[mythtv-users] Firewire channel change for SA4200?

Jarod Wilson jarod at wilsonet.com
Thu Jan 21 14:59:15 UTC 2010

On Wed, Jan 20, 2010 at 7:26 PM, Christian Szpilfogel
<chrisznews4 at rogers.com> wrote:
> steve wrote:
>> That did it, thanks...BUT
>> The other problem was that sa3250ch.c was empty (in fact all the files in
>> ./contrib/channel_changer/sa3250 were empty).  So I got the file from the
>> trunk and compiled it.  On testing it said "sorry device not supported
>> yet."
>> Harrumph.
>> So I found this post http://ubuntuforums.org/showthread.php?t=712789 which
>> gives a modified channel changer  that's supposed to work for my box, the
>> complete name of which is SA Explorer 4200HDC.
>> I modified it according to instructions to include my box's vendor_id and
>> model_id.  I compiled and test-ran it, and got output:
>> [root at mythtv sa3250ch]# ./sa3250ch -v 20
>> node 0: vendor_id = 0x00d00d1e model_id = 0x00000001
>> node 1: vendor_id = 0x0000252e model_id = 0x000010cc
>> Device acquired on node 1
>> Changing channel 20
>> AV/C Command: cmd0=0x00487ce7 cmd1=0x04001400 cmd2=0xff000000
>> Which would seem to indicate that it worked.  However the channel
>> indicator
>> on the box did not change.
>> Enacting Einstein's definition of insanity, I set it up as the external
>> channel changer on mythtvsetup and attempted a record.  Everything
>> appeared
>> to run normally, but it didn't actually change the channel (it recorded
>> the
>> channel it was originally set to).
>> On looking at the C code, it appears that the "Device acquired" message
>> doesn't result from any actual feedback from the box; it just gets printed
>> if it finds a valid id combo from the defined variables.
>> I'm also not sure what's on node 0.  I don't have any other firewire
>> devices
>> connected. Maybe this is the channel for data?
>> Anyway the question is: Is there some way to get this working
> Steve,
> Try the one at:
> https://wiki.ubuntu.com/majoridiot?action=AttachFile&do=view&target=mythchanger.10f.beta.tar
> <https://wiki.ubuntu.com/majoridiot?action=AttachFile&do=view&target=mythchanger.10f.beta.tar>
> and read the README file.

I knew of this thing's existence, but I keep forgetting about it.
Sounds like it does do more of what we'd ideally have in an included
external firewire channel changer, but I'm confused as to why this is
just sitting in the Ubuntu wiki, instead of being added to
mythtv/contrib/channel_changers/ in the mythtv source tree where
people are more likely to find it.

Jarod Wilson
jarod at wilsonet.com

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