[Starlink] It’s the Latency, FCC

Tue Apr 30 15:12:41 EDT 2024

>>> 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.

Sorry, not sure if that's Alexandre or Sebastion, but to those points:

Spotify is absolutely the correct metric because it's the commercial leader (and roughly aligned from a quality perspective with Amazon Music, Apple, iHeart Radio, and the others popular services). The fact that it's lower quality than what audiophiles (myself included) would prefer only proves the point: most users (AKA the "market") don't care enough about the audio quality to want to go beyond CD quality. This is how the market establishes a "sufficient" level of quality. It's not a fixed figure and can change over time. If some musical artist creates some popular music that sounds meaningfully different to most listeners between 44.1kHz CD quality and the newer higher quality 96kHz 7.1 surround sound AND if the cost in equipment and connections to hear that difference were attainable to the mass market, then that could move the standard, but that's what it would take. 

If it's only we few audiophiles who hear the difference, then the market won't care and will continue to say, "CD Quality is good enough. Now leave me alone with my music." :-)

If Spotify were in mono and sounded fuzzy like old AM radio, because that's clearly much worse even to the untrained ear, there would be an ongoing push for better quality audio. But that's not the situation. 

Same logic with video. Is 12K better than 8K better than 4K? Yes. Is that a commercially important distinction? No, not in 2024, and the video quality change vectors would suggest it won't be in the next 10 years either (maybe will be after that). This is because at that quality level (like CD quality for audio), the digital quality achieves a level where either original recording equipment or the average human eye, brain, and ear can no longer distinguish between further advances. This is not an argument against over-provisioning bandwidth capacity to plan for the future, just laying out that a future with greater bandwidth needs per video stream is nothing that's coming soon.

(As a LAN aside and parallel to show there is a common precedent with networking equipment for these growth rates, home and small business routers have had a max bandwidth of 1Gbps at mass market pricing for over a decade. Arguably, that's still the upper limit today. 10Gbps is still extremely rare and expensive for routers with more than a single 10Gbps uplink port, with 2.5Gbps being the more common upgrade both on PC motherboards and in the router ports.)

SD -> HD is a HUGE improvement. SD is fuzzy (like mono AM radio). Facial expressions are hard to see without filling the screen with the person's face. HD -> 4K is noticeable, but much less significant. 4K with compression artifacts looks WORSE than a high quality 1080p stream. 4K -> 8K is literally imperceptible to typical people on typical sized TV's. While there are video cameras that can record at 8K in good lighting (even good reasonably priced studio digital cameras cannot record quality above 4K without excellent lighting), the picture quality limits are defined more by the optics and what's in focus than by the number of pixels. Further, for displaying an image even on an 83" TV, when viewed from more than a few feet away, must humans can't tell the difference between 4K and 8K even if the 8K image truly is sharper (and remember, they're usually not due to camera limitations). 

But all of that technical explanation is also irrelevant. The fact is that Netflix, Amazon, Disney+, and some of the other big streaming services only offer 4K + HDR streams. None of them offer or have suggested that they intend to offer anything higher than that. The lion's share of TVs for sale today are also 4K TV. Even computer monitors, which have always been a leading indicator for TV resolutions, mostly top at 4K. There are a few 5K monitors, but the price jump from 4K to 5K is substantial. 8K monitors are rarer and even more expensive. This gives insight into a minimum timeframe before 4K is supplanted by 8K or something else: it's at least many years away. I suspect 3D may make a comeback before 8K (or maybe together – sometimes tech advances because it's paired with something else, like Blu-ray and 1080p). 

I worry that many of the discussions here around bandwidth needs are academic and not market driven. Engineers and scientists know better than the market HOW to do something, HOW to solve the problems, but market always knows better than the engineers WHAT it wants. To be clear on a point dear to many here, the market may not know how to describe what it wants (e.g., the failing of ISPs to promote the importance of latency), but ignorance on technical matters is not the same as not knowing what it likes and wants. We can easily test for those distinctions via focus groups to let people actually experience the differences or via usage surveys to find out what users want to do. If you have a statistically significant sample, you will get a statistically significant response on what matters. 

One last caveat: while the market is the ONLY group that matters in determining what it wants, the market also may be poor in explaining what it wants. If you'd asked the market what it wanted improved in a VCR, the market never would have said, "We want a DVD player" or "We want streaming video over the Internet." They would just say they don't like picture quality, rewinding tapes, tape wear, etc. All problems solved by DVD and modern streaming. So it's important for marketing teams working with engineers to ask the right questions and truly understand the responses so that clever engineers can innovate the best solutions to solve the market's pain points. 

Hope that helps everyone here.

Cheers,
Colin

-----Original Message-----
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Sent: Tuesday, April 30, 2024 10:56 AM
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Today's Topics:

   1. Re: It’s the Latency, FCC (Sebastian Moeller)

----------------------------------------------------------------------

Message: 1
Date: Tue, 30 Apr 2024 16:45:07 +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: <A53E11CF-FDA1-4AAE-A6EC-51EDD3B85995 at gmx.de>
Content-Type: text/plain;	charset=utf-8

Hi Alexandre,

> On 30. Apr 2024, at 16:40, Alexandre Petrescu <alexandre.petrescu at gmail.com> wrote:
> 
> 
> 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).

[SM] Not any more, but Amazon did offer a a storage truck (for latency insensitive transfers of huge data)
h++ps://www.cnbc.com/2024/04/17/aws-stops-selling-snowmobile-truck-for-c
h++loud-migrations.html
so this is more than just a concept...

> 
> 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-
>>>> shape-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-br
>>>> oadcast-and-broadband-television
>>>> 
>>>> Regards,
>>>> 
>>>> David