Sun, 15 June 2008
Intro: The Moving Picture Experts Group or MPEG, is a working group of ISO/IEC charged with the development of video and audio encoding standards. In this podcast we look at the MPEG standards and video delivery systems.
Mike: Gordon, what sources are we referring to here?
Wikipedia and white paper from the MPEG Industry Forum at www.m4if.org/public/documents/vault/m4-out-20027.pdf. we've also got a couple of diagrams from the Verizon website.
Mike: What's the history of MPEG?
Mike: Are these open standards?
Mike: What's the history? Can you tell us about MPEG-1?
Mike: How about MPEG-2?
Mike: We don't hear much about MPEG-3 - what's up with that?
Mike: Let's talk about MPEG-4 now.
Mike: What are some of the advantages of MPEG-4?
Mike: Let's switch gears and talk about carried video delivery systems - specifically the telcos and cable companies. How is this technology used?
It's different for broadcast and video on demand (VOD) content. Let's discuss broadcast systems and look at how Verizon (as an example) is setup.
Two National Super Head Ends (SHE) - one in Tampa and the other in Bloomington, IL:
- Diversely located
- Satellites collect video feeds
- Video is converted to digital MPEG-2 and packaged in a 10-GigE payload
- SHE servers “pitch” data to the Video Hub Office (VHO)
- Three OC-192 SONET (long haul) rings that drop and continue GigE to VHOs
Mike: What is OC-192?
Mike: OK, these video hub offices are distributed over Verizon's footprint - what happens when they get the video?
Video Hub Office (VHO) ex. Burlington MA Combines:
- National Channels
- VOD Servers “catch” data from the SHE servers
- Off-Air, program guide, public, education, and government (PEG) channels, and local ads are injected
- Encrypts all content
- Content sent over several 1-GigE links to local Video Serving Offices (VSO, ex. CO) over SONET (medium haul)
- VSO then sends it to the OLT and then to the PON network for delivery to customer.
Mike: Broadcast is still done using traditional RF modulation methods - correct?
Yes - that will change - rumor has it Verizon will be trialing IP Broadcasting this summer in Pennsylvania - just a rumor!
Mike: Now - Video on Demand (VOD) does things a little differently - correct?
Yes - VOD delivers IP content to the customer - it is not in RF format:
- Content is requested by user via the IP network (private subnet)
- Content is then streamed from the video pumps to the Video Distribution Routers (VDR) in the VHO (ex. Burlington)
- VDR then sends 10-GigE links to a Video Aggregation Router (VAR)
- The Video Aggregation Router (VAR) then sends it to the Gateway Router (GWR) in the VSO (ex. CO)
- GWR then sends it to the OLT and then to the PON network
Mike: So - Verizon is combining Voice, Video and Data services on the same fiber?
Yes - Here's another nice diagram from the Verizon website: