# 3rd stack GENTL (no VIN) : how to get timestamp

**URL:** <https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896>\
**Category:** Programming Questions\
**Tags:** acquisition, genicam, gigevision\
**Created:** [January 24, 2023, 4:06pm UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896 "2023-01-24T16:06:25Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![Mikael](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mikael](https://forum.commonvisionblox.com/u/Mikael)\
**Post date:** [January 24, 2023, 4:06pm UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/1 "2023-01-24T16:06:25Z")

</div>

Hello,  
I am working with an ATC6 camera and a dala Linea 2g GIGE camera.  
I use multipart image (because of ATC6).  
For ATC6, I can get timestamp and other info in chuck datas.

For Linea, I would like to retrive timestamp. I can do it with end of line meta data. But there must be something standard with CVB++ initialized with GENTL flag. I konw how to get it from the VIN, but not using CVB++ GenTL.

I’ve initialized my datastream with 🙂  
`m_dataStream = m_device->Stream<Cvb::CompositeStream>(); `  
How can I get the timestamp (moment image was triggered)?  
Best regards,  
Mikael.

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<div class="post-metadata">

**Author:** ![Simon](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.commonvisionblox.com/simon/32/847_2.png) [@Simon](https://forum.commonvisionblox.com/u/Simon)\
**Post date:** [January 25, 2023, 8:13am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/2 "2023-01-25T08:13:31Z")

</div>

Hi @Mikael,

did you activate _AttachChunk_ when using the GenTL?  
You can refere to here (only samples for .NET and Python): [https://forum.commonvisionblox.com/t/using-chunk-data-in-cvb/1895](https://forum.commonvisionblox.com/t/using-chunk-data-in-cvb/1895)

Otherwise you could use this C++ code snippet to activate _AttachChunk_ using GenTL:

```auto
auto vinDeviceNodemap = VinDeviceNodeMap(dev);
auto AttachChunk_node = vinDeviceNodemap->Node<Cvb::BooleanNode>(Cvb::String("AttachChunk"));
AttachChunk_node ->SetValue(true);

```

Afterwards handling _ChunkData_ is equal to using the vin driver.

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<div class="post-metadata">

**Author:** ![Mikael](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mikael](https://forum.commonvisionblox.com/u/Mikael)\
**Post date:** [January 25, 2023, 9:40am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/3 "2023-01-25T09:40:26Z")

</div>

Hi Simon,  
with Dalsa Linea, I get an exception:

`Node[Cost::AttachChunk] : no write access to node`

There are no chunkdata with Dalsa Linea.

If I use this below, it seems to give the timestamp after the image is received in the PC. Not the frame trigger timestamp.

```auto
std::tie(multiPartImage, waitStatus, enumeratorNodeMap) = streams[streamIndex]->WaitFor(TIMEOUT);

auto vinBufferNodemap = enumeratorNodeMap["VinBuffer"];

auto timeStamp = vinBufferNodemap->Node<Cvb::IntegerNode>("Timestamp")->Value();

```

How can I get frame trigger timestamp? Using VIN it was possible, I think with GenTL there must be something. I’ve checked it using end of line metadata.

Regards,  
Mikael.

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<div class="post-metadata">

**Author:** ![Simon](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.commonvisionblox.com/simon/32/847_2.png) [@Simon](https://forum.commonvisionblox.com/u/Simon)\
**Post date:** [January 26, 2023, 8:39am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/4 "2023-01-26T08:39:54Z")

</div>

Hi @Mikael,  
there are multiple reasons why this is not working.

Using the EndOfLineMetadata of the Linea differs from handling Metadata/Chunk Data from different camera models.  
In case of the Linea EndOfLineMetadata means that all information is added to the camera image using the last pixels for each line. The number of used pixels is depending on the number and type of activated metadata.  
Here are example images from the Linea grabbed using the GenICam Browser:  
Without Metadata:

 ![grafik](https://canada1.discourse-cdn.com/flex027/uploads/commonvisionblox/original/2X/6/65c3a5455782488170e9e4732e789424614189dc.png)

With Metadata Active (ExposureTime and Timestamp):

 ![grafik](https://canada1.discourse-cdn.com/flex027/uploads/commonvisionblox/original/2X/a/a4481378cf7637f5009e6b604864b9a981f04e6c.png)

The number of pixels per line stays equal to 2048 for the Linea 2K, so you will loose information from the pixels used for Metadata.

