The 4K First Mile: Launching 4K Streams

4K Webcast Encoder Options

If you need a portable, camera-mountable 4K webcast encoder, you will have to wait a bit longer for widespread end-to-end workflow solutions. Popular H.264 options don’t support 4K and newer H.265 options don’t enjoy CDN support with H.265 ingest and delivery.

There are two options you will want to look at if you require a portable H.265 webcast encoder. Teradek’s Cube 855 4K HEVC encoder is scheduled for release in Q4 2017 for a list price of $3,990. Boxcast also will be releasing a similar device called the Boxcaster Pro (Figure 4, below), which also features XLR inputs and supports HDR 10-bit. The Boxcaster Pro is scheduled for a Q3 2017 release for $990.

Figure 4. Boxcaster Pro

4K Webcast Service Providers

While webcast leaders IBM Cloud Video (formerly Ustream) and Livestream only list 720p webcast support for their Pro and Premium plans, respectively, IBM announced 4K support in June 2017 for its Enterprise plan. When I asked my IBM Cloud Video account manager, he was able to add 4K support to my Enterprise account (Figure 5, below).

Figure 5. IBM Cloud Video resolution settings

So while 4K webcasting isn’t currently available in all packages from all providers, I was able to confirm 4K H.264 webcast support from these popular webcast services: YouTube Live, Wowza Streaming Cloud, DaCast, and Amazon AWS.

4K Bandwidth Requirements

The HEVC H.265 compression standard is 50% more efficient than H.264. AV1 promises to be up to an additional 50% more efficient than H.265. Unfortunately, if you want to webcast in 4K today, you will likely be using the H.264 codec as I was not able to confirm any webcast services other than Wowza that currently support H.265 and none that support AV1 webcasting. The bigger issue is that there is a lack of widespread support for viewers being able to view H.265 or AV1.

Likely, CDNs may start accepting H.265 or AV1 signals but will transcode to H.264 for the majority of viewers. This is still a benefit for webcast producers as you don’t need as much bandwidth to upload an H.265 or AV1 video signal to a CDN, and this will benefit both 4K and HD webcast producers.

IBM recommends a bitrate of 14-30Mbs and Both DaCast and YouTube Live recommend 13–34 Mbps bitrates for 2160p30 webcasts using H.264. Wowza doesn’t specifically list a recommended bitrate for UHD webcast feeds, but defers to this bit-per-pixel formula for all resolutions of 0.10–0.15 bits per pixel:

(Bits/pixel x (width x height) x frame rate)/1000.
2160p30 = 25–37 Mbps, so Wowza is recommending a slightly higher bitrate for 4K streaming than DaCast and YouTube. The range covers limited action or high-motion, complex action. M

In my own testing with IBM Cloud Video Enterprise, I was successful in the 15–30 Mbps range for an H.264 2160P webcast using vMix and FFmpeg (Figure 6, below).

Figure 6. Streaming Settings

Webcasting 4K requires a lot of bandwidth. I am fortunate enough to be testing under optimum conditions at my studio with a dedicated 150 Mbps fiber internet connection that has a 2ms ping time and over-delivers with a 175 Mbps upload and download speed. Unfortunately, I can’t take this fiber connection with me, so even for my HD webcasts, I now rely on solutions to bond multiple internet connections together to ensure that I have fast and sustained upload and download speeds available to me.

Teradek ShareLink is a popular bonding subscription service that is compatible with the HD-only VidiU Pro, and I personally use Speedify VPN to bond multiple internet connections together when I webcast using vMix. The last webcast I produced provided the perfect test-case for using a bonding solution. The hotel internet was so poorly managed that the Ethernet had a fast upload but less-than-dial-up download speeds. The Wi-Fi was the exact opposite. I used Speedify to bond the Ethernet, Wi-Fi, and my cell phone signal (tethered via USB 3.1) into a rock-solid connection with fast upload and download speeds (Figure 7, below). I set my cell phone data to a lower-priority connection priority, as I do not have unlimited mobile data, and it was never needed. Speedify is free to test for your first 1GB of monthly data, and is $8.99 per month or $49.99 per year for unlimited data. The Speedify service allows for up to five simultaneous device connections.

Figure 7. Speedify

4K Viewer Experience

It goes without saying that to watch a 4K stream, you need a 4K device that can decode it. As I alluded to earlier, there are different codec options when working in 4K, and there is not one de facto standard like there is with H.264 when working with HD video. This isn’t to say that, if you push a 4K stream, all your viewers need to watch in 4K. Most popular CDNs and webcast services have the ability to offer multiple resolutions and codecs to support a wide range of devices and connection speeds on the viewer end.

In my own 4K UHD webcast tests, with a Sony X70, Blackmagic Intensity Pro 4K capture card, and vMix, Ustream offered my viewers five resolution options: 2160P, 720P, 480P, 360P, and 240P. Viewers could also select the Auto resolution option, which would deliver the highest resolution and bandwidth combination they could support, and would change dynamically if their internet speed slowed or increased.