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Commit ce70374b authored by Glenn Kasten's avatar Glenn Kasten
Browse files

New AudioTrack C++ API for audio timestamps 

This new API is intended to replace latency(), especially for A/V sync.
The application will receive periodic timestamp notifications.  The period
is unspecified, but will likely be more frequent after a pause or stop,
set position, underrun, display on/off change, route change, or when audio
framework notices drift.  It will be up to the higher level application
(e.g.  Stagefright) to reconstruct a clock that updates more frequently.

The current latency() method doesn't indicate when latency changes
due to screen on/off state, route changes, etc.

Includes squahsed change-Id: I2082f8752040be0c234b1a6f1be2e269abf2ce7c
 Dummy implementation of AudioTrack:getTimestamp()
 Rename AudioTrack::Timestamp to AudioTimestamp.
 Renaming and pulling up to a higher level allows more modules to use it.

Change-Id: Ibf7f6a207c3f8d8697f25ede2cd5200697fadb86
(cherry picked from commit dd69eb893867634fd169c03204a6ad7c74b351e7)
parent e07f5372

include/media/AudioTimestamp.h

0 → 100644
+33 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2013 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_AUDIO_TIMESTAMP_H

#define ANDROID_AUDIO_TIMESTAMP_H



#include <time.h>



class AudioTimestamp {

public:

    AudioTimestamp() : mPosition(0) {

        mTime.tv_sec = 0;

        mTime.tv_nsec = 0;

    }

    // FIXME change type to match android.media.AudioTrack

    uint32_t        mPosition; // a frame position in AudioTrack::getPosition() units

    struct timespec mTime;     // corresponding CLOCK_MONOTONIC when frame is expected to present

};



#endif  // ANDROID_AUDIO_TIMESTAMP_H

include/media/AudioTrack.h

+16 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 


#include <cutils/sched_policy.h>

#include <media/AudioSystem.h>

#include <media/AudioTimestamp.h>

#include <media/IAudioTrack.h>

#include <utils/threads.h>
@@ -62,6 +63,9 @@ public: 
                                    // voluntary invalidation by mediaserver, or mediaserver crash.

        EVENT_STREAM_END = 7,       // Sent after all the buffers queued in AF and HW are played

                                    // back (after stop is called)

        EVENT_NEW_TIMESTAMP = 8,    // Delivered periodically and when there's a significant change

                                    // in the mapping from frame position to presentation time.

                                    // See AudioTimestamp for the information included with event.

    };



    /* Client should declare Buffer on the stack and pass address to obtainBuffer()
@@ -107,6 +111,8 @@ public: 
     *          - EVENT_NEW_POS: pointer to const uint32_t containing the new position in frames.

     *          - EVENT_BUFFER_END: unused.

     *          - EVENT_NEW_IAUDIOTRACK: unused.

     *          - EVENT_STREAM_END: unused.

     *          - EVENT_NEW_TIMESTAMP: pointer to const AudioTimestamp.

     */



    typedef void (*callback_t)(int event, void* user, void *info);
@@ -564,6 +570,16 @@ public: 
    /* Get parameters */

            String8     getParameters(const String8& keys);



    /* Poll for a timestamp on demand.

     * Use if EVENT_NEW_TIMESTAMP is not delivered often enough for your needs,

     * or if you need to get the most recent timestamp outside of the event callback handler.

     * Caution: calling this method too often may be inefficient;

     * if you need a high resolution mapping between frame position and presentation time,

     * consider implementing that at application level, based on the low resolution timestamps.

     * Returns NO_ERROR if timestamp is valid.

     */

            status_t    getTimestamp(AudioTimestamp& timestamp);



protected:

    /* copying audio tracks is not allowed */

                        AudioTrack(const AudioTrack& other);

media/libmedia/AudioTrack.cpp

+5 −0
Original line number Diff line number Diff line
@@ -1712,6 +1712,11 @@ status_t AudioTrack::setParameters(const String8& keyValuePairs) 
    }

}



status_t AudioTrack::getTimestamp(AudioTimestamp& timestamp)

{

    return INVALID_OPERATION;

}



String8 AudioTrack::getParameters(const String8& keys)

{

    if (mOutput) {