Now extracting these data from code in CVB could look like this:

```auto
using Stemmer.Cvb;
using Stemmer.Cvb.Driver;
using Stemmer.Cvb.GenApi;

namespace CVB_LineaMetadata
{
  internal class Program
  {
    static void Main(string[] args)
    {
      DiscoveryInformationList discoveryList = DeviceFactory.Discover(DiscoverFlags.IgnoreVins);
      if (discoveryList[0].AccessToken.Contains("Linea"))
      {
        //discoveryList[0].SetParameter("AttachChunk", "1");
        //Open Linea using GenTL
        using (Device device = DeviceFactory.Open(discoveryList[0]))
        {
          Stream stream = device.Stream;
          NodeMap nodemap = device.NodeMaps[NodeMapNames.Device];

          //Activating Metadata
          EnumerationNode metadatamode = nodemap["Cust::endOfLineMetadataMode"] as EnumerationNode;
          metadatamode.Value = "Active";
          EnumerationNode metadataContentSelector = nodemap["Cust::endOfLineMetadataContentSelector"] as EnumerationNode;
          EnumerationNode metadataContentActivationMode = nodemap["endOfLineMetadataContentActivationMode"] as EnumerationNode;
          metadataContentSelector.Value = "ExposureTime";
          metadataContentActivationMode.Value = "True";
          metadataContentSelector.Value = "Timestamp";
          metadataContentActivationMode.Value = "True";

          //Get Metadata Size
          long metadataPixelCount = (nodemap["Cust::endOfLineMetadataPixelCount"] as IntegerNode).Value;
          //Get Line Width
          long linewidth = (nodemap["Std::Width"] as IntegerNode).Value;
          long imageheight = (nodemap["Std::Height"] as IntegerNode).Value;
          byte[,] metadata = new byte[imageheight, metadataPixelCount];
          int offsetMetadata = (int)(linewidth - 1 - metadataPixelCount);
          //Start Stream
          stream.Start();
          for (int i = 0; i < 10; i++)
          {
            using(Image image = stream.Wait())
            {
              LinearAccessData<byte> imageData = image.Planes[0].GetLinearAccess<byte>();
              for(int y = 0; y < imageheight; y++)
              {
                for(int x = 0; x < metadataPixelCount; x++)
                {
                  metadata[y,x] = imageData[(x+ offsetMetadata), y];
                }
              }
              //Decode Metadata...
            }
          }
          stream.Abort();
        }
      }
    }
  }
}

```

Note that Chunk Data do not need to be activated on the driver side as theese are not Chunk Data in this context and just data that are written to the transmitted image.

To receive the FrameTriggerTimestamp you would need to use a completely different approach.  
You will need to use Event handling to receive _Cust::EventValidFrameTriggerTimestamp_ for each valid frame trigger. How to use event data, please have a look [here](https://forum.commonvisionblox.com/t/gige-vision-events/190).

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<div class="post-metadata">

**Author:** ![Mikael](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mikael](https://forum.commonvisionblox.com/u/Mikael)\
**Post date:** [January 26, 2023, 10:45am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/5 "2023-01-26T10:45:10Z")

</div>

Hi Simon,  
I’ve used end of line metadata that is why I discovered that the timestamp from “VinBuffer” is not the frame trigger timestamp. This timestamp is more than 100ms after the last line timestamp in the image (in end of line metadata): it is probably a timestamp after the image is received in the PC. Which is not a reliable timestamp (if I make no mitake).  
 → this is strange, I have big doubts with this timestamp! A timestamp must come from the camera with the image.

If I compare with GENICAM.VIN, using “DCBinaryCommand DC\_BUFFER\_INFO\_TIMESTAMP” was reliable and associtated to frame trigger and coming from the camera.

Using GenTL should also give the same results. So where is the problem?

Regards,  
Mikael.

