Are Videophones Ready for Prime Time?

Amigan asks: "Looking for a gift for my parents who live 1500+ miles away, I came across the Vialta Beamer TV. This device, with its claimed ease of use, would be helpful for my parents to see my son via the phone, but I'm wondering if the glowing WSJ review or Tech TV review are for real. Is 4-15 fps viable for conversation?"

Comments

What's the point?

[floamy]

Why not just buy a webcam and do it online? With two good connections you're probably looking at a bettter framerate.

30fps would probably be better

[sakusha]

I read an interesting report (SF Chron I think) that said deaf users discovered that Apple's iChat has a sufficiently high frame rate and resolution to use sign language over video, and no other products had a high enough frame rate to do the job adequately. But then, AFAIK iChat and the iSight does 30fps. I suspect this doesn't directly apply to you, but I though you might find it interesting as some sort of benchmark.

video is a hassle

[oskillator]

Personally, I like being able to answer the phone without shaving, getting dressed, and combing my hair first.

Re:video is a hassle

[pyrote]

considering a good 90% of slashdotters goto work under those conditions, I doubt this is a concern :)

Re:video is a hassle

[kachuik]

Actually a good point.

We tried this a work a while back and it turns out that most people will not turn it on.
They don't want to see or be seen. It also got rid of the travel, meaning free lunch & time away from your desk.

It might be wise to try and find out if would actually be used before plunking down the cash.

Is 4-15 fps viable?

[Babbster]

It depends on what you and your family are looking for. If it's just a case of your mom wanting to see your face while you're talking, then it's probably fine (just don't move around too much). If you actually want to have a reasonably smooth conversation more closely approximating face-to-face contact, I think a consistent frame rate of 20-25 would be the bare minimum.

For a quick, kind of dirty solution the Beamer product looks to be adequate but, again, it's not going to feel like face to face.

If you're looking for something with higher quality, there are standalone units that work over IP. The obvious advantage is broadband speed allowing much nicer frame rates (as several people have described with the Mac iChat system) and they don't require a PC (though some ISPs require PCs to set up broadband service). The disadvantages are setup (might be tough to talk a non-techie through it) and broadband cost (of course, this is cancelled out with frequent use because of long-distance savings).

D-Link has two TV-connecting IP videophone models, both wireless and wireful (the latter goes for $149.95 after $50 mail-in rebate at Amazon).

14 fps.

[wowbagger]

Consider this:

Movies are 24 FPS.

TV is 30 FPS (NTSC) or 25 FPS (PAL). (frames per second, not fields per second).

The "killer app" for video phones is not business conferencing - it is "Look at Grandma! Wave to Grandma!".

And we USED to use postcards (1 frame per WEEK) for that.

15 fps adequate for some things

[michael_cain]

Several years ago I helped run some informal studies of people using small-frame video over IP for real-time communications. IIRC, some of the useful things that we learned were:

• People who watch 15 fps video on a regular basis rate it higher than people who hardly ever watch low-frame-rate video. 15 fps is clearly not as smooth as 24 or 30 fps, but people do get used to it.

• At 15 fps, body language and hand gestures are easily understood. For desktop conferencing, people tended to use the video as a body-language signaling channel -- I'm bored, I'm excited, I need to say something now.

• At 15 fps, you can tell whether the audio and video are properly synced by watching people's mouths -- at 10-12 fps the motion is too jerky to tell.

• At 15 fps, out-of-sync audio and video will drive you crazy -- many people have to look away so they can't see the video in order to continue the conversation.

• A black-and-white option can be useful. A black-and-white frame typically requires only about half as many bits as a color frame, so you can trade off color for fps. Some people preferred black-and-white at higher frame rates, some people preferred color at lower rates.

Frame rate needs to be 16 ...

[foobsr]

... to give the impression of continuous movement due to the idiosyncrasies of human perception.

Thats why the old fashioned 8mm movies were (usually) shot at that speed.

CC.