What compression do cable co's use?

[kitabata]

Hi,

had an interesting conversation recently w/ a friend who told me most cable co's don't use mpeg4 compression, what compression then is currently most prevalent?

[usually_quiet]

Digital cable uses MPEG-2 more often than MPEG-4.

[Jim44]

They're probably still using MPEG-2, based on a small sample of cable boxes that I know Comcast uses:
DCT-6412 (mine) - MPEG-2
http://broadband.motorola.com/dvr/dct6412.asp
DCH-3416 - MPEG-2
http://www.motorola.com/Business/US-EN/Business+Product+and+Services/TV+Video+Distribu.../DCH3416_US-EN

The DCX family of cable boxes add support for MPEG-4, but I don't know how wide-spread they are.

Just a couple of data points I found.

[edDV]

In almost all cases in No. America the answer is MPeg2.

[yoda313]

@eddv - do satellite companies use mpeg4 or are they mpeg2 as well?

[edDV]

@eddv - do satellite companies use mpeg4 or are they mpeg2 as well?

DirectTV and Dish have shifted HD channels to MPeg4. This gets them more channels per transponder not necessarily better quality.

[yoda313]

Thanks eddv.

Now is that the same mpeg4 we can use on say a zune or ipod? Or is this a special industrial grade that has more control factors in it for better picture quality? (I'm not saying you could take it off the sat box directly to the portable player I'm talking about the nuts and bolts specs of the file structure - would they be essentially the same?)

[edDV]

Thanks eddv.

Now is that the same mpeg4 we can use on say a zune or ipod? Or is this a special industrial grade that has more control factors in it for better picture quality? (I'm not saying you could take it off the sat box directly to the portable player I'm talking about the nuts and bolts specs of the file structure - would they be essentially the same?)

MPeg4 is scalable from low res cell phone to high quality HD. Sat is using medium quality HD (far from studio quality). They aren't using h.264. Their MPeg4 codec is proprietary and optimized for satellite transmission noise conditions.

[yoda313]

@eddv - thanks. So the codec is specific to the company but the rest is still the mp4 we can use. I appreciate the clarification.

[edDV]

@eddv - thanks. So the codec is specific to the company but the rest is still the mp4 we can use. I appreciate the clarification.

Sat subchannels are encrypted.