[mythtv-users] Comcast OnDemand on Multiple STBs

Michael T. Dean mtdean at thirdcontact.com
Fri Nov 9 03:00:19 UTC 2007

On 11/08/2007 10:00 AM, Worldnet wrote:
>>>> I am trying to create a setup where I can control multiple STBs and 
>>>> navigate the Comcast OnDemand menus. I have the channel changing  
>>>> scriptsworking using the serial ports but I can't find any way to send  
>>>> anythingother than the channel info to the STB. I need to send left,  
>>>> right, up,down and select to the STB but since there are 4 STBs this  
>>>> info willhaveto be sent through the backend to get to the right box. 
>>>> Mythtv breaks out the tuning info and sends it to the external tuner 
>>>> script but I don't see any way to send other info to the external tuner 
>>>> script. Is there a hook that I don't know about or is this something 
>>>> thatcould be implemented?
>>> This would work well but my question is number 3. I can alter the  
>>> scriptsto send the commands but how do you query the backend to see  
>>> which tuneryou are watching?If you can help me with #3 I would be more  
>>> than happy to send my notesas they might apply to your situation.
>> This is a question for the -users list. Ask there and I'll answer. A 
>> hint, though: you're going about it all wrong by trying to get Myth to 
>> send more data to the channel change script.
> Mike I would really like to do this through the backend so that I don't
> have to run a daemon on the backend to intercept the commands from each
> frontend. Sending the commands through the backend would get them to the
> correct STB with a minimum fuss. Doing a query for the tuner and using
> a script seemed like a doable workaround till I started to implement it
> and found that I would need to contact the backend to get the tuner id,
> then setup a daemon on the backend to listen for the command and forward
> it to the STB. This is doable but if I could just send the command to
> the channel change script through the backend it would be so much simpler
> and cleaner. if there is a better way that I am missing then I'm all ears.

By my understanding, the "extra information" you're trying to get from
the backend is which capture card is being used to record the show so
that you can use it to submit the commands to the STB using the proper
"remote codes."

If this is the case, you have 2 (easy) options:

a) Create 4 scripts, change_channel_stb1, change_channel_stb2,
change_channel_stb3, change_channel_stb4.  Then, map the appropriate
script to the "External channel change command" for the input connected
to that STB.  Since the "External channel change command" is a per-input
setting, you use each of the 4 scripts for your 4 inputs.

b) Create 1 script which accepts 2 arguments: the STB identifier and a
channel number.  Then, for the "External channel change command" for
each input, use "change_channel 1", "change_channel 2", ...  The channel
number will be appended to the command after the command and argument
you specify.  So, you use the STB ID (1, 2, 3, 4) to determine which
remote code to use and use the channel number to send the appropriate
codes to the STB.

So, the idea isn't to get Myth to send additional data to the channel
change script, but to call the "right" script (for a, or call the script
correctly, for b).  I used both approaches as various times to control
my 2 STB's.  Granted, I haven't used firewire output, before, but since
you mention Myth is sending channel information to an "external tuner
script," I'm assuming it works exactly the same way for firewire as it
does for analog capture cards.

HTH.  And, thanks for bringing the discussion to the -users list.


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