[mythtv] Re: [mythtv-users] HDTV: channel num versus program id]

Brandon Beattie brandon+myth at linuxis.us
Mon Jul 19 20:42:47 EDT 2004


myth-dev is CC'd, HDTV developers will want to read this.

I spoke with the tech at one of the stations here.  Apparently we can
blame USDTV for the problems, or bad setup in other areas.  What is
happening is in some encoders for stations, conditional transmission
(Such as USDTV that requires their encryption decoder and subscription to
view) are being hard set in the first digital subchannels streams over 
non-conditional.  This why WB has their own station Last in the data
stream although they want to be first.  It appears it's a hardware
limitation in some stations digital encoders.  The tech is trying to
find a way to make his station first but he can't do it right now with
the current encoder.  (Other reasons non-pvr related are that some setop
which have problems locking onto Digital signals have the best success
with the first subchannel)

The fix for those people trying to watch a station and it's not coming
through, I highly recommend grabbing the dtvstream program and running
it on that station (or all just to check) and find out which number the
stream you want is.  So in my case it would be the fifth stream or 48-5
that I would set for my freqid.  Now the never-ending problem I see
coming will be if they fix the problem, or USDTV adds or deletes a
station it will change the position of 48-5 and I'll have to notice the
problem and change it to 48-4 or 48-6 (Or 48-x).  The best fix I see
happening is for Myth to go through all stations, make it's own internal
mapping (using portons of dtvstream) and see 48-5 with the label
"KUWBDT" in that digital signal stream and know it's 30.1.  This would 1:
remove the need to manually lookup each digital signal (such as 30.1 is
really freqid 48-5, NTSC channel 30) and 2, if run daily (or by user
choice) will fix problems when people change what order their stream is.  

The idea in general would be:

1) portons of dtvstream goes through and checks every channel (14-83)
2) Makes a note of it's major freq (48) and subchannels (.1-.5) and then reads the labal for the channels ([48.1 is 99-50 STARZ] [48.2 is 99-12 FNC] [48.3 is 99-10 LIFE] [48.4 is 99-5 TOON] [48.5 is 30-1 KUWB-DT]
3) Maps program data from zap2it to the callsign (KUWBDT), not the channel. 

This may be a bit tricky, but if stations are going to be changing their
subchannels somewhat often (As it sounds like from the tech, maybe every
6 months to a year) if you have 13+ stations you can do the math.

Just thought I'd forward what I found out..

Below are some data dumps from dtvstream to help explain what is going
on.

--Brandon


**Note, all 99-** channels are USDTV Piggybacking ontop of 7 of my 13
main channels.

### Dump from channel 48 with USDTV piggybacking on main WB station ###
Stream contains 5 valid program(s).
    Program 59: 99-50 STARZ:
        Video (MPEG-2), language = eng
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa
    Program 21: 99-12 FNC:
        Video (MPEG-2), language = eng
        Audio (Dolby AC-3), language = eng
    Program 19: 99-10 LIFE:
        Video (MPEG-2), language = eng
        Audio (Dolby AC-3), language = eng
    Program 14: 99-5 TOON:
        Video (MPEG-2), language = eng
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa
        Unknown (0x0b)
        Unknown (0x0b)
    Program 2: 30-1 KUWB-DT:
        Video (MPEG-2), language = eng
        Audio (Dolby AC-3), language = eng

### END DUMP ###
(Note Porgram 2: 30-1 KUWB-DT is in slot 5, so you Must modify your
freqid setting for this channel to 48-5 to get 30.1)

### Dump from a non-USDTV channel ###

Stream contains 5 valid program(s).
    Program 1: 11-1 KBYU-HD:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
    Program 2: 11-2 KBYU-SD:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa
        Audio (Dolby AC-3), language = fre
    Program 3: 11-3 BYU-TV:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa
    Program 4: 11-4 KBYUkid:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa
    Program 5: 11-5 PBS-You:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
        Audio (Dolby AC-3), language = spa

### End DUMP ###
(No problems, Myth's always worked well with this for a year)


### Dump from another USDTV piggybacking station, but works fine, no
need to modify freqid to another value besides 36-1 vs just having 36
(The real frequency it's broadcasted on, as 9 is the NTSC channel) ###
    Program 2: 9-1 KULC:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
    Program 3: 9-2 KULC-2:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
    Program 13: 99-4 DISN:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
        Unknown (0x0b)
        Unknown (0x0b)
    Program 16: 99-7 DISC:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
    Program 17: 99-8 TLC:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng
    Program 91: 9-90 KUER:
        Video (MPEG-2)
        Audio (Dolby AC-3), language = eng

### End DUMP ###
(This channel works just fine because 9-1 and 9-2 are in the correct
positions, not in the wrong slots as with KUWB-DT. -- KUER, 9-90 is
actually a radio station owned by the College who owns the TV station)



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