Archive for the ‘Videos’ Category

Server that actually looks (and sounds) like a server

Sunday, February 28th, 2016

I was recently with a friend who runs a server which is a lot more impressive than mine, so I thought I’d show it off. It also sounds like a jet engine.

[Watch in HD]

For a start, it’s actually in a rack-mount case (2U), with ~17TB total disk capacity and 20GB of RAM (it usually has about 24, but he had to remove some to use in another machine, hence the sticks of RAM lying on top of the case). It’s running a few VMs for people (with Arch Linux as the host), acting as a NAS, and doing a few other things like running some IRC bots, but he shut it down and rebooted it so that I could hear the fans rev up. =D

Random Old Rubbish (Part 1)

Saturday, February 27th, 2016

I was cleaning out my room and found a load of random stuff (mostly toys), and some of it was interesting, so I decided to record it. Some of it’s around 14 years old. I didn’t intend for 50% of the video to be about Beyblades.

[Watch in HD]

Stress-test Audio CD

Monday, February 15th, 2016

Never mind just gapless playback – let’s throw 99 tracks at various CD players (hardware and software) within 40 seconds and see how they handle it!

The music I used is “Nature’s Gasp” by Atmozfears & Devin Wild. Big thanks to Atmozfears for letting me use it on YouTube (now let’s hope that YouTube’s automatic song recognition doesn’t punish me despite that…).

[Watch in HD]

This test just naturally emerged after I played around with splitting tracks in a hardstyle mix for seamlessly playing on a CD. The trick to ensuring no silence between tracks was to split on CDDA frame boundaries (every 2352 bytes, which makes 75 per second for audio CDs). It took me some time before I realised that Audacity can measure position in CDDA frames and that I didn’t have to convert the number of samples into CDDA frames myself every time…

I don’t have a grudge against Foobar or anything – it really did get stuck in a loop of spinning up and down the CD the last time I tried it. Also, this may be my most anticlimactic and rushed ending ever.

Multi-strike, multi-pass, colour correction (WIP: Dot matrix program)

Wednesday, February 10th, 2016

Showing off a couple more things not possible with the Epson driver: multi-strike printing and “quiet” (not really) mode, along with CMYK colour correction which is nearly invisible to my camcorder, so that part was a waste of video…

This is a program I’m casually working on every now and then to print images on any 24-pin ESC/P2 dot matrix printer (ESC/P2 is Epson’s control language for their dot matrix printers). It directly controls the printer by sending raw commands to it; you just need to tell Windows that it’s a “Generic / Text Only” printer on Windows, not using the official Epson driver, and Windows will pass the commands straight on to the printer without trying to translate them.

[Watch in HD]

This is a standalone program for printing image files, not a driver for printing from any program. I’ve not yet released it, but I intend to some time. Compared to the driver, it currently allows:

  • Printing in (lower) resolutions for high speed (down to 60 DPI).
  • Detailed control over colour dithering/thresholding.
  • Very tall print-outs not restricted to a paper length (e.g. for continuous paper).
  • Printing only individual component colour(s) of an image.
  • * Faster colour printing by doing large blocks of each colour at once.
  • * Multi-strike printing (optionally offsetting each one to fill in the gaps between the earlier ones’ dots).
  • * “Quiet” (multi-pass) printing (unfortunately, I can’t control the actual speed).

*The last three are somewhat “hacks”, abusing commands to try to force unofficial behaviour, and as such, they rarely work properly in combination with each other. In particular, the last two often don’t work when printing colour.

By the way, printing in blocks of colour is no longer done by relying on sending commands with the correct timing (as it did in the previous video), which means it’s now much more reliable and doesn’t get messed-up by pausing the printer, image content, etc.

Solar Panel Microphone (Experiment)

Sunday, January 31st, 2016

Here, I conneced a solar panel (via a transformer) to a sound interface as if it’s a microphone, to reveal the subtle pulsing and filckering of various light sources. If you don’t like 50 Hz, this video isn’t for you.

[Watch in HD]

Thankfully, the infrared light from my camcorder is apparently very clean (not pulsing), so I can use that to see things in the dark without affecting the sound.

The transformer is just designed to convert 230V AC to 12V DC, so its audio properties are not very good (it muffles things a lot). Ideally, I’d be using an audio transformer that’s designed to sound good, but this is all I had available. I am using it to remove the DC current that the solar panel makes, because I don’t fancy putting 17.5V into my Quad-Capture (sound interface)’s mic input. I originally tried to make a high-pass filter to remove the DC, using a capacitor and resistor, but it only worked until the capacitor became fully-charged, at which point the sound faded. It was much clearer-sounding than the transformer, but there was also a huge amount of background noise.

I want to revisit this idea in the future, especially to take it for a drive at night, listening to the street lights and car lights (since modern cars use PWM to dim the tail lights).

[MIDI] Nomico – Skip! (Moetan ED) [SC-88Pro] (60FPS)

Tuesday, August 11th, 2015

Here’s the Roland SC-88Pro synth being pushed quite hard by the power of moe (ending theme of the anime Moetan, “Skip!”, originally sung by Nomico, to my surprise). MIDITrail’s fancy 3D view is good for notes, but doesn’t show any control changes, so I included a scrolling view of those, too, next to the synth’s display. And hey, why not 60FPS for those who can view that? =)

[Watch in HD]

This MIDI took me about 5 days to make, plus a few hours of tweaking at the end. It sounded like it was nearly finished after 2 days, but the hardest stuff was still left to do at that point (I do hate struggling to transcribe barely-audible parts, but they really fill in the gaps and make it sound complete).

