diff options
Diffstat (limited to 'include/private/media/AudioTrackShared.h')
| -rw-r--r-- | include/private/media/AudioTrackShared.h | 94 |
1 files changed, 81 insertions, 13 deletions
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h index 31dff36..5644428 100644 --- a/include/private/media/AudioTrackShared.h +++ b/include/private/media/AudioTrackShared.h @@ -24,9 +24,8 @@ #include <utils/threads.h> #include <utils/Log.h> #include <utils/RefBase.h> -#include <media/nbaio/roundup.h> +#include <audio_utils/roundup.h> #include <media/SingleStateQueue.h> -#include <private/media/StaticAudioTrackState.h> namespace android { @@ -54,22 +53,64 @@ namespace android { struct AudioTrackSharedStreaming { // similar to NBAIO MonoPipe // in continuously incrementing frame units, take modulo buffer size, which must be a power of 2 - volatile int32_t mFront; // read by server - volatile int32_t mRear; // write by client + volatile int32_t mFront; // read by consumer (output: server, input: client) + volatile int32_t mRear; // written by producer (output: client, input: server) volatile int32_t mFlush; // incremented by client to indicate a request to flush; // server notices and discards all data between mFront and mRear volatile uint32_t mUnderrunFrames; // server increments for each unavailable but desired frame }; +// Represents a single state of an AudioTrack that was created in static mode (shared memory buffer +// supplied by the client). This state needs to be communicated from the client to server. As this +// state is too large to be updated atomically without a mutex, and mutexes aren't allowed here, the +// state is wrapped by a SingleStateQueue. +struct StaticAudioTrackState { + // Do not define constructors, destructors, or virtual methods as this is part of a + // union in shared memory and they will not get called properly. + + // These fields should both be size_t, but since they are located in shared memory we + // force to 32-bit. The client and server may have different typedefs for size_t. + + // The state has a sequence counter to indicate whether changes are made to loop or position. + // The sequence counter also currently indicates whether loop or position is first depending + // on which is greater; it jumps by max(mLoopSequence, mPositionSequence) + 1. + + uint32_t mLoopStart; + uint32_t mLoopEnd; + int32_t mLoopCount; + uint32_t mLoopSequence; // a sequence counter to indicate changes to loop + uint32_t mPosition; + uint32_t mPositionSequence; // a sequence counter to indicate changes to position +}; + typedef SingleStateQueue<StaticAudioTrackState> StaticAudioTrackSingleStateQueue; +struct StaticAudioTrackPosLoop { + // Do not define constructors, destructors, or virtual methods as this is part of a + // union in shared memory and will not get called properly. + + // These fields should both be size_t, but since they are located in shared memory we + // force to 32-bit. The client and server may have different typedefs for size_t. + + // This struct information is stored in a single state queue to communicate the + // static AudioTrack server state to the client while data is consumed. + // It is smaller than StaticAudioTrackState to prevent unnecessary information from + // being sent. + + uint32_t mBufferPosition; + int32_t mLoopCount; +}; + +typedef SingleStateQueue<StaticAudioTrackPosLoop> StaticAudioTrackPosLoopQueue; + struct AudioTrackSharedStatic { + // client requests to the server for loop or position changes. StaticAudioTrackSingleStateQueue::Shared mSingleStateQueue; - // This field should be a size_t, but since it is located in shared memory we - // force to 32-bit. The client and server may have different typedefs for size_t. - uint32_t mBufferPosition; // updated asynchronously by server, - // "for entertainment purposes only" + // position info updated asynchronously by server and read by client, + // "for entertainment purposes only" + StaticAudioTrackPosLoopQueue::Shared + mPosLoopQueue; }; // ---------------------------------------------------------------------------- @@ -96,7 +137,8 @@ struct audio_track_cblk_t uint32_t mServer; // Number of filled frames consumed by server (mIsOut), // or filled frames provided by server (!mIsOut). // It is updated asynchronously by server without a barrier. - // The value should be used "for entertainment purposes only", + // The value should be used + // "for entertainment purposes only", // which means don't make important decisions based on it. uint32_t mPad1; // unused @@ -313,8 +355,28 @@ public: virtual void flush(); #define MIN_LOOP 16 // minimum length of each loop iteration in frames + + // setLoop(), setBufferPosition(), and setBufferPositionAndLoop() set the + // static buffer position and looping parameters. These commands are not + // synchronous (they do not wait or block); instead they take effect at the + // next buffer data read from the server side. However, the client side + // getters will read a cached version of the position and loop variables + // until the setting takes effect. + // + // setBufferPositionAndLoop() is equivalent to calling, in order, setLoop() and + // setBufferPosition(). + // + // The functions should not be relied upon to do parameter or state checking. + // That is done at the AudioTrack level. + void setLoop(size_t loopStart, size_t loopEnd, int loopCount); + void setBufferPosition(size_t position); + void setBufferPositionAndLoop(size_t position, size_t loopStart, size_t loopEnd, + int loopCount); size_t getBufferPosition(); + // getBufferPositionAndLoopCount() provides the proper snapshot of + // position and loopCount together. + void getBufferPositionAndLoopCount(size_t *position, int *loopCount); virtual size_t getMisalignment() { return 0; @@ -326,7 +388,9 @@ public: private: StaticAudioTrackSingleStateQueue::Mutator mMutator; - size_t mBufferPosition; // so that getBufferPosition() appears to be synchronous + StaticAudioTrackPosLoopQueue::Observer mPosLoopObserver; + StaticAudioTrackState mState; // last communicated state to server + StaticAudioTrackPosLoop mPosLoop; // snapshot of position and loop. }; // ---------------------------------------------------------------------------- @@ -447,10 +511,13 @@ public: virtual uint32_t getUnderrunFrames() const { return 0; } private: + status_t updateStateWithLoop(StaticAudioTrackState *localState, + const StaticAudioTrackState &update) const; + status_t updateStateWithPosition(StaticAudioTrackState *localState, + const StaticAudioTrackState &update) const; ssize_t pollPosition(); // poll for state queue update, and return current position StaticAudioTrackSingleStateQueue::Observer mObserver; - size_t mPosition; // server's current play position in frames, relative to 0 - + StaticAudioTrackPosLoopQueue::Mutator mPosLoopMutator; size_t mFramesReadySafe; // Assuming size_t read/writes are atomic on 32 / 64 bit // processors, this is a thread-safe version of // mFramesReady. @@ -459,7 +526,8 @@ private: // can cause a track to appear to have a large number // of frames. INT64_MAX means an infinite loop. bool mFramesReadyIsCalledByMultipleThreads; - StaticAudioTrackState mState; + StaticAudioTrackState mState; // Server side state. Any updates from client must be + // passed by the mObserver SingleStateQueue. }; // Proxy used by AudioFlinger for servicing AudioRecord |