Viofo A139 Pro 2CH: Great Video, But Is It Reliable?

Viofo A139 Pro 4K+1080p dash cam

Technical Specifications

– Dual channel dash cam
– Released 2022
– Max. resolution: front 4K, rear 1080p
– Price: Amazon US / CAAliExpressmore countries & vendors (sponsored)
– Wi-Fi (2.4 or 5 GHz)
– Video format: MP4
– Supports up to 512 GB MicroSD cards
– Time and date stamp on video
– Lock file button
– CPL filter
– Novatek 96687 chipset
– Loop recording, auto on/off, G-Sensor, motion detection
– Parking modes: Buffered, time-lapse, low bit rate
– Operating temperature: from -20°C to 65°C (-4°F to 149°F)
– Storage temperature: from -20°C to 70°C (-4°F to 158°F)
– Apps for Android / iOS
– Internal capacitor instead of battery
– Internal microphone and speaker
– Adhesive mount
– Voice notifications
– CPL filter

Front Camera:
– Max. resolution: 3840×2160 @ 30fps
– Max. bit rate: 45 Mbps
– Size: 112mm x 60mm x 40mm
– Sony STARVIS 2 Sensor 8MP IMX678
– Aperture: f/1.6
– Angle of view: 140° diagonal

Rear camera:
– Max. resolution: 1920×1080 @ 30fps
– Max. bit rate: 16 Mbps
– Size: 53mm x 34mm x 28mm
– Sony STARVIS Sensor 2MP IMX291
– Angle of view: 170° diagonal

Viofo A139 Pro 2CH Review

We were excited about the Viofo A139 Pro because it’s the very first dash cam that uses Sony’s new Starvis 2 sensor. This camera records 4K resolution to the front and 1080p to the rear, and the new sensor really makes a huge difference in terms of video quality!

There is also a 3-channel version of this camera (4K+1080p+1080p), and a 1-channel version (4K front camera only).

Design & Use

Viofo A139 Pro 2CH dash camThe A139 Pro doesn’t have a screen. Like most Viofo dash cams, it is wedge shaped and thus quite discreet with its matte black finish.

The forward lens can be swiveled about 300° around a horizontal axis, to precisely adjust the field of view. You can even turn it around far enough to record the interior of the car when desired.

On the back side of the camera there are five buttons, including a large “lock file” or “emergency” button in the middle. This is the button that marks a video file for safe keeping, so it doesn’t get overwritten when the camera’s loop recording kicks in.

The other buttons are Power, Record, Mute Mic, and Toggle Wi-Fi buttons.

Red and blue LEDs show whether the camera is recording video and/or audio, and whether GPS and/or Wi-Fi are active.

A CPL filter is included by default. This is a first for Viofo: Previous Viofo cameras used to only offer a CPL filter as an optional extra.

This camera has no screen, so it is mainly operated through the smart phone app. It also supports a limited number of voice notifications (but no actual voice control).

The coaxial cable that runs from the front to the rear camera is quite thin, so you can easily stow it behind your car’s interior lining. It is only about 2.88mm (0.11″) in diameter.

Video Quality

Unlike most other 4K dashboard cameras, whose video quality drops off considerably at night, the Viofo A139 Pro 2CH records very good video with its forward camera both at day and at night time.

The same can be said for the 1080p rear camera: Video quality is always clear enough to be able to read license plates of other cars, even when they are in motion.

Check out the video samples below: This is the best quality footage we have seen from a dash cam in 2023.

Parking Modes

When powered with a hard-wiring kit (available separately), the Viofo A139 Pro 2CH supports three different types of parking mode:

  • Time-lapse: Records continuously, at a lower number of frames per second
  • Low bit rate: Records continuously, at a lower video quality
  • Buffered (“Auto Event Detection”): Records continuously, but only saves footage when an event is detected

We recommend buffered parking mode, because it only saves the footage you will actually need. In buffered mode, the A139 Pro saves video from 15 seconds before to 30 seconds after an event, such as an impact, is detected.

Overheating Issues

Several users have reported problems with this camera becoming very hot while recording. Some even reported the camera turning off or failing.

Apparently the high bit rate does make for a heavy load on the processor. So bear this in mind, especially if you are looking for a camera to use in hot climates.

Other Observations

The English language user manual is 18 pages. You can download a copy here (PDF). It seems to be well written and explains the functionality of the camera comprehensively.

The following extras are available for this camera (not included in the base price):

  • Hard-wiring kit (HK3-C or HK4, necessary for parking mode)
  • Bluetooth remote lock file button (can be placed conveniently near or on the steering wheel)


The Viofo A139 Pro 2CH records the best video quality we have seen so far (as of mid-2023). However, its tendency to overheat in warmer climates is a trade-off that we hope Viofo can fix at some point.


  • Best video quality in 2023
  • CPL filter included
  • Buffered parking mode


  • Overheating issues
  • No screen

Viofo A139 Pro 2CH Video Samples

For full original video quality, make sure to watch on full screen and select maximum video resolution (use the cog icon in lower right corner). You may have to rewind the video after changing the resolution.

Day Time Front Video Sample

Day Time Rear Video Sample

Night Time Front And Rear Video Sample

Video quality is very good, in all scenarios. You can easily read license plates of other cars, even when driving by at some distance.

Compare Prices And Buy Online Today

The Viofo A139 Pro is available for sale from the following vendors:

Amazon US / CA / DE / FR / ES / IT

eBay US / CA / UK / AU

AliExpress (global)


Links to vendors are affiliate links, and help to support this site.