[mythtv] Firewire code and ticket #10277: Warning: No Input in xxx msec

Peter Bennett cats22 at comcast.net
Mon Apr 30 00:52:06 UTC 2012

On 04/29/12 18:33, Peter Bennett wrote:

> I had developed a fix for the firewire bug where never ending messages
> occur filling up logs and losing recordings: Warning: No Input in 50
> msec . . .  etc.
> This was working perfectly on mythtv 0.24 for a few months.
> Version 0.25 has broken my fix. I am reworking it. I am astonished how
> many changes there are to the firewire code since Daniel had said that
> he sees not much future for it since so few people are using it.
> The logging is considerably changed, but I suppose that is a generic
> change across everything.
> StartRecording() is renamed run().
> The way StopRecording() works is changed and it moved up to RecorderBase.
> The pause in the run() loop is changed from 50 ms to 1 second.
> A new function call ResetForNewFile() is added to the Open(). I am
> guessing this is trying to make sure the start of a file is on a key frame?
> However what is I believe an existing bug (the firewire port is never
> closed) is not fixed - I have the fix for that in my patch.
> I am not complaining - the opposite in fact. It looks like a lot of nice
> work is being done even in firewire where so few people are using it.
> Hopefully I will have my 0.25 patch working soon and attach it to the
> ticket.
> Peter
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On 4/29/2012 7:26 PM, Martin Purschke wrote:
> Peter,
> thank you very much for working on this; I haven't found much time to
> invest in anything with firewire lately (I'm the author of the
> "sa_control" channel changer for one flavor of the SciAtlanta cable
> boxes - now that I have a new box I may get back to it).
> I was surprised at Daniel's statement that few people use firewire. I
> record the majority of my channels through firewire, and I personally
> know two more people who do, so while 3 may not be a big number, your
> work is highly appreciated. And as long as there are providers which
> keep most of the channels open and not 5C-protected, it's hard to beat
> the quality of the all-digital recordings.
> Which brings me to a slightly related issue. Every once in a while, a
> new channel gets added which is protected, or a so-far open channel goes
> dark. In this case, we can never get a lock, and the backend
> continuously loops the "no input..." message but also never arrives at a
> failure state. The messages continue past the nominal end of the
> recording, and the backend seems stuck indefinitely (I have to release
> it by manually ending the recording). If you can find a way to make the
> backend give up gracefully after it has exhausted all the options you
> mention and return to an idle state, that would be great. If you need
> another guinea pig to test something, please drop me a mail.
> Thank you very much,
> `    Martin
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Hi Martin

My patch is designed so that if after a couple of attempts it cannot
recover from the error, it will fail the recording. That part was
working in 0.24 and I should be able to get it working in 0.25. A good
test for this is to unplug the firewire cable while recording, the
released versions 0.24 and 0.25 go into the loop of "No Input .. "
messages until the end of the recording time. My patch will fail the
recording after a minute or so, then at least the system can try record
it again and you do not get the log full of those errors.

I am not sure about it going past the end of the recording time. I did
have that issue yesterday but it was caused by my coding bug I believe.

If you are on 0.24, my patch is already available in the ticket. I hope
to have the 0.25 soon. Any testing you can do is helpful - if you notice
any problem with the patch let me know.

You said you have a channel changer for scientific altanta boxes. I  had
never got that to work so eventually I got an IR blaster. I have the
scientific atlanta 3250. Do you have a solution for that?

Unfortunately some of my channels are copy protected - in haphazard way,
for example History channel and the HD version of FX, but On-Demand is
not protected. I called Comcast and they assured me that EVERYTHING was
protected, so no joy there.


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