[Starlink] It’s the Latency, FCC
Ulrich Speidel
u.speidel at auckland.ac.nz
Thu May 2 05:28:25 EDT 2024
> Switching between IP video channels has a much longer latency than
> switching a dial on an analog TV tuner. This latency is also
> exhibited on radio listening, be it analog or digital DAB.
>
>> I attribute that to buffer bloat and high latency.
>
> It has multiple sources. I suspect the highest latency factor is that
> of digital processing compared to analog processing; the next factor
> of latency (by size) may be some buffers related to data transmission,
> such as IP.
>
> The digital processing has huge advantages over analog processing but
> the large latency of switching between channels (aka 'tuning in') is a
> clear inconvenient.
>
There's a bit more than that. If you are getting your video channel via
IP off a CDN system, then there will need to be:
* A DNS lookup to see which CDN server is meant to serve your channel,
based on your IP address. This is usually done via geolocation
lookup, which can take some time.
* Your client then needs to contact the CDN server, which may need to
import that stream from an origin server elsewhere. To do that
properly, it needs to get an idea as to how much sustainable
bandwidth there is between you and the CDN server, so the CDN server
knows which resolution to request from the origin server.
* The CDN server will then want to buffer some of the video to make
sure it's not going to suffer from buffer starvation if there's a
lag in timely delivery from the remote origin server. That's so your
video doesn't go stop-start all that often.
* Last but not least, your client then also wants to buffer some in
order to be able to deal with irregular deliveries from the CDN
server in times of high jitter or packet loss. The more you buffer,
the less likely that you'll suffer disruption later.
* With video encoding, there's also a need to buffer a few frames just
to be able to decode, which can add a part of a second also.
Once that's all in place, latency and bufferbloat as such shouldn't
matter all that much theoretically, except of course that the protocol
that's feeding your client is often still TCP, and they contribute to
making life hell for TCP as it's struggling to match its congestion
window to the BDP, and the BDP keeps changing due to the buffers filling
and emptying. Most TCP connections in video streaming therefore don't
get their cwnd anywhere near BDP, as each connection just downloads a
chunk of video before the next one takes over for the next chunk.
>
> Alex
>
>> *
>>
>>
>> * With a happy household user watching streaming media, a second
>> user could have terrible shopping experience with Amazon. The
>> interactive response could be (is often) horrible. (Personally, I
>> would be doing email and working on a shared doc. The Amazon
>> analogy probably applies to more people.)
>>
>>
>> How can we deliver graceful performance to both persons in a household?
>> Is seeking graceful performance too complicated to improve?
>> (I said “graceful” to allow technical flexibility.)
>>
>> Gene
>> ----------------------------------------------
>> Eugene Chang
>>
>>
>>> On Apr 30, 2024, at 8:05 AM, Colin_Higbie via Starlink
>>> <starlink at lists.bufferbloat.net> wrote:
>>>
>>> [SM] How that? Capacity and latency are largely independent... think
>>> a semi truck full of harddisks from NYC to LA has decent
>>> capacity/'bandwidth' but lousy latency...
>>>
>>>
>>> Sebastian, nothing but agreement with you that capacity and latency
>>> are largely independent (my old dial-up modem connections 25 years
>>> ago at ~50kbps had much lower latencies than my original
>>> geostationary satellite connections with higher bandwidth). I also
>>> agree that both are important in their own ways. I had originally
>>> responded (this thread seems to have come back to life from a few
>>> months ago) to a point about 10Mbps capacity being sufficient, and
>>> that as long as a user has a 10Mbps connection, latency improvements
>>> would provide more benefit to most users at that point than further
>>> bandwidth increases. I responded that the minimum "sufficient"
>>> metric should be higher than 10Mpbs, probably at 25Mbps to support
>>> 4K HDR, which is the streaming standard today and likely will be for
>>> the foreseeable future.
