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26 January 2021

Google poised to mandate support for AV1 in Android TV

It seems that Google is on the cusp of mandating native support for the AV1 codec for Android TV devices. However, if the rumored deadline of March is indeed correct, that would be a severe shake-up in this market, as only a few silicon designs are currently available. Given that Google’s own hardware doesn’t have AV1 support yet, this is a bit bemusing.

The latest round of reporting was triggered by XDA Developers, after the outlet saw an internal slide from a Google presentation that seemed to corroborate the much older rumor mill reports. So, it does seem that March is going to be a cut-off, of sorts, for any media player device that runs Android 10 or 11. This would then mean that all Android TV designs from that point on must support AV1 – unless the internal deadline has been updated, which may well have happened, as the presentation spied by XDA was given earlier in 2020.

But there seems to be a significant gap between this requirement and the state of the market. As it stands, there are not many options for set-top chipsets with AV1 support. Looking around, there is the Broadcom BCM7218X, announced in September 2019, and a trio of designs from Amlogic – the S905X4, the S908X, and the S805X2, which were announced in December 2019 and have started trickling into set-tops and smart TVs.

Notably, LG confirmed that its 2020 range of 8K TVs support AV1, but these are based on its own a9 processor design, specifically the third generation design. Sony’s new range of 4K and 8K Bravia XR TVs also support AV1 natively, but we are unsure what silicon those are based on.

Sony has historically used MediaTek silicon, and the latter’s T30/T31/T32 range of SoCs are likely candidates. Realtek’s RTD2851M SoC has also appeared, in TCL’s X915 8K design, and Samsung has also talked about AV1 support in its 8K TVs, using its own processor designs, although there is some speculation that many other Samsung 2020 models support AV1 – but aren’t advertised as such. However, you can see that AV1 is a flagship feature, across the board, that is not going to see mass market adoption in these massive form factors.

Away from fixed screens, there are a couple of other mobile designs. The Rockchip RK3588 could fit in a smartphone, but is more likely to appear in larger mobile devices, and MediaTek’s Dimensity 1000 5G SoC is currently the only proper smartphone offering for AV1. Samsung’s own Exynos 2100 SoC supports AV1 in hardware.

There’s not much insight to be gained from the Alliance for Open Media (AOMedia) website either. The organization behind the AV1 codec, which it publishes free of charge and doesn’t require membership to read, doesn’t have a public list of silicon that supports AV1 yet. It does point to Allegro, Chips&Media, and Verisilicon as having reference hardware designs, however.

On the content side of things, there is still little AV1 video to actually try out on these devices. YouTube has begun using AV1 on a select few Android TV devices, and typically only for 4K content. Vimeo has some ‘Staff Picks’ titles in AV1 too, and Netflix will also push to AV1 when a compatible device enables Data Saving Mode.

Back in October, Google launched the Chromecast with Google TV. The shiny new $50 dongle was a debut, of sorts, for the Google TV environment, which is essentially the user-facing elements. Under the hood, the Chromecast with Google TV is still running Android TV, as its operating system, but the Google TV interface is a clear differentiation from the Android TV versions that our operator crowd play with.

This was a demarcation for the Chromecast family, as it had effectively graduated from the lightweight CastOS platform. Now, the dongles are being treated as standalone video environments, and not just awkward middlemen. One thing that Google had not sorted out, however, was the branding problem. There is going to be immense confusion between the Chromecast, Google TV, regular YouTube, and the YouTube TV subscription service.

Looking back, there was no mention of AV1 support at launch, and digging around, it seems that the beefed-up dongle is using an Amlogic S905D3 – an SoC that does not support AV1 in hardware. The newer version of that design, the S905X4 does support the feature, but it would be a complete mess if you had Chromecasts that did and others that did not support AV1 in silicon.

This would imply that we are going to wait another generation until Google’s flagship video products support AV1 natively. It’s not the worst thing in the world, but it isn’t a great look. Google can’t be slinging stones in glass houses, after all.

Then in December, we had a moan about the latest Qualcomm flagship SoC, the Snapdragon 888, lacking hardware support for AV1. We thought it quite glaring that one of the biggest names in the Android ecosystem had not included AV1 in its design, and postulated that politics were to blame for this snub – because surely the lowly Rockchip and MediaTek couldn’t have beaten Qualcomm to the punch.

To that end, Qualcomm’s absence from the Alliance for Open Media (AOMedia) membership list strikes quite a tone – that it favors the MPEG family of codecs, which have evolved from H.264 (AVC), H.265 (HEVC), and now onto H.266 (VVC), as well as the supporting EVC and LCEVC protocols. It’s also notable that no PR departments have rushed to correct us, about our assertion that Qualcomm has picked a side.

Of course, with these codecs, the savings that you achieve in bandwidth come at the expense of computing complexity. The encoders have to get significantly more powerful, to process that native video file and output a suitably compressed encoded file. In turn, the decoders need to do a lot more computation to decode this file and display it on the device.

With hardware support, a specialized chip or silicon element has been created that is very good at one specific task – such as decoding AV1. However, that design is going to struggle with general purpose workloads, and so it is only playing a supporting role.

The alternative is to perform the decoding in a software environment, but this is not efficient, and requires a lot of resources. As such, hardware support is how you bring the new codecs to devices, without crippling their power consumption or requiring a significant bump in the system resources. Slamming a Xeon server-grade CPU in a set top would provide AV1 support in software, but that’s not exactly scalable.