Aswath Weblog

Place Shifting by IP Communications Clients

Om has posted an exclusive that Sightspeed will facilitate placeshifting (a la Sling Media) via their voice/video soft client. Now we have a semi-official confirmation of this by Andy. If you really think about it, the whole thing is kind of easy for Sightspeed to do. After all, their soft client handles video. In other words, it is able to take a video stream, encode it and stream it across the Internet to another client. The only catch is whether the video codec is good enough to render commercial TV. In a whitepaper, they explain that they have a proprietary codec that uses 400 kbps for full motion video to present 30 fps 320x240 video while consuming only 15 ms delay, even though the codec is implemented in software. It seems it uses a “psycho-visual model” – you need to read the paper to know what it is.

Om may have scooped the specific information regarding Sightspeed and Andy tells us that this was a “skunk works” project taking place over the last few months. But readers of these pages would have known of this from previous posts here, here and here. These posts appeared seven months back.

Of course other IP Communications clients can replicate this feat, by selecting an appropriate video codec. My preference will be that they not use yet another proprietary codec; instead they should consider using Ogg, “a patent-free, fully open multimedia bitstream container format designed for efficient streaming and file compression (storage)” (taken from Wikipedia entry).

By the way, I want to draw your attention to the fact that Sightspeed uses a SIP URI to identify the “server”, unlike Sling Box, which (if I remember correctly) uses a long, alpha-numeric string. Also note that embedding this into a device (as opposed to run it on a Media Center PC) is not that difficult and I am sure they will do that once they identify a market need for such devices.