Sunday, May 31, 2009

Scalable Bandwidth in Miami?

May 27, 2009
Miami, FL

You know you are approaching Miami, when the pilot tells you the descent will be bumpy, and he spends the next few minutes swerving around magnificent thunderheads. But, I love Miami for it's diversity, vibrant neighborhoods and general good vibe. However, at this time of year, you can count on rain.

This afternoon, I had the pleasure to speak to one of Panasonic's customers. This is a company that specializes in IT design and installation and they have recently purchased an HMC150 camera. They plan on using the camera to produce both internal training videos as well as online sales and marketing efforts. I pulled out Ole Betsy (my trusty HMC150 camera) and walked them through the basic camera set-ups. But, when they told me about their web-based goals, I showed them a little understood, but very cool feature of the Panasonic HMC150, namely scalable bandwidth.

So, what is scalable bandwidth? Well, one way to think about this, is that whenever you shoot digital HD video, you are recording your information (or data) at a certain number of mega bits per second. This is also referred to as bandwidth. Among other things, the higher the number of mega bits per second, the better your image will look, but also the bigger your files will be.
The HMC150 camera was the first camera to record in the AVCHD format with the new PH (professional mode) at up to 24 megabits per second. The results are stunning images.

However, the HMC150 also allows you to record at different and lower bandwidth settings. As noted, the HMC150 will shoot 1080/60i in the PH mode (up to 24 mega bits per second), but also in the HA mode (17 mega bits per second) HG mode (13 mega bits per second) and HE mode (6 mega bits per second).

When I first heard about this I was confused. If I have a camera that will shoot at 24 mega bits per second, why in the world would I want to set it to record at a lower bit rate? As, I thought about it, I came to the conclusion that if I was shooting a static talking head, with not much action maybe, just maybe, you could get away with a lower bit rate.

Well, a few months ago, we decided to do a side by side bit rate comparison, so we could see what happens to the quality when the bit rate changes. Here is one of those tests, courtesy of Panasonic. This piece was shot by Bentley Nelson.

I realize that this is hard to critically evaluate over the internet, so, if you would like to see this and more clips, in better detail, stop in at your Panasonic Professional Broadcast Products dealer. Play with the camera and ask him to show you the AG-HMC150 DVD that contains these bandwidth tests (under the DVD ROM content).

Frankly, I was stunned at the results. The HE mode at 6 mega bits per second looks surprising good. Is it as good at the PH mode at 24? No, but it is not bad at all. Most importantly, the resulting file size is very small. So small that the files can even be sent via ftp. That is pretty amazing, HD files zipping through the internet as ftp files.

The customer agreed that the 6 mega bit clip looked really good. I suggested that for their initial in- house training videos they shoot at 1080/60i in the PH mode. But for their web-based clips, I suggested they should do some tests at the lower bit rates. It is quite possible that 6 mega bits will work just fine for them. It will be interesting to see how they proceed.

Tomorrow, I am off to present to the University of Miami and then to the So. Florida Final Cut User Group Meeting. Should be an exciting day. Hope the rain stops.
More to come.
The Road Warrior

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