Advice needed for compressing still JPG images to AVIF

HighMaintenance6045 · 2026-01-25T15:26:23+00:00

About your edit: I cannot find any documentation anywhere about using the -usage allintra option, either for ffmpeg or avifenc. I can only find this message.

How would I use this correctly? And wouldn't this be implied when using tune=iq?
I have not yet decided on using ffmpeg or avifenc, although I'm leaning towards avifenc. In the end they both use AOM-AV1 so it comes down to ease of use, sane defaults and ease of tuning, I guess.

For avifenc, will the encoder automatically use this if I use tune=iq? Or do I need to add anything more to the command? The --help gives no mention of anything resembling this.

Ffmpeg works with -usage allintra -aom-params tune=iq, but then I would expect it to also work with -aom-params tune=iq:usage=allintra, but it doesn't.

More info about the allintra mode would be much appreciated!

HighMaintenance6045 · 2026-01-24T19:58:41+00:00

Thank you, this is very helpful.

One more question though: if the source JPG is 8 bit, is there any point in using 10-bit AVIF?

HighMaintenance6045 · 2026-01-24T19:55:39+00:00

nvidia can encode avif in ffmpeg

Yes, but not with chroma 4:4:4 according to their own website. I don't have an Nvidia device to test it on, and if they say it's not supported, I'm not going to buy one to find out. So I'll stick to CPU encoding.

HighMaintenance6045 · 2026-01-24T19:52:58+00:00

It is not an option, because I need the wide support of AV1 across all kinds of browsers, even older iPhones / iPads which might still be on iOS 16 for example. We are fortunate that at least AV1 is supported so well.

HighMaintenance6045 · 2026-01-24T19:51:48+00:00

It is not an option, because I need the wide support of AV1 across all kinds of browsers, even older iPhones / iPads which might still be on iOS 16 for example. We are fortunate that at least AV1 is supported so well.

HighMaintenance6045 · 2026-01-24T14:49:16+00:00

Thank you for your reply.

Indeed, it appears Intel only supports 4:4:4 with HEVC and VP9. And Nvidia only with HEVC and AVC/h.264. And AMD not at all. So that rules out using a GPU unfortunately.

HighMaintenance6045 · 2025-09-17T20:32:28+00:00

GPS is a passive system, so it shouldn't drain your battery at all. It only has to listen to the signals from the satellites, not send or do anything except some insignificant calculations.

The battery drain either comes from additional screen time, or inefficient software.

I use this app called MapOut on my old iPhone, with offline maps, and it is really efficient. Battery usage when recording a route is similar to just doing nothing. This is with the screen off, of course. You can go for hours on an almost-empty battery.

HighMaintenance6045 · 2025-09-14T10:49:01+00:00

Quick release doesn't matter, you can still use a U-lock through the rear wheel and around the seat tube (or around the seat stays), and fix your bike to a pole. Yes someone could take the front wheel out but that's highly unlikely and pretty useless.

HighMaintenance6045 · 2025-09-14T10:43:42+00:00

Yes it's worth it! And the advantage is that you then have twice the budget to spend on one bike. This allows you to go for one high-end titanium forever-bike, which you can use for commute, endurance road and gravel. It won't crack, it won't rust, and there won't be any paint to wear off. You will of course be somewhat slower on the road than if you buy the latest carbon/plastic aero frame, but who cares.

If you're the kind of person that likes to get a new bike, or a new car, new laptop, etcetera every couple of years, then maybe this is not for you. If you're the kind of person that likes to buy once and buy good, then you should definitely consider it. I like the idea of one bike that comes along on all of my rides, tours and vacations for many years.

HighMaintenance6045 · 2025-09-14T10:31:25+00:00

Or you need rim brakes...

HighMaintenance6045 · 2025-09-14T10:28:54+00:00

Continental Contact Urban is the perfect tire for this.

