[mythtvnz] Skystar2/Freeview Idiot questions
Steve Hodge
mythtvnz@lists.linuxnut.co.nz
Wed, 27 Jun 2007 15:42:33 +1200
------=_Part_38851_6767544.1182915753070
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
On 6/27/07, Barry Clearwater <barryc@bcsystems.co.nz> wrote:
>
> Regarding the two transponders, is it therefore the case that all
> canwest channels go through one transponder (on the dish?) and the TVNZ
> through the other?
Yes.
Regarding being able to concurrently record, with the reference to this
> in development, how many concurrent recordings are possible (or being
> developed) with one card?
Theoretically as many as the transponder carries. In practice it may be
limited by disk bandwidth or other factors.
I'm still getting to grips with satellite tv - one carrier, multiple
> digital video signals - right?
Yes, sort of. With DVB-S you have one carrier (aka transponder, multiplex,
et al. on a particular frequency and polarity). The signal is packetized -
it's a stream of distinct blocks of data (packets), called an MPEG Transport
Stream. Each packet makes up part of an Elementary Stream which is a video
or audio stream, or other data (EPG data, service descriptions, interactive
program data such as MHEG data, etc). So a single Transport Stream usually
carries multiple Elementary Streams, all mixed up, and usually this
capability is used to provide multiple TV channels. Either the DVB-S card or
software filters out the packets that belong to the channel you're
interested in and discards the rest, but there's nothing to stop you keeping
everything, i.e. recording all the channels on that transponder at once.
I mean terrestrial television is VHF/UHF with one receiver for each RF
> channel so if I want to record two channels I need two receiver cards.
Currently (with MythTV) the situation is the same with DVB-S. The work that
is being developed at the moment will allow a DVB-S card to record all
channels on a single transponder at the same time. Hopefully this work will
be complete before the end of the year. It will mean that instead of six
DVB-S cards to record all the Freeview channels (One, 2, 3, C4, Maori, One
Sport Extra) we'll only need two (one for the TVNZ transponder, one for the
Canwest transponder).
Cheers,
Steve
------=_Part_38851_6767544.1182915753070
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
On 6/27/07, <b class="gmail_sendername">Barry Clearwater</b> <<a href="mailto:barryc@bcsystems.co.nz">barryc@bcsystems.co.nz</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Regarding the two transponders, is it therefore the case that all<br>canwest channels go through one transponder (on the dish?) and the TVNZ<br>through the other?</blockquote><div><br>Yes. <br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Regarding being able to concurrently record, with the reference to this<br>in development, how many concurrent recordings are possible (or being<br>developed) with one card?</blockquote><div><br>Theoretically as many as the transponder carries. In practice it may be limited by disk bandwidth or other factors.
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I'm still getting to grips with satellite tv - one carrier, multiple<br>digital video signals - right?
</blockquote><div><br>Yes, sort of. With DVB-S you have one carrier (aka transponder, multiplex, et al. on a particular frequency and polarity). The signal is packetized - it's a stream of distinct blocks of data (packets), called an MPEG Transport Stream. Each packet makes up part of an Elementary Stream which is a video or audio stream, or other data (EPG data, service descriptions, interactive program data such as MHEG data, etc). So a single Transport Stream usually carries multiple Elementary Streams, all mixed up, and usually this capability is used to provide multiple TV channels. Either the DVB-S card or software filters out the packets that belong to the channel you're interested in and discards the rest, but there's nothing to stop you keeping everything,
i.e. recording all the channels on that transponder at once.<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I mean terrestrial television is VHF/UHF with one receiver for each RF
<br>channel so if I want to record two channels I need two receiver cards.</blockquote><div><br>Currently (with MythTV) the situation is the same with DVB-S. The work that is being developed at the moment will allow a DVB-S card to record all channels on a single transponder at the same time. Hopefully this work will be complete before the end of the year. It will mean that instead of six DVB-S cards to record all the Freeview channels (One, 2, 3, C4, Maori, One Sport Extra) we'll only need two (one for the TVNZ transponder, one for the Canwest transponder).
<br></div><br></div><br>Cheers,<br>Steve<br>
------=_Part_38851_6767544.1182915753070--