>>>
>>> I have not seen any responses that provided a sound argument against
>>> that conclusion. A lot of responses like "but 8K is coming" (it's
>>> not, only experimental YouTube videos showcase these resolutions to
>>> the general public, no studio is making 8K content and no streaming
>>> service offers anything in 8K or higher) and "I don't need to watch
>>> 4K, 1080p is sufficient for me, so it should be for everyone else
>>> too" (personal preference should never be a substitute for market
>>> data). Neither of those arguments refutes objective industry
>>> standards: 25Mbps is the minimum required bandwidth for multiple of
>>> the biggest streaming services.
>>>
>>> None of this intends to suggest that we should ease off pressure on
>>> ISPs to provide low latency connections that don't falter under
>>> load. Just want to be sure we all recognize that the floor bandwidth
>>> should be set no lower than 25Mbps.
>>>
>>> However, I would say that depending on usage, for a typical family
>>> use, where 25Mbps is "sufficient" for any single stream, even 50ms
>>> latency (not great, but much better than a system will have with bad
>>> bufferbloat problems that can easily fall to the hundreds of
>>> milliseconds) is also "sufficient" for all but specialized
>>> applications or competitive gaming. I would also say that if you
>>> already have latency at or below 20ms, further gains on latency will
>>> be imperceptible to almost all users, where bandwidth increases will
>>> at least allow for more simultaneous connections, even if any given
>>> stream doesn't really benefit much beyond about 25Mbps.
>>>
>>> I would also say that for working remotely, for those of us who work
>>> with large audio or video files, the ability to transfer
>>> multi-hundred MB files from a 1Gbps connection in several seconds
>>> instead of several minutes for a 25Mbps connection is a meaningful
>>> boost to work effectiveness and productivity, where a latency
>>> reduction from 50ms to 10ms wouldn't really yield any material
>>> changes to our work.
>>>
>>> Is 100Mbps and 10ms latency better than 25Mbps and 50ms latency? Of
>>> course. Moving to ever more capacity and lower latencies is a good
>>> thing on both fronts, but where hardware and engineering costs tend
>>> to scale non-linearly as you start pushing against current limits,
>>> "sufficiency" is an important metric to keep in mind. Cost matters.
>>>
>>> Cheers,
>>> Colin
>>>
>>>
>>> -----Original Message-----
>>> From: Starlink <starlink-bounces at lists.bufferbloat.net> On Behalf Of
>>> starlink-request at lists.bufferbloat.net
>>> Sent: Tuesday, April 30, 2024 10:41 AM
>>> To: starlink at lists.bufferbloat.net
>>> Subject: Starlink Digest, Vol 37, Issue 11
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Tue, 30 Apr 2024 16:32:51 +0200
>>> From: Sebastian Moeller <moeller0 at gmx.de>
>>> To: Alexandre Petrescu <alexandre.petrescu at gmail.com>
>>> Cc: Hesham ElBakoury via Starlink <starlink at lists.bufferbloat.net>
>>> Subject: Re: [Starlink] It’s the Latency, FCC
>>> Message-ID: <D3B2FA53-589F-4F35-958C-4679EC4414D9 at gmx.de>
>>> Content-Type: text/plain;charset=utf-8
>>>
>>> Hi Alexandre,
>>>
>>>
>>>
>>>> On 30. Apr 2024, at 16:25, Alexandre Petrescu via Starlink
>>>> <starlink at lists.bufferbloat.net> wrote:
>>>>
>>>> Colin,
>>>> 8K usefulness over 4K: the higher the resolution the more it will
>>>> be possible to zoom in into paused images. It is one of the
>>>> advantages. People dont do that a lot these days but why not in
>>>> the future.
>>>
>>> [SM] Because that is how in the past we envisioned the future, see
>>> here h++ps://www.youtube.com/watch?v=hHwjceFcF2Q 'enhance'...
>>>
>>>> Spotify lower quality than CD and still usable: one would check not
>>>> Spotify, but other services for audiophiles; some of these use
>>>> 'DSD' formats which go way beyond the so called high-def audio of
>>>> 384khz sampling freqs. They dont 'stream' but download. It is
>>>> these higher-than-384khz sampling rates equivalent (e.g. DSD1024 is
>>>> the equivalent of, I think of something like 10 times CD quality, I
>>>> think). If Spotify is the king of streamers, in the future other
>>>> companies might become the kings of something else than
>>>> 'streaming', a name yet to be invented.
