AtariAge Forums: AtariAge Forums -> EricBall's Tech Projects

This weekend while my wife was in Miami and my son was at school or asleep I played far too much Half Life 2. I got the game as part of the Orange Box for the PS3, which I bought to play Portal. But HL2 is an FPS and thus is verbotten in my wife's opinion. But what she doesn't know. . . Based on the walkthrough, I've played through over half of the game (maybe even two thirds). And although I had fun, it wasn't quite as satisfying as the original. I will say that I thought many of the environments were extremely well done. City 17 felt real. You could feel the oppression, depression and collapse. The sheer hopelessness is amazing. Ravenholm was convincing as a zombie town. And the train bridge captured the feeling of climbing hundreds of feet over the river.But there were many other things which I didn't like. The biggest is how linear the game is. You can't get lost, although you may have to search a little to find the next exit. But when I was...

Most developers understand it is possible to trade off space for speed, e.g. unrolling loops or using table lookups instead of complex calculations. This is particularly true for low level programming where you are often trying to squeeze out the maximum speed in the minimum space. But I've recently discovered Propeller Assembly (PASM) it's possible to maximize speed and minimize space simultaneously.The Propeller is different from most processors in there are no dedicated ALU registers. Instead, any 32 bit entry in processor RAM may be used as a register. Thus processor RAM can be looked at as a 512 entry register file. Or 496 instructions (16 of the registers are dedicated to I/O), with each instruction taking a single register. Or 496 32 bit data values. It is even possible (and sometimes necessary) to modify an instruction using ALU operations.In the program I'm working on, I've programmed two 16.16 x 0.16 fixed point multiplies; multiplying one value twice...

If you do any kind of signal processing, you've probably heard of an "FFT" or Fast Fourier Transform. An FFT is an algorithm (and there are several) which calculates a Discrete Fourier Transform in less operations, typically O(N*log2(N)), where N is the number of samples. The Fourier Transform changes a time based function into a frequency based function. (The reverse is also possible.) The Discrete Fourier Transform is the same thing except it handles time and frequency samples rather than a continuous function.However, the Fourier Transfer (and therefore the DFT and FFT) work with complex numbers; which means twice as much storage and three times as many calculations than if real numbers were used. (Some of this can be reduced, but it adds complexity to the algorithm.) One alternative is the Hartley Transform and the Discrete Hartley (nee Bracewell) Transform which uses only real numbers.The DHT is very simple: Y[m] = SUM n=0..N-1 X[n] * cas(n*m*2pi/N) /...

I've enhanced my workflow, so I'll share it for others who may want to do something similar.Step 1 - using a simple video capture program and an analog capture card, I capture the video at 720x480 (YUV2 compressed with HuffYUV), and 48KHz 16bit audio to NTFS formated disk.Step 2 - use AVCutty to detect scene changes. I created a custom scene index to simplify the next step.Step 3 - compress the scenes to DV format using ffmpeg -ss hh:mm:ss.00 -t hh:mm:ss.00 -i capture.avi -target ntsc-dv "clip-yyyy-mm-dd hh;mm;ss.dv"Step 4 - copy to NTFS formated external disk using /v parameter (actually a 27GiB partition).Step 5 - connect external drive to Mac, and import DV files to HFS+ formated external disk (actually a second partition on the same drive).

Why is it people think that because the 2600 is "simple" (at least in terms of what level of graphics it can produce) that it will be easy to emulate?

The reason it isn't is because the 6507 and the TIA are "tightly coupled" - each can do things which have an immediate impact on the other. The 7800 and NES are loosely coupled unless interrupts are used. But In the 2600 the 6507 & TIA could almost be regarded as a single entity.

Anyway, occasionally people suggest creating a 2600 emulator for the Propeller. In their mind they assign a cog (processor) to each function - CPU, graphics, sound, input, etc. I typically scoff at them, citing the difficulty in emulating the 2600 - if for no other reason than the clock relationship between the 6507 and the TIA.

But earlier this week I started thinking - why not give it a shot. Put together a 6502 emulator with an eye to making it usable in a 2600 project. It might be fast enough or feature complete enough,...

Last friday was my son's 9th birthday, so I got him Scribblenauts for the DS. After playing through the first world (11 "puzzle" levels and 11 "action" levels), I have to say I'm fairly impressed. The game manages to squeeze a mind boggling number of items onto the cartridge. And there's another nine worlds to be played through (each with 11 puzzle & 11 action levels). I also like how it makes you think - and the spelling is a good "edutainment" angle.And yet, I have a few complaints:

• Handwriting recognition is hit & miss. You'd think after 20+ years of research and improvements in computing power that it could accurately recognize "R" correctly rather than "P" or "K". I'd prefer to write than use the keyboard, but the mistakes can be frustrating and make writing slower than tapping.
• ...

A decade or so ago I bought a Hi8 camcorder. With it my wife and I have shot the usual assortment of home movies. Now my wife wants to use iMovie to change those tapes into DVDs. (Probably not a bad idea - before those tapes start dying.). These days we use the movie capability of my wife's Canon S3 instead of the camcorder. Of course, getting from point A to B isn't a simple process. The first step is to use the capture card in my old PC to make an AVI using HuffYUV lossless compression. This gets saved to a internal drive with 60GB free. Even with this much space it can only hold 90 minutes. Although HuffYUV is great for capturing video, iMovie is fairly picky on what video formats it will import. So the next step is to use ffmpeg to convert the AVI to DV and write it to a 60GB NTFS partition on an external USB drive. This is a time consuming process and converting the 90 minutes capture takes over 3.5 hours. Because DV is compressed the drive will hold 4.5 hours. Then she...

My wife saw Beatles Rock Band in the store the other day and made some "wanna have it" noises. Now, although when RB2 & GHWT we talked about buying one of them, we never did. My main problem with them (and B:RB) is they are, at heart, rhythm games. You aren't just rockin' along to some tunes you know. Nope, the game want you to do the right thing at the right time, or no cookie for you. I downloaded an Aerosmith demo and played through it using my controller. (Yes, not ideal, but enough to get the basic flavor.) And, let me tell you, it's annoying when the song ends part way through and your avatar hangs his head in shame because you couldn't keep up with the beats. I also don't relish the thought of having a bunch of plastic instruments cluttering up my living room.But, what about a karaoke game? Singing along with songs sounds a lot more fun than trying to play a plastic instrument. Unfortunately, the two PS3 karaoke games are both less...

Today Apple announced the 5th generation Nano, including features not available on any other iPod models: video camera & microphone, speaker, and FM receiver. (I think the other features are 90% software, i.e. the pedometer uses the existing accelerometer.) Okay, so the iPhone has the camera and microphone, but the iPod Touch and Classic don't. (And both the Touch & iPhone have a speaker)My question is why the Nano got the goodies instead of the Touch. Maybe it's the price point. Apple wants to bring down the price of the Touch to drive AppStore sales. (Although I find it funny. Apple trumpets they've sold 20M Touches, and Wikipedia says they've sold a similar number of iPhones; for a total of 40M. But (again, from Wikipedia) Sony has sold 56M PSPs and Nintendo has sold over 100M DSs. So the Touch/iPhone has a good slice of the portable gaming market but they are still third.)Where was I. Oh right, price. So the price of the Touch dips under that...

WB has pushed back the release of Lord of the Rings on Blu-Ray to next year. And although I'd love to have LotR on bluray, I don't care - cause this is the theatrical release, not the extended version. Annoyingly, WB hasn't mentioned anything about the extended version yet. But I can wait, I have patience.