06.23.09

All over the place

Posted in Development, complexity at 10:17 am by Twm

I’m doing some work with location based services at the moment. A colleague told me of some of the problems they had had with the software. One was related to the SkyHook system. This is the system that Apple used and helps to improve the speed of acquiring a fix by mapping the location of Wifi hotspots and cell towers.

the app would for the most part correctly report the position but during field testing- say when heading down the M25 – it would occasionally report the location as being back in central London. This erratic behaviour was a bit of a puzzle to the the engineers until they discovered that National Express have been installing Wifi access points on their buses.

A new Wilhelm?

Posted in Uncategorized at 10:10 am by Twm

Much as I adore Wilhelm spotting, it’s not as fun now that it’s so widely known about outside the film industry.

If you don’t know what I’m talking about, then you probably wondered why some people at the cinema laugh seemingly inappropriately at horrific explosions and falls.
The Wilhelm scream is a sound effect regarded with affection by sound engineers and directors alike, it’s the calling card of someone who knows their movie heritage and has been discretely slipped into 100s of Hollywood films. (See link above for a compilation).

After watching Breaking Bad Season 1, we might have alternative : The Dean Scream.(Youtube).

06.19.09

Peg it

Posted in Graphics at 12:04 am by Twm

ffmpeg is an extraordinary program, it seems to deal with just about any video format I care to throw at it.
If you are not one of the enlightened, ffmpeg is a command line tool which supports transcoding of content from one format to another. Many of the $10 video converters on-line are simply rips offs of the ffmpeg code base with a crap UI on top. (see the mmfpeg hall of shame for uncredited use)

As with any command line tool, the complexity of the arguments kill it for most. But generally you will be encoding for a particular device or standard format and so a quick google will give you the options you need.
I’ve been using ffmpeg to convert video content (including iplayer films) for Sony Walkman NWZ-A815 (which is very particular about the video size and bitrate).

I can’t even remember what the options do, but I wrote a python script to transcode all videos in a directory and spits out about 290mb per hour of video (assumes ffmpeg.exe is in your path).

import glob
import os

fileNames = glob.glob("*.*")
print(fileNames)

commandTemplate = "ffmpeg.exe -i \"%FILENAME%\" -b 567k -s 320x240 " + \
"-vcodec mpeg4 -ab 220k -ar 44100 -ac 2 -acodec libfaac \"%FILENAME%_TRANSCODED.mp4\""

for file in fileNames:
	if not "TRANSCODED" in file:
		command = commandTemplate.replace("%FILENAME%", file)
		print("Executing: ",command);
		os.system(command)

06.15.09

Con Air

Posted in Uncategorized at 11:37 am by Twm

Booking Ryan Air flights. I noticed that they have a credit card/debit card charge £5 per journey per person (£20 for a trip for two). I’m sure the debit card at least used to be free.

However, I noticed that there was no charge for a Visa Electron (the sort of card you get with your griffin saver when you come of age). Some banks will allow you to have a Visa electron as well as your mastro, but you can also apply on-line for a Halifax basic account:

http://www.halifax.co.uk/bankaccounts/otherbankaccounts.asp

If you intend to do a few trips, then it’s well worth getting one. But remember that funds must be present in the account before you book (this can take 3 days).

06.09.09

Defib

Posted in medicine at 8:33 pm by Twm

Good blend of medicine and computing. A footballer with a known heart condition suffers a heart attack (some sort of ventricular fibrillation/tachycardia). Luckily he has been fitted with a implantable cardioverter defibrillator which kicks in at 0:15.

edfa

The defibrillator paces the heart as needed, delivering a shock which causes the heart to stop and hopefully restart with a normal rhythm.