Example Code
Code and Documents
Attachment
Inspired from LabVIEW portal - reference link
Library and examples provided as is, minor bugs (aka. features) included but still can be useful for someone who needs to acquire, compress and edit video/audio streams from various sources, directshow compatible devices and internet streams.
Works with GigE cameras if manufacturer provides directshow compatible filter. (Tested with Basler family).
DirectShow has a steep learning curve but once you get familiar with GraphEdit then samples from internet and examples from below should be sufficient to create sophisticated applications.
To back check your LabVIEW creating add
Wire it to your FilterGraph and open in GraphEdit program for inspection and debugging.
Requires:
Microsoft Windows SDK - download
Directshow.net library - download
DirectX.Capture class library - download
References:
DirectShow Debugging/ConceptProofing Tools:
GraphEdit (Microsoft Windows SDK)
Alphabetical and Numerically Logical String Array Sort for user menu facelift
BEFORE Opening any vi make sure you have in the same directory:
DirectShowLib-2005.dll
DShowNET.dll
DirectX.Capture.dll
logicalstringarraysort.llb
Great links:
H.264 CUDA Encoder directshow filter -> Examples Added 02/16/2013
Directshow virtual video capture source - aka printscreen
Other articles from Maxim Kartavenkov
02/16/2013 Update
H264Encoder requires:
- BaseClassesNET.dll
- H264Encoder.dll
I went with wrapper mode implementation. Check Maxim Kartavenkov forum for details.
H264 CUDA Encoder directshow filter example can be done entirely in BaseClassesNET.dll. Which might be done one day...
No error checking on CUDA capabilities.
Use with Nvidia GPU's only
Examples:
- Capture Video and H264 CUDA.vi
- Render Media Stream.vi
Updates to Library:
- Add H264 CUDA Filter.vi
- Create AviMux.vi - overrite file option added
- Enum Pin Media Type.vi
- Enum PinMediaTypes.vi
- Enum Pins.vi
- Free PinInfo.vi
- H264 CUDA Get Filter Options.vi
- H264 CUDA Set Filter Options.vi
- H264 Object Wrapper.vi
- H264 Settings.ctl
- Media Mode.ctl
- Media State.ctl
- MediaFormatType to String.vi
- MediaSubType to String.vi
- MediaType to String.vi
- AMMediaType to String.vi
- Picture Snap (32-bit RGB Image).vi - updated auto init
- Picture Snap (DIB Image).vi - updated auto init
- Set Sample Grabber.vi
- WaveFormatEx.ctl
- Capture.vi - updated to reflect above changes
- Minor tweaks
02/07/2013 Update
Examples:
- Acquire Video.vi
- Acquire Audio.vi
- Acquire Video plus Sample Grabber.vi
- Capture Video.vi
- Capture Video with Preview.vi
- Capture Video with Preview and Sample Grabber.vi
Updates to Library:
- Release Object.vi
- Init Capture Preview.vi
- Configure Capture plus Preview.vi
- Configure Video with Sample Grabber.vi
- Media Control - StartStopPause.vi
Updates to Capture.vi
- Preview in Capture Mode
- Proper Objects release upon start/stop/exit
Update 10/08/2014:
DShow - JPEG dump example.
-Artur
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.
Hello,
I find that the library is a great job.
Iam pretty new. I'm trying to use the example "DirectShow - Example - Sample Acquire Video plus Grabber.vi". On the computer with a USB webcam (logitech C270, Windows 10 and LabView 2014) it works properly. But I try to run on a tablet with Windows 10 (https://www.pccomponentes.com/energy-system-energy-tablet-8---windows-lego-edition) and I can see the image of the front camera, but it does not grab me (I get a picture in black, attached capture).
I noticed that the cameras of the tablet have a NV12 format camera and computer has a RGB format. In the case of I only need to transform from one to another, what would you add and where?
P.S .: If I connect the webcam on the tablet, it also works
Thanks in advanvance.
A greeting
Hi, Thank you.
