DVB-S channel scan does not work on Eutelsat W4 (36.0E)

[Andrew Junev <a-j@…>]

Channel scan does not work when searching for channels on Eutelsat W4 (36.0E).

If I choose a "Full Scan (tuned)" in mythtv-setup, put in the transponder data, I get that particular transponder scanned. Those channels work Ok until I scan a different transponder on this satellite. Whenever a second transponder is scanned, all of the channels stop working.

I noticed there are some transponders that have equal 'transportid' on this particular satellite (not sure if it's common for all DVB-S). This doesn't seem to be working properly in Myth. In my situation it lead to the following: During a scan of the first transponder, there are some channels found that are (for example) on frequency 12096000 which is a multiplexid 495. When I scan a different transponder, mythtv-setup updates dtv_multiplex table and multiplexid=495 gets mapped to a new frequency (let's say, 12245000). Of course the old channels won't work any longer.

But that doesn't seem to be the only problem with channel scan. I discovered that 'transponder list' that is automatically detected for Eutelsat W4 is always the same, although it is far from being complete. When I scan only transponders from the transponder list (without adding new ones), dtv_multiplex remains unchanged. But 'multiplexid' in the 'channel' table still gets changed "without any reason" whenever I do a new scan. In any case the result is the same: I can't watch any channels if I scan more than one transponder.

This behaviour is stable and repeatable for Eutelsat W4. I first detected it with myth 0.20.2 and now it's the same in the SVN of 0.21.

# /usr/local/bin/mythbackend --version Source code version : 14946 SVN branch : trunk Library API version : 0.21.20071123-1 Network Protocol Version: 36 Options compiled in:

linux release using_oss using_alsa using_arts using_backend using_dbox2 using_dvb using_frontend using_hdhomerun using_iptv using_ivtv using_joystick_menu using_lirc using_v4l using_x11 using_xrandr using_xv using_xvmc using_xvmcw using_xvmc_vld using_bindings_perl using_opengl using_live

# uname -a Linux mythbackend 2.6.22.9-61.fc6 #1 SMP Thu Sep 27 18:48:03 EDT 2007 i686 i686 i386 GNU/Linux

I can do additional tests and provide some logs, if needed. I just don't know which logs to provide, as it seems that the 'regular' logs does not contain anything to trace this problem.

[panachoi@…]

I dont think this is restricted to DVB-S; had exactly the same problem with DVB-C tuner recently. This might be related to tickets 4138, 4303, 4163, 4154 -- there seem to be multiple problems with the DVB Scanner, regardless of the medium involved (-T, -C, -S).

[Dibblah]

Duplicate of #5827