Cable Forum - Tivo mpeg 2 or 4?

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gadge

20-12-2010 15:40

Tivo mpeg 2 or 4?

As the title when we get our hands on it is it as the title says mpeg 2 or 4?.

Andrewcrawford23

20-12-2010 16:32

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by gadge (Post 35140739)

As the title when we get our hands on it is it as the title says mpeg 2 or 4?.

mpeg 4 fro what i haev read in the specs thinkt hat why oyu can record more than you would on SA with 1tb

nialli

20-12-2010 16:35

Re: Tivo mpeg 2 or 4?

How great is the difference between Mpeg2 and Mpeg4? If an hour of Mpeg2 is 2Gb for SD, what is an hour of Mpeg4? Is the difference the same for HD recordings (one hour = 8Gb)?

gadge

20-12-2010 16:41

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by nialli (Post 35140758)

How great is the difference between Mpeg2 and Mpeg4? If an hour of Mpeg2 is 2Gb for SD, what is an hour of Mpeg4? Is the difference the same for HD recordings (one hour = 8Gb)?

Well at the moment on our samsung v+ we have,

steptoe and son ride again,
two ronnies xmas special,
the desent hd,

and there is 66hrs left.

Andrewcrawford23

20-12-2010 16:51

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by gadge (Post 35140761)

Well at the moment on our samsung v+ we have,

steptoe and son ride again,
two ronnies xmas special,
the desent hd,

and there is 66hrs left.

samsung although has mpeg4 is using it for recording it turned off but can be turned on in th future or it record mroe than teh SA box so they hve problem marketing one boxc at 160 and another at 200+ hours cant remember the difference

Stuart

20-12-2010 17:03

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by gadge (Post 35140761)

Well at the moment on our samsung v+ we have,

steptoe and son ride again,
two ronnies xmas special,
the desent hd,

and there is 66hrs left.

AFAIK, all the currently used cable boxes do NOT reencode or recompress the data they recieve. When any current v+ "records" a programme or film, it merely saves the data stream sent to it from VM's head end.

The advantage of MP4 is (very simply put) that it can reproduce the same quality as Mp2 at a given bitrate, but using around half that bitrate. Will we see any increase in quality when VM switch to MP4? Probably not, They'll be looking at the fact that they can cram twice as many channels in.

We will have the advantage that the apparent storage capacity on the Tivo will be a lot higher than it would otherwise.

devilincarnate

20-12-2010 17:27

Re: Tivo mpeg 2 or 4?

From what i have read the box is backwards compatable so will be able to switch from the current MPEG that they use to the other ( trying to find the quote for this )

Stuart

20-12-2010 17:55

Re: Tivo mpeg 2 or 4?

It will, but if they are only sending MP2, I doubt the box will re-encode the video.

Andrewcrawford23

20-12-2010 20:02

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by Stuart (Post 35140808)

It will, but if they are only sending MP2, I doubt the box will re-encode the video.

i believ teh tivo box will record in mpeg4 ie compress the mpeg2 signal i could be wrong but i am pretty sure that how t ogin ot work and that why it can record mroe than current v+ box if they had 1tb drive

mersey70

20-12-2010 20:14

Re: Tivo mpeg 2 or 4?

I thought the next generation of cable compression is DVB-C2 which isn't the same as MPEG4, much the same as DVB-T2 as used here isn't the same as MPEG4 DTT in Ireland.

Do any cable operators worldwide actually use MPEG4, I though DVB-C is mainly used but DVB-C2 is just being rolled out in Europe.

Stuart

20-12-2010 20:31

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by Andrewcrawford23 (Post 35140875)

I'd be surprised if it did. The quality loss would be significant and would give Sky a huge selling point.

---------- Post added at 21:31 ---------- Previous post was at 21:18 ----------

Quote:

Originally Posted by mersey70 (Post 35140881)

You are getting compression (MPEG2, MPEG4) and data structure mixed up. DVB-C, DVB-C2, DVB-T etc define the structure of the data being sent. This data can be compressed using either MPEG 2 or MPEG 4.

Think of it this way. When you download something from the Internet, it is usually carried using TCP/IP packets (not always, but most downloads are). The hardware carrying the packets has no specific "knowledge" of what it is sending. That data can be an image, a web page, an application or whatever. The TCP/IP protocol does not care what is sent, merely that the data it has is sent to the correct address. DVB-C2 is like TCP/IP in this respect.

The compression defines what data is sent. That is sorted out by what happens to be at the end of the connection, be it a computer or cable box.

mersey70

20-12-2010 21:08

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by Stuart (Post 35140885)

I'd be surprised if it did. The quality loss would be significant and would give Sky a huge selling point.

