Hi all, someone knows what is the recommended time between Channel changes when using MPEG2 or MPEG4(H.264).

Tks in advance

Well, from a consumer standpoint, the time between channels changing should be as little as possible. I don't think there is an actual "recommended" time for this.

I know from seeing Microsoft IPTV demonstrations that they have as close to instantaneous channel changing I have seen.

 

Anonymous wrote:

Well, from a consumer standpoint, the time between channels changing should be as little as possible. I don't think there is an actual "recommended" time for this. I know from seeing Microsoft IPTV demonstrations that they have as close to instantaneous channel changing I have seen.

Yes but with significant impact to network !! Zapping is from MPOV only magic card.

Hi ,

           For ensuring that user does not experience any service degradation due to longer channel switching times as compared to the analog TV , it is recommended that . Mean Channel Change Delay should not be more than 300ms . And yes, truly the Microsoft's ICC feature caters to this bussiness requirement .

 

Regards ,

Parag Parmanand

parag.parmanand@gmail.com

I would not give a hard number of milliseconds to this question, but rather more an equivalent with what the satellite or cable zapping time is today.
Half a second is the usual time to zap these days. This constraint is more or less respected these days. The trouble comes from new arriving compression format. For instance, with MPEG-4 or WM9, if one wants to optimize the bw used, the compression rate will become higher than it is today. therefore, it will take more time to retrieve the video signal at a zap than before. why ? because, the STB has to wait the right frame to reach it (and the more you compress, the less frequently you send this frame...). this is true for all systems that are to come.

 

The zap time should be 500 msec maximum.

That means each router, switch, DSLAM, etc. in the network path needs to contribute a minimum amount of delay, so that the sum of all the delays from each network device adds to no more than 500 msec.

Also the buffer time in the set-top box adds some delay.

Microsoft's ICC helps with this, but it isn't truly "instant".

 

The problem with ICC from Microsoft is that it only works for adjacent channels and needs to do a unicast stream from head end to STB... This implies that their head end has to be as close to the STB as possible, otherwise you will need a lot of extra bandwidth on your network...

 

Sergio Sevileanu

From my experience, it is hard to go under 1.5-2 seconds in advanced coding scearios.

Scarcer intra frames, buffer filling, etc. make it difficult to go under these figures.

Regards,
Hoopz

Actualy we have a ICC during about 200ms, here in Portugal with MEO IPTV service.