Re: [Starlink] It’s the Latency, FCC

Alexandre Petrescu
2024-03-16T17:21:49Z

I retract the message, sorry, it is true that some teleoperation and
visioconf also use 4K. So the latency is important there too.

A visioconf with 8K and 3D 16K might need latency reqs too.

Le 16/03/2024 à 18:18, Alexandre Petrescu via Starlink a écrit :
>
> Le 15/03/2024 à 21:31, Colin_Higbie via Starlink a écrit :
>> Spencer, great point. We certainly see that with RAM, CPU, and
>> graphics power that the software just grows to fill up the space. I
>> do think that there are still enough users with bandwidth constraints
>> (millions of users limited to DSL and 7Mbps DL speeds) that it
>> provides some pressure against streaming and other services requiring
>> huge swaths of data for basic functions, but, to your point, if there
>> were a mandate that everyone would have 100Mbps connection, I agree
>> that would then quickly become saturated so everyone would need more.
>>
>> Fortunately, the video compression codecs have improved dramatically
>> over the past couple of decades from MPEG-1 to MPEG-2 to H.264 to VP9
>> and H.265. There's still room for further improvements, but I think
>> we're probably getting to a point of diminishing returns on further
>> compression improvements. Even with further improvements, I don't
>> think we'll see bandwidth needs drop so much as improved quality at
>> the same bandwidth, but this does offset the natural
>> bloat-to-fill-available-capacity movement we see.
>
> I think the 4K-latency discussion is a bit difficult, regardless of
> how great the codecs are.
>
> For one, 4K can be considered outdated for those who look forward to
> 8K and why not 16K; so we should forget 4K.  8K is delivered from
> space already by a japanese provider, but not on IP.  So, if we
> discuss TV resolutions we should look at these (8K, 16K, and why not
> 3D 16K for ever more strength testing).
>
> Second, 4K etc. are for TV.  In TV the latency is rarely if ever an
> issue.  There are some rare cases where latency is very important in
> TV (I could think of betting in sports, time synch of clocks) but they
> dont look at such low latency as in our typical visioconference or
> remote surgery or group music playing use-cases on Internet starlink.
>
> So, I dont know how much 4K, 8K, 16K might be imposing any new latency
> requirement on starlink.
>
> Alex
>
>>
>>
>> -----Original Message-----
>> From: Spencer Sevilla
>> Sent: Friday, March 15, 2024 3:54 PM
>> To: Colin_Higbie
>> Cc: Dave Taht via Starlink <starlink@lists.bufferbloat.net>
>> Subject: Re: [Starlink] It’s the Latency, FCC
>>
>> Your comment about 4k HDR TVs got me thinking about the bandwidth
>> “arms race” between infrastructure and its clients. It’s a particular
>> pet peeve of mine that as any resource (bandwidth in this case, but
>> the same can be said for memory) becomes more plentiful, software
>> engineers respond by wasting it until it’s scarce enough to require
>> optimization again. Feels like an awkward kind of malthusian
>> inflation that ends up forcing us to buy newer/faster/better devices
>> to perform the same basic functions, which haven’t changed almost at
>> all.
>>
>> I completely agree that no one “needs” 4K UHDR, but when we say this
>> I think we generally mean as opposed to a slightly lower codec, like
>> regular HDR or 1080p. In practice, I’d be willing to bet that there’s
>> at least one poorly programmed TV out there that doesn’t downgrade
>> well or at all, so the tradeoff becomes "4K UHDR or endless
>> stuttering/buffering.” Under this (totally unnecessarily forced upon
>> us!) paradigm, 4K UHDR feels a lot more necessary, or we’ve otherwise
>> arms raced ourselves into a TV that can’t really stream anything. A
>> technical downgrade from literally the 1960s.
>>
>> See also: The endless march of “smart appliances” and TVs/gaming
>> systems that require endless humongous software updates. My stove
>> requires natural gas and 120VAC, and I like it that way. Other stoves
>> require… how many Mbps to function regularly? Other food for thought,
>> I wonder how increasing minimum broadband speed requirements across
>> the country will encourage or discourage this behavior among network
>> engineers. I sincerely don’t look forward to a future in which we all
>> require 10Gbps to the house but can’t do much with it cause it’s all
>> taken up by lightbulb software updates every evening /rant.
>>
>>> On Mar 15, 2024, at 11:41, Colin_Higbie via Starlink
>>> <starlink@lists.bufferbloat.net> wrote:
>>>
>>>> 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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