Fake camera with a mock video pattern don't get picked up by arvtools/arviewer.

[Rz-Rz]

Describe the bug
I'm trying to build a fake camera source with my own specific pattern using opencv. However the camera starts but seems to never get picked up by the arvtools/arvviewer.

To Reproduce
Here's my code:

#include <arv.h>
#include <glib.h>
#include <iostream>
#include <opencv2/opencv.hpp>
#include <signal.h>

// Define image properties
#define WIDTH 320
#define HEIGHT 240
#define PIXEL_FORMAT ARV_PIXEL_FORMAT_MONO8 // Using MONO8 for simplicity

struct FillPatternData {
  guint64 frame_counter;
  int width;
  int height;
};

// Correct callback signature matching ArvFakeCameraFillPattern
void fill_pattern_callback(ArvBuffer *buffer, void *user_data, guint32 width,
                           guint32 height, guint32 padding_x) {
  FillPatternData *data = static_cast<FillPatternData *>(user_data);

  // Generate a new 8-bit grayscale image using OpenCV
  cv::Mat gray_image(data->height, data->width, CV_8UC1, cv::Scalar(0));

  // Create a dynamic pattern that changes with frame_counter
  // For simplicity, we'll create a moving horizontal gradient
  for (int y = 0; y < data->height; y++) {
    for (int x = 0; x < data->width; x++) {
      gray_image.at<uchar>(y, x) =
          static_cast<uchar>((x + data->frame_counter) % 256);
    }
  }

  // Get the buffer data pointer and size
  size_t buffer_size;
  void *buffer_data = (void *)arv_buffer_get_data(buffer, &buffer_size);
  if (!buffer_data) {
    std::cerr << "Failed to get buffer data" << std::endl;
    return;
  }

  // Ensure that the generated image fits into the buffer
  size_t image_size = data->width * data->height; // 1 byte per pixel for MONO8
  if (image_size > buffer_size) {
    std::cerr << "Image size exceeds buffer size. Image size: " << image_size
              << ", Buffer size: " << buffer_size << std::endl;
    return;
  }

  // Copy the grayscale image data into the buffer
  memcpy(buffer_data, gray_image.data, image_size);

  // Increment frame counter
  data->frame_counter++;
}

static gboolean stop = FALSE;

static void control_c_signal(int signal) { stop = TRUE; }

int main(int argc, char **argv) {
  // Initialize the type system (required by GObject in older GLib versions)
#if !GLIB_CHECK_VERSION(2, 35, 0)
  g_type_init();
#endif

  // Initialize Aravis
  arv_update_device_list();

  // Set the GenICam XML file for the fake camera
  arv_set_fake_camera_genicam_filename("fake_camera_genicam.xml");

  // Create a fake GigE Vision camera
  ArvFakeCamera *gv_fake_camera =
      arv_fake_camera_new_full("3", "fake_camera_genicam.xml");
  if (!gv_fake_camera) {
    std::cerr << "Failed to create fake camera" << std::endl;
    return EXIT_FAILURE;
  }

  // Initialize fill pattern data
  FillPatternData fill_data;
  fill_data.frame_counter = 0;
  fill_data.width = WIDTH;
  fill_data.height = HEIGHT;

  // Set fill pattern callback with the correct signature
  arv_fake_camera_set_fill_pattern(ARV_FAKE_CAMERA(gv_fake_camera),
                                   fill_pattern_callback, &fill_data);

  // Set trigger frequency (frame rate)
  arv_fake_camera_set_trigger_frequency(ARV_FAKE_CAMERA(gv_fake_camera),
                                        10.0); // 10 FPS

  std::cout << "Fake Aravis camera is running. Press Ctrl+C to stop."
            << std::endl;

  // Handle SIGINT and SIGTERM to allow graceful exit
  signal(SIGINT, control_c_signal);
  signal(SIGTERM, control_c_signal);

  // Create and run the main loop
  GMainLoop *main_loop = g_main_loop_new(NULL, FALSE);

  // Run the main loop until interrupted
  while (!stop) {
    g_main_context_iteration(NULL, FALSE);
  }

  // Cleanup
  g_main_loop_unref(main_loop);
  g_object_unref(gv_fake_camera);

  return EXIT_SUCCESS;
}

The xml context I used:

<?xml version="1.0" encoding="UTF-8"?>
<GenICamXML>
  <Device>
    <DeviceModelName>Fake_Aravis_Camera</DeviceModelName>
    <DeviceVendorName>FakeVendor</DeviceVendorName>
    <SerialNumber>3</SerialNumber>
    
    <!-- Pixel Format Enumeration -->
    <PixelFormat>
        <EnumEntry name="Mono8">
    <Value>0x01080001</Value> <!-- Standard GenICam value for Mono8 -->
  </EnumEntry>
      <!-- You can add more pixel formats here if needed -->
    </PixelFormat>
    
    <!-- Width Parameter -->
    <Width>
      <Int64Min>1</Int64Min>
      <Int64Max>800</Int64Max>
      <Int64Inc>1</Int64Inc>
      <Int64Default>320</Int64Default>
    </Width>
    
