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rtlsdr doesn't open in qt android c++

I have a qt android project in c++. When I call "rtlsdr_get_device_name" function it returns the "Generic RTL2832U OEM" message. But when I call "rtlsdr_open" function it return -3. Please help me how can I solve this problem.

thank you silicontrip.
My project is a qt android project.
rtlsdr_dev_t *RtlSdrDevice;
int devicecount = rtlsdr_get_device_count();
if (devicecount != 0)
{
QString rtlname = rtlsdr_get_device_name(0);
//this function returns "Generic RTL2832U OEM "
retvalue = rtlsdr_open(&RtlSdrDevice, 0);
//this function returns "-3"
if (retvalue == 0) //if open rtl correctly
{
....
}
...
}
the rtlsdr device doesn't open successfully.

Get mangled name of function when using .so shared library from Android c++ side? (libAudioFlinger.so)

i have been working on this problem for 2 weeks now, i have integrate C++ code into my Voip call recording app, the code is supposed to take care of forcefully setting Input_source of mediaRecorder to same one as from the Voip Call (in my case it is input_source=7 / Voice_Communication).
In order to achieve my goal i load shared library : libaudioflinger.so and attempt to reach SetParameters function, as can be seen from the snipet below :
handleLibAudioFlinger = dlopen("libaudioflinger.so", RTLD_LAZY | RTLD_GLOBAL);
if (handleLibAudioFlinger != NULL) {
func = dlsym(handleLibAudioFlinger, "setParameters"); // i do not know the mangled name of
SetParameters function
if (func != NULL) {
__android_log_print(ANDROID_LOG_ERROR, "TRACKERS", "%s", "Function is not null");
result = 0;
}
audioSetParameters = (lasp) func;
} else {
__android_log_print(ANDROID_LOG_ERROR, "TRACKERS", "%s", "Function is null");
result = -1;
}
dlopen does not return null, but dlsym does, reason is that i need to have the exact mangled name of the function setParameters from AudioFlinger.cpp As in Android source code.
i am new to handling android c++ code and dealing with shared libraries,etc... if someone can tell me step by step how to get correct mangled name for the function that i need?

TensorFlow Lite 2.0 advanced GPU using on Android with C++

I am new in TensorFlow. I built TensorFlow Lite libraries from sources. I try to use TensorFlow for face recognition. This one a part of my project. And I have to use GPU memory for input/output e.g. input data: opengl texture, output data: opengl texture. Unfortunately, this information is outdated: https://www.tensorflow.org/lite/performance/gpu_advanced. I tried to use gpu::gl::InferenceBuilder for building gpu::gl::InferenceRunner. And I have problem. I don’t understand how I can get the model in GraphFloat32 (Model>) format and TfLiteContext.
Example of my experemental code:
using namespace tflite::gpu;
using namespace tflite::gpu::gl;
const TfLiteGpuDelegateOptionsV2 options = {
.inference_preference = TFLITE_GPU_INFERENCE_PREFERENCE_SUSTAINED_SPEED,
.is_precision_loss_allowed = 1 // FP16
};
tfGPUDelegate = TfLiteGpuDelegateV2Create(&options);
if (interpreter->ModifyGraphWithDelegate(tfGPUDelegate) != kTfLiteOk) {
__android_log_print(ANDROID_LOG_ERROR, "Tensorflow", "GPU Delegate hasn't been created");
return ;
} else {
__android_log_print(ANDROID_LOG_INFO, "Tensorflow", "GPU Delegate has been created");
}
InferenceEnvironmentOptions envOption;
InferenceEnvironmentProperties properties;
auto envStatus = NewInferenceEnvironment(envOption, &env, &properties);
if (envStatus.ok()){
__android_log_print(ANDROID_LOG_INFO, "Tensorflow", "Inference environment has been created");
} else {
__android_log_print(ANDROID_LOG_ERROR, "Tensorflow", "Inference environment hasn't been created");
__android_log_print(ANDROID_LOG_ERROR, "Tensorflow", "Message: %s", envStatus.error_message().c_str());
}
InferenceOptions builderOptions;
builderOptions.usage = InferenceUsage::SUSTAINED_SPEED;
builderOptions.priority1 = InferencePriority::MIN_LATENCY;
builderOptions.priority2 = InferencePriority::AUTO;
builderOptions.priority3 = InferencePriority::AUTO;
//The last part requires a model
// GraphFloat32* graph;
// TfLiteContext* tfLiteContex;
//
// auto buildStatus = BuildModel(tfLiteContex, delegate_params, &graph);
// if (buildStatus.ok()){}

