[mythtv-users] Way to change channel (setchannel doesn't work)

Graham gravety at grahamvoce.com
Thu Dec 22 15:20:33 EST 2005


Graham wrote:

>Nick wrote:
>
>  
>
>>On 14/12/05, Graham <gravety at grahamvoce.com> wrote:
>> 
>>
>>    
>>
>>>Hi,
>>>
>>>I am hoping someone can help me.  I have written an external channel
>>>change script that does the following:
>>>
>>>1) If the freqid passed in is less that 100 it treats it as a
>>>terrestrial channel and tries to change the channel on the device using
>>>'v4lctl -c /dev/video0 setchannel $1'
>>>2) Else sets channel to the channel my Sky+ RF is on and executes a
>>>channel changer command for my Sky control box.
>>>
>>>Trouble is the setchannel doesn't work - I just get a burst of white
>>>then snow!
>>>
>>>It works fine through MythTV if I remove the external channel change
>>>command (through setup).  If I try and use xawtv it moans about DGA -
>>>though I did get it working with the '-remote' option but you still
>>>couldn't change channels using setchannel.
>>>
>>>I don't know what command MythTV uses to change the channel (as it
>>>works!) any ideas? - Thanks.
>>>   
>>>
>>>      
>>>
>>If using an internal tuner (i.e. on an analogue TV card or DVB card),
>>it is taken care of internally. If using an external tuner, it will
>>use whatever channel change script you tell it to use (defined in
>>capture card setup).
>> 
>>
>>    
>>
>Yes I am aware of this (it is an internal analogue tuner), I just
>wondered if there was any way to emulate the MythTV internal method.
>
>  
>
>>The 'normal' way of setting this up is to define 2 separate video
>>sources (e.g. Terrestrial, Sky) and then attach these to the tuner and
>>direct inputs for your capture cards. You can then give preference to
>>the terrestrial channels, and provide a channel change script just for
>>the Sky source. This should negate the need to code more complicated
>>if/else channel change scripts and keep things much simpler in terms
>>of maintenance.
>> 
>>
>>    
>>
>Thanks!  I had considered this a while back as it should give a better
>Sky picture too.  The only problem with this method is that the Sky box
>is in another room.  Now, there is already an RF cable running round the
>house but to achieve this I would need to run a composite lead round as
>well and split this into the 2 TV cards.
>
>Apart from that this is a good solution.
>
>Graham
>  
>
Ahh, problems - no audio (of course) as I have two TV-cards and am
pulling audio over the PCI bus.  Hence, I don't have any way to get the
audio in with the composite/s-video signal...

So, it looks like the only way I can achieve what I want is to tune the
cards from the script and use only the RF inputs.  However, with a
*broken* setchannel command I don't know how!

Any ideas?

>  
>
>>Nick
>>
>> 
>>
>>    
>>
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