>>>> For each of them, it is true, normal use will not expose any more
>>>> advantage than the previous version (no advantage of 8K over 4K, no
>>>> advantage of 88KHz DVD audio over CD, etc) - yet the progress is
>>>> ongoing on and on, and nobody comes back to CD or to DVD audio or
>>>> to SD (standard definition video).
>>>> Finally, 8K and DSD per se are requirements of just bandwidth. The
>>>> need of latency should be exposed there, and that is not
>>>> straightforward. But higher bandwidths will come with lower
>>>> latencies anyways.
>>>
>>> [SM] How that? Capacity and latency are largely independent... think
>>> a semi truck full of harddisks from NYC to LA has decent
>>> capacity/'bandwidth' but lousy latency...
>>>
>>>
>>>> The quest of latency requirements might be, in fact, a quest to see
>>>> how one could use that low latency technology that is possible and
>>>> available anyways.
>>>> Alex
>>>> Le 30/04/2024 à 16:00, Colin_Higbie via Starlink a écrit :
>>>>> David Fernández, those bitrates are safe numbers, but many streams
>>>>> could get by with less at those resolutions. H.265 compression is
>>>>> at a variable bit rate with simpler scenes requiring less
>>>>> bandwidth. Note that 4K with HDR (30 bits per pixel rather than
>>>>> 24) consistently also fits within 25Mbps.
>>>>>
>>>>> David Lang, HDR is a requirement for 4K programming. That is not
>>>>> to say that all 4K streams are in HDR, but in setting a required
>>>>> bandwidth, because 4K signals can include HDR, the required
>>>>> bandwidth must accommodate and allow for HDR. That said, I believe
>>>>> all modern 4K programming on Netflix and Amazon Prime is HDR. Note
>>>>> David Fernández' point that Spain independently reached the same
>>>>> conclusion as the US streaming services of 25Mbps requirement for 4K.
>>>>>
>>>>> Visually, to a person watching and assuming an OLED (or microLED)
>>>>> display capable of showing the full color and contrast gamut of
>>>>> HDR (LCD can't really do it justice, even with miniLED
>>>>> backlighting), the move to HDR from SDR is more meaningful in most
>>>>> situations than the move from 1080p to 4K. I don't believe going
>>>>> to further resolutions, scenes beyond 4K (e.g., 8K), will add
>>>>> anything meaningful to a movie or television viewer over 4K. Video
>>>>> games could benefit from the added resolution, but lens aberration
>>>>> in cameras along with focal length and limited depth of field
>>>>> render blurriness of even a sharp picture greater than the pixel
>>>>> size in most scenes beyond about 4K - 5.5K. Video games don’t
>>>>> suffer this problem because those scenes are rendered, eliminating
>>>>> problems from camera lenses. So video games may still benefit from
>>>>> 8K resolution, but streaming programming won’t.
>>>>>
>>>>> There is precedent for this in the audio streaming world: audio
>>>>> streaming bitrates have retracted from prior peaks. Even though
>>>>> 48kHz and higher bitrate audio available on DVD is superior to the
>>>>> audio quality of 44.1kHz CDs, Spotify and Apple and most other
>>>>> streaming services stream music at LOWER quality than CD. It’s
>>>>> good enough for most people to not notice the difference. I don’t
>>>>> see much push in the foreseeable future for programming beyond UHD
>>>>> (4K + HDR). That’s not to say never, but there’s no real benefit
>>>>> to it with current camera tech and screen sizes.
>>>>>
>>>>> Conclusion: for video streaming needs over the next decade or so,
>>>>> 25Mbps should be appropriate. As David Fernández rightly points
>>>>> out, H.266 and other future protocols will improve compression
>>>>> capabilities and reduce bandwidth needs at any given resolution
>>>>> and color bit depth, adding a bit more headroom for small
>>>>> improvements.
