Wednesday, 18 November 2009

So... do ColorCode (Amber+Blue) 3D glasses work with LCD Projectors?

I said I would test it out, and the verdict is... yes.

At least, it did with the Dell projector I tried it on. While I initially found that there was more ghosting on the projector image when viewed through ColorCode (Amber+Blue) glasses, than my LCD monitor, at least it was 3D.

I have not yet had success with Cyan+Red at all on a projector.

Changing "Video Mode" improves image

The Dell projector I used allowed me to change the "video mode", which is basically a bunch of different colour level presets. I found that in "game mode" the ghosting pretty much vanished even on the projector.

So there you have it.

ColorCode (Amber+Blue) can work with a projector.

Tuesday, 10 November 2009

Channel-4 3D Week

I was at Sainsbury's today (unusual, but I happened to be near one) and came across a big point-of-sale bin thing with loads of FREE 3D glasses in it. Apparently Channel-4 is hosting a 3D week, which according to my 3D glasses arm will feature "never-seen-before archive footage and continue[s] through the week with loads of awesome 3D films and concerts to enjoy".

Anaglyph TV

Now, the image below (from the C4 website) doesn't look like anything special to the naked eye, but when viewed through the special Sainsbury's glasses will take on a 3D appearance. It is an anaglyph.

To view anaglyphs you need special "3D glasses" that have coloured filters. But there are several different colour combinations around, and you have to make sure you get the right one for what you are watching. You can get Red Blue, Red Cyan (the most popular), Red Green and, as I learned today, Blue Ochre (sometimes called Blue Amber, or Blue Brown).

And guess which ones Channel-4 have opted for?

Blue Ochre of course - which means you probably don't have an old pair of 3D glasses hanging round the house which will work for 3D week. Your "Journey to the Centre of the Earth" glasses will not work, and neither will your "Shark Boy and Lava Girl" pair.

Better get yourself down to Sainsbury's and get some Blue Ochre.

But what's with all the different types?

Why not just stick to one type and have done with it? Simply put, different colour combinations have different benefits. Red Cyan is probably the most popular because it allows the creation of both colour and B&W anaglyphs (as does Red Green). Red Blue only allows B&W and the images are very dark.

But more information on the different types can be found here:

However, and this was news to me until today, Blue Ochre when viewed in a dark room, has better colour transmission than the others. So this is probably why Channel-4 opted for it. After all, if you want people to think that 3D is more than just a gimmick, it needs to look good.

Blue Ochre not free but very clever

While all the other anaglyph colour methods are pretty much public domain, the Blue Ochre combination is apparently patented. Not the idea of the anaglyph - that has been around for too long, you can't patent that - but according to this website it is the method for converting an image for Blue Ochre is patented:

What makes it patentable (the "secret sauce") is the mathematical formula that modifies the luminance of the right eye record and the luminance and chrominance of the left eye record to best transmit the colour information. The darker brown is necessary for balance, because blue is low luminance.

Whilst I haven't read the patent ( thoroughly, their process doesn't seem to attempt to determine which point in each image represents each point in the three dimensional scene, so it seems to me that they are effectively presenting a luminance-based stereoscopic pair combined with a flat chrominance image based on the average of the two views.


Apparently this method was invented at the Technical University of Denmark, and has been branded as ColorCode. More information can be found here:

What makes it so clever, and therefore worth paying for perhaps, is explained on their website:

The ColorCode 3-D system is the only in the world to reproduce high quality 3-D Stereo images and movies with full color- and depth information on all display types.


And I can't argue with this claim. I know from experience that Red Cyan may work on a CRT or TFT monitor, but utterly fail on a projector. You can also get a fair amount of ghosting. If ColorCode (Blue Ochre) can crack this, it will be worth the license fees for TV companies who want good quality 3D without a trace of gimmick.

I will test my new Sainsbury's ColorCode glasses on the LCD projector at work, and if the result is good I will be very impressed and let you know.

Monday, 9 November 2009

Flash Projects #7 - Making a Flash MP3 Player

Finally here is the solution. It turns out you can use NetConnect and NetStream to make an MP3 player in Flash, but only if you encapsulate all your MP3s as FLV files. Not really very helpful since it means converting your MP3 files - it just makes more work.

And busy designers really don't want the job to take longer.

However there is another way to make an MP3 player in Flash, that still gives us all the control we need, but the pausing and playing is just a tad more complicated. But nothing you can't handle I am sure.

The Code

First, here's the code, then I will explain it:

//set default starting position for playback in seconds
var playpoint = 0;
//create sound object
var audio_sound:Sound = new Sound();
//play button
this.play_btn.onPress = function() {
//play the mp3 from the point defined in the variable playpoint
//pause button
this.stop_btn.onPress = function() {
//define the variable playpoint as the same as the current position, this is given in milliseconds so we divide it by 1000 to convert it into seconds
playpoint = (audio_sound.position/1000);
//stop the playback
this.m1_btn.onPress = function() {
audio_sound.loadSound("track1.mp3", false);
//true = streaming and therefore autoplay, false = not streaming and therefore just sets the file for when you hit the play button.
this.m2_btn.onPress = function() {
audio_sound.loadSound("track2.mp3", false);

The Explanation

Here goes. First, instead of using NetConnect and NetStream as we did for the video player, we are going to use loadSound. This still gives us a fair amount of control, in some ways more than the NetStream would give us, but it doesn't automatically pause when you play something that is already playing, as NetStream does. So while the rest is no more difficult, just different, pausing and then playing again is slightly more complicated using loadSound.

As with any program, we can only work with the information available, or that we can find out. With the loadSound approach we can find out one very important thing that will help us make a pause/play mechanism - we can find out our current position in the MP3 as it plays. In the code above we do this as follows:


Not hard, but on its own it is not a pause/play mechanism. We make it into a pause/play by storing the current position as a variable called playpoint at the time of pause. In effect we remember where we got up to. Then, when we play, we tell it to play from where we left off by asking the variable playpoint to tell us where we got to. As follows:

When pausing:

this.stop_btn.onPress = function() {
playpoint = (audio_sound.position/1000);

First we set the variable playpoint to store our current position. This is actually given in milliseconds so we divide it by 1000 to convert it to seconds - and that's what you see being done here. Then we tell it to stop.

When resuming playing:

this.play_btn.onPress = function() {
//play the mp3 from the point defined in the variable playpoint

We simply tell it to start, but include the start position as playpoint so it resumes from where we left off.

Isn't that what pausing/playing really is? Stopping, and then starting from where you left off?

The other code is effectively a menu, allowing you to choose which track to listen to. The term false on the end means the track won't play straight away, but will wait for you to press play as well. Change the false into a true and just clicking on the menu will make the track start as well.

Have fun.