[mythtv-users] SA3250 Channel Change over Firewire

[Allan Wilson]

I had this problem back in the day and now it works if you use firewire to
view the content. Here is something from the thread. If this doesn't help
let me know and I'll try to pull out my notes. It is a patch that you can
apply with the diff command.

Brian Meehan wrote:
> I've been watching this discussion in hopes of learning something to
> get my firewire capture running too. I also have no picture, but I've
> noticed that the channel changing is crazy. I have channel 09 set as
> the startup channel for firewire input (local cable news broadcast,
> probably not 5C encrypted). The SA3250 changes the channel to 48. ???!
> When I set it to channel 508 (G4 TV) it changes to 13hundred
> something. But it's always consistent. Channel 9 is always channel 48.
> Channel 508 is always that 13xx channel. I'll try some more and see if
> I can find a pattern.
>
> Could that be the patched channel changer you were talking about? I'm
> running Myth from ATRPMs on FC5.

The behavior you are seeing is similar to what I saw when I allowed
mythbackend
to use its internal channel changing code for my SA3250HD.  I too would get
changes to channel 48 for a lot of different channels I tested on.

I am attaching the diff for my changes to mythtv/contrib/sa3250ch.c.

You'd have to grab sa3250cs.c from svn, patch it, compile it, and install it
somewhere, then in the mythtv-setup screen (I believe it's when you link the
video source to the capture card) where you can define an external change
channel command, you put the full path to sa3250ch that you built and
installed.

I got this patch from someone in the #mythtv-users channel.  Their SA3250HD
had
a different vendor id as displayed when using gscanbus, so they updated the
sa3250ch.c to recognize the particular vendor id of their hardware.  Mine
matched the vendor id already in sa3250ch.c, so I left it alone and just
made
the changes to the code that sends the commands.
- Show quoted text -


-matt

--
matt mead

http://collectivity.goof.com/

*** sa3250ch.c.orig     2006-04-07 18:01:29.000000000 -0400
--- sa3250ch.c  2006-04-18 21:50:33.000000000 -0400
***************
*** 121,127 ****
--- 121,130 ----
    dig[0] = 0x30 | ((chn % 1000) / 100);

    cmd[0] = CTL_CMD0 | AVC1394_SA3250_OPERAND_KEY_PRESS;
+    /* MCM
    cmd[1] = CTL_CMD1 | (dig[0] << 16) | (dig[1] << 8) | dig[2];
+    */
+    cmd[1] = CTL_CMD1 | (chn << 8);
    cmd[2] = CTL_CMD2;

    if (verbose)
***************
*** 130,135 ****
--- 133,140 ----

    avc1394_transaction_block(handle, 0, cmd, 3, 1);
    cmd[0] = CTL_CMD0 | AVC1394_SA3250_OPERAND_KEY_RELEASE;
+    cmd[1] = CTL_CMD1 | (chn << 8);
+    cmd[2] = CTL_CMD2;

    if (verbose)
       printf("AV/C Command: %d%d%d = cmd0=0x%08x cmd2=0x%08x
cmd3=0x%08x\n",
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mythtv.org/pipermail/mythtv-users/attachments/20070522/33cb2062/attachment.htm