Google also needs to offer some of those nine resolutions in multiple codecs, which dictate how the video is compressed on its way over the Internet. These are all different video files, and every one needs to be created from the original 8K uploaded file-and keep in mind, this is just for your specific device. You can see part of this work yourself just by clicking on the gear for an 8K video, where you'll see nine total resolutions created from a single upload: 144p, 240p, 360p, 480p, 720p, 1080p, 1440p, 2160p, and 4320p.
That means using a codec that is supported by your device and picking a resolution that matches your display (and not blowing up your Internet connection with a massive file).įor Google, that means transcoding a single video into a lot of other videos. Since then, Google has aggressively fought to keep the site's cost down, often reinventing Internet infrastructure and copyright in order to make it happen. Today, the primary infrastructure problem YouTube needs to solve for end users is providing video that works just right for your device and bandwidth while maintaining quality. Google YouTube’s unfathomably large transcoding problemīecause YouTube is the world's biggest video site, keeping it running was originally seen as an impossible task until Google bought the company in 2006. Google says the cards resemble GPUs because they are what fit in its existing accelerator trays. CNET reports that "thousands of the chips are running in Google data centers right now," and thanks to the cards, individual video workloads like 4K video "can be available to watch in hours instead of the days it previously took." Advertisement
Each compute cluster in YouTube's system will house a section of dedicated "VCU machines" loaded with the new cards, saving Google from having to crack open every server and load it with a new card. The cards are specifically designed to slot into Google's warehouse-scale computing system.
Google provided a lovely chip diagram that lists 10 "encoder cores" on each chip, with Google's white paper adding that "all other elements are off-the-shelf IP blocks." Google says that "each encoder core can encode 2160p in realtime, up to 60 FPS (frames per second) using three reference frames." There's even what looks like an 8-pin power connector on the end because PCI-E just isn't enough power.
A board has two Argos ASIC chips buried under a gigantic, passively cooled aluminum heat sink.
Google's Jeff Calow said the Argos chip has brought "up to 20-33x improvements in compute efficiency compared to our previous optimized system, which was running software on traditional servers." The VCU package is a full-length PCI-E card and looks a lot like a graphics card. The company detailed its new "Argos" chips in a YouTube blog post, a CNET interview, and in a paper for ASPLOS, the Architectural Support for Programming Languages and Operating Systems Conference. Just as there are GPUs for graphics workloads and Google's TPU (tensor processing unit) for AI workloads, the YouTube infrastructure team says it has created the "VCU" or "Video (trans)Coding Unit," which helps YouTube transcode a single video into over a dozen versions that it needs to provide a smooth, bandwidth-efficient, profitable video site. Google has decided that YouTube demands such a huge transcoding workload that it needs to build its own server chips.