![](/static/253f0d9b/assets/icons/icon-96x96.png)
If I did want to capture the raw signal
Never done this; see recommended techniques by the vhs-decode
community.
If I did want to capture the raw signal
Never done this; see recommended techniques by the vhs-decode
community.
the composite to HDMI converter has a single switch from 720p to 1080p
Composite is 480i/60*. That is, 60 times per second a blanking interval occurs, then 240 lines of picture are drawn - either the top (odd) or bottom (even) field. This is neccessary for CRT TVs because a 30Hz refresh rate would cause seizures but drawing all 480 lines 60 times per second would be wasteful. Look it up online for details: if you want videos, I recommend the Television playlist by Technology Connections on YouTube, especially the first video.
*Technically, the vertical frequency for NTSC is 59.94 Hz (precisely 60000/1001) to avoid interference between color and audio while keeping compatibility with B/W sets. In practice, you should check that the video output is actually at this frequency; if it’s 60 then every 1000th frame will be duplicated - no big deal usually unless this also swaps odd&even fields. No such problem exists for PAL, which was always exactly 50 Hz.
If the converter only outputs 720p or 1080p (presumably at 60 Hz), all 720/1080 lines are drawn 60 times per second, which means lines are added with some scaling technique, after some kind of deinterlacing happens.
Deinterlacing is basically a task similar to scaling but with key differences:
There are various deinterlacing techniques that could be used here:
Don’t use the converter if it cannot output 480i or at the very least 480p! Scaling should happen during playback, the files should be original resolution. You can also try non-trivial upscaling with some AI tools (best use them after the “computation-heavy” deinterlacing method, see above) but still DEFINITELY keep the original resolution file for archival.
use a [separate] worse quality VCR for cleaning
I don’t have experience with moldy tapes. It might be a good idea but adds wear; I’d just clean the VCR after every tape if I suspect mold. You’d still need to clean the cleaning VCR after every tape to avoid cross-contamination so it would be no easier.
Is [advanced deinterlacing] possible in OBS?
Idk, I just keep my files interlaced and stored as high-bitrate H.264 (I don’t have enough computing power to encode sufficiently good bitrate in better codecs). If I wanted deinterlacing, I could process the files with ffmpeg
filters or some other tools.
I don’t expect newer VCRs to be made, there’s a lot of precise mechanical engineering and the R&D that would need to go into making a professional-grade VCR today does not make financial sense. However, there is an option to refurbish existing ones and capture the magnetic signal as directly as possible. On media such as VHS or LaserDisc, the signal is not quite composite video, as that would require some 6 MHz of bandwidth. Instead, the color subcarrier is remodulated to a way lower frequency and then back to normal for playback. The folks behind ld-decode
(a project that takes raw signal from a LaserDisc’s laser pickup and translates it into composite video) and its fork vhs-decode
have made software that captures everything the head picks up into a raw file, and then does TBC and chroma decoding to create the best possible video. They also documented what hardware can be used for the capture (usually a firmware-modded Conexant video capture card or a beefy FPGA) and how to connect it to some VCRs’ circuitry.
Of course, this is quite an over-the-top effort for home tapes, I’d just go with a generic composite capture card that does not deinterlace nor upscale and not bother with TBC.
Why a separate VCR for cleaning tapes? It’s enough to clean the heads AFAIK.
Also, you should definitely not use default deinterlacing techniques for the video, especially not ones built into these generic dongles. Capture it interlaced, preferrably as losslessly as possible, then use deinterlacing software where you can fine-tune the settings if you need to.
No, TBC most likely cannot be done in software, unless the video features a prominent vertical bar (such as a black border). It depends on the quality you want to reach, look closely and decide if the jitter is acceptable.
Edit: TBC can obviously be done in software if you have the raw composite or head signal but that is not possible with the capture cards you have.
Well, then you’re going to hear
most of the time, much like Spotify.
(Last time I was in a Spotify-“enhanced” waiting room was 6 years ago so no idea if that still holds.)
