该函数主要执行configureQueueLocked和registerBuffersLocked两个函数

status_t Camera3OutputStream::configureQueueLocked() {
    status_t res;

    mTraceFirstBuffer = true;
    if ((res = Camera3IOStreamBase::configureQueueLocked()) != OK) {
        return res;
    }

    ALOG_ASSERT(mConsumer != 0, mConsumer should never be NULL);

    // Configure consumer-side ANativeWindow interface
    res = native_window_api_connect(mConsumer.get(),
            NATIVE_WINDOW_API_CAMERA);
    if (res != OK) {
        ALOGE(%s: Unable to connect to native window for stream %d,
                __FUNCTION__, mId);
        return res;
    }

    res = native_window_set_usage(mConsumer.get(), camera3_stream::usage);
    if (res != OK) {
        ALOGE(%s: Unable to configure usage %08x for stream %d,
                __FUNCTION__, camera3_stream::usage, mId);
        return res;
    }

    res = native_window_set_scaling_mode(mConsumer.get(),
            NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW);
    if (res != OK) {
        ALOGE(%s: Unable to configure stream scaling: %s (%d),
                __FUNCTION__, strerror(-res), res);
        return res;
    }

    if (mMaxSize == 0) {
        // For buffers of known size
        res = native_window_set_buffers_dimensions(mConsumer.get(),
                camera3_stream::width, camera3_stream::height);
    } else {
        // For buffers with bounded size
        res = native_window_set_buffers_dimensions(mConsumer.get(),
                mMaxSize, 1);
    }
    if (res != OK) {
        ALOGE(%s: Unable to configure stream buffer dimensions
                 %d x %d (maxSize %zu) for stream %d,
                __FUNCTION__, camera3_stream::width, camera3_stream::height,
                mMaxSize, mId);
        return res;
    }
    res = native_window_set_buffers_format(mConsumer.get(),
            camera3_stream::format);
    if (res != OK) {
        ALOGE(%s: Unable to configure stream buffer format %#x for stream %d,
                __FUNCTION__, camera3_stream::format, mId);
        return res;
    }

    int maxConsumerBuffers;
    res = mConsumer->query(mConsumer.get(),
            NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, &maxConsumerBuffers);//支持的最大buffer数量
    if (res != OK) {
        ALOGE(%s: Unable to query consumer undequeued
                 buffer count for stream %d, __FUNCTION__, mId);
        return res;
    }

    ALOGV(%s: Consumer wants %d buffers, HAL wants %d, __FUNCTION__,
            maxConsumerBuffers, camera3_stream::max_buffers);
    if (camera3_stream::max_buffers == 0) {
        ALOGE(%s: Camera HAL requested max_buffer count: %d, requires at least 1,
                __FUNCTION__, camera3_stream::max_buffers);
        return INVALID_OPERATION;
    }

    mTotalBufferCount = maxConsumerBuffers + camera3_stream::max_buffers;//至少2个buffer
    mHandoutTotalBufferCount = 0;
    mFrameCount = 0;
    mLastTimestamp = 0;

    res = native_window_set_buffer_count(mConsumer.get(),
            mTotalBufferCount);
    if (res != OK) {
        ALOGE(%s: Unable to set buffer count for stream %d,
                __FUNCTION__, mId);
        return res;
    }

    res = native_window_set_buffers_transform(mConsumer.get(),
            mTransform);
    if (res != OK) {
        ALOGE(%s: Unable to configure stream transform to %x: %s (%d),
                __FUNCTION__, mTransform, strerror(-res), res);
    }

    return OK;
}

这里重点关注以下几个buffer的相关属性信息：

比如native_window_set_buffer_count是设置当前Window所需要的buffer数目：