>>>>>
>>>>> Cheers,
>>>>> Colin
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: Starlink <starlink-bounces at lists.bufferbloat.net> On Behalf Of
>>>>> starlink-request at lists.bufferbloat.net
>>>>> Sent: Tuesday, April 30, 2024 9:31 AM
>>>>> To: starlink at lists.bufferbloat.net
>>>>> Subject: Starlink Digest, Vol 37, Issue 9
>>>>>
>>>>>
>>>>>
>>>>> Message: 2
>>>>> Date: Tue, 30 Apr 2024 11:54:20 +0200
>>>>> From: David Fernández <davidfdzp at gmail.com>
>>>>> To: starlink <starlink at lists.bufferbloat.net>
>>>>> Subject: Re: [Starlink] It’s the Latency, FCC
>>>>> Message-ID:
>>>>> <CAC=tZ0rrmWJUNLvGupw6K8ogADcYLq-eyW7Bjb209oNDWGfVSA at mail.gmail.com>
>>>>> Content-Type: text/plain; charset="utf-8"
>>>>>
>>>>> Last February, TV broadcasting in Spain left behind SD
>>>>> definitively and moved to HD as standard quality, also starting to
>>>>> regularly broadcast a channel with 4K quality.
>>>>>
>>>>> A 4K video (2160p) at 30 frames per second, handled with the HEVC
>>>>> compression codec (H.265), and using 24 bits per pixel, requires
>>>>> 25 Mbit/s.
>>>>>
>>>>> Full HD video (1080p) requires 10 Mbit/s.
>>>>>
>>>>> For lots of 4K video encoded at < 20 Mbit/s, it may be hard to
>>>>> distinguish it visually from the HD version of the same video
>>>>> (this was also confirmed by SBTVD Forum Tests).
>>>>>
>>>>> Then, 8K will come, eventually, requiring a minimum of ~32 Mbit/s:
>>>>> https://dvb.org/news/new-generation-of-terrestrial-services-taking-sh
>>>>> ape-in-europe
>>>>>
>>>>> The latest codec VVC (H.266) may reduce the required data rates by
>>>>> at least 27%, at the expense of more computing power required, but
>>>>> somehow it is claimed it will be more energy efficient.
>>>>> https://dvb.org/news/dvb-prepares-the-way-for-advanced-4k-and-8k-broa
>>>>> dcast-and-broadband-television
>>>>>
>>>>> Regards,
>>>>>
>>>>> David
>>>>>
>>>>> Date: Mon, 29 Apr 2024 19:16:27 -0700 (PDT)
>>>>> From: David Lang <david at lang.hm>
>>>>> To: Colin_Higbie <CHigbie1 at Higbie.name>
>>>>> Cc: David Lang <david at lang.hm>, "starlink at lists.bufferbloat.net"
>>>>> <starlink at lists.bufferbloat.net>
>>>>> Subject: Re: [Starlink] Itʼs the Latency, FCC
>>>>> Message-ID: <srss5qrq-7973-5q87-823p-30pn7o308608 at ynat.uz>
>>>>> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>>>>>
>>>>> Amazon, youtube set explicitly to 4k (I didn't say HDR)
>>>>>
>>>>> David Lang
>>>>>
>>>>> On Tue, 30 Apr 2024, Colin_Higbie wrote:
>>>>>
>>>>>
>>>>>> Date: Tue, 30 Apr 2024 01:30:21 +0000
>>>>>> From: Colin_Higbie <CHigbie1 at Higbie.name>
>>>>>> To: David Lang <david at lang.hm>
>>>>>> Cc: "starlink at lists.bufferbloat.net"
>>>>>> <starlink at lists.bufferbloat.net>
>>>>>> Subject: RE: [Starlink] Itʼs the Latency, FCC
>>>>>>
>>>>>> 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 at lang.hm>
>>>>>> Sent: Monday, April 29, 2024 8:40 PM
>>>>>> To: Colin Higbie <colin.higbie at scribl.com>
>>>>>> Cc: starlink at 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 at lists.bufferbloat.net>
>>>>>>> Reply-To: Colin Higbie <colin.higbie at scribl.com>
>>>>>>> To: "starlink at lists.bufferbloat.net"
>>>>>>> <starlink at 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
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Starlink mailing list
>>>>>>> Starlink at lists.bufferbloat.net
>>>>>>> https://lists.bufferbloat.net/listinfo/starlink
>>>>>>>
>>>>>>
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>>>> _______________________________________________