I think colorspace filter in front of samplegrabber filter would do the job, but would be nice to check with GraphEdit program but you are on win10 tablet... Good luck 
I will be back in ofiice on Friday and check if i can re-produce your case on my PC.
-Artur
Thank you very much for answering so quickly.
My main problem is that I do not know how the library works and although I tried to find information, I still do not learn anything. I do not know how to connect terminals (if it had worked, it would have been lucky only).
I created a filter just before the filter "Grabber". But nothing changes. Surely it is not well done .
(I attached a screenshot of where I put the filter)
Thanks again.
Greetings
Hello,
I am checking the camera sensor and it is an Unicam ov2680.
Checking at the Internet the valid formats, it said that the supported valid format is RAW 10-bit RGB
How is that posible?
I could not find the "enum filters" vi so I creted this similar vi:
And the results that I get :
Hello,
I saw that you have the DirectShow JPEG Dump.vi that creates a JPEG string. However how do i then write this string to a JPG file?
Thank you for your help,
Russell
I was able to get the JPEG string to save to a file. One of my coworkers pointed me to the problem. There are null characters at the end of the JPEG string because the string buffer size. When we delete these characters at the end then we were able to write to a binary file and the image looked correct.
Thanks I had to set the prepend array or string size boolean to false as well.
Is there way with your VIs to set the input source type (i.e DVI, RGB) as well as all of the resolution and image settings?
Also do you know why the picture control might be show a black image (i.e. not the captured image), but the number of dropped fames is zero and the non dropped frames is increasing?
Thanks I was looking at one of the examples.
However I am still not getting an image in the picture control display. I can see that frames are being acquired, but they are not being shown in the display. I am trying to acquire from a DVI framegrabber that uses RGB video format. I have the framegrabber vendor's application that also uses DirectShow and the video is displayed properly. Since they are using DirectShow too I can see that the settings are same between your VI and their application. I actually built your VI into an executable since the computer framegrabber is in does not have LabVIEW installed.
Any thoughts on why the image is not being displayed in the DirectShow Capture.vi?
Unfortunately this comment section does not allow me to attach the VI. But I am using your DirectShow Capture.vi with no changes all I did was build it into an executable. Here is a picture of what I see when I try to run it:
I think the problem might be related to the video frame format and not the actual software program as a whole. If I use a PCIe frame grabber card with video frame format of RGB the image is not displayed. But I used PCIe frame grabber with video frame format of YUY2 and the image is displayed properly. My built in webcam uses MJPG and YUY2 and it also works properly.
So my question is there any reason the RGB video frame format might not be working?
Thank you,
Russell
Hi, Have you solved your problem?
Attached screen shot of Color Space converter, which should be placed automatically between pins if they are not compatible but can be converted with color space converter. Video renederer accepts RGB32, so RGB, RGB24, BGR and others should be upscaled to RGB32...
Hello,
I haven't had a chance to try your suggestion yet. Unfortunately I probably won't have a chance until Thursday. I will let you know what I find out.
Thank you for your help,
Russell
Hello,
I tried to use the GraphEdit tool, but for unfortunately it didn't install with the Windows Standalone SDK for Windows 10. However I did check the Video Capture Pin settings and it is configured for RGB32, see attached image. Unfortunately I have this frame grabber on loan from the vendor and I will need to send it back soon so I won't be able to do anymore testing. I think I will most likely go with another framegrabber because it worked in LabVIEW with no problems. I really appreciate your help. 
Have you checked top-level vi inside llb?
You should be able to do that with pop-up dialogs or programmatically.
Examples designed to be simple
-Artur
Thanks
Dear GriffinRU,
This is a job well done. Can you comment on whether or not I should expect stability if using multiple graphs with multiple cameras? I am especially interested in being able to store grabbed images as .bmps and have found that if I put the grab and store in a loop using multiple cameras, I eventually get a 1172 error for a .net assembly issue for either "Bitmap region is already locked." or "Object in Use". The error appears to be happening within the DirectShow - SampleGrabber Snap (Buffer).vi only if I call the following code on the same snapped image box.
Please let me know if you have any advice or need more information. Thank you for a very helpful project.
