IT技術(shù) 2010-01-28 15:56:41 閱讀397 評論1 字號：大中小
1. 音頻播放
示例代碼
MediaPlayer mp = new MediaPlayer();
mp.setDataSource(PATH_TO_FILE);
mp.prepare();
mp.start();
1.1 MediaPlayer mp = new MediaPlayer()
| 函數(shù)調(diào)用 | 文件 |
| MediaPlayer:: MediaPlayer | MediaPlayer.Java |
| MediaPlayer::native_setup | MediaPlayer.Java |
| android_media_MediaPlayer_native_setup | android_media_MediaPlayer.cpp |
| MediaPlayer::MediaPlayer | MediaPlayer.cpp |
1.2 mp.setDataSource(PATH_TO_FILE)
| 函數(shù)調(diào)用 | 文件 |
| MediaPlayer:: setDataSource | MediaPlayer.Java |
| MediaPlayer::setDataSource | MediaPlayer.Java |
| android_media_MediaPlayer_setDataSource | android_media_MediaPlayer.cpp |
| MediaPlayer:: setDataSource | MediaPlayer.cpp |
| MediaPlayer::getMediaPlayerService | MediaPlayer.cpp |
| IMediaPlayerService | IMediaPlayerService.h |
| MediaPlayerService:: MediaPlayerService[f1] | MediaPlayerService.cpp |
| MediaPlayerService::create | MediaPlayerService.cpp |
| MediaPlayerService::Client::Client | MediaPlayerService.cpp |
| MediaPlayerService::Client::setDataSource | MediaPlayerService.cpp |
| MediaPlayerService.cpp | |
| MediaPlayerService::Client::createPlayer | MediaPlayerService.cpp |
| createPlayer | MediaPlayerService.cpp |
| PVPlayer | PVPlayer.h |
| MidiFile | MidiFile.cpp |
| VorbisPlayer | VorbisPlayer.cpp |
| AudioOutput::AudioOutput | MediaPlayerService.cpp |
1.3 mp.prepare()
| 函數(shù)調(diào)用 | 文件 |
| MediaPlayer:: prepare | MediaPlayer.Java |
| MediaPlayer:: prepare | MediaPlayer.Java |
| android_media_MediaPlayer_ prepare | android_media_MediaPlayer.cpp |
| MediaPlayer:: prepare | MediaPlayer.cpp |
| PVPlayer:: prepare | PVPlayer.h |
| MidiFile:: prepare | MidiFile.cpp |
| VorbisPlayer:: prepare | VorbisPlayer.cpp |
| VorbisPlayer::createOutputTrack | VorbisPlayer.cpp |
| AudioOutput::open | MediaPlayerService.cpp |
| AudioTrack::AudioTrack | AudioTrack.cpp |
| AudioSystem::get_audio_flinger | AudioSystem.cpp |
| AudioFlinger::createTrack | AudioFlinger.cpp |
1.4 mp.start()
| 函數(shù)調(diào)用 | 文件 |
| MediaPlayer:: start | MediaPlayer.Java |
| MediaPlayer:: start | MediaPlayer.Java |
| android_media_MediaPlayer_ start | android_media_MediaPlayer.cpp |
| MediaPlayer:: start | MediaPlayer.cpp |
| PVPlayer:: start | PVPlayer.h |
| MidiFile:: p start | MidiFile.cpp |
| VorbisPlayer:: start | VorbisPlayer.cpp |
| AudioTrack::start | AudioTrack.cpp |
[f1]由systemserver進(jìn)程創(chuàng)建，在文件system_init.cpp里的函數(shù)system_init()調(diào)用MediaPlayerService::instantiate創(chuàng)建
[f2]返回3種player
PV_PLAYER:播放mp3
SONIVOX_PLAYER:播放midi
VORBIS_PLAYER:播放ogg,
簡單說來，軌跡如下：
Java端發(fā)起調(diào)用，MediaPlayer會轉(zhuǎn)至MediaPlayerService,然后會調(diào)用相應(yīng)的解碼工具解碼后創(chuàng)建AudioTrack，所有待輸出的AudioTrack在AudioFlinger::AudioMixer里合成，然后通過AudioHAL(AudioHardwareInterface的實(shí)際實(shí)現(xiàn)者)傳至實(shí)際的硬件來實(shí)現(xiàn)播放
