On Thu, 2007-09-06 at 09:28 +0200, Alberto Hernando wrote: > El Miércoles, 5 de Septiembre de 2007 23:16, escribió: > > hi alberto :) > > thx for your informative reply on the freevo list, but i have another > > question, which imho is not really directly about freevo, so i thought, i'd > > try and contact you directly, hope u don't mind ;) > > > > > Some cards have two receivers/tuners. It's just like having two cards. > > > Also, each digital stream have more than one channel. So it's possible to > > > record two channels if they are in the same stream (with one receiver, of > > > course). > > > > you say if they are in the same stream, sorry but i'm not so knowledgable > > ;) but what does that mean exactly? what are those streams exactly and how > > can find out e.g. which channels my dvb-C so digital cable provider puts in > > which streams etc.? how do i find out which channels are in which stream > > and how many streams there are? thank you very much in advance have a good > > one ;) > > Hi. > > I don't mind answering to you, but you could also ask the same in the list. > So > I'm cc'ing there. > > Your question: what about streams? In analog tv, every channel comes in a > frequency (so to speak) and each frequency only carries a channel. So when > you want to see a channel, your card tells the tuner to receive that > frequency, and then the data can be received and so on. In digital tv, this > is a bit different. In digital technology, as you surely know, all data is > converted into binay symbols (1/0). So every tv channel (with audio, video, > subtitles, etc) in converted into 1 and 0. The good point is that you take > several tv channels and put all their 1 and 0 together. You are multiplexing > them. Then, you call all this an stream. You air the stream with a frequency, > so this frequency carries more than one channel. In dvb-t it's four channels, > and in dvb-s it might be 8, but I'm not sure. It doesn't matter either. So
The number of channels carried depends on the bandwidth available (which depends on the coding method (FEC) and signal width) and the amount of bandwidth each channel uses when compressed using MPEG2 or MPEG4. In the UK we have DVB-T multiplexes (the name for the collection of digital channels broadcast on one frequency) ranging from 17Mbps to about 24Mbps and the can carry anywhere from about 4 active channels up to ~10/12 (this includes some audio only and interactive channels) DVB-S and S2 have even more bandwidth so can carry more channels. > what's the point? If you have two cards (or a card with two tuners) you can > see/record two channels at once. That's obvious. But if you have only one, > and you are lucky enough to want to see/record two channels from the same > stream, then only one card is needed. Of course, you need the software to > handle this, but as I said, I think freevo 2 will have this feature. So, how > can you know? You should check if your provider gives you this info. For > example, using an example from Spain, I know how dvb-t is working, so I know > that I could see "tve1" while recording "la 2" with only one card, but I > couldn't see "la sexta 1" while recording "la sexta 2". You need info for > this. I don't know if epg (electronic program guide) has this info. The way you can find out whether you can record the channels at the same time is whether they have the same frequency in your channels.conf file. I don't have time at the moment to add the necessary stuff to freevo 1 to add multiple channel recording, but check out DVBStreamer ( http://dvbstreamer.sourceforge.net/mediawiki/index.php/Streaming_Multiple_Services ) for ways on doing it manually if you are interested. > > I hope that my explanation is clear enough. > > Alberto > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Freevo-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freevo-users ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Freevo-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freevo-users