---------- Post added at 21:31 ---------- Previous post was at 21:18 ----------

You are getting compression (MPEG2, MPEG4) and data structure mixed up. DVB-C, DVB-C2, DVB-T etc define the structure of the data being sent. This data can be compressed using either MPEG 2 or MPEG 4.

Think of it this way. When you download something from the Internet, it is usually carried using TCP/IP packets (not always, but most downloads are). The hardware carrying the packets has no specific "knowledge" of what it is sending. That data can be an image, a web page, an application or whatever. The TCP/IP protocol does not care what is sent, merely that the data it has is sent to the correct address. DVB-C2 is like TCP/IP in this respect.

The compression defines what data is sent. That is sorted out by what happens to be at the end of the connection, be it a computer or cable box.

I won't pretend to understand all that but do any cable operators currently use MPEG4?

Some of the big cable operators of Europe are pushing for DVB-C2 which supposedly is 30% more efficient than DVB-C, VM have said they do not have any plans to use it though.

http://www.broadbandtvnews.com/2009/...-dvb-c2-ibc09/

Stuart

20-12-2010 21:42

Re: Tivo mpeg 2 or 4?

Quote:

Originally Posted by mersey70 (Post 35140898)

DVB-C and C2 define how the data is formatted. They do not define what that data is. The current Cable system uses DVB-C to carry MPEG2 compressed data. As I understand it, there is no reason it cannot carry MPEG 4 compressed data.

And yes, some cable companies do use MPEG 4..

---------- Post added at 22:42 ---------- Previous post was at 22:40 ----------

Quote:

Originally Posted by mersey70 (Post 35140898)

DVB-C and C2 define how the data is formatted. They do not define what that data is. The current Cable system uses DVB-C to carry MPEG2 compressed data. As I understand it, there is no reason it cannot carry MPEG 4 compressed data.

And yes, some cable companies do use MPEG 4..

It's unlikely that the new Tivo box will have enough processing power required to encode MPEG 4.

Stephen

21-12-2010 15:14

Re: Tivo mpeg 2 or 4?

It will probably be compatible with both just like the Samsing V+ is but VM only broadcast on MPEG2 currently.

IMO anyway.

gadge

21-12-2010 15:35

Re: Tivo mpeg 2 or 4?

Thanks for all the replys i asked because when we were with ntl their version of the tv drive was to be mpeg 4 but when merged with telewest they used the mpeg 2 version.

Jameseh

21-12-2010 18:20

Re: Tivo mpeg 2 or 4?

Why do boxes not record in H.264? Requires more 'uumph' but has significantly smaller file sizes.

Lew	21-12-2010 18:26

Re: Tivo mpeg 2 or 4?

I don't think they record, they just dump the stream straight to disc. If they recorded they'd have to re-encode (which would also require extra hardware), which would lose quality.

*awaits post from spiderplant to say I've got it completely wrong…* :D

spiderplant

21-12-2010 18:35

Re: Tivo mpeg 2 or 4?

Sorry to disappoint Lew, but you are completely right. :)

Stuart

21-12-2010 19:31

Re: Tivo mpeg 2 or 4?

Yep, and not only would the extra encoding reduce video quality (probably noticably, especially on large screens), but would add extra to the cost of the box.

Even though the chipset is only a couple of pounds for each box, bear in mind that the reason a lot of PCs don't come with firewire (despite nearly all consumer camcorders and Mini DV recorders using Firewire) is that the cost of the chipset and licencing adds a few dollars to the cost of a motherboard.

carbon60

21-12-2010 20:31

Re: Tivo mpeg 2 or 4?

Does anyone know if the Tivo box supports DVB-C2? Something tells me if Virgin Media aren't bothered about DVB-C2 then they won't have spent the extra money to put it in the Tivo box but it would help 'future-proof' it.

indie1982

21-12-2010 22:31

Re: Tivo mpeg 2 or 4?

From what I've read, I would very much doubt that the Virgin Media TiVo box will have DVB-C2 tuners. I found an article which says VM are "supportive of DVB-C2" but have "no plans" to deploy it, although that's from 2009.

If VM have the capacity they say they do then they won't need DVB-C2 for a number of years, spending the money on upgrading infrastructure and customer hardware right now wouldn't be the most frugal of moves. VM are working towards an analog switch off which will give them even more of the spectrum to play with just with DVB-C.

Having said that, spectrum efficiency can be greatly in increased with DVB-C2 and gains in downstream capacity can be as much as 60% over DVB-C deployments once analog has been switched off.

It's definitely something VM will have to look at but I think they can afford to wait for the next generation of boxes we'll see after this incarnation of TiVo to implement.

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