I will need you to generate a trace file for me of the problem occurring using the Windows Performance Recorder from the Windows Performance Toolkit (part of the Windows 8.1 ADK) for me to provide assistance into what is happening here - instructions below.
1. Download/Run the installer for the Windows 8.1 ADK:
https://www.microsoft.com/en-us/download/details.aspx?id=39982
2. Use the default installation path, and click "Next":
3. After accepting the EULA, select to install just the Windows Performance Toolkit, and click "Install":
4. Installation should begin:
5. On a 64bit install of Windows, you will need to open an elevated CMD prompt and execute the following command, and then reboot:
If you have run the command successfully (as seen above), you will need to reboot. Reboot now, then continue.
6. Next, again from an elevated CMD prompt, run the following command to bring up the trace UI we will use to select tracing options and begin the trace:
7. This should open a window that looks like the one below (note that you may need to expand the "More Options" chevron on the left to get the full box). Select the "Audio glitches" or "Video glitches" checkboxes, depending on what problem you're having (audio or video stuttering, or both), along with the "First level triage" box (which should already be checked by default). Click the "Start" button to start tracing, and begin reproducing the problem:
8. Once running, you should see something like this - when you've traced the problem for at least a few seconds, click the "Save" button:
9. Enter a path to somewhere you can find it easily - C:\Trace.etl in this example (the file must use the .ETL extension), and then click the "Save" button:
10. If the file saved successfully, you will see something like this:
Compress (.zip, .rar, .7z, etc.) the resulting .etl file and upload to a file sharing site, then link back to your post so it can be downloaded and analyzed.