Error getting native address of native library

Nathan Sokalski 4,116

When running my Xamarin.Android app, I receive the following message:

Java.Lang.IllegalStateException: 'Error getting native address of native library: task_vision_jni'

This occurs on the following line:

ObjectDetector objdetector = ObjectDetector.CreateFromFile(Application.Context, "model.tflite");

I know what NuGet package task_vision_jni is referring to (Xamarin.TensorFlow.Lite.Task.Vision), but I don't know where the jni file is or how to fix it. I have looked at the following:

https://learn.microsoft.com/en-us/xamarin/android/platform/java-integration/working-with-jni?source=recommendations
https://learn.microsoft.com/en-us/xamarin/android/platform/native-libraries

But they didn't seem to help. What can I do fix this? Thanks.

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 35,571 Reputation points Microsoft Vendor

2022-09-05T08:55:10.667+00:00

Java.Lang.IllegalStateException: 'Error getting native address of native library: task_vision_jni'

In the TensorFlow GitHub Page, there is an issue with the same error message, you could refer to java.lang.IllegalArgumentException: Error occurred when initializing ObjectDetector: Mobile SSD models are expected to have exactly 4 outputs, found 8 #55664.

In this issue, it is caused by the tflite file. You could try to use this official tflite file: mobilenet_v1_0.75_160_quantized to check whether it is caused by it.
Nathan Sokalski 4,116 Reputation points

2022-09-05T18:33:14.473+00:00

My error is slightly different, although it still starts by mentioning task_vision_jni (I may have changed a small amount of code, but the message is still similar):

[TaskJniUtils] Error getting native address of native library: task_vision_jni
[TaskJniUtils] java.lang.RuntimeException: Error occurred when initializing ObjectDetector: Input tensor has type kTfLiteFloat32: it requires specifying NormalizationOptions metadata to preprocess input images.

But the line/code that the debugger points to is still the same as the one in my original post. Also, note that my error is a java.lang.RuntimeException (not any of the Exception types at the link you mention). I will also mention (just in case it matters, although assuming it is created correctly, I wouldn't think it would) that I am getting my model.tflite file from Microsoft Azure's Custom Vision service, and my model was trained and exported as General (Compact) domain.
Nathan Sokalski 4,116 Reputation points

2022-09-06T03:42:07.363+00:00

I think what I may need to do is switch from using ObjectDetector.CreateFromFile to ObjectDetector.CreateFromFileAndOptions. The problem is I cannot figure out how to create an ObjectDetector.ObjectDetectorOptions object for the last parameter. Is this what I need to do? If so, how do I do it? Thanks.
Nathan Sokalski 4,116 Reputation points

2022-09-09T04:12:41.727+00:00

I noticed that the exported zip file also includes a file named metadata_properties.json, which contains properties that include CustomVision.Preprocess.NormalizeMean & CustomVision.Preprocess.NormalizeStd (which I believe are used for normalization). Is there somewhere that I should be using this file, or is there some way that this metadata should have already been included as part of model.tflite? If I need to do something with it, what do I need to do?
bofei li 20 Reputation points

2024-03-05T17:10:41.85+00:00

Do you solve your issue yet ? I have met the same.