Sesse__

2,529 karmajoined hace 6 años

https://www.sesse.net/

comments

hace 6 díasdiscuss

The sad part is that most employers don't care particularly about performance optimization skills (the economics don't work out, they can often just fix the problem cheaper with more hardware—and even if they can't, they mostly don't bear the cost themselves).

The fun part is that when your employer _does_ care about software optimization, few people are actually good at it and your skills are more exclusive :-)

hace 8 díasdiscuss

I once measured a 80s-communally-built event space with a laser meter (it was useful to have digital floor maps for event planning). No measurement was a perfectly round number. No angle was perfectly right. Nothing really lined up. Except… there was this one set of stairs leading up to the stage. It was perfect. Every step was exactly the same in all dimensions, to the millimeter. It was perfectly level. I always wondered who this stair craftsman was, who prided themselves on doing such professional work among the presumed chaos. :-)

hace 9 díasdiscuss

> Also to your point, this is why compliant peak meters use a mandatory 4x upsampling at 48k.

This isn't due to latency, it's because the true peak (in the analog waveform) could be between samples.

hace 13 díasdiscuss

It's behind a flag, if you want to play with it. (The easiest way is usually just to test in Canary.)

hace 17 díasdiscuss

Did you actually test? I did it and it worked fine (and zooming in confirmed that the RGB bars are nicely preserved). Be sure to put your subsampling at 4:4:4.

hace 18 díasdiscuss

Why do you think it wouldn't work for a JPEG? I just made one like that, and it worked just fine.

hace 20 díasdiscuss

Just remove the A record, and nearly all the scrapers disappear. :-) (And then you get one email per month or so that “your host does not resolve in DNS”.)

hace 22 díasdiscuss

Are you maybe confusing “downstream” with “mainstream”? Being “downstream” of a product means that you are a derivative of that product (your upstream), taking in basically all of their code and adding your own on top.

hace 22 díasdiscuss

> And while they've recently announced more of this stuff will move to FOSS soon, at the same time their response rate to new bug reports has become worse than ever before, which is deeply worrying.

A huge chunk[1] of the MySQL developers were laid off (and also large amounts of QA etc.), so it's not surpising at all that they are struggling to keep the lights on. There are talks about an external group trying to form to take more ownership, but so far, your best bets are MariaDB or Postgres, depending on whether you think MySQL 5.1 was the epitome of relational databases or not.

[1] From what I gather, about 75%. In the first wave.

hace 22 díasdiscuss

MySQL has never been downstream of MariaDB.

hace 22 díasdiscuss

They are using a fork, although nobody _really_ knows how up-to-date it is.

hace 23 díasdiscuss

It's the one that nags you to upload all your IMAP passwords and email to Microsoft's cloud.

hace 24 díasdiscuss

FFmpeg has its own native H.264, HEVC, MP3, Speex and AAC decoders. It's true that they don't have an H.264 or HEVC _encoder_ without calling out to external libraries, but they have a pretty good AAC encoder now, and TBH most use of FFmpeg is for decoding, not encoding.

hace 25 díasdiscuss

> due to FFmpeg back then lacking any framework for code sharing between components and codecs

Funny, I remember this being completely different; FFmpeg bundled ffserver, which transcoded to a bunch of codecs at the same time (sharing motion search and everything) precisely to demonstrate how similar the codecs were and how much could be shared. (Of course, that could easily be spaghetti, but not spaghetti for non-code-sharing reasons.) All on the 400MHz-class machines we had at the time. Do I remember wrong? I haven't looked at these old releases in forever.

hace 25 díasdiscuss

The idea of having two arguments to fread() is presumably to be able to do something else than all-or-nothing when there's a short read.

hace 28 díasdiscuss

> ffmpeg and other media frameworks (Windows Media Foundation, Apple’s AVFramwork) only support static pipelines.

FFmpeg doesn't do “pipelines”. It's a library, not a framework.

hace 30 díasdiscuss

It's a signal. It's not a strong signal, and you certainly should not base your entire perf on it, but if the number is unusually high or low, it's a signal that could warrant further investigation.

(I once worked with an engineer that had two PRs, both fairly small bug fixes, in a given calendar year, and when I looked more carefully, they did not have any other obvious output or impact.)

el mes pasadodiscuss

Also, performance is generally pretty low; I've been on projects where we rewrote OpenCV code into more-or-less obvious hand-rolled code and won 5x perf. The abstractions are generally a bit too thick and oriented around single pixels (which also makes the API a bit too verbose for my taste).

el mes pasadodiscuss

Useful, then, that you can start several vectorized floating-point muls each cycle. (E.g., most modern x86 are 3/0.5 cycles for vmulps. No 20 cycles in sight.)

el mes pasadodiscuss

You should multiply by 255.0, optionally add a dither (triangular is okay), and then let the FPU round using its default IEEE 754 round-to-nearest-ties-to-nearest-even mode. None of this crazy 0.5 stuff. :-)