int main(int argc, char** argv)
{
signal(SIGPIPE, SIG_IGN);
char value[PROPERTY_VALUE_MAX];
bool doLog = (property_get("ro.test_harness", value, "0") > 0) && (atoi(value) == 1);
pid_t childPid;
// FIXME The advantage of making the process containing media.log service the parent process of
// the process that contains all the other real services, is that it allows us to collect more
// detailed information such as signal numbers, stop and continue, resource usage, etc.
// But it is also more complex. Consider replacing this by independent processes, and using
// binder on death notification instead.
if (doLog && (childPid = fork()) != 0) {
....
} else {
// all other services
if (doLog) {
prctl(PR_SET_PDEATHSIG, SIGKILL); // if parent media.log dies before me, kill me also
setpgid(0, 0); // but if I die first, don't kill my parent
}
sp<ProcessState> proc(ProcessState::self());
sp<IServiceManager> sm = defaultServiceManager();
ALOGI("ServiceManager: %p", sm.get());
AudioFlinger::instantiate();
MediaPlayerService::instantiate();
CameraService::instantiate();
AudioPolicyService::instantiate();
registerExtensions();
ProcessState::self()->startThreadPool();
IPCThreadState::self()->joinThreadPool();
}
}
void MediaPlayerService::instantiate() {
defaultServiceManager()->addService(
String16("media.player"), new MediaPlayerService());
}
MediaPlayerService::MediaPlayerService()
{
ALOGV("MediaPlayerService created");
mNextConnId = 1;
mBatteryAudio.refCount = 0;
for (int i = 0; i < NUM_AUDIO_DEVICES; i++) {
mBatteryAudio.deviceOn[i] = 0;
mBatteryAudio.lastTime[i] = 0;
mBatteryAudio.totalTime[i] = 0;
}
// speaker is on by default
mBatteryAudio.deviceOn[SPEAKER] = 1;
MediaPlayerFactory::registerBuiltinFactories();
}
//這裏有幾種類型的播放器，會在mediaplayerservice服務類 的構造函數中來註冊，
//代碼如下代碼中可以看出，一般情況下，STGHT_PLAYER爲默認播放器
void MediaPlayerFactory::registerBuiltinFactories() {
Mutex::Autolock lock_(&sLock);
if (sInitComplete)
return;
registerFactory_l(new StagefrightPlayerFactory(), STAGEFRIGHT_PLAYER);
registerFactory_l(new NuPlayerFactory(), NU_PLAYER);
registerFactory_l(new SonivoxPlayerFactory(), SONIVOX_PLAYER);
registerFactory_l(new TestPlayerFactory(), TEST_PLAYER);
sInitComplete = true;
}
status_t MediaPlayerFactory::registerFactory_l(IFactory* factory,
player_type type) {
if (NULL == factory) {
ALOGE("Failed to register MediaPlayerFactory of type %d, factory is"
" NULL.", type);
return BAD_VALUE;
}
if (sFactoryMap.indexOfKey(type) >= 0) {
ALOGE("Failed to register MediaPlayerFactory of type %d, type is"
" already registered.", type);
return ALREADY_EXISTS;
}
if (sFactoryMap.add(type, factory) < 0) {
ALOGE("Failed to register MediaPlayerFactory of type %d, failed to add"
" to map.", type);
return UNKNOWN_ERROR;
}
return OK;
}
//下面挑選STAGEFRIGHT_PLAYER類型作爲例子看下
//比較簡單，就是一些判斷條件，這裏還提供了createPlayer，返回實際的播放器對象
class StagefrightPlayerFactory :
public MediaPlayerFactory::IFactory {
public:
virtual float scoreFactory(const sp<IMediaPlayer>& client,
int fd,
int64_t offset,
int64_t length,
float curScore) {
char buf[20];
lseek(fd, offset, SEEK_SET);
read(fd, buf, sizeof(buf));
lseek(fd, offset, SEEK_SET);
long ident = *((long*)buf);
// Ogg vorbis?