Firsts for me include the fast arpeggio effect (surprisingly, the 88P never complained about this), wah effect on the quiet guitar (on the right), and gratuitous use of “All Sound Off” whenever possible, to try to keep things running quickly enough. Also, 4 sound effects I’ve never used before!

3 channels get re-used for different instruments (16 channels has never been so insufficient), but more annoyingly, the synth’s update speed drops really low during the chorus because of all the playing voices, making pitch-bends sound jumpy, and it took a lot of tweaking and quite some luck to get a clean recording. I kind of wonder if it’s just my 88P which slows down so much when many notes are playing (even if there are not many MIDI messsages), or if it’s simply a limitation of its CPU speed. It might just be a coincidence, but it seemed to handle it better immediately after power-up, so perhaps it becomes worse as it gets hotter. In that case, maybe I could attach a heat sink to the CPU, or just put a fan in there (I don’t really want to drill holes, though). The case doesn’t really get very hot, though. I kind of wish I could limit it to playing only 32 voices at once, instead of letting it struggle with 64. Lowering release times only gets you so far.

Somehow, the fact that an anime of Moetan had been made eluded me for 8 years and I only recently discovered it. “YOU MAGGOTS ARE HUFFING AND PUFFING–” oh wait, wrong English-teaching mahou shoujo.

[MIDI] Prince Of The Yolkfolk (DOS version) [SC-88Pro]

Sunday, August 9th, 2015

Something a little different this time. I had a burst of nostalgia and got this theme stuck in my head, so I decided to try to remake it for the SC-88Pro synth. It’s the first MIDI I’ve made in less than 18 hours (including sleep)! It’s also the first I’ve made for the 88P which doesn’t use all the sound channels (4 are untouched), despite using 3 just for trying to emulate the FM snare. And the first that messes around with time signatures to keep in-sync with the original while still having the notes align sensibly in my MIDI editor…

[Watch in HD]

This is a remake of the music from the DOS version of the game “Dizzy: Prince of the Yolkfolk”. It was released on many different platforms, and I’m sure the instruments vary a lot on the different versions, but I’ve only ever played the DOS version. It used AdLib music (technically, the Yamaha OPL2 FM synth).

I’ve seen some remixes of this, but I tried to stay faithful to the original (including overlapping notes, monophonic channels and notes that get cut because of the limitations of the AdLib hardware). Originally, I was going to use a synth trumpet sound to really match the original, but I couldn’t find a suitable FM-style harpsichord to go along with it, and synth trumpets sounded stupidly out-of-place when paired with the realistic harpsichord, so I had to go for modern-sounding brass instruments.

Yamaha music on a Roland synth… heresy!

Clockwork Westminster chime striking 4 o’clock

Sunday, July 12th, 2015

Somebody requested this on my “Clock Overclock” video from my other channel, so here it is (better late than never, right? orz).

[Watch in HD]

Inside a Cassette Deck & Dolby Noise Reduction Demo

Sunday, May 10th, 2015

A quick look inside a Yamaha KX-393 cassette deck from the 90s, and demo of Dolby noise reduction. That damn tape counter gives away all the times I cut out my failure to speak properly. =P

Headphones are recommended for the noise reduction demo.

[Watch in HD]

The waveforms displayed while Dolby is selected are simulations – versions of the original audio processed by a compressor/expander. In reality, Dolby mostly only affects the treble (as you can hear), since that’s where most of the tape hiss is, so you wouldn’t get big low-frequency waves, but hey, it’s easier to visualise this way.

My usual video editor did not feel like working, so I made this entire thing in Avisynth – it’s like coding, but for video. Please kill me now. Well, I used VirtualDub for the cropping out of all the dead air, my failures to speak, and misinformation which I said by mistake. On the plus side, I learned a lot of stuff by editing this way (such as how badly Avisynth is designed regarding modifying audio). Also, I didn’t have to screen-capture anything to get those waveforms – they’re being made in realtime by the Waveform plugin, which is processing audio from different Dolby simulations which are also being made in realtime by SoxFilter‘s “compand” function.

This video didn’t turn out as well as I would’ve liked – from the poor view of the mechanism to the incomplete demonstration of the functions and different tape types, and the fact that the only time I could record this (free of disturbances and noise) was a 45-minute slot was when I was half-asleep. So, if people are interested, I might re-visit this.

With all the old technologies on my blog/YouTube channel such as a dot matrix printer, FM MIDI synth, SC-88Pro, and now a cassette recorder, perhaps I should rename this place to “SomethingRetro”. There’s an old VCR here just waiting to be opened, too…

Dojikko Gets Side Sensors

Monday, April 20th, 2015

I’ve given her another 2 ultraound sensors on either side, so that she can see how well lined-up she is to walls on either side of her. This is to try to keep her heading directly towards a wall, so that the head ultrasound sensor will get the best reflections possible (assuming that her environment uses lots of right-angles).

[Watch in HD]

The Arduino fires all 3 ultrasound sensors and listens for their echoes at the same time in order to “see” at the highest frame rate possible (typically 20-50 FPS), but this causes issues with echoes from one sensor bouncing around and returning to a different sensor. Although the code avoids any clearly-bad echoes like this (e.g. 2 echoes on the same sensor), it’s far from perfect, and she often thinks that she’s crashed into something (an object is very close to the head) when she hasn’t. I think there’s also a strange bug in the function that times the echo delays, or something strange is going on with hardware interrupts, because the function sometimes returns 0 for a sensor which clearly has an object in range, and at the same time, the sound of the tone playing on the speaker (using the built-in tone() function) becomes distorted so that it doesn’t even sound like a square wave anymore. I’ve never experienced that before, and I have no idea what’s wrong there. Oh well, she looks cool aligning herself half of the time.

Fun game to play: See how many inconsistencies there are in this video. It’s a combination of videos recorded 7 months apart.