Cubietruck---31.蓝牙耳机与有线耳机的声音输出

getOutput的过程

./frameworks/av/services/audioflinger/AudioPolicyService.cpp

1. audio_io_handle_t AudioPolicyService::getOutput(audio_stream_type_t stream...)
   
2. {
   
3.     return mpAudioPolicy->get_output(mpAudioPolicy, stream, samplingRate, format, channelMask, flags);
   
4. }

./hardware/libhardware_legacy/audio/audio_policy_hal.cpp

1. static audio_io_handle_t ap_get_output(struct audio_policy *pol,
   
2.                                        audio_stream_type_t stream,
   
3.                                        uint32_t sampling_rate,
   
4.                                        audio_format_t format,
   
5.                                        audio_channel_mask_t channelMask,
   
6.                                        audio_output_flags_t flags)
   
7. {
   
8.     struct legacy_audio_policy *lap = to_lap(pol);
   
9. 
   
10.     dbmsg("tid %d", gettid());
    
11.     return lap->apm->getOutput((AudioSystem::stream_type)stream,
    
12.                                sampling_rate, (int) format, channelMask,
    
13.                                (AudioSystem::output_flags)flags);
    
14. }

./hardware/libhardware_legacy/audio/AudioPolicyManagerBase.cpp

1. audio_io_handle_t AudioPolicyManagerBase::getOutput(AudioSystem::stream_type stream,
   
2.                                     uint32_t samplingRate,
   
3.                                     uint32_t format,
   
4.                                     uint32_t channelMask,
   
5.                                     AudioSystem::output_flags flags)
   
6. {
   
7.     audio_io_handle_t output = 0;
   
8.     uint32_t latency = 0;
   
9.     routing_strategy strategy = getStrategy((AudioSystem::stream_type)stream);
   
10.     audio_devices_t device = getDeviceForStrategy(strategy, false /*fromCache*/);
    
11.     // open a direct output if required by specified parameters
    
12.     IOProfile *profile = getProfileForDirectOutput(device,
    
13.                                                    samplingRate,
    
14.                                                    format,
    
15.                                                    channelMask,
    
16.                                                    (audio_output_flags_t)flags);
    
17.     if (profile != NULL) {
    
18. 
    
19.         dbmsg("getOutput() opening direct output device %x", device);
    
20. 
    
21.         AudioOutputDescriptor *outputDesc = new AudioOutputDescriptor(profile);
    
22.         outputDesc->mDevice = device;
    
23.         outputDesc->mSamplingRate = samplingRate;
    
24.         outputDesc->mFormat = (audio_format_t)format;
    
25.         outputDesc->mChannelMask = (audio_channel_mask_t)channelMask;
    
26.         outputDesc->mLatency = 0;
    
27.         outputDesc->mFlags = (audio_output_flags_t)(flags | AUDIO_OUTPUT_FLAG_DIRECT);;
    
28.         outputDesc->mRefCount[stream] = 0;
    
29.         outputDesc->mStopTime[stream] = 0;
    
30.         output = mpClientInterface->openOutput(profile->mModule->mHandle,
    
31.                                         &outputDesc->mDevice,
    
32.                                         &outputDesc->mSamplingRate,
    
33.                                         &outputDesc->mFormat,
    
34.                                         &outputDesc->mChannelMask,
    
35.                                         &outputDesc->mLatency,
    
36.                                         outputDesc->mFlags);
    
37. 
    
38.         // only accept an output with the requested parameters
    
39.         if (output == 0 ||
    
40.             (samplingRate != 0 && samplingRate != outputDesc->mSamplingRate) ||
    
41.             (format != 0 && format != outputDesc->mFormat) ||
    
42.             (channelMask != 0 && channelMask != outputDesc->mChannelMask)) {
    
43.             dbmsg("getOutput() failed opening direct output: output %d samplingRate %d %d,"
    
44.                     "format %d %d, channelMask %04x %04x", output, samplingRate,
    
45.                     outputDesc->mSamplingRate, format, outputDesc->mFormat, channelMask,
    
46.                     outputDesc->mChannelMask);
    
47.             if (output != 0) {
    
48.                 mpClientInterface->closeOutput(output);
    
49.             }
    
50.             delete outputDesc;
    
51.             return 0;
    
52.         }
    
53.         addOutput(output, outputDesc);
    
54.         dbmsg("getOutput() returns direct output %d", output);
    
55.         return output;
    
56.     }
    
57. 
    
58.     // ignoring channel mask due to downmix capability in mixer
    
59. 
    
60.     // open a non direct output
    
61. 
    
