This help article is linked from the two help articles Making Video Recordings and Broadcasting Your Sessions.
In this help article, we explain how to crop your JamKazam session video in OBS so that you capture only the part of the screen you want in your video. You don't have to do this, but if you want a polished, high-quality broadcast, you will need to do this one time, and then it will save your crop settings for all future recordings. We also explain how to adjust the overall audio volume in your video recording (if too high or low), and how to adjust the sync of video vs. audio (if not well synchronized), but you probably won't need to do these things.
Cropping Your JamKazam Video in OBS
There is one adjustment you will very likely need to make to capture great video for session recordings and broadcasts. When you open the OBS Studio app (with JamKazam video turned on in your session), take a close look at the video preview you see there (pictured below), and note that I can see part of the browser toolbar at the top of the browser window that is displaying my JamKazam session video. You may also see some of the video user interface controls at the bottom of the JamKazam session video in OBS.
You probably don't want this included in your video recording. Unfortunately, JamKazam can't automatically crop out the exact "right" portion of the screen for you because every user's system is a little bit different. So you will likely need to crop your own JamKazam video screen (just one time) in OBS to tweak and fix this for your computer. To do this, on a Windows computer, right mouse click on the "Window Capture" control listed under "Sources" in OBS Studio (pictured below). On a Mac, hold down the "control" key and click the mouse on the "Window Capture" control.
You'll see a menu displayed (shown above). Click on the Filters option near the bottom of this menu. You will now see a dialog box displayed that previews the JamKazam video window (pictured below).
Click the "+" button at the bottom of the Effect Filters (pictured above with arrow). A menu of filter options is displayed (pictured below). Click on the "Crop/Pad" option.
A dialog is displayed (pictured below).
You can just click the OK button to accept this. Now you'll see a dialog box with cropping controls you can use to get rid of things you don't want visually included in your recorded video (pictured below).
To get rid of the browser bar at the top of your screen, start increasing the numeric crop value of "Top". You can do this by holding down the up/down arrow on Top, or by entering a number directly using your keyboard. You'll see real-time visual feedback as you do this to help you get it set in the right place. I had to set Top cropping to 175 to fully get rid of my browser bar. You may also need to crop the "Bottom" of the video window if you're seeing any of JamKazam's video UI controls that are displayed in the lower right part of the video screen. You shouldn't need to crop Left or Right, but you certainly can if you want to. When you're happy with the video that's being captured in the preview, simply click the Close button in the lower right of the dialog box. You'll now be back to the main OBS Studio screen, and you'll see an updated video capture that should reflect your new cropping settings (pictured below), and the parts of the session video window you didn't want to record or broadcast are gone.
If you're happy with this, you're good to go. OBS will remember this setting, so you don't need to do it every time you make a video recording.
Adjusting Volume and Audio/Video Synchronization
A couple of other features for video recording and broadcasting that you probably won't need to use - but are worth reviewing just in case - are covered below. To access these features, click the gear icon at the bottom of the OBS Audio Mixer controls (pictured below with arrow).
You'll see a dialog box with various audio controls (pictured below).
There are two controls you may find useful here.
Volume - If you find that the overall volume of the audio in your video recording or live broadcast is lower or higher than you'd like, you can use the Volume control to increase or decrease the volume that's coming from JamKazam into OBS. For example, if you use the up/down arrows to increase Volume to 6.0dB, it increases the session audio volume from JamKazam by 6 decibels.
Sync Offset - If you find that video is slightly ahead of or behind the audio in your recording (e.g. you strum your guitar in the video after you hear the strum in the audio), you can use the Sync Offset control to adjust this. Let's say your video seems to be about one tenth of a second ahead of your audio in a video recording you've made. In this case, you would set the Sync Offset value to 100ms. This is 100 milliseconds. One millisecond is one thousandth of one second, so 100 milliseconds is one tenth of one second. This Sync Offset value will move your audio "to the right" in your recording by one tenth of one second, which would make the audio in sync with the video of your guitar strum.