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

Jå§òÑ M@¢þhè®$Øñ jason.macpherson at gmail.com
Fri Jan 29 15:46:07 UTC 2010


> 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?

[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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