if (ident == 0x5367674f) // 'OggS'
return 1.0;
return 0.0;
}
virtual sp<MediaPlayerBase> createPlayer() {
ALOGV(" create StagefrightPlayer");
return new StagefrightPlayer();
}
};
StagefrightPlayer::StagefrightPlayer()
: mPlayer(new AwesomePlayer) {
ALOGV("StagefrightPlayer");
mPlayer->setListener(this);
}
AwesomePlayer::AwesomePlayer()
: mQueueStarted(false),
mUIDValid(false),
mTimeSource(NULL),
mVideoRenderingStarted(false),
mVideoRendererIsPreview(false),
mAudioPlayer(NULL),
mDisplayWidth(0),
mDisplayHeight(0),
mVideoScalingMode(NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW),
mFlags(0),
mExtractorFlags(0),
mVideoBuffer(NULL),
mDecryptHandle(NULL),
mLastVideoTimeUs(-1),
mTextDriver(NULL) {
CHECK_EQ(mClient.connect(), (status_t)OK);
DataSource::RegisterDefaultSniffers();
mVideoEvent = new AwesomeEvent(this, &AwesomePlayer::onVideoEvent);
mVideoEventPending = false;
mStreamDoneEvent = new AwesomeEvent(this, &AwesomePlayer::onStreamDone);
mStreamDoneEventPending = false;
mBufferingEvent = new AwesomeEvent(this, &AwesomePlayer::onBufferingUpdate);
mBufferingEventPending = false;
mVideoLagEvent = new AwesomeEvent(this, &AwesomePlayer::onVideoLagUpdate);
mVideoEventPending = false;
mCheckAudioStatusEvent = new AwesomeEvent(
this, &AwesomePlayer::onCheckAudioStatus);
mAudioStatusEventPending = false;
reset();
}
//獲得BpOMX對象，
status_t OMXClient::connect() {
sp<IServiceManager> sm = defaultServiceManager();
sp<IBinder> binder = sm->getService(String16("media.player"));
sp<IMediaPlayerService> service = interface_cast<IMediaPlayerService>(binder);
CHECK(service.get() != NULL);
mOMX = service->getOMX();
CHECK(mOMX.get() != NULL);
//如果client ID不等於server ID，構造本地的MuxOMX對象
//否則使用MediaPlayerService端的MuxOMX對象
if (!mOMX->livesLocally(NULL /* node */, getpid())) {
ALOGI("Using client-side OMX mux.");
mOMX = new MuxOMX(mOMX);
}
return OK;
}
MuxOMX::MuxOMX(const sp<IOMX> &remoteOMX)
: mRemoteOMX(remoteOMX) {
}
//構造一個OMX對象，該對象繼承了BnOMX，從而具有Binder通信的功能
sp<IOMX> MediaPlayerService::getOMX() {
Mutex::Autolock autoLock(mLock);
if (mOMX.get() == NULL) {
mOMX = new OMX;
}
return mOMX;
}
OMX::OMX()
: mMaster(new OMXMaster),
mNodeCounter(0) {
}
//構造Component的管理對象，負責保存並初始化系統支持的Component，
OMXMaster::OMXMaster()
: mVendorLibHandle(NULL) {
addVendorPlugin();
addPlugin(new SoftOMXPlugin);
}
void OMXMaster::addVendorPlugin() {
addPlugin("libstagefrighthw.so");
}
void OMXMaster::addPlugin(const char *libname) {
mVendorLibHandle = dlopen(libname, RTLD_NOW);
if (mVendorLibHandle == NULL) {
return;
}
typedef OMXPluginBase *(*CreateOMXPluginFunc)();
CreateOMXPluginFunc createOMXPlugin =
(CreateOMXPluginFunc)dlsym(
mVendorLibHandle, "createOMXPlugin");
if (!createOMXPlugin)
createOMXPlugin = (CreateOMXPluginFunc)dlsym(
mVendorLibHandle, "_ZN7android15createOMXPluginEv");
if (createOMXPlugin) {
addPlugin((*createOMXPlugin)());
}
}
//單獨加載stagefrighthw的庫文件，應該是OEM廠商實現的，並記錄到hash表中
void OMXMaster::addPlugin(OMXPluginBase *plugin) {
Mutex::Autolock autoLock(mLock);
mPlugins.push_back(plugin);
OMX_U32 index = 0;
char name[128];
OMX_ERRORTYPE err;
while ((err = plugin->enumerateComponents(
name, sizeof(name), index++)) == OMX_ErrorNone) {
String8 name8(name);
if (mPluginByComponentName.indexOfKey(name8) >= 0) {
ALOGE("A component of name '%s' already exists, ignoring this one.",
