Hollyland Mars 300 Pro HDMI Wireless Transmitter/Receiver Set: Sending a Camera Feed to Your Computer

The short answer

The Hollyland Mars 300 Pro is a matched pair of devices: a transmitter that takes an HDMI signal from your camera, and a receiver that outputs that signal over HDMI somewhere else, without a long cable between them. It replaces the cable run. It does not turn your camera into a webcam by itself.

Most computers cannot accept an HDMI signal as a camera input, because their HDMI ports are usually outputs for displays. To use the receiver's output in Zoom, Teams, Meet or a browser-based call, connect the receiver to an HDMI-to-USB capture device. A capture device converts the HDMI video into something the computer recognizes as a camera. The full chain looks like this:

• Camera HDMI output → Mars 300 Pro transmitter
• Mars 300 Pro transmitter → wireless link → Mars 300 Pro receiver
• Receiver HDMI output → HDMI-to-USB capture device
• Capture device USB → computer, where it appears as a selectable camera

If your goal is a monitor or TV rather than a computer, skip the capture device and connect the receiver directly to the display's HDMI input.

What the supplied information does not confirm

No verified specifications were available for this guide. That means it makes no claims about the set's range, latency, supported resolutions and frame rates, power options, battery compatibility, audio passthrough, or price. Before you build a setup around any of those, check the official product page, the printed manual, or the retailer listing for the exact model you own or plan to buy. Where a step below depends on one of these details, it is marked as something to verify.

What you need before you start

• A camera with HDMI output. Many DSLR and mirrorless cameras use a mini or micro HDMI port, so you may need a cable with the matching connector on the camera end.
• The Mars 300 Pro transmitter and receiver, plus whatever power each one requires (verify in the manual).
• An HDMI-to-USB capture device that your operating system supports, if the video is going into a computer.
• A way to keep the camera powered during a long call, such as a mains adapter or dummy battery made for your camera model, if one exists for it.
• A separate microphone, or a confirmed audio path through the camera, as covered in the audio section below.

Step 1: Prepare the camera's HDMI output

The camera has to send a usable picture before anything downstream can work. Look through its menus for these settings. Their names vary by manufacturer.

• Clean HDMI output: turn off on-screen information, such as focus points, battery icons and exposure readouts, so it does not appear in your call. Some cameras call this HDMI info display; on others it is tied to a specific shooting mode.
• HDMI output resolution and frame rate: choose a mode that both the Mars 300 Pro and your capture device accept. Check both devices' documentation. A mismatch is a common cause of a black screen.
• Auto power-off and sleep timers: disable them, or set them as long as possible, so the camera does not switch off mid-call.
• Video or movie mode: some cameras only provide a continuous clean feed in this mode.

Some cameras limit HDMI output or overlay information that cannot be removed. If yours does, the wireless set cannot fix that, because it only carries what the camera sends.

Step 2: Connect and pair the transmitter and receiver

• Connect the camera's HDMI output to the transmitter's HDMI input.
• Power on the transmitter and the receiver.
• Pair them or select a matching channel, following the procedure in the Mars 300 Pro manual. The exact buttons and indicator behavior were not part of the information available here.
• Connect the receiver's HDMI output to a monitor first, if you have one. This confirms the wireless link carries a picture before you add a capture device.

Wireless video links are generally more reliable with a clear line of sight between the transmitter and receiver, and with the units kept away from metal obstructions and other busy wireless equipment. If the picture drops out, move the units closer or reposition them before changing other settings.

Step 3: Bring the signal into the computer

• Connect the receiver's HDMI output to the capture device's HDMI input.
• Connect the capture device to the computer by USB. Use a port that provides the bandwidth the capture device requires, which is listed in its documentation.
• Wait for the operating system to recognize it. Many capture devices work as standard USB video devices without extra drivers, but confirm this for your model.
• Open your call app or browser and select the capture device from the camera list. It usually appears under the capture device's name, not the camera's.

Step 4: Check each stage separately

A camera appearing in a list, a working picture, and a good call are three different results. Checking them in order shows where a problem sits.

• Detection: the capture device appears as a camera option in your operating system or app. This proves the computer sees the hardware, not that video is arriving.
• Video capture: the preview shows a live, moving image from your camera. If the device is listed but the preview is black, the problem is upstream: the camera output, the wireless link, or a resolution mismatch.
• Call quality: other participants see a clear, smooth picture. This also depends on your internet connection, the call service's compression and your computer's load, none of which the wireless set controls. A test call or the app's own preview is the most direct way to judge it.

Browser and operating-system permissions

If the capture device works in one app but not in a browser-based call, permissions are a likely cause.

• Windows: open Settings, then Privacy & security, then Camera. Make sure camera access is on for the device and allowed for desktop apps or the specific app you use.
• macOS: open System Settings, then Privacy & Security, then Camera. Make sure your browser or call app is allowed. You may need to restart the app after changing this.
• Browsers: when the site asks for camera access, allow it. If you previously blocked it, change the site's camera permission in the browser's site settings, usually reached from the icon beside the address bar. Then choose the capture device in the site's video settings.
• Only one app at a time: on some systems, if another program such as recording software is already using the capture device, the call app may show a black or frozen image. Close the other program and try again.

Audio: decide where your sound comes from

HDMI can carry audio alongside video, but the available information does not confirm whether the Mars 300 Pro passes the camera's audio through to the receiver. Treat that as something to check in the manual and to test yourself. Two common approaches:

• Audio through the camera: a microphone plugs into the camera, the camera embeds the audio in its HDMI output, and the capture device presents it to the computer as a microphone input. This only works if every link in the chain carries audio: the camera, the wireless set and the capture device.
• Separate microphone: a USB microphone or headset connects directly to the computer and is selected as the input in your call app. This avoids depending on the wireless set for sound.

Verify audio the same layered way as video. The microphone being listed is detection. The input level meter moving when you speak is input activity. A test recording or test call sounding clear is intelligible sound. Passing the first two does not guarantee the third.

With a separate microphone, the video passes through the wireless link and the capture device while the audio goes straight to the computer, so the two can drift slightly out of sync. If your lips and voice don't match in a test recording, some software, such as OBS, lets you add an audio delay to compensate. Whether this is needed depends on your specific equipment, so test before an important call.

Quick troubleshooting

Symptom | Likely cause | What to check

No picture on a monitor connected to the receiver | Camera not outputting HDMI, units not paired, or unsupported output mode | Camera HDMI settings, pairing per the manual, a different output resolution

Picture on the monitor, black in the computer | Capture device does not accept the incoming format, or another app is using it | The capture device's supported formats; close other video apps

Capture device not listed at all | USB connection, drivers or port | A different USB port or cable; the capture device's compatibility notes

Works in a desktop app, not in the browser | Browser or operating-system camera permission | Site permissions and system privacy settings

Camera menus or icons visible in the call | Clean HDMI output not enabled | The camera's HDMI info display setting

Picture cuts out intermittently | Wireless obstruction, distance or interference | Line of sight and distance between the units

Camera shuts off during calls | Auto power-off or battery drain | Power-saving settings and a continuous power source

When the wireless set is worth it

A wireless HDMI link is most useful when the camera sits far from the computer, when a cable across the room would be a trip hazard or an eyesore, or when the same feed also goes to a monitor or switcher. If your camera sits on the desk next to the computer, a direct HDMI cable to the capture device does the same job with fewer parts to power, pair and troubleshoot.