[This post is taking part in our Designing Hardware for HD series. Be sure to check it out!]
This is the first real post in this series, so I’d like to start off with the reason for writing this series.
We’ve set out here to create a product to assist customers with developing a high definition video client – our BEEHD. The main “theme” behind this product is to reduce the hassles involved with dealing with standards and video coding technologies to a point where our customers have only to focus on the user interface of the application.
What we “missed” is that there is an additional area where our customers and prospects face challenges – designing a hardware suitable for video conferencing. It is not that we missed that part, it’s just that we assumed our customers will be able to cope with it on their own. But there is good reason why designing such hardware isn’t that easy: the processing requirements for HD video are humungous.
Just to give some kind of a glimpse to what is necessary, here’s a chart that shows the amount of pixels in an image per resolution. CIF and 4CIF is where standard definition is today. HD is either 720p or 1080p in the chart.
Pixels per resolution
To make things worse, going HD also means increasing frame rates from 15 per second to at least 30 per second, which will again double the amount of data you will need to process in a given amount of time.
You might think that this only affects the video encoding and decoding parts, where a lot of processing power is required to get the job done, but there are other areas that need to be taken care of:
- High end motion camera that can capture HD resolution
- HD requires more bandwidth on video inputs and outputs (usually by means of faster clock speeds and larger bus mechanisms)
- HD requires more processing when scaling the image to fit the display
All of these issues makes a video endpoint something that can’t fit today in a single chip, which means the videophone application itself needs to be distributed between several chipsets in the solution (a software issue) AND that the data path of the video inputs and outputs are longer as they need to traverse through more chips (a hardware issue).
A HD videophone system also needs to support HD Voice – the ability to work with something better than the measly sound spectrum of up to 3.3 KHz we’re used to from our phones today. and that is also not a trivial task.
Why? Because again, as video traverses several components/modules within the videophone, so does audio. And while the issues here are not related directly to processing power, they do relate to a lot of sensitivity issues that arise when dealing with audio.
What I wanted to do was touch 7 of the challenges related to designing the hardware for HD video terminals. It is by no means an exhaustive list, but it does reflect the challenges that our prospects face the most.
These challenges are:
- Where to place the video coding processes?
- How does video scaling and window layouts affect the design?
- Searching for a good HD camera
- Taking care of the on screen display
- A closer look at the audio system
- Dealing with the host chip and managing connectivity
- Future-proofing the hardware
Now, as this is a work in progress, I will be very happy to hear your comments and understand where you would like assistance – this might alter the challenges I’ll discuss here on the blog or even generate new ones.