[mythtv-users] Firewire troubles after upgrade. Is test-mepg2 mightier than MythTV?

Jarod Wilson jarod at wilsonet.com
Sat Jan 30 05:16:50 UTC 2010


On Fri, Jan 29, 2010 at 10:46 AM, Jĺ§ňŃ M@˘ţhč®$Řń
<jason.macpherson at gmail.com> wrote:
>> Would be interesting to see if
>> MythTV 0.22 worked on Ubuntu 7.10 or if MythTV 0.21 worked on current
>> Fedora or Ubuntu. Offhand, I'm not aware of any changes that have been
>> made to the firewire code in a long long time, but I haven't watched
>> the commit logs that closely of late.
>
> That will be my next test.
>
>
> I've patched linuxfirewiredevice.cpp to test a theory of mine.
>
> I replaced the function call-back passed to iec61883_mpeg2_recv_init()
> with my own function.
>
> For reference, this is the code I'm referring to:
> http://svn.mythtv.org/trac/browser/trunk/mythtv/libs/libmythtv/linuxfirewiredevice.cpp#L566
>
> My callback function simply writes the stream to a file.  The mpeg
> file written by my patched mythbackend is playable with mplayer.
>
> So I can finally confirm that Mythtv does have access to the video
> stream.  The problem may within the mpeg parsing code (PID/PMT/PAD).
> Maybe my box is sending an invalid stream that mplayer can accept, but
> Mythtv is rejecting.
>
> I'm learning the mpeg format as I go along here.  I not sure what a
> valid stream should look like.
>
> But one thing that I find somewhat odd is that my program ID is always
> 0x1394.  Shouldn't this number vary over time and channel?

I'd have to guess it is a firewire header of some sort, given that its
always 1394 -- ieee1394 == firewire. Nb: I know squat about the actual
video header format you should be seeing there...

> [root at myth ~]# grep -i pid /tmp/mythbackend.log
>  program number     1 has PID 0x1394   data  0x 0 0x 1 0xf3 0x94
> 2010-01-25 21:38:21.572 desired_program(1) pid(0x1394)
> 2010-01-25 21:38:21.572 pmt_pid(0x1394)
>  program number     1 has PID 0x1394   data  0x 0 0x 1 0xf3 0x94
> 2010-01-25 21:38:21.572 Program Map Table ver(24) pid(0x1394) pnum(1)
> len(19)
> Program Map Table ver(24) pid(0x1394) pnum(1) len(13)
> 2010-01-25 21:38:21.572 Program Map Table ver(24) pid(0x1394) pnum(1)
> len(13)
>  program number     1 has PID 0x1394   data  0x 0 0x 1 0xf3 0x94
> 2010-01-25 21:38:21.737 desired_program(1) pid(0x1394)
> 2010-01-25 21:38:21.737 pmt_pid(0x1394)
>  program number     1 has PID 0x1394   data  0x 0 0x 1 0xf3 0x94
> 2010-01-25 21:38:21.737 Program Map Table ver(24) pid(0x1394) pnum(1)
> len(19)
> Program Map Table ver(24) pid(0x1394) pnum(1) len(13)
> 2010-01-25 21:38:21.737 Program Map Table ver(24) pid(0x1394) pnum(1)
> len(13)
>
>
>
> Jason Macpherson
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>



-- 
Jarod Wilson
jarod at wilsonet.com


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