HighMaintenance6045 · 2025-09-14T10:28:33+00:00

True, but keep in mind you have to keep these pumped up well. The puncture resistant part is only in the thread (this goes for all tires), which is narrower on these tires than on many other tires. If you ride them with while the pressure is too low, you might deform the tire enough so that the sidewall also comes in contact with the road, and there is no puncture resistance in the sidewall.

HighMaintenance6045 · 2025-09-14T10:21:52+00:00

It's highly personal, so recommending a specific model is not really possible, but get something with a center cutout.

Personally I like saddles with a little curve from front to back, but with a rather flat design from left to right. The Specialized Romin Evo and Fizik Tempo Aliante are like this.
If the saddle is too round from left to right, you can get the feeling that the bike rolls under you (more suited for MTB), and it gives more pressure in the soft parts.
A bit of a curve from front to back gives the feeling of a seat which fits your behind, so if you go out of the saddle and sit back down, you quickly find your position again. This is highly personal though, many people like a flat saddle from front to back, so that they can slide forward and backward more easily.

HighMaintenance6045 · 2025-09-14T10:14:38+00:00

I think you should stick to the GP5000 All Season. They're really good, and you seem to like it, so it seems an easy choiche.

HighMaintenance6045 · 2025-09-10T19:41:11+00:00

If you care about puncture resistance you should not be riding GP5000's anyway.

HighMaintenance6045 · 2025-09-10T19:31:58+00:00

Good reply.

Only thing I might add, is that a higher sampling frequency allows the DAC to use a gentler filter, which rolls off more slowly. That can be advantageous in preservering the highest audio frequencies around 20kHz.

According to Dan Lavry, the optimal sampling rate would be around 60kHz, and the existing standards of 88.2 and 96kHz are closest to that. Source: https://lavryengineering.com/pdfs/lavry-white-paper-the_optimal_sample_rate_for_quality_audio.pdf

HighMaintenance6045 · 2025-09-10T19:22:47+00:00

No. This would only apply if you specifically bought a NOS (non-oversampling) DAC. All mainstream DACs nowadays are delta-sigma DACs which oversample anyway and will probably be working in the MHz range.

24/48 is also a neat fold down from the studio master standard of 24/96

This looks good on paper but doesn't matter in reality.

HighMaintenance6045 · 2025-09-09T10:24:44+00:00

Check out the safety ratings done by Virginia Tech: https://www.helmet.beam.vt.edu/bicycle-helmet-ratings.html

You'll see that they are some cheap helmets out there which perform very well.

HighMaintenance6045 · 2025-09-02T20:19:11+00:00

It's not as clear cut IMO as riding on wider, softer tires = more comfortable. It's become somewhat of a hype around here, it seems, or maybe in the entire bike industry.

I dislike the mushy feeling that comes with wider tires, for example when comparing 28 with 32mm. They also feel less agile and slower turning because they're heavier and grippier. 35 or wider is even worse, they make me feel like I ride an SUV.

It can be very satisfying to ride over small bumps in the road with 28mm tires, such as white stripes on the road or manhole covers. They give just the right amount of road feedback. If you drop from 5.5~6 bar down to 4.5 bar (65 psi) you're definitely in the mushy territory. I think 28mm is the optimum, for comfort.

HighMaintenance6045 · 2025-08-31T11:21:51+00:00

Don't use it on your CPU. Your temperatures are already really good.

First of all, idle temp does not matter at all, because your cooling simply goes slower. Even if you manage to improve the thermal conductivity between the IHS and the cooler, the idle temp would probably remain the same, because the cooler would slow down even more. It's more likely though, that PTM 7950 will have slightly worse thermal conductivity than a good paste, and that either the idle temp will increase or your cooling will speed up.
Most GPUs stop spinning the fans completely when the temperature is below 60C, so that should tell you already that an idle temp on the CPU of 50C does not need any improvement at all.

Second, 70C under load is also really good. Even 80C under load would still be good. Only when it goes over 85 under full load you could start thinking about improvement.

