Monty Montgomery

Changing the sample rate of audio only affects the frequency range. All audio signal is _perfectly_ represented in a digital form. I am ashamed to admit this took me a long time to properly understand. For further reading I'd recommend: https://people.xiph.org/~xiphmont/demo/neil-young.html https://www.youtube.com/watch?v=cIQ9IXSUzuM

> https://people.xiph.org/~xiphmont/demo/neil-young.html That's a great article; thank s.

> 24-bit audio is obviously a noticeable improvement even on $150 headphones Not going to question your subjective experience, but I do not think most people will hear any difference between 16 and 24 bit playbacks under normal conditions, even with fancy headphones. "120dB is greater than the difference between a mosquito somewhere in the same room and a jackhammer a foot away.... or the difference between a deserted 'soundproof' room and a sound loud enough to cause hearing damage in seconds. 16 bits is enough to store all we can hear, and will be enough forever." [1] [1] https://people.xiph.org/~xiphmont/demo/neil-young.html

I'd rather trust solid hearing biology/physics plus all the other failed tests > the effective dynamic range of 16 bit audio reaches 120dB in practice [13], more than fifteen times deeper than the 96dB claim. > 120dB is greater than the difference between a deserted 'soundproof' room and a sound loud enough to cause hearing damage in seconds. > 16 bits is enough to store all we can hear, and will be enough forever. https://people.xiph.org/~xiphmont/demo/neil-young.html#toc_1bv2b

> High frequencies are IMO mostly pointless for anyone with the money to spend on audio hardware. We have the best hearing as children, so unless you're a wealthy 12 year old you probably won't benefit from anything above 20 KHz. You can be the most pristine kid in the world and you are still better off without excessively high frequencies. https://people.xiph.org/~xiphmont/demo/neil-young.html

video codec is an undocumented mine field. If you want to know how to decode and encode video, looking at libav's example code or gstreamer's example code is the best way. If you want to understand the fundamentals. The best I know is this https://people.xiph.org/~xiphmont/demo/daala/demo1.shtml

It also contains no technical information about Disneyland or the Superbowl, despite their mentions. Technical information about any of the three would be equally (ir)relevant to the article's topic: intellectual property law. If you're really hard up for technical specs, the most cursory search might reveal https://news.ycombinator.com/item?id=16796127 regarding https://people.xiph.org/~xiphmont/demo/av1/demo1.shtml, or the part 2 follow-up https://news.ycombinator.com/item?id=17417586 regarding https://hacks.mozilla.org/2018/06/av1-next-generation-video-the-constr…

What is missing in the announcement is a link to a quality / bitrate comparison with perceptual quality. Netflix seems to have a good automated perceptual metric. PSNR is still a popular metric because it's "objective", but codecs optimized for PSNR produce ugly, blurry results, like all the VPx codecs. That said, a codec with great PSNR can probably be tuned for great perceptual results. The Vorbis people, who were involved in AV1, have produced some impressive perceptual improvements even with inferior technology (Ogg Theora, based on VP3.2), so they know what to do and how: https://people.xiph.org/~xiphmont/demo/theora/demo9.html

Typing this on an LED SXGA X61, you want: https://people.xiph.org/~xiphmont/thinkpad/led-kit.shtml No banding on the bottom, accurate colors, and great brightness.

Honest question: Why is archive.org using 24-bit FLAC when >51% of the internet tells you HD Audio is useless and can even worsen the listening experience? "A consumer will never need 24-bit. Ever."[1] "24 bit audio is as useless as 192kHz sampling"[2] I would love to hear a good explanation so I can decide about the future of my audio library. [1] http://gizmodo.com/5768446/why-24-bit-audio-will-be-bad-for-users [2] https://people.xiph.org/~xiphmont/demo/neil-young.html

Oh! Derp! I guess I am used to marketing-level abuses of language. >More practically, since browsers won't have an flif decoder there isn't an easy way to embed the images online without reencoding them in a different format, which would rather defeat the purpose of putting up sample images. Did you follow the link I posted? I think Bellard put together a pretty nifty demo. Note: Bellard credits xiph.org as the originator of the demo page. http://people.xiph.org/~xiphmont/demo/daala/update1-tool2b.shtml

JPEG is quite old. Some of the best still image compressors are found as I-frame compressors in video codecs. Daala for example uses adaptive block sizes and inter-block prediction. See: https://people.xiph.org/~xiphmont/demo/daala/demo2.shtml

This was posted here before, but it's a great article if anyone still didn't read it yet: https://people.xiph.org/~xiphmont/demo/neil-young.html

This reminded me of this (somewhat related) article about the science behind audio quality, signals and all the myths surrounding it. Very recommended. http://people.xiph.org/~xiphmont/demo/neil-young.html

This test is pretty uninteresting, but I'm glad the author linked to the Xiph article because it's one of the best articles on the subject I've read. http://people.xiph.org/~xiphmont/demo/neil-young.html

Check out his fantastic demo pages for a look at the work being done on Daala. http://people.xiph.org/~xiphmont/demo/daala/demo1.shtml This is great news!

