[Android N]MediaRecorder系列之StagefrightRecorder录制TS流flow(四)

来源：互联网发布：上古卷轴5男捏脸数据编辑：程序博客网时间：2024/09/21 08:57

MPEG2TSWriter::readMore()

回到MPEG2TSWriter里面，调用完start()函数之后，会call readMore(),

这里写图片描述

MediaCodecSource::read

mBufferQueue里面存放则encoder好的数据，通过流程图来看下，camera的raw数据是怎么送到OMX中encoder好，再送出来到这个mBufferQueue中。

status_t MediaCodecSource::read(        MediaBuffer** buffer, const ReadOptions* /* options */) {    Mutexed<Output>::Locked output(mOutput);    *buffer = NULL;    while (output->mBufferQueue.size() == 0 && !output->mEncoderReachedEOS) {        output.waitForCondition(output->mCond);    }    if (!output->mEncoderReachedEOS) {        *buffer = *output->mBufferQueue.begin();        output->mBufferQueue.erase(output->mBufferQueue.begin());        return OK;    }    return output->mErrorCode;}

再puller函数中对kWhatStart的处理，mSource->start之后会调用schedulePull();，

void MediaCodecSource::Puller::onMessageReceived(const sp<AMessage> &msg) {    switch (msg->what()) {        case kWhatStart:        {            sp<RefBase> obj;            CHECK(msg->findObject("meta", &obj));            {                Mutexed<Queue>::Locked queue(mQueue);                queue->mPulling = true;            }            status_t err = mSource->start(static_cast<MetaData *>(obj.get()));            if (err == OK) {                //这开始去拉数据                schedulePull();            }        ....        }}void MediaCodecSource::Puller::schedulePull() {    (new AMessage(kWhatPull, this))->post();}

这里写图片描述

void MediaCodecSource::Puller::onMessageReceived(const sp<AMessage> &msg) {        case kWhatPull:        {            Mutexed<Queue>::Locked queue(mQueue);            queue->mReadPendingSince = ALooper::GetNowUs();            if (!queue->mPulling) {                handleEOS();                break;            }            queue.unlock();            MediaBuffer *mbuf = NULL;            status_t err = mSource->read(&mbuf);            queue.lock();            queue->mReadPendingSince = 0;            // if we need to discard buffer            if (!queue->mPulling || queue->mPaused || err != OK) {                if (mbuf != NULL) {                    mbuf->release();                    mbuf = NULL;                }                if (queue->mPulling && err == OK) {                    msg->post(); // if simply paused, keep pulling source                    break;                } else if (err == ERROR_END_OF_STREAM) {                    ALOGV("stream ended, mbuf %p", mbuf);                } else if (err != OK) {                    ALOGE("error %d reading stream.", err);                }            }            if (mbuf != NULL) {                queue->pushBuffer(mbuf);            }            queue.unlock();            //mNotify存放的就是kWhatPullerNotify，pull到了数据之后，就抛出去            if (mbuf != NULL) {                mNotify->post();                msg->post();            } else {                handleEOS();            }            break;        }

这里audioSource和CameraSource都是走的同样的flow，那么encoder是在哪里做选择的？
我们最后是从这里去拿到数据的，找这个mEncoder可以很快找到答案，这个放在后面的文章讲
status_t err = mEncoder->getOutputBuffer(index, &outbuf);

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