    <!-- Height Parameter -->
    <Height>
      <Int64Min>1</Int64Min>
      <Int64Max>600</Int64Max>
      <Int64Inc>1</Int64Inc>
      <Int64Default>240</Int64Default>
    </Height>
    
    <!-- Trigger Frequency Parameter -->
    <TriggerFrequency>
      <FloatMin>0.0</FloatMin>
      <FloatMax>1000.0</FloatMax>
      <FloatInc>0.1</FloatInc>
      <FloatDefault>10.0</FloatDefault>
    </TriggerFrequency>
    
    <!-- Acquisition Mode Enumeration -->
    <AcquisitionMode>
      <EnumEntry name="Continuous">
        <Value>0</Value>
      </EnumEntry>
      <EnumEntry name="SingleFrame">
        <Value>1</Value>
      </EnumEntry>
      <EnumEntry name="MultiFrame">
        <Value>2</Value>
      </EnumEntry>
    </AcquisitionMode>
    
    <!-- Add more parameters as needed -->
  </Device>
<GenICamXML/>

Expected behavior
The camera should appear in the arviewer or in the arvtools.

Platform description:

• Aravis version 0.8.33
• OS: 5.10.192-tegra
• Hardware arm64

[EmmanuelP]

Hi,

The XML data you have attached is really what you are giving to the fake camera ? It is highly incomplete.

[Rz-Rz]

Do you have an example on how to properly write this document? Since I have limited knowledge of aravis/gigevision I would love to have any kind of info on how to properly populate the xml document.

[Rz-Rz]

I also tried a simpler method without an xml and a custom fill pattern but it does not work :

#include <arv.h>
#include <csignal>
#include <iostream>

static GMainLoop *g_main_loop = nullptr;

// Callback matching ArvFakeCameraFillPattern signature.
// Parameters:
//   - buffer: The image buffer to fill.
//   - user_data: A user pointer (unused in this example).
//   - width, height: Dimensions of the image.
//   - payload: The expected size of the image buffer in bytes.
void fill_pattern_callback(ArvBuffer *buffer, void *user_data,
                           unsigned int width, unsigned int height,
                           unsigned int payload) {
  size_t size;
  // Obtain a writable pointer to the buffer data (casting away const is safe
  // here).
  uint8_t *pixels = const_cast<uint8_t *>(
      static_cast<const uint8_t *>(arv_buffer_get_data(buffer, &size)));
  if (!pixels)
    return;

  // Fill with a simple gradient pattern.
  for (unsigned int y = 0; y < height; ++y) {
    for (unsigned int x = 0; x < width; ++x) {
      pixels[y * width + x] = static_cast<uint8_t>((x + y) & 0xFF);
    }
  }
}

static void signal_handler(int signum) {
  if (g_main_loop)
    g_main_loop_quit(g_main_loop);
}

int main(int argc, char **argv) {
  // g_type_init() is deprecated in GLib 2.36 and later, so only call it if
  // needed.
#if !GLIB_CHECK_VERSION(2, 36, 0)
  g_type_init();
#endif

  // Create a fake GigE Vision camera. Passing nullptr uses the loopback
  // interface.
  ArvGvFakeCamera *gv_cam = arv_gv_fake_camera_new(nullptr, "SIMCAM01");
  if (!gv_cam) {
    std::cerr << "Failed to create fake camera\n";
    return -1;
  }

  // Get the underlying fake camera object.
  ArvFakeCamera *fake_cam = arv_gv_fake_camera_get_fake_camera(gv_cam);

  // Set our custom fill pattern callback.
  arv_fake_camera_set_fill_pattern(fake_cam, fill_pattern_callback, nullptr);

  // Set the frame rate to 30 FPS.
  arv_fake_camera_set_trigger_frequency(fake_cam, 30.0);

  std::cout << "Fake camera streaming on loopback (serial: SIMCAM01)\n";
  std::cout << "Press Ctrl+C to exit." << std::endl;

  std::signal(SIGINT, signal_handler);

  // Start the GLib main loop to keep the fake camera running.
  g_main_loop = g_main_loop_new(nullptr, FALSE);
  g_main_loop_run(g_main_loop);

  // Cleanup.
  g_object_unref(gv_cam);
  g_main_loop_unref(g_main_loop);

  return 0;
}

When I try to read it using aravissrc I get :

gst-launch-1.0 aravissrc camera-name=SIMCAM01 ! videoconvert ! autovideosink

Setting pipeline to PAUSED ...
ERROR: from element /GstPipeline:pipeline0/GstAravis:aravis0: Could not find camera "SIMCAM01": Device 'SIMCAM01' not found
Additional debug info:
../gst/gstaravis.c(457): gst_aravis_init_error (): /GstPipeline:pipeline0/GstAravis:aravis0
ERROR: pipeline doesn't want to preroll.
ERROR: from element /GstPipeline:pipeline0/GstAravis:aravis0: GStreamer error: state change failed and some element failed to post a proper error message with the reason for the failure.
Additional debug info:
../libs/gst/base/gstbasesrc.c(3556): gst_base_src_start (): /GstPipeline:pipeline0/GstAravis:aravis0:
Failed to start
ERROR: pipeline doesn't want to preroll.
Failed to set pipeline to PAUSED.
Setting pipeline to NULL ...
Freeing pipeline ...