Another impressive piece by Monty. I really enjoy his articles. Just the right mix of text, graphics and formulas. He also made a few videos: https://www.xiph.org/video/ And the audiphile's "favorite" topic: "24/192 Music Downloads ...and why they make no sense" http://people.xiph.org/~xiphmont/demo/neil-young.html

TL;DR: Firstly I highly recommend that you read the entire article (starting with the first part https://people.xiph.org/~xiphmont/demo/daala/demo1.shtml ) because it's a very good introduction to some technical details of how Daala is discarding the received wisdom of the last 20+ years of video encoding with the hopes of escaping the local maxima we currently find ourselves in.

Monty and the Xiph.org team have been slaving away at this for quite some time. They put an amazing amount of work into it, and it really shows. You might be interested to know that there were about 50k lines of code[1] written for the demonstrations, all of which is available. Also, don't miss the original video[2], or the article on HD audio[3]. [1] https://wiki.xiph.org/Videos/Digital_Show_and_Tell#Use_The_Source_Luke [2] http://xiph.org/video/vid1.shtml [3] http://people.xiph.org/~xiphmont/demo/neil-young.html

How do you know that the 24/96 and 16/44 came from the same masters? If this isn't controlled for then of course the result might be different.[0] Also, what is xm1000w3s? I can't find any record of this so I'm guessing maybe it is referring to the WH1000XM3 headphones? Given ldac is also mentioned this seems a reasonable guess as it's a bluetooth model. If that's the case I wouldn't call it "good listening equipment", the default frequency response curve of the wh1000xm3 is incredibly bad, it's barely worth listening to classical music on without using AutoEq[1] or something equivalent (I have a pair and it's much worse than my old Ath M50s which were like half the price). The bass heavy curve of the headphones is far more noticeable than any difference between 16/24 bit audio would ever make. [0] https://people.xiph.org/~xiphmont/demo/neil-young.html#toc_dmdm [1] https://autoeq.app/

One thing not really mentioned is in threads is...software. Every soundcard used to compete by trying to offer better 3d or better effects processing than the others. Game developes had a half dozen sound sdk's they could write their game audio for (EAX, Aureal... I dunno there's probably at least half a dozen). Cards competed on features. In the pro segments, literal megabytes of midi sample space & dsp coprocessors attracted audiences. Each of these tended to have one of any number of software toolkits... so you needed games or apps to all get onboard too. Many SDKs had software fallbacks so many users would even care that they didnt have Aureal3D support or whatever. The actual advantages of doing things in hardware quickly faded, as cpus became ever more powerful. But just as much, the various apis didnt really ascend, or their technologies (head-related transfer function) got swallowed/mainstreamed. Namely DirectSound3D (1996), which grew various hardware offloads (EAX), and eventually because DirectX Audio. The pressure to compete deflated under thus mainstreamification... few people wanted to the extra 100 miles to support bespoken fancy hardware capabilities 0.01% of gamers might have, when they got 90% there using the common denominator. I dont actually know what folks like gamedevs do now. Both Xbox & Playstation say they tick a lot of really good 3d audio boxes, they support an array of common 3d audio standards that I dont really know that much about. I'd love…

CD may be 40 years old, but human ears didn't change at all in that time. If you can tell CD from other recordings, it is almost certainly because the mastering (which is not something intrinsic to the standard) was deliberately changed for CD because it could reproduce sound better, so no format-specific mastering hacks were needed to make it sound good. Face it, you don't have golden ears. For example, if a studio today were to master something for cassette, it would dramatically turn up the high end to compensate and probably bypass some saturation or exciters because the format has its own. Similarly, any studio not tweaking their masters for the perfection of CD was probably doing the material a disservice. Heck, today, some tracks are deliberately mastered to sound good on iPhone earbuds. (The usual article cited in these discussions is https://people.xiph.org/~xiphmont/demo/neil-young.html, which happens to make this point briefly under "Different media, different master" and "Better masters". Edit: another fun article is https://www.soundguys.com/high-bitrate-audio-is-overkill-cd-quality-is… with the fantastic pull quote, "There is no safe listening level to hear the difference between these files".) CD doesn't need to be the pinnacle of digital technology, because our ears don't know any different beyond it.