---

<div class="post-metadata">

**Author:** ![Simon](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.commonvisionblox.com/simon/32/847_2.png) [@Simon](https://forum.commonvisionblox.com/u/Simon)\
**Post date:** [January 26, 2023, 12:31pm UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/6 "2023-01-26T12:31:15Z")

</div>

Hi @Mikael,

the best option to get the correct timestamp from the camera would be using the [StreamImage Class](https://help.commonvisionblox.com/NextGen/14.1/cvbpp/d0/dc1/class_cvb_1_1_driver_1_1_stream_image.html) for image acquisition which will contain the camera timestamp as using “DCBinaryCommand DC\_BUFFER\_INFO\_TIMESTAMP”.

You could also read the timestamp from the last or first acquired line using EndOfLineMetadata. Depending on which timestamp you really require.  
Third option is to use the Event Data mentioned above from the camera where you can exactly specify which event should be tracked (Valid Frame Trigger, Frame Start, Frame End)

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<div class="post-metadata">

**Author:** ![Mikael](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mikael](https://forum.commonvisionblox.com/u/Mikael)\
**Post date:** [January 26, 2023, 1:56pm UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/7 "2023-01-26T13:56:29Z")

</div>

Thanks Simon,

I am using an ATC6 camera and Linea 2k camera (and later a linea swir).  
Because of ATC6, I used for all cams a composite stream.  
I cannot fing RawTimeStamp in that case (or I did not find the way to do it).

How can I do to get RawTimeStamp? Was composite stream the good choice?

Regards,  
Mikael.

---

<div class="post-metadata">

**Author:** ![Simon](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.commonvisionblox.com/simon/32/847_2.png) [@Simon](https://forum.commonvisionblox.com/u/Simon)\
**Post date:** [January 27, 2023, 11:58am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/8 "2023-01-27T11:58:31Z")

</div>

Dear @Mikael

pleas see the following code to acquire the GEV Timestamp from the VinBuffer using 3rd generation image acquisition stack:

```auto
auto devices = DeviceFactory::Discover(DiscoverFlags::IgnoreVins);
auto device = DeviceFactory::Open<GenICamDevice>(devices[0].AccessToken(), AcquisitionStack::GenTL);
auto stream = device->Stream<CompositeStream>(); // default: index = 0 (1)
stream->Start(); // (2)
for (int i = 0; i < 10; ++i)
{
  CompositePtr composite;
  WaitStatus status;
  NodeMapEnumerator nodeMaps;
  std::tie(composite, status, nodeMaps) = stream->Wait(); // C++14 (3)
  auto [composite, status, nodeMaps] = stream->Wait(); // C++17 (3)
  auto vinBufferNodemap = nodeMaps["VinBuffer"];
  auto bufferTimpestamp = vinBufferNodemap->Node<Cvb::IntegerNode>("Timestamp")->Value();
}
stream->Abort(); // (4)

```

Instead of CompositeStream you can use ImageStream for the Dalsa Linea.  
This will give you the timestamp of acquisition start from the camera.  
When I read the VinBuffer Nodemap Timestamp and compare it to the timestamps from my first and last line the result is as as follows:  
VinBuffer-Timestamp: 3897064003  
First Line: 3897064013  
Last Line: 3897166313  
So the VinBuffer Timestamp is to an earlier stage as the first line is acquired.

---

<div class="post-metadata">

**Author:** ![Mikael](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mikael](https://forum.commonvisionblox.com/u/Mikael)\
**Post date:** [January 27, 2023, 2:36pm UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/9 "2023-01-27T14:36:07Z")

</div>

Hi Simon,  
I understand my mistake.  
I was reading Metadata on the previous image!!!  
So the timestamp was always different from the timestamp given by “VinBuffer”.  
Sorry for ennoying you about this.  
Now I can see the timestamp has roughtly the same value than the timestamp in metadata of the first line.  
Thanks for your help.  
Mikael.

---

<div class="post-metadata">

**Author:** ![Simon](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.commonvisionblox.com/simon/32/847_2.png) [@Simon](https://forum.commonvisionblox.com/u/Simon)\
**Post date:** [January 30, 2023, 6:47am UTC](https://forum.commonvisionblox.com/t/3rd-stack-gentl-no-vin-how-to-get-timestamp/1896/10 "2023-01-30T06:47:00Z")

</div>

Hi @Mikael,

sounds good! I am happy that I could be of help.