4K IP Delivery: Encoding and Streaming 4K
In this article, we'll document a viable 4k encoding workflow assembled for in-house testing, and look at some of the inherent challenges, as well as current products and enabling technologies used to make it work.
The feeds came from the camera through the Quad Encoder to the decoder D-Streamer Quad, and the test was on.
The first step in the encoding process was setting up the HCoder Quad’s 4 Simultaneous HDMI inputs (below). Click the image to see it at full size.
Each HDMI (quadrant) input has its own solo output. Click the image to see it at full size.
The 4 solo outputs muxed into a single synced multiprogram stream (below). Click the image to see it at full size.
After the Quad Encoder is done encoding the 4 1080p muxed stream, the muxed stream is sent to the quad channel decoder. Now the reverse of the of the process happens. The muxed (4 1080p’s) video is demultiplexed (demux). After the demux it’s set into separate outputs so each quadrant can be sent to its own HD-SDI output (below). Click the image to see it at full size.
After the input of the Decoder is set, each of the corresponding outputs is set via the GUI. The decoder quad was able to accept and send out all 4 demuxed feeds via HD-SDI and displayed each video in its corresponding quadrant (below). Click the image to see it at full size.
The biggest challenge in this whole process is receiving all 4 quadrants in perfect sync, because if one is off by one millisecond, the whole video will not be appealing to the eye and will actually cause discomfort. There are ways to adjust the delivery latency if there is an issue but that should be last resort if possible.
From the 4 HD-SDI outputs of the D-Streamer Quad you could feed a device like a Sony MPE 200, AnalogWay Ascender, or Vista Systems Spyder that will do edge-blending for larger 4k displays like the JVC PS-840UD, or to a projector or other display device.
Recently, AJA released their Hi5-4k, which is a 4 HD-SDI-to-1 HDMI converter. So this is a perfect device to add to this workflow. Attach this to the Quad HD-SDI Decoder and convert to one 4K HDMI feed that can be used with a variety of 4K TVs or monitors.
Conclusion
Streaming 4k content is now possible, provided you have the necessary bandwidth. This test scenario worked well for the quad-split 4k off cameras and other devices. This same workflow would be useful with the Sony F55, F65, Blackmagic Design Cinema Camera, and some of the REd Digital cameras.
The above workflow is great for closed-circuit distribution or dedicated point-to-point systems. 30-40Mbps or higher isn’t practical for most applications. However, delivery content from special events is obviously affordable and plausible.
With a Multiprogram recorder/player you will be able to record at the encode side or at the receive side. So this would be a modified workflow: The Quad Encoder (with mux) will send the muxed feed to the MPTS recorder player. The Recorder/Player will act also as a gateway for the decoder. The live feed will be recorded and then passed through to the decoder. After a period of recording, use the player/record with built-in scheduler to send the previously recorded content to the decoder via the same IP address/streams it was already receiving. With the recorder at the receive side, once the recording is playing back, bandwidth can be saved. Use the bandwidth only when you need it, and send it to the 4K Decoder locally. The whole idea is to keep everything in sync and to have guaranteed delivery.
For delivering 4k point A to point B when you have the proper bandwidth, this is fully doable. For example, maybe a church or a concert venue needs to have a satellite facility or the venue wants to be able to display extra content or the feeds throughout the location. This could be sporting events, concerts, education, or any place where you need to share the feed on a giant display at really high resolution (cinema resolution).
For general public distribution, the viability 4K delivery is still a bit off. The bandwidth requirement is a bit high, and you would want a special player that can take the quadrants and blend together. H.265 is going to be the selling point for public 4k use. It will give you tighter compression and the bandwidth requirement won’t be as large. HEVC/H.265 is designed to be encoder-heavy but decode-light, and is expected to drop the bandwidth needed between 30-50%. Plus, in the near future you have to expect more bandwidth to the door.
However, for niche point-to-point workflows, this 4k approach is very doable today. Bandwidth will be the sticking point, but that is all addressable and possible.