>>>> Starlink mailing list
>>>> Starlink at lists.bufferbloat.net
>>>> https://lists.bufferbloat.net/listinfo/starlink
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 2
>>> Date: Tue, 30 Apr 2024 16:40:58 +0200
>>> From: Alexandre Petrescu <alexandre.petrescu at gmail.com>
>>> To: Sebastian Moeller <moeller0 at gmx.de>
>>> Cc: Hesham ElBakoury via Starlink <starlink at lists.bufferbloat.net>
>>> Subject: Re: [Starlink] It’s the Latency, FCC
>>> Message-ID: <727b07d9-9dc3-43b7-8e17-50b6b7a4444a at gmail.com>
>>> Content-Type: text/plain; charset=UTF-8; format=flowed
>>>
>>>
>>> Le 30/04/2024 à 16:32, Sebastian Moeller a écrit :
>>>> Hi Alexandre,
>>>>
>>>>
>>>>
>>>>> On 30. Apr 2024, at 16:25, Alexandre Petrescu via Starlink
>>>>> <starlink at lists.bufferbloat.net> wrote:
>>>>>
>>>>> Colin,
>>>>> 8K usefulness over 4K: the higher the resolution the more it will
>>>>> be possible to zoom in into paused images. It is one of the
>>>>> advantages. People dont do that a lot these days but why not in
>>>>> the future.
>>>> [SM] Because that is how in the past we envisioned the future, see
>>>> here h++ps://www.youtube.com/watch?v=hHwjceFcF2Q 'enhance'...
>>>>
>>>>> Spotify lower quality than CD and still usable: one would check
>>>>> not Spotify, but other services for audiophiles; some of these use
>>>>> 'DSD' formats which go way beyond the so called high-def audio of
>>>>> 384khz sampling freqs. They dont 'stream' but download. It is
>>>>> these higher-than-384khz sampling rates equivalent (e.g. DSD1024
>>>>> is the equivalent of, I think of something like 10 times CD
>>>>> quality, I think). If Spotify is the king of streamers, in the
>>>>> future other companies might become the kings of something else
>>>>> than 'streaming', a name yet to be invented.
>>>>> For each of them, it is true, normal use will not expose any more
>>>>> advantage than the previous version (no advantage of 8K over 4K,
>>>>> no advantage of 88KHz DVD audio over CD, etc) - yet the progress
>>>>> is ongoing on and on, and nobody comes back to CD or to DVD audio
>>>>> or to SD (standard definition video).
>>>>> Finally, 8K and DSD per se are requirements of just bandwidth.
>>>>> The need of latency should be exposed there, and that is not
>>>>> straightforward. But higher bandwidths will come with lower
>>>>> latencies anyways.
>>>> [SM] How that? Capacity and latency are largely independent...
>>>> think a semi truck full of harddisks from NYC to LA has decent
>>>> capacity/'bandwidth' but lousy latency...
>>>
>>> I agree with you: two distinct parameters, bandwidth and latency.
>>> But they evolve simultenously, relatively bound by a constant
>>> relationship. For any particular link technology (satcom is one)
>>> the bandwidth and latency are in a constant relationship. One
>>> grows, the other diminishes. There are exceptions too, in some details.
>>>
>>> (as for the truck full of harddisks, and jumbo jets full of DVDs -
>>> they are just concepts: striking good examples of how enormous
>>> bandwidths are possible, but still to see in practice; physicsts
>>> also talked about a train transported by a train transported by a
>>> train and so on, to overcome the speed of light: another striking
>>> example, but not in practice).
>>>
>>> Alex
>>>
>>>>
>>>>
>>>>> The quest of latency requirements might be, in fact, a quest to
>>>>> see how one could use that low latency technology that is possible
>>>>> and available anyways.