You may look function BuildFromFlatBuffer (https://github.com/tensorflow/tensorflow/blob/6458d346470158605ecb5c5ba6ad390ae0dc6014/tensorflow/lite/delegates/gpu/common/testing/tflite_model_reader.cc). It creates Interpreter and graph from it.
Also Mediapipe uses InferenceRunner you may find for useful in files:
https://github.com/google/mediapipe/blob/master/mediapipe/calculators/tflite/tflite_inference_calculator.cc
https://github.com/google/mediapipe/blob/ecb5b5f44ab23ea620ef97a479407c699e424aa7/mediapipe/util/tflite/tflite_gpu_runner.cc

Gstreamer video on Android (Qt C++)

I try to use Gstreamer on Android via Qt C++.
I already use Gstreamer on these platforms but now I have an issues with the plugins:
G_BEGIN_DECLS
GST_PLUGIN_STATIC_DECLARE(coreelements);
GST_PLUGIN_STATIC_DECLARE(audioconvert);
GST_PLUGIN_STATIC_DECLARE(playback);
G_END_DECLS
void MainWindow::play(){
GST_PLUGIN_STATIC_REGISTER(coreelements);
GST_PLUGIN_STATIC_REGISTER(audioconvert);
GST_PLUGIN_STATIC_REGISTER(playback);
GstElement *pipeline;
GError *error = NULL;
pipeline = gst_parse_launch("playbin uri=http://docs.gstreamer.com/media/sintel_trailer-368p.ogv", &error);
if (!pipeline) {
ui->label->setText("error");
return;
}
if(error != NULL){
qDebug("GST error: ");
qDebug(error->message);
}else{
qDebug("GST without errors");
}
gst_element_set_state(pipeline, GST_STATE_READY);
gst_video_overlay_set_window_handle(GST_VIDEO_OVERLAY(pipeline), this->ui->playback_widget->winId());
gst_element_set_state(pipeline, GST_STATE_PLAYING);
ui->label->setText("Playing...");
}
After executing of this code I don't get either video in the playback_widget or the audio, but error var is clear(equals NULL) and label set to "Playing...". So, maybe I missed something?

Android C# HtmlAgilityPack

How do I use HtmlAgilityPack with Android (Mono for Android - C#)? I've added the reference, but I keep getting this error:
Error CS0012: The type 'System.Xml.XPath.IXPathNavigable' is defined
in an assembly that is not referenced. You must add a reference to
assembly 'System.Xml, Version=2.0.0.0

I have incorporated HtmlAglilityPack into the base library assembly I use in all of my MonoDroid projects with great success. I have not even tried to use them in precompiled form, but simply added it's source to my project.
I then shamelessly edited HtmlWeb.cs to throw out the Windows stuff:
lines 893 to 903 (may have somewhat changed, just look around near there):
if (!helper.GetIsDnsAvailable())
{
#if Android
contentType = def;
#else
//do something.... not at full trust
try
{
RegistryKey reg = Registry.ClassesRoot;
reg = reg.OpenSubKey(extension, false);
if (reg != null) contentType = (string)reg.GetValue("", def);
}
catch (Exception)
{
contentType = def;
}
#endif
}
lines 934 to 946 (may have somewhat changed, just look around near there):
if (helper.GetIsRegistryAvailable())
{
#if Android
ext = def;
#else
try
{
RegistryKey reg = Registry.ClassesRoot;
reg = reg.OpenSubKey(#"MIME\Database\Content Type\" + contentType, false);
if (reg != null) ext = (string)reg.GetValue("Extension", def);
}
catch (Exception)
{
ext = def;
}
#endif
}
I then added Android to the conditional compilation symbols of my project.
My references are:
Microsoft.CSharp
Mono.Android
System
System.Core
System.Data
System.Xml
System.Xml.Linq
Please add a comment, telling if you can compile it now, or if you need more information.