The Megapixel Test Program and more details
June 28th, 2007 by ken
The iApps like iChat and Photo Booth only request a 640×480 or smaller image from the iSight. Therefore it can be troublesome to find a way to test the full capabilities of the new 1.3 MP iSight. That’s why we wrote our own little test program.
Today we cleaned it up and are posting it here so new-MacBook-Pro-having visitors can try it out see the new and improved image for themselves.
The app requests and displays a video stream from the camera at 1280×1024. If you’re on an older iSight it will still stretch the VGA image out to be this size but it won’t look very good. The app will report the frame actual size from the ImageDescription at the top.
There’s also a snapshot button so you can take your own picture and make your friends jealous of your fancy new laptop. Sorry: no Photo Booth effects yet! 
If you get to try it, leave a comment and let me know how it works for you.
The Test App (68 k)
Tech Talk Follows:
The app does Hi-Lite™ a potential reason why Apple might not be yelling from the rooftops about the new camera: You can see right away how slow it is to stream the full sized video. Why? It’s more than four times more data than VGA. The Sequence Grabber was designed decades ago and wasn’t designed to handle more than NTSC/PAL sizes. Until the Sequence Grabber is revamped, it’s a little too slow to run such a large stream.
1,280 x 1,024 = 1,310,720 pixels
It’s 4:2:2 compressed YUV data, so that’s 2 bytes per pixel or 2,621,440, or 2.5 megabytes per raw frame.
So for full 30 fps video, this translates to about 75 megabytes per second or 600 Mbps.
Now keep in mind the camera controller allows for a compressed MJPEG mode which cuts the required USB bandwidth signifcantly. (You’d never fit that over USB 2.0 without compression.)
But even if it is being compressed on-camera, it’s then being decompressed in the driver and passed to QuickTime in YUV. That’s a lot of data to push through the poor Sequence Grabber pipes. Technically, you should be able to request MJPEG data from the sequence grabber, but the default seems to be YUV. I haven’t tried requesting other compression types as I don’t actually have one of these new machines in front of me.*
More details about the new camera:
The original iSight didn’t advertise itself as a UVC device (It was Vendor Specific).
The new one does advertise as UVC, so you can easily use USB Prober to decode the device descriptor:
According to the descriptor the camera supports the following frame formats:
MJPEG 640×480 @ up to 60fps
MJPEG 720×480 @ up to 60fps
MJPEG 800×600 @ up to 30fps
MJPEG 1024×576 @ up to 30fps
MJPEG 1024×768 @ up to 30fps
MJPEG 1280×960 @ up to 30fps
MJPEG 1280×1024 @ up to 30fps
Uncompressed 640×480 @ up to 30 fps
Uncompressed 352×288 @ up to 30 fps
Uncompressed 160×120 @ up to 30 fps
Uncompressed 704×576 @ up to 25 fps
Uncompressed 720×480 @ up to 25 fps
Maybe another SequenceGrabber savvy engineer out there with the new MBP could experiment and see what you get back from VDGetCompressionTypes. Can we request MJPEG data through the pipes?
*Another thanks to Dave for running some tests for me on his MBP. Dave is a web designer and has a website that I’ll plug.
June 28th, 2007 at 12:09 pm
[...] here come the MacDaddies from Ecamm Network « Whoops, 10.4.10 Breaks Some Webcam Mics The Megapixel Test Program and more details [...]
July 10th, 2007 at 11:44 am
works well, thanks. Handy when you want a higher rez. You should market it as some sort of “super photo booth”. Just get those effects (and more) and you’ll be able to make some $$.
Best,
Chuck
July 17th, 2007 at 4:25 am
just to confirm that this works great on my 2.2GHz MBP!
August 8th, 2007 at 7:26 am
Also true of the new iMacs, as tested in the Apple Store in London
August 16th, 2007 at 11:15 am
[...] For simple pictures, there’s this test app. [...]
October 3rd, 2007 at 11:07 am
Glamour Photography Agency…
hey great stuff…
December 30th, 2007 at 8:17 am
nice app but on my MB 2,2 it makes the CPU jump to more than 100% and the temperature to more than 80° C!
And how can I see the whole window in my monitor?
January 16th, 2008 at 1:20 am
Works for me — I was wondering if it would be possible to get the source code for this nifty little program. It is so weird that there is this 1/2 second delay in the video — where are all of those bits being stored all that time!
Thad
February 3rd, 2008 at 7:42 pm
This works just fine with QuickCam Pro 9000 at 1600×1200, which looks amazing… as long as you don’t move about much… nice work.
February 5th, 2008 at 5:28 pm
glamour designer…
Its fried rice, you plick!…
March 5th, 2008 at 1:22 pm
Tried it on MB. Could not see video capture. Also could not change any settings. Your program looks to have great promise. I would love to capture in HD. No need to stream for me.
Thanks
J
April 8th, 2008 at 3:21 am
Hi it is Philippe DEWOST from Qipit, Inc.
Thank you for this discovery and explanations. Actually, they were useful to one of our subscribers who is now using his 1.3 Mp iSight with our Qipit Mobile Copy Service.
Qipit allows you to turn photographs of documents (think notes, doodles, or finer print if you have a higher resolution) into clear crisp, legible copies of the original. You can then archive the copie, share it, fax it, or even publish it on the web or into your blog. And the current service is FREE.
Here is a test made by this subscriber with his iSight and MadDaddy’s help :
http://www.qipit.com/public/jerome2l/isight_qipit
See for yourselves and let us know how you manage to copy documents with your iSight too.
–/Phil
http://www.qipit.com
July 3rd, 2008 at 3:20 am
I have Santa Rosa MB Pro 2.4, how can I record video at the highest possible @ 1280×1024 @ 30fps.?
August 17th, 2008 at 6:06 pm
Thanks for the program- works really great on my 2.5 ghz 17″ MBP.
A few notes from experimentation:
QuickTime Pro and Photo Booth record at 640×480 video or stills).
iMovie does video recording at either 640×480 or 1024×576. To get this 16:9 image, it crops the top and bottom of the screen.
An enhancement that would be nice on the MacDaddy app would be if it would flash the screen white during the exposure to act as flash. thanks.
June 14th, 2009 at 6:44 am
oops, never mind my prior post, I missed the fact that quicktime 7 had the upgrade
November 20th, 2009 at 7:32 am
Any word on getting access to the motion jpeg stream from the camera?