Everything You Wanted to Know About iPhone 3GS Video

the 'eye' of iPhone 3GSThe iPhone 3GS feature that I was most excited about was video. The very first thing I did when I got my phone was shoot Technologic Overkill, so I could put the video camera through it's paces. In the process I discovered quite a few useful bits information about how the video works. Here is random list of that information:

  • The video quality is surprisingly good for a cameraphone. In bright daylight the camera performs excellently. Like most small video cameras, it performs worse in low light. The iPhone will automatically lower the framerate in low light to compensate. The Frame rate will not go lower than 15fps
  • The iPhone shoots 640x480 at 30 frames per second. It records to the h264 codec at about 3700 kilobits per second. This equates to roughly 28 megabytes per minute. That's not too shabby. Audio is recorded in Mono at 44.1 khz using the AAC codec.
  • Compression artifacting is not very prevalent in good lighting. I think this is where a device like iPhone shines over other small video cameras. It has a very good CPU comparably, which allows for higher quality compression.
  • You can select your focus point in video mode by tapping, but only when you are not recording. When you begin recording focus is locked to the point you chose. This means you cannot rack focus while recording. This is a small gripe, but if you consider most tiny video cameras are fixed focus, it is still a big improvment.
  • Close focus is the same as in still mode -- 10cm. This is a great feature. When you are filming at a macro distance you can achieve a pretty decent shallow depth of field look.
  • Where you tap on the screen also 'guides' the exposure of the video. However, as opposed to focus, exposure remains on 'auto'. If your scene changes enough the exposure will automatically compensate.
  • The video works very nicely in iMovie, which is expected. One thing I noticed is that you do not have to convert the video to use the slow and fast motion feature. The codec Apple uses is already suitable for that.
  • The "Jelly" effect that most small video cameras exhibit is prevalent in the 3GS. This is due to a rolling shutter.

Here is a short video illustrating some of these points.

iPhone Friendly Youtube Link.

One thing I keep thinking about is how the iPhone 3GS video compares to my Flip MinoHD. In resolution, the Mino beats iPhone hands down -- the iPhone is not HD. However, the other features of the iPhone 3GS might just compensate for its lack of HD. Let's compare and contrast:

  • The iPhone 3GS has autofocus with a macro mode, the MinoHD is fixed focus at 1m
  • Exposure on the iPhone 3GS can be influenced by touching a point, the MinoHD is 'full auto'
  • The viewing screen on the iPhone 3GS is gargantuan compared to the MinoHD.
  • The iPhone has the ability to upload video directly to the web, the MinoHD does not.
  • The MinoHD has 4GB of storage, the iPhone 3GS has either 16 or 32 GB.
  • You can trim video on the iPhone(I did this on Technologic Overkill while riding the tram to save time making in/out points.)
  • The iPhone's lens is wider than the Flip.

Here is the biggest benefit of the iPhone 3GS over the Flip, and in fact, all video cameras. I always have it with me. There is a saying: "The best camera is the one you have with you." The same is true for video cameras. I enjoy capturing unique moments in daily life (I post these videos in my Pocket Cam series). A video capable iPhone means that I will never miss out on these moments.

After all of my glowing about the iPhone 3GS, here is a wish list of what I would like from it.

  • Full manual exposure. Maybe this is possible for third party developers with the API
  • Manual focus -- being able to input a focus distance.
  • Ability to change focus while recording. Being able to program pull focus would be great.
  • Apps! Something that allows you to cut clips, add titles/effects in the phone!
  • And the obivious one, HD.

It is interesting to not that most of my wants could potentially be fixed by software -- all but the HD thing.

Ok, now the big picture. Why is the iPhone special? There are many small video cameras that can achieve the same quality. In fact, there have been cameraphones that can do the same for ages. Many people are asking, what is the big deal? To me there are a few obvious reasons. First, the iPhone is ubiquitous. It is the most popular smart phone. This puts a lot of attention on its functions, which makes more people aware of their ability to record video. There are probably many people with phones that can shoot video, but don't because they just don't think to. I think that the 400% increase in mobile uploads to Youtube since the 3GS release is proof enough of this. Second, is ease of use. The iPhone is incredibly simple to use, it has an large screen, and the videos are easily transferred and edited on your computer. Most other cameraphones can't say this. Finally, there is the quality. The iPhone 3GS has very good quality for a cameraphone, there are competitive phones -- but not many. The 3GS has good enough quality that a local news station in South Florida shot a report about the iPhone with one (very meta.) I am also not the only one who has shot a music video with it. I know of at least one more. Pro video/film accessory manufacturer Zacuto thinks the quality is good enough, that they even made a special hand grip for it.

