ChronoSync for backup

Econ Technologies, Inc.: "ChronoSync also makes an excellent, lightweight file backup utility, making it easy to keep duplicate working copies of your precious files. Using the scheduling capabilities, you can devise quite sophisticated backup strategies. Hourly, daily, and weekly synchronizations can be scheduled to make sure that, at any instant, you have a working copy that you can revert to for any reason. Backup to external storage devices or other computers including Mac OS 9, Windows, Linux, or any operating system Mac OS X can mount to."

- supplement to Retrospect, backup user folders to mounted image over network

One person's view of digital camcorders

Using the Sony TRV900

This page represents my collected knowledge about the TRV900, some other cameras, the latest models, and digital video in general.

I love this type of page. One person's view based on their own experience. The TRV900 is a legend, the lessons here are generalizeable.

SimplyDV: Canopus ADVC-100 Analogue to Digital Video Converter

SimplyDV: Canopus ADVC-100 Analogue to Digital Video Converter

A well regarded A/D converter. An alternative to replacing my Hi8 with a digital camera.

Another Hint on merging iPhoto Libraries

macosxhints - Merge old iPhoto libraries on CD with iPhoto 5 libraries

If you drag and drop an iPhoto library to a CD, the 'magic XML' file isn't created and iPhoto won't recognize the archived library for importing.

This hint discusses several workarounds, and also digresses into problems with copying OS X symlinks from CD. A finder copy may not handle the symlinks, which are relative symlinks, correctly. Using ditto or archive seems to do the trick.

Good discussion, even if it illustrates the problems with iPhoto. It would help if there was some documentation.

The horror: letterbox camcorders, iMovie, DVD, old TVs, oh my, oh my

This is a long and quite tortured post. Read at your own peril. I started down this road because I was trying to figure out if it made sense to try to capture video on my new camcorder at a 16:9 aspect ratio (widescreen) instead of the old, generic 4:3 ratio that works well on TV. In particular, I decided I'd try to figure out which aspect ratio used the data acquired by the CCD most effectively. I'd rather not use 16:9 if I can help it since iMovie 2 can't handle that ratio. (iMovie 5 can -- see iMovie HD Help: iMovie HD automatically adjusts footage to better fit the screen but I don't have my new G5 yet.

Now, after some very helpful comments, I'm still not sure of the answer. I'm not confident I can infer the physical geometry of the chip all that well, and it seems like the chip can capture more resolution than the camera. I think I'll end up using 4:3 for now, and when I get my new G5 with iLife 5 I'll study the frame data size using both methods. The pixel count may be my best guide to which format makes the best use of the sensor. Despite the complexity of the 16:9 format (can't play back on a non-widescreen TV without some iDVD trickery) it does compensate slightly for the dismal wide angle lenses in today's cruddy camcorder market.

If you want to read more, here's the essay ...

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Groan. I thought still camera digital vs. 35mm film aspect ratio wars were bad, but this is worse. I highly recommend this site as a resource on this topic, it's also a uniquely great guide to buying a camcorder. I'll start with old-fashioned TV and move on from there ...

Older TVs display images in a 4:3 (width x height) ratio - 1.33. Not coincidentally, this is the ratio of an 640x480 VGA display (4:3) and most consumer digital cameras. The TV came first, all else followed. Sort of like the wheeblase of roman carts allegedly determining road widths in some way.

Except that in the film world 35mm was already around, which is roughly 3:2 - 1.5. So printing consumer digital camera images to "standard" 4x6 prints is a pain, but the images display well on older 4:3 monitors (but not newer widescreen LCD displays!).

In the movie world things have varied over the past century, but even the 35 mm 1 3/8" (diagonal) has ruled:

In May 1889 Thomas Edison had ordered a Kodak camera from the Eastman Company and was apparently fascinated by the 70mm roll of film used. Thereupon W.K.L.Dickson of his laboratory ordered a roll of film of 1 3/8"(ca. 35 mm) width from Eastman. This was half the film size used in Eastman Kodak cameras. It was to be used in a new type of Kinetoscope for moving images on a strip of celluloid film, which could be viewed by one person at the time.

But, you say, if movie film is 3:2 (1.5), why are modern movies shown as 16:9 (1.78) in theaters? All I can guess is they are filmed as 1.5 but are then somehow masked to be 16:9. If my brother were around he'd explain it to me.

Now to a reasonably modern mid-market camera -- the Optura 50. The sensor on the Optura 50 is 1/3.4. That, apparently, is a measurement in square inches -- so the sensor is 0.3 inches squared. That's in the "higher range" of single sensor cameras (which is why the Optura is less "zoomy" than the Elura -- if lens size is fixed a bigger sensor means less magnification. Tragically the Optura still has crappy wide angle coverage.

But what's the aspect ratio of the sensor? My main clue is the recording pixels for the still camera, which maxes out at 1632 x 1224 (1.33 or 4:3) [1]. That's our old TV 4:3 aspect ratio; so the sensor is shaped like an old fashioned TV. Given that aspect ratio and the surface are of 0.3 sq in then the working sensor is about 0.84 x 0.63 inches (sorry for all the US units!). (This assumes the still camera uses the entire sensor -- this is a reach and in retrospect is an unreliable assumption.)

So how does the camera manage to produce 16:9 letterbox output -- with all its associated editing and display problems (need iMovie 5.01, need to define project, lots of hassles everywhere) -- when the physical aspect ration is 4:3?! (I don't really know, but if you assume the sensor is phsyically .84x.63 inches then ...)

