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For one, 4K can be considered outdated for those who look forward to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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