Android 13 - Media框架（22）- MediaCodec（三）

这一节开始我们将重新回到 MediaCodec 这一层来学习 buffer 的流转
cpp 复制代码
status_t MediaCodec::dequeueOutputBuffer(
        size_t *index,
        size_t *offset,
        size_t *size,
        int64_t *presentationTimeUs,
        uint32_t *flags,
        int64_t timeoutUs) {
    sp<AMessage> msg = new AMessage(kWhatDequeueOutputBuffer, this);
    msg->setInt64("timeoutUs", timeoutUs);

    sp<AMessage> response;
    status_t err;
    if ((err = PostAndAwaitResponse(msg, &response)) != OK) {
        return err;
    }

    CHECK(response->findSize("index", index));
    CHECK(response->findSize("offset", offset));
    CHECK(response->findSize("size", size));
    CHECK(response->findInt64("timeUs", presentationTimeUs));
    CHECK(response->findInt32("flags", (int32_t *)flags));

    return OK;
}

status_t MediaCodec::renderOutputBufferAndRelease(size_t index) {
    sp<AMessage> msg = new AMessage(kWhatReleaseOutputBuffer, this);
    msg->setSize("index", index);
    msg->setInt32("render", true);

    sp<AMessage> response;
    return PostAndAwaitResponse(msg, &response);
}

status_t MediaCodec::renderOutputBufferAndRelease(size_t index, int64_t timestampNs) {
    sp<AMessage> msg = new AMessage(kWhatReleaseOutputBuffer, this);
    msg->setSize("index", index);
    msg->setInt32("render", true);
    msg->setInt64("timestampNs", timestampNs);

    sp<AMessage> response;
    return PostAndAwaitResponse(msg, &response);
}

status_t MediaCodec::releaseOutputBuffer(size_t index) {
    sp<AMessage> msg = new AMessage(kWhatReleaseOutputBuffer, this);
    msg->setSize("index", index);

    sp<AMessage> response;
    return PostAndAwaitResponse(msg, &response);
}

status_t MediaCodec::signalEndOfInputStream() {
    sp<AMessage> msg = new AMessage(kWhatSignalEndOfInputStream, this);

    sp<AMessage> response;
    return PostAndAwaitResponse(msg, &response);
}

status_t MediaCodec::getOutputFormat(sp<AMessage> *format) const {
    sp<AMessage> msg = new AMessage(kWhatGetOutputFormat, this);

    sp<AMessage> response;
    status_t err;
    if ((err = PostAndAwaitResponse(msg, &response)) != OK) {
        return err;
    }

    CHECK(response->findMessage("format", format));

    return OK;
}