Ahh, that's the bad news. The camera must be using only a part of the sensor and adjusting the display appropriately. You can get a good idea of how much is being thrown away by looking at the size of the image on the swing-out LCD viewfinder -- in 16:9 widescreen mode there are black bands above and below the display. If my math is right then the camera uses the full width of the sensor but only 75% (0.47/0.63) of the height. So almost 25% of the sensor data is being disgarded in order to produce that spiffy letterbox effect.

Now if a camera had a true 16x9 sensor that would be a different story!

Update 3/20/05: And NOW, for a contrary opinion!! I'm leaning now to the conclusion that the real constraint is iMovie. So I'll stay 4:3 until I ready to try iMovie 5, then switch.

---- Footnote -- on resolution ---------

[1] The still images are 2 megapixels - idiotic toy camera. The spec sheet says the movie 1,230,000 pixels or 1280x960, so much less than the still camera. That's apparently typical for a mid-range consumer sensor; the image stabilizer uses up some of the pixels that are available for still camera use.

Now, consider how TVs work (this site is also useful). With 525 scan line NTSC video the usual image displayed is only a 480 lines high, of which 240 are displayed at any one time (alternating240 at 60/sec, so a 480 at 30/sec). In data terms this is roughly equivalent to a 640x480 display or about .3 megapixels.

Obviously the sensor can capture a higher resolution than NTSC can represent. So where does all the extra resolution go? Seems like a waste.

PS. This data was kindly posted in response to my query in an Apple support forum, its based on SONY data:

Maximum playback resolution for different camcorder video sources:

8MM - Up To 240 Lines of Resolution
8MM XR - Up To 280 Lines of Resolution
Hi-8 - Up To 400 Lines of Resolution
Hi-8 XR - Up To 440 Lines of Resolution
----- the NTSC signal standard maxes out above here -------------
D8 (Digital 8) - Up To 500 Lines of Resolution
Mini DV - Up To 530 Lines of Resolution
High Definition - Up To 1080 Interlaced Lines of Resolution

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Updated 3/19: trying to correct my most egregious errors.

Progress in consumer electronics is not linear

In fact, sometimes progress moves in reverse. The entire consumer camcorder market has gone to seed!

Consdier the Optura 50

Last year Canon's mid-range cameras had a reasonable wide-angle lens and S-video analog input.

This year Canon's mid-range camera have no S-video and mediocre wide-angle (thought the Elura 90 has a wide angle adapter in the box).

The high end cameras have S-video and mediocre wide-angle and lots of noise at low light levels. The wide angle adapter is yet more money.

The zoom is very annoying. At least they post their 35mm equivalents

f=4.6-46 mm, f/1.8-2.8, 10x power zoom
35mm equivalent:
Tape: 4:3 recording: 47.8-478 mm
16:9 recording: 40.9-409 mm

A 48mm lens is basically a standard lens. So there's no wide angle at all. Zip.

Most of the video I do is of our kids in the house. The only use for a 10x zoom (or a 20x zoom in the smaller sensor Elura 90) is for a close-up of nasal hair.

Update 3/19: I pursued this further with a usenet thread.

Paul Rubin kindly filled me in. He recommended I look for a used SONY TRV 900.

There is no mystery. The consumer market wanted camcorders to also be able to take megapixel still pictures, which means megapixel sensors, smaller pixels for a given sensor size, which means less light hitting each pixel, which means worse low-light performance. The TRV900 came from before the era of megapixel stills, so it had big pixels and good low-light performance. The VX2100 similarly doesn't take megapixel stills because somewhat outside the normal consumer market (it's a semi-pro camera popular with student filmmakers and the like), so its users don't want that feature.

And Ptravel added some more grim news about what's happened to camcorder sensors:

The VX2000/2100 uses, if I recall correctly, 1/3" sensors. I think the TRV900 used 1/4" sensors. The current line of consumer camcorders uses sensors as small as 1/6". Remember, too, that light sensitivity will decrease logarithmically rather than linerally as sensor size falls.

So the mystery is solved. It was good product management and stupid consumers that destroyed the consumer camcorder market. Still camera capability is a marker for a camcorder that can't handle low light situations.

Update 3/20/05: A plaintive letter to SONY in Jan 2003. Two years later, things are worse.

Raindance VOIP conferencing - with spam included

Video conferencing, net meeting, and web conferencing solutions Raindance

The Raindance website doesn't mention this, but they're a VOIP conferencing solution with integrated video. I was on one of their calls recently, a 3 way international call using phones. One speaker was a bit echoish but overall quality was good.

They offer a non-audio free one-to-one meeting service; roughly comparable to Microsoft, AOL and Yahoo's. Unfortunately when you sign up for the free account you give full rain for them to spam unmercifully and sell your contact information to the lowest of the low. Wow. If I were the CEO of Raindance, a publicly traded company, I'd have an absolute cow about this. How the heck would they ever hope to attract corporate customers for their non-free (not cheap) services if they spam on evaluation? Sigh. Of course I have them my trash account.

It seems to have installed a Java client on Firefox, but I won't be able to test it with distant colleagues given their terms of service. It really amazes me what some companies think is good business.

Here's the blurb from their web site:

Raindance Meeting Edition offers you the flexibility of several account levels, each providing the same powerful web conferencing features, but set for different meeting sizes and prices. All accounts include:

* Unlimited online meetings with easy-to-use video and web conferencing features
* Integration with Microsoft Outlook for automated invitations and meeting information
* A range of collaborative features that improve participation, enabling you to share applications, present documents, share browsers, chat and whiteboard online