AudioTrackShared.h revision b1cf75c4935001f61057989ee3cf27bbf09ecd9c 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_AUDIO_TRACK_SHARED_H
18#define ANDROID_AUDIO_TRACK_SHARED_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <utils/threads.h>
24
25namespace android {
26
27// ----------------------------------------------------------------------------
28
29// Maximum cumulated timeout milliseconds before restarting audioflinger thread
30#define MAX_STARTUP_TIMEOUT_MS  3000    // Longer timeout period at startup to cope with A2DP init time
31#define MAX_RUN_TIMEOUT_MS      1000
32#define WAIT_PERIOD_MS          10
33#define RESTORE_TIMEOUT_MS      5000    // Maximum waiting time for a track to be restored
34
35#define CBLK_UNDERRUN_MSK       0x0001
36#define CBLK_UNDERRUN_ON        0x0001  // underrun (out) or overrrun (in) indication
37#define CBLK_UNDERRUN_OFF       0x0000  // no underrun
38#define CBLK_DIRECTION_MSK      0x0002
39#define CBLK_DIRECTION_OUT      0x0002  // this cblk is for an AudioTrack
40#define CBLK_DIRECTION_IN       0x0000  // this cblk is for an AudioRecord
41#define CBLK_FORCEREADY_MSK     0x0004
42#define CBLK_FORCEREADY_ON      0x0004  // track is considered ready immediately by AudioFlinger
43#define CBLK_FORCEREADY_OFF     0x0000  // track is ready when buffer full
44#define CBLK_INVALID_MSK        0x0008
45#define CBLK_INVALID_ON         0x0008  // track buffer is invalidated by AudioFlinger:
46#define CBLK_INVALID_OFF        0x0000  // must be re-created
47#define CBLK_DISABLED_MSK       0x0010
48#define CBLK_DISABLED_ON        0x0010  // track disabled by AudioFlinger due to underrun:
49#define CBLK_DISABLED_OFF       0x0000  // must be re-started
50#define CBLK_RESTORING_MSK      0x0020
51#define CBLK_RESTORING_ON       0x0020  // track is being restored after invalidation
52#define CBLK_RESTORING_OFF      0x0000  // by AudioFlinger
53#define CBLK_RESTORED_MSK       0x0040
54#define CBLK_RESTORED_ON        0x0040  // track has been restored after invalidation
55#define CBLK_RESTORED_OFF       0x0040  // by AudioFlinger
56
57struct audio_track_cblk_t
58{
59
60    // The data members are grouped so that members accessed frequently and in the same context
61    // are in the same line of data cache.
62                Mutex       lock;           // sizeof(int)
63                Condition   cv;             // sizeof(int)
64    volatile    uint32_t    user;
65    volatile    uint32_t    server;
66                uint32_t    userBase;
67                uint32_t    serverBase;
68                void*       buffers;
69                uint32_t    frameCount;
70                // Cache line boundary
71                uint32_t    loopStart;
72                uint32_t    loopEnd;
73                int         loopCount;
74
75                // Channel volumes are fixed point U4.12, so 0x1000 means 1.0.
76                // Left channel is in [0:15], right channel is in [16:31].
77                // Always read and write the combined pair atomically.
78                // For AudioTrack only, not used by AudioRecord.
79                uint32_t    volumeLR;
80
81                uint32_t    sampleRate;
82                // NOTE: audio_track_cblk_t::frameSize is not equal to AudioTrack::frameSize() for
83                // 8 bit PCM data: in this case,  mCblk->frameSize is based on a sample size of
84                // 16 bit because data is converted to 16 bit before being stored in buffer
85
86                uint8_t     frameSize;       // would normally be size_t, but 8 bits is plenty
87                uint8_t     pad1;
88                uint16_t    bufferTimeoutMs; // Maximum cumulated timeout before restarting audioflinger
89
90                uint16_t    waitTimeMs;      // Cumulated wait time
91private:
92                uint16_t    mSendLevel;      // Fixed point U4.12 so 0x1000 means 1.0
93public:
94    volatile    int32_t     flags;
95
96                // Cache line boundary (32 bytes)
97
98                            audio_track_cblk_t();
99                uint32_t    stepUser(uint32_t frameCount);
100                bool        stepServer(uint32_t frameCount);
101                void*       buffer(uint32_t offset) const;
102                uint32_t    framesAvailable();
103                uint32_t    framesAvailable_l();
104                uint32_t    framesReady();
105                bool        tryLock();
106
107                // No barriers on the following operations, so the ordering of loads/stores
108                // with respect to other parameters is UNPREDICTABLE. That's considered safe.
109
110                // for AudioTrack client only, caller must limit to 0.0 <= sendLevel <= 1.0
111                void        setSendLevel(float sendLevel) {
112                    mSendLevel = uint16_t(sendLevel * 0x1000);
113                }
114
115                // for AudioFlinger only; the return value must be validated by the caller
116                uint16_t    getSendLevel_U4_12() const {
117                    return mSendLevel;
118                }
119};
120
121
122// ----------------------------------------------------------------------------
123
124}; // namespace android
125
126#endif // ANDROID_AUDIO_TRACK_SHARED_H
127