePeriod);
              status_t    getPositionUpdatePeriod(uint32_t *updatePeriod);
  
  
      /* Sets playback head position within AudioTrack buffer. The new position is specified
       * in number of frames. 
       * This method must be called with the AudioTrack in paused or stopped state.
       * Note that the actual position set is <position> modulo the AudioTrack buffer size in frames. 
       * Therefore using this method makes sense only when playing a "static" audio buffer 
       * as opposed to streaming.
       * The getPosition() method on the other hand returns the total number of frames played since
       * playback start.
       *
       * Parameters:
       *
       * position:  New playback head position within AudioTrack buffer.
       *
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - INVALID_OPERATION: the AudioTrack is not stopped.
       *  - BAD_VALUE: The specified position is beyond the number of frames present in AudioTrack buffer 
       */
              status_t    setPosition(uint32_t position);
              status_t    getPosition(uint32_t *position);
  
      /* Forces AudioTrack buffer full condition. When playing a static buffer, this method avoids 
       * rewriting the buffer before restarting playback after a stop.
       * This method must be called with the AudioTrack in paused or stopped state.
       *
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - INVALID_OPERATION: the AudioTrack is not stopped.
       */
              status_t    reload();
  
      /* returns a handle on the audio output used by this AudioTrack.
       *
       * Parameters:
       *  none.
       *
       * Returned value:
       *  handle on audio hardware output
       */
              audio_io_handle_t    getOutput();
  
      /* returns the unique ID associated to this track.
       *
       * Parameters:
       *  none.
       *
       * Returned value:
       *  AudioTrack ID.
       */
              int    getSessionId();
  
  
      /* Attach track auxiliary output to specified effect. Used effectId = 0
       * to detach track from effect.
       *
       * Parameters:
       *
       * effectId:  effectId obtained from AudioEffect::id().
       *
       * Returned status (from utils/Errors.h) can be:
       *  - NO_ERROR: successful operation
       *  - INVALID_OPERATION: the effect is not an auxiliary effect.
       *  - BAD_VALUE: The specified effect ID is invalid
       */
              status_t    attachAuxEffect(int effectId);
  
      /* obtains a buffer of "frameCount" frames. The buffer must be
       * filled entirely. If the track is stopped, obtainBuffer() returns
       * STOPPED instead of NO_ERROR as long as there are buffers availlable,
       * at which point NO_MORE_BUFFERS is returned.
       * Buffers will be returned until the pool (buffercount())
       * is exhausted, at which point obtainBuffer() will either block
       * or return WOULD_BLOCK depending on the value of the "blocking"
       * parameter.
       */
  
          enum {
              NO_MORE_BUFFERS = 0x80000001,
              STOPPED = 1
          };
  
              status_t    obtainBuffer(Buffer* audioBuffer, int32_t waitCount);
              void        releaseBuffer(Buffer* audioBuffer);
  
  
      /* As a convenience we provide a write() interface to the audio buffer.
       * This is implemented on top of lockBuffer/unlockBuffer. For best
       * performance
       *
       */
              ssize_t     write(const void* buffer, size_t size);
  
      /*
       * Dumps the state of an audio track.
       */
              status_t dump(int fd, const Vector<String16>& args) const;
  
  private:
      /* copying audio tracks is not allowed */
                          AudioTrack(const AudioTrack& other);
              AudioTrack& operator = (const AudioTrack& other);
  
      /* a small internal class to handle the callback */
      class AudioTrackThread : public Thread
      {
      public:
          AudioTrackThread(AudioTrack& receiver, bool bCanCallJava = false);
      private:
          friend class AudioTrack;
          virtual bool        threadLoop();
          virtual status_t    readyToRun();
          virtual void        onFirstRef();
          AudioTrack& mReceiver;
          Mutex       mLock;
      };
  
              bool processAudioBuffer(const sp<AudioTrackThread>& thread);
              status_t createTrack_l(int streamType,
                                   uint32_t sampleRate,
                                   uint32_t format,
                                   uint32_t channelMask,
                                   int frameCount,
                                   uint32_t flags,
                                   const sp<IMemory>& sharedBuffer,
                                   audio_io_handle_t output,
                                   bool enforceFrameCount);
              void flush_l();
              status_t setLoop_l(uint32_t loopStart, uint32_t loopEnd, int loopCount);
              audio_io_handle_t getOutput_l();
              status_t restoreTrack_l(audio_track_cblk_t*& cblk, bool fromStart);
  
      sp<IAudioTrack>         mAudioTrack;
      sp<IMemory>             mCblkMemory;
      sp<AudioTrackThread>    mAudioTrackThread;
  
      float                   mVolume[2];
      float                   mSendLevel;
      uint32_t                mFrameCount;
  
      audio_track_cblk_t*     mCblk;
      uint32_t                mFormat;
      uint8_t                 mStreamType;
      uint8_t                 mChannelCount;
      uint8_t                 mMuted;
      uint8_t                 mReserved;
      uint32_t                mChannelMask;
      status_t                mStatus;
      uint32_t                mLatency;
  
      volatile int32_t        mActive;
  
      callback_t              mCbf;
      void*                   mUserData;
      uint32_t                mNotificationFramesReq; // requested number of frames between each notification callback
      uint32_t                mNotificationFramesAct; // actual number of frames between each notification callback
      sp<IMemory>             mSharedBuffer;
      int                     mLoopCount;
      uint32_t                mRemainingFrames;
      uint32_t                mMarkerPosition;
      bool                    mMarkerReached;
      uint32_t                mNewPosition;
      uint32_t                mUpdatePeriod;
      bool                    mFlushed; // FIXME will be made obsolete by making flush() synchronous
      uint32_t                mFlags;
      int                     mSessionId;
      int                     mAuxEffectId;
      Mutex                   mLock;
      status_t                mRestoreStatus;
  };
  
  
  }; // namespace android
  
  #endif // ANDROID_AUDIOTRACK_H
  