Don't get me wrong, the iPhone will not replace any professional cameras. I will not be proposing use of an iPhone on my next job. However, I do foresee a lot of legitimate use of the 3GS beyond shooting videos of your cats -- particularly in the areas of hobby filmmaking, documentary and journalism. In fact imagine that in the not to distant future (with the right apps) I think we will see journalists shoot, edit and file reports from the field with only an iPhone. That will be very fascinating.


"Understanding the Financial Crisis" or "This is Why We're Screwed"

The EconomyThe Economy: Like Flamingos in the SnowThis is one of my rare non-visual-media related posts. It is going to verge on a rant, but ultimately it is more about sharing educational sources with as many people as possible. This is not intended to be blog spam, but a way to share several sources in one place.

I just finished listening to the latest episode of This American Life called "Bad Bank." This episode explains, in regular language, the mess our banking system is in right now. I think what it elucidates is how complex and unstable the situation is. As much as I would like all those banks that made terrible decisions to go out of business, this podcast has shown me how unfeasible that is -- and how there is no miracle solution. 

This latest "This American Life" was a cooperation between them and NPR. It is hosted by Alex Blumberg and Adam Davidson who have created similarly educational audio about the economy in the past.

Here is a list of podcasts by this group. If you listen to these in order, you can at least have some understanding of why we're screwed. 

Subscribe to This American Life via iTunes1. The Giant Pool of Money

2. Another Frightening Hour About the Economy

3. Bad Bank

Tie these together with a daily listening of:

4. The Planet Money Podcast

What I like about these shows is the excellence of their reporting. They present every side of the argument with a rational approach, they explain the issues clearly, and most importantly, they leave it open for you to form your own opinion. This is brilliant radio.

Subscribe to Planet Money via iTunesIf you learned as much as I did, please think about donating to these public services:

Donate to This American Life

Donate to NPR

Do you know any other great sources for understanding this mess? Leave a comment below.

About Frame Rates or Why 29.97?

I recently remembered this popular post from my old blog. Since that blog no longer exists, I thought I would repost it here.

Since I wrote this post about a decade ago, many others of done a much better job describing this in detail. I highly recommend the following two videos by Alec Watson from Technology Connections on youtube. The rest of his videos are also great, consider donating to his Patreon

Watch: Compatible Color: The Ultimate Three-For-One Special
Watch: Analog Color TV Wrap-Up--Some extra info


Source: Wikimedia CommonsIt is fairly common knowledge that the video on your TV is playing at 30 frames per second (fps) — unless you live in europe where it is 25fps. However, have you ever thought about why these are the frame rates? Why not 50 or 100? You probably haven’t, but since I think about moving pictures all day I actually know the answer to this.

The main thing I would like to point out, which some of the geekier of you might already know, is that 30fps is just an approximation of the actual frame rate of video in the US. The real framerate is 29.97fps. Why this incredibly strange number you say? Well, i’ll tell you.

In order to make video play back at a fixed rate there needs to be some kind of timing circuit. When television was first beginning, there weren’t any of the high tech silcon-based chips that we used for this task today. So the brilliant engineers back then used the oscillation of AC electricty as the basis for their timing circuit. In the US, electricity cycles at 60 times per second (60hz.) So using half of that gives us the frame rate of 30fps. (In Europe, electricity flows at 50hz. 50/2 = 25fps)

So the frame rate of television was actually exactly 30 frames per second at one point in time. However that all changed when color television was introduced. When a signal for color information was added to the television transmission there was a big problem. The color carrier signal was phasing with with the sound carrier signal because they were very close in the spectrum. This made the picture look un-watchable. The quick fix they came up with was to reduce the framerate by .03fps which moved the two signals out of phase.

We have been stuck with this frame rate ever since.

So I hope you found that educational. If you really want to read about this on a more technical level read the link at the bottom of this story. I checked here to refresh my memory on some of the details.

Technical Description: http://artistoftheyear.broadcastengineering.com/ar/broadcasting_format_conversion/

Also more info on the Wikipedia Page