The Tor Browser: dom/system/gonk/android_audio/AudioTrack.h@b8a032363ba2 (annotated)

dom/system/gonk/android_audio/AudioTrack.h@b8a032363ba2 (annotated)

dom/system/gonk/android_audio/AudioTrack.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * 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 "IAudioFlinger.h"
 #include "IAudioTrack.h"
 #include "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         channelCount;
         int         format;
         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. AudioSystem::MUSIC).
      * sampleRate:         Track sampling rate in Hz.
      * format:             Audio format (e.g AudioSystem::PCM_16_BIT for signed
      *                     16 bits per sample).
      * channels:           Channel mask: see AudioSystem::audio_channels.
      * 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 channels         = 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 channels        = 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 channels        = 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(int streamType,
                                  uint32_t sampleRate,
                                  int format,
                                  int channelCount,
                                  int frameCount,
                                  uint32_t flags,
                                  const sp<IMemory>& sharedBuffer,
                                  audio_io_handle_t output,
                                  bool enforceFrameCount);
     sp<IAudioTrack>         mAudioTrack;
     sp<IMemory>             mCblkMemory;
     sp<AudioTrackThread>    mAudioTrackThread;
     float                   mVolume[2];
     float                   mSendLevel;
     uint32_t                mFrameCount;
     audio_track_cblk_t*     mCblk;
     uint8_t                 mStreamType;
     uint8_t                 mFormat;
     uint8_t                 mChannelCount;
     uint8_t                 mMuted;
     uint32_t                mChannels;
     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;
     uint32_t                mFlags;
     int                     mSessionId;
     int                     mAuxEffectId;
     uint32_t                mPadding[8];
 };
 }; // namespace android
 #endif // ANDROID_AUDIOTRACK_H

The Tor Browser / annotate

dom/system/gonk/android_audio/AudioTrack.h@b8a032363ba2 (annotated)

dom/system/gonk/android_audio/AudioTrack.h