Is 4k video on WebRTC feasible?

4k video-webrtc

A number of vendors today are building their product differentiation by offering 4k video conferencing capabilities, but here we present the practical challenges that one faces with using 4k video. Even if you have a monitor/device that supports the resolution 4k comes with, the chances are that your browser might not be supportive of it. The API GetUserMedia, which is used to access a user’s webcam and microphone directly through the browser (not through a plug-in), is available only on Google Chrome 21 browser. And provided you have that too, there are still a number of challenges that need addressing-

A higher Resolution implies higher bandwidth

A 4k video has a resolution of 4096 x 2160 (or 3840 x 2160). As a result, the internet speed required to render these videos is in the range of 15-20 Mbps per stream. And this is just one user we are considering here. If you add more users to the scenario (which is inevitably the case with video conferences), the bandwidth requirement increases by 20 Mbps for every user. To sum up, in a 3-party call, you need 60 Mbps bandwidth for smooth video transmission (20 Mbps uplink and 40 Mbps downlink).

To provide you with a frame of reference, here is a summary of the possible resolutions of a video and the corresponding bandwidths required-

RATE OF STREAMING Mode
15-20 Mbps 4K
4-8 Mbps 1080p
1-4 Mbps 720p
500K – 1 Mbps VGA(640×480)
300K – 500K QVGA(320×320)

As is evident, a 4k video requires 5 times the bandwidth required for a regular 720p video. It is a no-brainer then that the cost involved shall be much higher too.

Is the required speed sustainable?

Now, let us say you are willing to bear the cost. Even in that case, there is a graver issue that surrounds this transmission. The issue of consistent uplink-downlink speeds by the ISP. Consider this- you are assuming that the internet connection equipped with the network elements involved in transmitting this high-resolution video from one browser to another will also have to possess the high speed for the data to be transported. But in most ISP connections the upload link is not as fast as the download link. Also, the speed fluctuates depending on the current load. For example, a 100 Mbps connection might be providing you with only 10 Mbps on an average; with some peaks to 30-40 Mbps of course. But does that suffice for continuous streaming of a 4k video? Doubtful.

Even if you begin with a 2-party call, a constant need of 20 Mbps uplink and downlink can result in a lot of buffering and network saturation. Surely, user experience needs to be rated higher than the intermittent resolution.

Does your browser support 4k?

Like we said at the beginning of this article, not all browsers are 4k ready. Also, imagine having to use this on-the-go on your mobile phone. There is no doubt that the mobile phones of today have much higher processing capabilities but this constant upkeep with higher bandwidth to maintain the resolution might just wipe your battery out sooner than you think. Most mobile browsers as well might not be supportive of the APIs needed to enable such video calls via 4k.

In summary, we are not trying to discourage the use of 4k. We are clearly inching towards a time when 4k shall be more easily accessible via better network speeds and better processing equipment; but for now, we think there is still time till that happens. WebRTC can support 4k but rendering 4k videos might not be practically and commercially viable as on today.


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