62.     // get which output is suitable for the specified stream. The actual routing change will happen
    
63.     // when startOutput() will be called
    
64.     SortedVector<audio_io_handle_t> outputs = getOutputsForDevice(device, mOutputs);
    
65.     output = selectOutput(outputs, flags);
    
66.     ALOGW_IF((output ==0), "getOutput() could not find output for stream %d, samplingRate %d,"
    
67.             "format %d, channels %x, flags %x", stream, samplingRate, format, channelMask, flags);
    
68. 
    
69.     dbmsg("getOutput() returns output %d", output);
    
70. 
    
71.     return output;
    
72. }

播放声音
./frameworks/base/media/java/android/media/SoundPool.java
SoundPool::play
  SoundChannel::play


一.数据的写入
frameworks/av/services/audioflinger/AudioFlinger.cpp

1. void AudioFlinger::PlaybackThread::threadLoop_write()
   
2. {
   
3. ssize_t framesWritten = mNormalSink->write(mMixBuffer, count);
   
4. }

frameworks/av/media/libnbaio/AudioStreamOutSink.cpp

1. ssize_t AudioStreamOutSink::write(const void *buffer, size_t count)
   
2. {
   
3.     ssize_t ret = mStream->write(mStream, buffer, count << mBitShift);
   
4.     return ret;
   
5. }

1.2 耳机的输出


1.1 蓝牙耳机的输出
external/bluetooth/bluedroid/audio_a2dp_hw/audio_a2dp_hw.c

1. static ssize_t out_write(struct audio_stream_out *stream, const void* buffer,
   
2.                          size_t bytes)
   
3. {
   
4.     struct a2dp_stream_out *out = (struct a2dp_stream_out *)stream;
   
5.     sent = skt_write(out->audio_fd, buffer, bytes);
   
6.     return sent;
   
7. }

1. static int skt_write(int fd, const void *p, size_t len)
   
2. {
   
3.     int sent;
   
4.     struct pollfd pfd;
   
5.     pfd.fd = fd;
   
6.     pfd.events = POLLOUT;
   
7.     if (poll(&pfd, 1, 500) == 0)
   
8.         return 0;
   
9.     sent = send(fd, p, len, MSG_NOSIGNAL);
   
10.     
    
11.     return sent;
    
12. }

蓝牙耳机的声音播放
在frameworks/av/services/audioflinger/AudioPolicyService.cpp中

1. audio_io_handle_t AudioPolicyService::getOutput(audio_stream_type_t stream,...)
   
2. {
   
3.     if (mpAudioPolicy == NULL) {
   
4.         return 0;
   
5.     }
   
6.     Mutex::Autolock _l(mLock);
   
7.     return mpAudioPolicy->get_output(mpAudioPolicy, stream, ...);
   
8. }

hardware/libhardware_legacy/audio/audio_policy_hal.cpp:ap_get_output(146)

1. static audio_io_handle_t ap_get_output(struct audio_policy *pol, audio_stream_type_t stream,...)
   
2. {
   
3.     struct legacy_audio_policy *lap = to_lap(pol);
   
4.     return lap->apm->getOutput((AudioSystem::stream_type)stream,);
   
5. }

hardware/libhardware_legacy/audio/AudioPolicyManagerBase.cpp:getDeviceForStrategy(2214), STRATEGY_MEDIA

1. audio_io_handle_t AudioPolicyManagerBase::getOutput(AudioSystem::stream_type stream, )
   
2. {
   
3.     routing_strategy strategy = getStrategy((AudioSystem::stream_type)stream);
   
4.     audio_devices_t device = getDeviceForStrategy(strategy, false );
   
5.     IOProfile *profile = getProfileForDirectOutput(device,...);
   
6.     if (profile != NULL) {
   
7.     }
   
8.     SortedVector<audio_io_handle_t> outputs = getOutputsForDevice(device, mOutputs);
   
9.     output = selectOutput(outputs, flags);
10.     return output;
    
11. }

I/cong    ( 1346): hardware/libhardware_legacy/audio/AudioPolicyManagerBase.cpp:getA2dpOutput(1919), 
I/cong    ( 1346): hardware/libhardware_legacy/audio/AudioPolicyManagerBase.cpp:getOutput(522), getOutput() stream 1, samplingRate 0, format 0, channelMask 3, flags 0
I/cong    ( 1346): hardware/libhardware_legacy/audio/AudioPolicyManagerBase.cpp:getOutput(614), getOutput() returns output 6
I/cong    ( 1346): frameworks/av/services/audioflinger/AudioPolicyService.cpp:getOutput(228), getOutput() tid 2538