but using arv camera it seems it is recognizable :

 ./arv-camera-test-0.8
Looking for the first available camera
vendor name            = Aravis
model name             = Fake
device serial number   = SIMCAM01
image width            = 512
image height           = 512
horizontal binning     = 1
vertical binning       = 1
exposure               = 10000 µs
gain                   = 0 dB
payload                = 262144 bytes
gv n_stream channels   = 1
gv current channel     = 0
gv packet delay        = 0 ns
gv packet size         = 1400 bytes
  6 frames/s -    1.57 MiB/s
  5 frames/s -    1.31 MiB/s
^C  5 frames/s -    1.31 MiB/s
n_completed_buffers    = 16
n_failures             = 0
n_underruns            = 0
n_timeouts             = 0
n_aborted              = 0
n_missing_frames       = 0
n_size_mismatch_errors = 0
n_received_packets     = 3120
n_missing_packets      = 0
n_error_packets        = 0
n_ignored_packets      = 0
n_resend_requests      = 0
n_resent_packets       = 0
n_resend_ratio_reached = 0
n_resend_disabled      = 0
n_duplicated_packets   = 0
n_transferred_bytes    = 4219968
n_ignored_bytes        = 0

[Rz-Rz]

Using arv-tool-0.8 I got :

Aravis-Fake-GV01 (127.0.0.1)                                                                                                                                                           
Aravis-Fake-SIMCAM01 (127.0.0.1) 

But when reading them :

gst-launch-1.0 -v aravissrc camera-name=Fake_1 ! videoconvert ! autovideosink                                                                                                        
                                                                                                                                                                                       
Setting pipeline to PAUSED ...                                                                                                                                                         
ERROR: from element /GstPipeline:pipeline0/GstAravis:aravis0: Could not find camera "Fake_1": Device 'Fake_1' not found                                                                
Additional debug info:                                                                                                                                                                 
../gst/gstaravis.c(457): gst_aravis_init_error (): /GstPipeline:pipeline0/GstAravis:aravis0                                                                                            
ERROR: pipeline doesn't want to preroll.                                                                                                                                               
ERROR: from element /GstPipeline:pipeline0/GstAravis:aravis0: GStreamer error: state change failed and some element failed to post a proper error message with the reason for the failu
re.                                                                                                                                                                                    
Additional debug info:                                                                                                                                                                 
../libs/gst/base/gstbasesrc.c(3556): gst_base_src_start (): /GstPipeline:pipeline0/GstAravis:aravis0:                                                                                  
Failed to start                                                                                                                                                                        
ERROR: pipeline doesn't want to preroll.                                                                                                                                               
Failed to set pipeline to PAUSED.                                                                                                                                                      
Setting pipeline to NULL ...                                                                                                                                                           
Freeing pipeline ...              

// OR

gst-launch-1.0 -v aravissrc camera-name=Aravis-Fake-SIMCAM01 ! videoconvert ! autovideosink                                                                                          
                                                                                                                                                                                       
Setting pipeline to PAUSED ...                                                                                                                                                         
Pipeline is live and does not need PREROLL ...                                                                                                                                         
Pipeline is PREROLLED ...                                                                                                                                                              
Setting pipeline to PLAYING ...                                                                                                                                                        
New clock: GstSystemClock                                                                                                                                                              
/GstPipeline:pipeline0/GstAravis:aravis0: stream = (null)                                                                                                                              
/GstPipeline:pipeline0/GstAravis:aravis0.GstPad:src: caps = video/x-raw, format=(string)GRAY8, width=(int)512, height=(int)512, framerate=(fraction)5/1                                
/GstPipeline:pipeline0/GstVideoConvert:videoconvert0.GstPad:src: caps = video/x-raw, width=(int)512, height=(int)512, framerate=(fraction)5/1, format=(string)YUY2                     
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = video/x-raw, width=(int)512, height=(int)512, framerate=(fraction)5/1, format=(st
ring)YUY2                                                                                                                                                                              
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage.GstPad:sink: caps = video/x-raw, width=(int)512, height=(int)512, framerate=(f
raction)5/1, format=(string)YUY2                                                                                                                                                       
/GstPipeline:pipeline0/GstAutoVideoSink:autovideosink0.GstGhostPad:sink: caps = video/x-raw, width=(int)512, height=(int)512, framerate=(fraction)5/1, format=(string)YUY2             
/GstPipeline:pipeline0/GstVideoConvert:videoconvert0.GstPad:sink: caps = video/x-raw, format=(string)GRAY8, width=(int)512, height=(int)512, framerate=(fraction)5/1                   
Redistribute latency...                                                                                                                                                                
^Chandling interrupt.                                                                                                                                                                  
Interrupt: Stopping pipeline ...                                                                                                                                                       
Execution ended after 0:00:05.321237118                                                                                                                                                
Setting pipeline to NULL ...                                                                                                                                                           
Freeing pipeline ...                                 

I just get black screen.