>>>>> Alex
>>>>> Le 30/04/2024 à 16:00, Colin_Higbie via Starlink a écrit :
>>>>>> David Fernández, those bitrates are safe numbers, but many
>>>>>> streams could get by with less at those resolutions. H.265
>>>>>> compression is at a variable bit rate with simpler scenes
>>>>>> requiring less bandwidth. Note that 4K with HDR (30 bits per
>>>>>> pixel rather than 24) consistently also fits within 25Mbps.
>>>>>>
>>>>>> David Lang, HDR is a requirement for 4K programming. That is not
>>>>>> to say that all 4K streams are in HDR, but in setting a required
>>>>>> bandwidth, because 4K signals can include HDR, the required
>>>>>> bandwidth must accommodate and allow for HDR. That said, I
>>>>>> believe all modern 4K programming on Netflix and Amazon Prime is
>>>>>> HDR. Note David Fernández' point that Spain independently reached
>>>>>> the same conclusion as the US streaming services of 25Mbps
>>>>>> requirement for 4K.
>>>>>>
>>>>>> Visually, to a person watching and assuming an OLED (or microLED)
>>>>>> display capable of showing the full color and contrast gamut of
>>>>>> HDR (LCD can't really do it justice, even with miniLED
>>>>>> backlighting), the move to HDR from SDR is more meaningful in
>>>>>> most situations than the move from 1080p to 4K. I don't believe
>>>>>> going to further resolutions, scenes beyond 4K (e.g., 8K), will
>>>>>> add anything meaningful to a movie or television viewer over 4K.
>>>>>> Video games could benefit from the added resolution, but lens
>>>>>> aberration in cameras along with focal length and limited depth
>>>>>> of field render blurriness of even a sharp picture greater than
>>>>>> the pixel size in most scenes beyond about 4K - 5.5K. Video games
>>>>>> don’t suffer this problem because those scenes are rendered,
>>>>>> eliminating problems from camera lenses. So video games may still
>>>>>> benefit from 8K resolution, but streaming programming won’t.
>>>>>>
>>>>>> There is precedent for this in the audio streaming world: audio
>>>>>> streaming bitrates have retracted from prior peaks. Even though
>>>>>> 48kHz and higher bitrate audio available on DVD is superior to
>>>>>> the audio quality of 44.1kHz CDs, Spotify and Apple and most
>>>>>> other streaming services stream music at LOWER quality than CD.
>>>>>> It’s good enough for most people to not notice the difference. I
>>>>>> don’t see much push in the foreseeable future for programming
>>>>>> beyond UHD (4K + HDR). That’s not to say never, but there’s no
>>>>>> real benefit to it with current camera tech and screen sizes.
>>>>>>
>>>>>> Conclusion: for video streaming needs over the next decade or so,
>>>>>> 25Mbps should be appropriate. As David Fernández rightly points
>>>>>> out, H.266 and other future protocols will improve compression
>>>>>> capabilities and reduce bandwidth needs at any given resolution
>>>>>> and color bit depth, adding a bit more headroom for small
>>>>>> improvements.
>>>>>>
>>>>>> Cheers,
>>>>>> Colin
>>>>>>
>>>>>>
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Starlink <starlink-bounces at lists.bufferbloat.net> On Behalf Of
>>>>>> starlink-request at lists.bufferbloat.net
>>>>>> Sent: Tuesday, April 30, 2024 9:31 AM
>>>>>> To: starlink at lists.bufferbloat.net
>>>>>> Subject: Starlink Digest, Vol 37, Issue 9
>>>>>>
>>>>>>
>>>>>>
>>>>>> Message: 2
>>>>>> Date: Tue, 30 Apr 2024 11:54:20 +0200
>>>>>> From: David Fernández <davidfdzp at gmail.com>
>>>>>> To: starlink <starlink at lists.bufferbloat.net>
>>>>>> Subject: Re: [Starlink] It’s the Latency, FCC
>>>>>> Message-ID:
>>>>>> <CAC=tZ0rrmWJUNLvGupw6K8ogADcYLq-eyW7Bjb209oNDWGfVSA at mail.gmail.com>
>>>>>> Content-Type: text/plain; charset="utf-8"
>>>>>>
>>>>>> Last February, TV broadcasting in Spain left behind SD
>>>>>> definitively and moved to HD as standard quality, also starting
>>>>>> to regularly broadcast a channel with 4K quality.
