BlackVue Sub-Stream Technology is an exclusive feature supported by BlackVue’s high-end dashcam models. Learn how it allows BlackVue dashcams to combine high-quality recording and fast wireless video browsing and reviewing.

How Sub-Stream came to be?

BlackVue’s engineers were in a pickle, faced with two seemingly contradictory user needs to satisfy: bigger file sizes and faster connectivity. How to maintain a smooth user experience—including quick reviewing of videos via smartphone—while raising the bar in terms of video fidelity?
As microSD card capacity keeps going up—faster than connection speed—and users clamor for ever higher bitrate/better video quality, the challenge seemed insurmountable. 

Combining larger file size and faster download speed

To improve video quality, a solution is to increase the bitrate, which is the amount of data recorded per second. The BlackVue DR750S Series launched with a maximum bitrate of 12 Megabits per second. In February 2018, an updated increased the bitrate to 25 Mbps for the front camera. Users loved the improved video quality but some of them complained about the longer time required to review files over Wi-Fi or the Cloud.
A couple months later, the DR900S 4K dashcam series’ launch introduced sub-streams, which solved the problem for both DR750S and DR900S models.

The solution

Rather than compromising on image quality, BlackVue opted to combine low-resolution and full-resolution videos in a single file.  

As we wrote in our review of new features introduced in 2018: 

Sub-streams are small-sized copies of the original videos recorded by your dashcam. While the original files are large and usually require some buffering to play even over direct Wi-Fi, sub-streams play instantly. Even over the Cloud, buffering is almost nonexistent.

For example, a 1-minute video at 25Mbps (Extreme) will be about 187MB in size. That’s a lot of data to load over Wi-Fi.
By comparison, the sub-stream version (called Quick Play file in the app and Viewer) is only about 4MB! 

How to use it? 

Sub-streams are saved and don’t need to be activated. When viewing a video over Wi-Fi or the Cloud, you will be asked to choose to view the Quick Play file or Original resolution file. Simply choose Quick Play file. In can you tick the “Don’t show again” box, you can change this setting in the App settings menu of the BlackVue app. From the Main menu, swipe from left to right > App settings > Video streaming/playback quality.