name8.string());
continue;
}
mPluginByComponentName.add(name8, plugin);
}
if (err != OMX_ErrorNoMore) {
ALOGE("OMX plugin failed w/ error 0x%08x after registering %d "
"components", err, mPluginByComponentName.size());
}
}
static const struct {
const char *mName;
const char *mLibNameSuffix;
const char *mRole;
} kComponents[] = {
{ "OMX.google.aac.decoder", "aacdec", "audio_decoder.aac" },
{ "OMX.google.aac.encoder", "aacenc", "audio_encoder.aac" },
{ "OMX.google.amrnb.decoder", "amrdec", "audio_decoder.amrnb" },
{ "OMX.google.amrnb.encoder", "amrnbenc", "audio_encoder.amrnb" },
{ "OMX.google.amrwb.decoder", "amrdec", "audio_decoder.amrwb" },
{ "OMX.google.amrwb.encoder", "amrwbenc", "audio_encoder.amrwb" },
{ "OMX.google.h264.decoder", "h264dec", "video_decoder.avc" },
{ "OMX.google.h264.encoder", "h264enc", "video_encoder.avc" },
{ "OMX.google.g711.alaw.decoder", "g711dec", "audio_decoder.g711alaw" },
{ "OMX.google.g711.mlaw.decoder", "g711dec", "audio_decoder.g711mlaw" },
{ "OMX.google.h263.decoder", "mpeg4dec", "video_decoder.h263" },
{ "OMX.google.h263.encoder", "mpeg4enc", "video_encoder.h263" },
{ "OMX.google.mpeg4.decoder", "mpeg4dec", "video_decoder.mpeg4" },
{ "OMX.google.mpeg4.encoder", "mpeg4enc", "video_encoder.mpeg4" },
{ "OMX.google.mp3.decoder", "mp3dec", "audio_decoder.mp3" },
{ "OMX.google.vorbis.decoder", "vorbisdec", "audio_decoder.vorbis" },
{ "OMX.google.vp8.decoder", "vpxdec", "video_decoder.vp8" },
{ "OMX.google.vp9.decoder", "vpxdec", "video_decoder.vp9" },
{ "OMX.google.vp8.encoder", "vpxenc", "video_encoder.vp8" },
{ "OMX.google.raw.decoder", "rawdec", "audio_decoder.raw" },
{ "OMX.google.flac.encoder", "flacenc", "audio_encoder.flac" },
{ "OMX.google.gsm.decoder", "gsmdec", "audio_decoder.gsm" },
};
static const size_t kNumComponents =
sizeof(kComponents) / sizeof(kComponents[0]);
SoftOMXPlugin::SoftOMXPlugin() {
}
//統一加載Google原生的軟解碼庫文件，根據後綴不同，將當前系統支持
//的Component保存在hash對象中，一個plugin對象對應多個Component
void OMXMaster::addPlugin(OMXPluginBase *plugin) {
Mutex::Autolock autoLock(mLock);
mPlugins.push_back(plugin);
OMX_U32 index = 0;
char name[128];
OMX_ERRORTYPE err;
while ((err = plugin->enumerateComponents(
name, sizeof(name), index++)) == OMX_ErrorNone) {
String8 name8(name);
if (mPluginByComponentName.indexOfKey(name8) >= 0) {
ALOGE("A component of name '%s' already exists, ignoring this one.",
name8.string());
continue;
}
mPluginByComponentName.add(name8, plugin);
}
if (err != OMX_ErrorNoMore) {
ALOGE("OMX plugin failed w/ error 0x%08x after registering %d "
"components", err, mPluginByComponentName.size());
}
}
OMX_ERRORTYPE SoftOMXPlugin::enumerateComponents(
OMX_STRING name,
size_t /* size */,
OMX_U32 index) {
if (index >= kNumComponents) {
return OMX_ErrorNoMore;
}
strcpy(name, kComponents[index].mName);
return OMX_ErrorNone;
}
通過以上分析，可以發現MediaPlayservice的初始化其實就是註冊了幾種播放器：
1、StagefrightPlayer： 默認播放器，本地文件基本都使用其播放
2、NuPlayerDriver：主要用於播放網絡視頻,http https rtsp等
3、SonivoxPlayer：用於播放midi等類型的音樂
StagefrightPlayer的初始化就是創建了一個Component的管理對象，該對象通過枚舉，保存了當前系統支持的所有Component（decode和encode）。
後續客戶端可以通過調用OMXClient對象的mOMX變量來獲取MuxOMX對象，然後使用decod和encod庫。
調用關係爲：
StagefrightPlayer->AwesomePlayer->OMXClient->MediaPlayerService->OMX
->OMXMaster->SoftOMXPlugin->SoftOMXComponent(SimpleSoftOMXComponent(具體的decod和encod對象))