>>>>>>
>>>>>> A 4K video (2160p) at 30 frames per second, handled with the HEVC
>>>>>> compression codec (H.265), and using 24 bits per pixel, requires
>>>>>> 25 Mbit/s.
>>>>>>
>>>>>> Full HD video (1080p) requires 10 Mbit/s.
>>>>>>
>>>>>> For lots of 4K video encoded at < 20 Mbit/s, it may be hard to
>>>>>> distinguish it visually from the HD version of the same video
>>>>>> (this was also confirmed by SBTVD Forum Tests).
>>>>>>
>>>>>> Then, 8K will come, eventually, requiring a minimum of ~32 Mbit/s:
>>>>>> https://dvb.org/news/new-generation-of-terrestrial-services-taking-s
>>>>>> hape-in-europe
>>>>>>
>>>>>> The latest codec VVC (H.266) may reduce the required data rates
>>>>>> by at least 27%, at the expense of more computing power required,
>>>>>> but somehow it is claimed it will be more energy efficient.
>>>>>> https://dvb.org/news/dvb-prepares-the-way-for-advanced-4k-and-8k-bro
>>>>>> adcast-and-broadband-television
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>> David
>>>>>>
>>>>>> Date: Mon, 29 Apr 2024 19:16:27 -0700 (PDT)
>>>>>> From: David Lang <david at lang.hm>
>>>>>> To: Colin_Higbie <CHigbie1 at Higbie.name>
>>>>>> Cc: David Lang <david at lang.hm>, "starlink at lists.bufferbloat.net"
>>>>>> <starlink at lists.bufferbloat.net>
>>>>>> Subject: Re: [Starlink] Itʼs the Latency, FCC
>>>>>> Message-ID: <srss5qrq-7973-5q87-823p-30pn7o308608 at ynat.uz>
>>>>>> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>>>>>>
>>>>>> Amazon, youtube set explicitly to 4k (I didn't say HDR)
>>>>>>
>>>>>> David Lang
>>>>>>
>>>>>> On Tue, 30 Apr 2024, Colin_Higbie wrote:
>>>>>>
>>>>>>
>>>>>>> Date: Tue, 30 Apr 2024 01:30:21 +0000
>>>>>>> From: Colin_Higbie <CHigbie1 at Higbie.name>
>>>>>>> To: David Lang <david at lang.hm>
>>>>>>> Cc: "starlink at lists.bufferbloat.net"
>>>>>>> <starlink at lists.bufferbloat.net>
>>>>>>> Subject: RE: [Starlink] Itʼs the Latency, FCC
>>>>>>>
>>>>>>> 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 at lang.hm>
>>>>>>> Sent: Monday, April 29, 2024 8:40 PM
>>>>>>> To: Colin Higbie <colin.higbie at scribl.com>
>>>>>>> Cc: starlink at 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 at lists.bufferbloat.net>
>>>>>>>> Reply-To: Colin Higbie <colin.higbie at scribl.com>
>>>>>>>> To: "starlink at lists.bufferbloat.net"
>>>>>>>> <starlink at 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
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Starlink mailing list
>>>>>>>> Starlink at lists.bufferbloat.net
>>>>>>>> https://lists.bufferbloat.net/listinfo/starlink
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>>>>> _______________________________________________
>>>>> Starlink mailing list
>>>>> Starlink at lists.bufferbloat.net
>>>>> https://lists.bufferbloat.net/listinfo/starlink
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>>>
>>> ------------------------------
>>>
>>> Subject: Digest Footer
>>>
>>> _______________________________________________
>>> Starlink mailing list
>>> Starlink at lists.bufferbloat.net
>>> https://lists.bufferbloat.net/listinfo/starlink
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>>>
>>> ------------------------------
>>>
>>> End of Starlink Digest, Vol 37, Issue 11
>>> ****************************************
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--
****************************************************************
Dr. Ulrich Speidel
School of Computer Science
Room 303S.594 (City Campus)
The University of Auckland
u.speidel at auckland.ac.nz
http://www.cs.auckland.ac.nz/~ulrich/
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