Re: [Starlink] Itʼs the Latency, FCC

Colin_Higbie
2024-04-30T01:30:25Z

Was that 4K HDR (not SDR) using the standard protocols that streaming services use (Netflix, Amazon Prime, Disney+, etc.) or was it just some YouTube 4K SDR videos? YouTube will show "HDR" on the gear icon for content that's 4K HDR. If it only shows "4K" instead of "HDR," then means it's SDR. Note that if YouTube, if left to the default of Auto for streaming resolution it will also automatically drop the quality to something that fits within the bandwidth and most of the "4K" content on YouTube is low-quality and not true UHD content (even beyond missing HDR). For example, many smartphones will record 4K video, but their optics are not sufficient to actually have distinct per-pixel image detail, meaning it compresses down to a smaller image with no real additional loss in picture quality, but only because it's really a 4K UHD stream to begin with.

Note that 4K video compression codecs are lossy, so the lower quality the initial image, the lower the bandwidth needed to convey the stream w/o additional quality loss. The needed bandwidth also changes with scene complexity. Falling confetti, like on Newy Year's Eve or at the Super Bowl make for one of the most demanding scenes. Lots of detailed fire and explosions with fast-moving fast panning full dynamic backgrounds are also tough for a compressed signal to preserve (but not as hard as a screen full of falling confetti).

I'm dubious that 8Mbps can handle that except for some of the simplest video, like cartoons or fairly static scenes like the news. Those scenes don't require much data, but that's not the case for all 4K HDR scenes by any means.

It's obviously in Netflix and the other streaming services' interest to be able to sell their more expensive 4K HDR service to as many people as possible. There's a reason they won't offer it to anyone with less than 25Mbps – they don't want the complaints and service calls. Now, to be fair, 4K HDR definitely doesn’t typically require 25Mbps, but it's to their credit that they do include a small bandwidth buffer. In my experience monitoring bandwidth usage for 4K HDR streaming, 15Mbps is the minimum if doing nothing else and that will frequently fall short, depending on the 4K HDR content.

Cheers,
Colin

-----Original Message-----
From: David Lang <david@lang.hm>
Sent: Monday, April 29, 2024 8:40 PM
To: Colin Higbie <colin.higbie@scribl.com>
Cc: starlink@lists.bufferbloat.net
Subject: Re: [Starlink] Itʼs the Latency, FCC

hmm, before my DSL got disconnected (the carrier decided they didn't want to support it any more), I could stream 4k at 8Mb down if there wasn't too much other activity on the network (doing so at 2x speed was a problem)

David Lang

On Fri, 15 Mar 2024, Colin Higbie via Starlink wrote:

> Date: Fri, 15 Mar 2024 18:32:36 +0000
> From: Colin Higbie via Starlink <starlink@lists.bufferbloat.net>
> Reply-To: Colin Higbie <colin.higbie@scribl.com>
> To: "starlink@lists.bufferbloat.net" <starlink@lists.bufferbloat.net>
> Subject: Re: [Starlink] It’s the Latency, FCC
>
>> I have now been trying to break the common conflation that download "speed"
>> means anything at all for day to day, minute to minute, second to
>> second, use, once you crack 10mbit, now, for over 14 years. Am I
>> succeeding? I lost the 25/10 battle, and keep pointing at really
>> terrible latency under load and wifi weirdnesses for many existing 100/20 services today.
>
> While I completely agree that latency has bigger impact on how responsive the Internet feels to use, I do think that 10Mbit is too low for some standard applications regardless of latency: with the more recent availability of 4K and higher streaming, that does require a higher minimum bandwidth to work at all. One could argue that no one NEEDS 4K streaming, but many families would view this as an important part of what they do with their Internet (Starlink makes this reliably possible at our farmhouse). 4K HDR-supporting TV's are among the most popular TVs being purchased in the U.S. today. Netflix, Amazon, Max, Disney and other streaming services provide a substantial portion of 4K HDR content.
>
> So, I agree that 25/10 is sufficient, for up to 4k HDR streaming. 100/20 would provide plenty of bandwidth for multiple concurrent 4K users or a 1-2 8K streams.
>
> For me, not claiming any special expertise on market needs, just my own personal assessment on what typical families will need and care about:
>
> Latency: below 50ms under load always feels good except for some
> intensive gaming (I don't see any benefit to getting loaded latency
> further below ~20ms for typical applications, with an exception for
> cloud-based gaming that benefits with lower latency all the way down
> to about 5ms for young, really fast players, the rest of us won't be
> able to tell the difference)
>
> Download Bandwidth: 10Mbps good enough if not doing UHD video
> streaming
>
> Download Bandwidth: 25 - 100Mbps if doing UHD video streaming,
> depending on # of streams or if wanting to be ready for 8k
>
> Upload Bandwidth: 10Mbps good enough for quality video conferencing,
> higher only needed for multiple concurrent outbound streams
>
> So, for example (and ignoring upload for this), I would rather have latency at 50ms (under load) and DL bandwidth of 25Mbps than latency of 1ms with a max bandwidth of 10Mbps, because the super-low latency doesn't solve the problem with insufficient bandwidth to watch 4K HDR content. But, I'd also rather have latency of 20ms with 100Mbps DL, then latency that exceeds 100ms under load with 1Gbps DL bandwidth. I think the important thing is to reach "good enough" on both, not just excel at one while falling short of "good enough" on the other.
>
> Note that Starlink handles all of this well, including kids watching YouTube while my wife and I watch 4K UHD Netflix, except the upload speed occasionally tops at under 3Mbps for me, causing quality degradation for outbound video calls (or used to, it seems to have gotten better in recent months – no problems since sometime in 2023).
>
> Cheers,
> Colin
>
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