Yes but you’ll need to intercept the HDMI cable with a beefy microcontroller to turn it back on when displaying patient data again so you don’t get fired. At this point, I’d be looking to disable the corresponding software if the computer is accessible.
In the Czech Republic, BILLA uses them and they respond to the RFID reader on my phone. It’s a different kind though, most have black-white-red displays.
Can’t wait for somebody to hack them, the displays are certainly neat. Especially if they manage to add it to an existing Home Automation network without extra hardware.
AFAIK, they use RFID now so they must be changed manually but maybe someday, they will devise a price-gouging scheme involving face detection and tracking people with security cameras.
“Here comes this lady that always buys four cans of dog food despite the last price increase! Let’s notch it up it by another 20%!”
I am talking about the cdwifi.cz captive portal with its 30-second video ad. I cannot just disable large media because then the “Continue” button never gets enabled.
Is there a way to capture these pages and report them to uBlock filter authors once online? I’d like to add a filter (or better, userscript that just enables and “clicks” the “continue” button) for my country’s rail company’s Wi-Fi captive portal but the JavaScript is obfuscated or compiled from another language so I have no idea what anything does, and of course the element classes are all randomized.
“1/4/12”
Excel is going to have a Date with you, and it’s not asking further questions. If you didn’t wish to consent to have your col’n shattered, you should have preceded it with a '
.
How many upvotes does 💲🄄Ƽ᱐ buy, really?
It’s not just digits. Nobody is expecting it to understand language yet but the parser is-number
still returns true
for "2e3"
or "0x0F"
. It tells you whether the string can be interpreted as a real numeric value.
You are right, “elf” is a stretch, it does not make sense to parse it as a number. But in some languages, the string “15 240,5” is just how a number is written (yes, that’s a U+2009 THIN SPACE
, you can’t stop me from using it as a thousand separator in German). Obviously, despite having a ,
on their numpads, German programmers still expect computers to parse numbers with decimal dots and interpret commas as list values.
So the only valid digits are arabic numbers but arabic script numbers are not a valid digit?
Some people writing Regex implementations have that opinion. I’ve refrained from saying mine.
If we want programming to be inclusive then doesn’t that make sense to also include the arabic script number?
Maybe. IMO, number tests should be chosen/implemented based on the project’s requirements. If you want to include every Unicode character or string pattern anyone’s ever used to convey a numeric value, that would be a long and growing list. Arguably, it’s impossible: the word “elf” means a number if interpreted as German for “eleven” but not if interpreted as English for 🧝.
You may argue that writiing 2024 as “MMXXIV
” and not “ⅯⅯⅩⅩⅣ
” is a mistake but while typists who’d use “2OlO
” for “2010
” (because they grew up using cost-reduced typewriters) are dying out, you’ll never get everyone to use the appropriate Unicode for Roman numerals.
If you think is-number
can be replaced with a one-liner, you don’t have the enterprise code mindset. What if the world gets more inclusive and MMXXIV, ½ and ⠼⠁ become recognized as numbers? 𒐍𓆾 were numbers in the past but what if people start assigning numeric value to other characters? Are 🖐🔟💯🆢🂵🀌🁅 numbers of the future???
/s
I’m not even all kidding, Regex implementations are split on whether “٣” matches \d
.
Me who chose the AMD Ryzen version of a laptop last year instead of Intel Raptor Lake because it was $10 cheaper:
It’s been a while since I’ve done this but unless you’re recovering the Ark of the Covenant, it should be enough to follow these simple steps: use H.264 in OBS with high bitrate on a fast PC and preferrably using a USB 3.0+ port (even if the capture card is 2.0) to avoid clashing with other devices on the bandwidth-limited 2.0 bus. Check that the output is indeed interlacd. Look at stats/logs to see of any frames are dropped and investigate if it’s just the 59.94 Hz compensation, actual blank sections of tape or some part of the processing chain unable to keep up. Adjust audio levels; you might get better results using your PC’s mic socket rather than the capture card’s audio ADC (most tapes are mono anyway) but make sure to disable auto-gain or else quiet sections will get boosted like crazy, increasing the noise.