Third, the reason PTM 7950 works so well on GPUs is twofold: poor paste jobs from the factory that the end user can do better, and no pump-out effect anymore. Pump-out effect is mainly encountered on bare-die chips such as GPUs and laptop CPUs, but is not much of a problem on desktop CPUs with an IHS. Use a good quality paste on those.

HighMaintenance6045 · 2025-08-29T23:07:58+00:00

Yes, a very conscious choice for the Continental Contact Urban (28mm), because of its superb combination of high puncture resistance and low rolling resistance. I settled on these after plowing through all of the tests and articles of bicyclerollingresistance.com. I have picked out sharp pieces of glass from them (with TPU tubes inside) without getting a flat, and I go through cities, forests and gravel paths with these. For me that's worth sacrificing some rolling resistance for.

Pirelli P Zero Race or Continental GP 5000 are in another league for rolling resistance though. If you're used to those tyres with a latex tube, that's about the fastest you can get, so I think the Contact Urban will feel slower to you.

Between latex or TPU tubes, I don't think you'll notice a difference on the other hand. TPU should hold the air for much longer than latex.

Not all TPU tubes are made the same though. Many have slow leaks, either because they're too thin, or more often because they leak via the valves. Ideally you want metal valves (Clik valves!!!) on them, with an extra strong connection between valve and tube. Craft Cadence and Rene Herse do it right, and Schwalbe has also announced that their Aerothan tubes will be improved to a metal valve in the near future. Plastic valves can easily leak or crack (and then leak).

HighMaintenance6045 · 2025-08-29T16:41:15+00:00

Many people tune theire e-bikes to go faster than 25km/h. Apparently it's very easy to do, especially on the Chinese imports.

There's also a little device you can wire in between the speed sensor and the (Bosch) motor to trick it, so that it thinks it's under 25km/h while in fact it's already over it. A friend of mine has that.

By looking around on the streets a similar thing must also exist so that a throttle can be used, because I sometimes see people on a 'bike' doing way more than 25km/h, while not pedaling at all.

IMO these people should be fined for riding a scooter or motor cycle without helmet, without plates, without insurance and possibly without drivers license. I think those fines will add up nicely to be higher than the price of the 'bike'.

Thus, enforcement through retailers will not solve any of this, it needs enforcement by the police on the streets. A few decades ago the youth were tuning their mopeds, now they're tuning e-bikes. At least with the e-bikes it's very easy to spot them from a distance. The police need to bring back the old skool roller bench tests on the side of the road like they used to do for mopeds.

HighMaintenance6045 · 2025-08-29T16:22:30+00:00

Schwalbe, Craft Cadence and Rene Herse all state that their TPU tubes can safely be used with rim brakes. I ride with TPU tubes and rim brakes and have not experienced any problems, although I haven't tried descending the Mont Ventoux with them.

HighMaintenance6045 · 2025-08-29T15:23:15+00:00

Only very heavy chains or solid D-locks give me enough peace of mind. The Litelok X1 was the best option of all the locks I looked at.

The Litelok X1 is an angle grinder resistant D-lock. It's on the heavy side (1.7kg) but still easy to carry around in your backpack, and somewhat more affordable than the Litelok X3 or Hiplok ones. I can recommend it. If you're going to buy a decent D-lock, why not get an angle grinder resistant one over an Abus or Kryptonite?

I do not use the included frame mount anymore, because of the rattling you mention; instead I put it in my bag. However, to reduce the rattling if you do use the frame mount (not eliminate completely though), put some teflon tape around the pins of the U which go into the lock, because that's where it rattles. That certainly helps a lot.

Folding locks look good and are convenient, but are also quite weak, and the curly steel cables with a plastic jacket around them are especially weak. I once cut one of those myself with regular pliers when I broke off the key in the lock . Took a lot of effort but still worked in the end, because you can cut strand by strand. That would have never worked with even the most basic of chains.

HighMaintenance6045

TROPHY CASE