void UVCPreview::addCaptureFrame(uvc_frame_t *frame) {
	pthread_mutex_lock(&capture_mutex);
	if (LIKELY(isRunning())) {
		// keep only latest one
		if (captureQueu) {
			recycle_frame(captureQueu);
		}
		captureQueu = frame;
		pthread_cond_broadcast(&capture_sync);
	}else{
	    //Add By Hsj
	    recycle_frame(frame);
	}
	pthread_mutex_unlock(&capture_mutex);
}

int UVCPreview::stopPreview() {
    bool b = isRunning();
    if (LIKELY(b)) {
       mIsRunning = false;
        //Add lock for fix pthread_join() can't be end
       pthread_mutex_lock(&preview_mutex);
       pthread_cond_signal(&preview_sync);
       pthread_mutex_unlock(&preview_mutex);
       pthread_cond_signal(&capture_sync);
       if (pthread_join(capture_thread, NULL) != EXIT_SUCCESS) {
           LOGW("UVCPreview::terminate capture thread: pthread_join failed");
       }
       if (pthread_join(preview_thread, NULL) != EXIT_SUCCESS) {
           LOGW("UVCPreview::terminate preview thread: pthread_join failed");
       }
       clearDisplay();
    }
    ...
}

void UVCPreview::do_capture_callback(JNIEnv *env, uvc_frame_t *frame) {
    ...
    //mFrameCallbackObj or iframecallback_fields.onFrame maybe null
    if (isCapturing()) {
        jobject buf = env->NewDirectByteBuffer(callback_frame->data, callbackPixelBytes);
        env->CallVoidMethod(mFrameCallbackObj, iframecallback_fields.onFrame, buf);
        env->DeleteLocalRef(buf);
    }
    ...
}