> Where oh where is the x60 of today? It's an ordeal, but it's possible to have one. This[1] is my primary computer. It's an X61 chassis with a Core i7-5600U, 32GB of RAM, and 1TB SSD. The screen is a 12" 1400x1050 IPS LCD (matte, not glossy). It's my favorite laptop. Putting it together took months. There's a group of enthusiasts in China called 51nb that make modern internals for old ThinkPad chassis[2]. I ordered a barebones chassis from them in March and received it in June. After that I replaced the LCD's ancient CCFL backlight with an LED conversion kit[3], improving battery life and brightness. If you want to know more, I wrote a blog post detailing the whole experience[4]. 1. https://geoff.greer.fm/photos/x62/DSC_2304.JPG 2. https://www.51nb.com/benzhanshiye/2017-06-08/83668.html 3. https://people.xiph.org/~xiphmont/thinkpad/led-backlight.shtml 4. https://geoff.greer.fm/2017/07/16/thinkpad-x62/

While personal anecdotes are not typically good for discussions, in this case it's important to compare your equipment against the reviewers: he's using $300 headphones in a quiet room, using well-sourced high-quality music. The original proposition for this device involved unleashing a world of 24bit, 192khz audio downloads, which is not worth it by a long shot [0]. I don't doubt that the engineering inside the Pono player is top notch, but it will require an ecosystem of other top-notch gear to take advantage of it -- including music that wasn't specifically engineered to be played out of a smartphone's earbuds (Mastered for iTunes, for example). And if you're going to get all that gear together, you're going to want at least decent conditions for listening (quiet, mainly) or those details you paid $400 to get out of the music will be drowned out. I guess the point I'm making is - who is this DAC meant for? It seems like its attempting to fill a space (or create one) that is already filled. [0]http://people.xiph.org/~xiphmont/demo/neil-young.html

I think Mozilla is right to tread carefully and not commit to yet another format for a minor improvement. In my opinion our web clients are bloated enough as is, and they're only getting bigger. Once you add support for a format and it gains mainstream traction on the web, it'll be really hard to remove, and we'll be stuck with software that has to support so many things for reasons that do not make sense in the near future. As for the study, I have to admit I did not read it. But the first thing to note is that computed metrics (SSIM, PSNR) are not reliable approximations of perceived quality. Optimizing for either will produce a codec that pleases the computer, not the eye. This is why the tuning of image and video codecs for psychovisual effects is such a laborious, manual process -- you have to have a human viewer to assess the quality. In the long term I think it would be good if a new still-image format was derived from the intra portion of some reasonably advanced video codec, as they all beat JPEG handily. This is essentially what WebP is, but if I recall correctly, Google didn't really give VP8 the love it needed when they acquired On2. Instead they rushed with a "release early, release often" mentality, presumably hoping the community would jump the boat first and do the grunt work for them later (this was during html5 video wars when some thought Theora sucks and others thought h.264 is too encumbered -- VP8 was Google's resolution). The details are…

Steve Jobs was not a "hacker". [‡] He knew almost nothing about computer languages, computer architecture, and according to Neil Young, he listened to vinyl records at home [1] — which shows that he was ignorant of how audio quality works (see [2]). Steve did not contribute any original ideas or any important technological innovations. He claimed during his Stanford commencement speech that if Macintosh had not included eye pleasing typography, then computers would never have had typographically pleasing typefaces (because "Microsoft just copied Apple); this is ludicrous. In fact, Apple's software patents for digital typography added unnecessary difficulties. [3] Many people are unhappy about Apple culture of paranoia, litigation, and features that restrict user's freedoms that Steve created. Steve is known for having a great sense of design, but it seems that he only had taste in choosing among the good designs of others. Just look at the yacht he designed without Jonathan Ive's collaboration. [4] Many of you may say that I'm missing the point; that his ability to convince others of what was important and his "vision" is what made him great. My contention is that he appropriated other people's original ideas, and other people implemented his modifications. I'll admit that directing such efforts is not an easy thing to do, and most breakthroughs are improvements upon others' ideas. But it is very rare for the original creators to be alive and ignored while the modifier is…

> It's all 48kHz (or multiples of that, for snake oil) Oversampling can be a useful internal detail for ADCs and DACs. For example, if the digital audio stream is mathematically converted to 96 kHz with a high-quality FIR low-pass filter and then fed to a DAC, then the analog low-pass filter can have a much shallower roll-off and be more easily designed. Same goes for ADCs, where the analog filter can be simple and gentle, then digitized at 96 kHz, then downsampled digital to 48 kHz with high-quality but more computationally intensive filters. ( https://en.wikipedia.org/wiki/Oversampling , https://en.wikipedia.org/wiki/Delta-sigma_modulation , etc.) But yes, listening to or distributing audio at anything over 48 kHz is a complete waste of resources. [email protected] explained very well in: https://people.xiph.org/~xiphmont/demo/neil-young.html

Interesting, if hard-to-understand. It would be nice to see ELi5 explanations for items like this akin to Monty's 'A Digital Media Primer for Geeks' ( https://people.xiph.org/~xiphmont/demo/#:~:text=Xiph )

> I've written a BASH function which will produce a pivot table of the most active contributors in any given git repository. What? > FFMPEG doesn't support using dav1d for encoding Cause it's a decoder, not a codec.. I was hoping this would go into detail about how to encode AV1 video, like the Xiph articles about Daala: https://people.xiph.org/~xiphmont/demo/daala/demo4.shtml It's just downloading and trying out some encoders and decoders.

24/96 for audio distribution makes no sense. If you don't believe me, fine, I'll have to link this for the 1000th time: https://people.xiph.org/~xiphmont/demo/neil-young.html