[mythtv-users] channel musical chairs

[faginbagin]

On 11/27/2023 12:24 AM, Ross Boylan wrote:
> This is a followup report on the effects of some changes.  I took a
> channel, 4.1 in San Francisco, that apparently had only a change in
> frequency and program #.  I had exactly one existing plex at the new
> frequency, and I changed mplexid in the relevant row of the channel
> table to point to it.
>
> This alone seems to have been enough so that myth could tune to the
> channel, which must mean it is either ignoring the program #, which I
> think is what channel.serviceid is, or looking harder if it seems not
> to work.
>
> And clearly having the correct freqid is not important, though I
> eventually changed it and the seriesid to match what I think are the
> right values (from the OTA scan of HDHR).
>
> The channel listings I'm getting seem to match what is broadcast.
> Although my last scan said the channel was KRON-TV, my listing seems
> to identify it as the CW.  The internet confirms the station is more
> or less owned by The CW.
>
> Ross
>
What I have observed about the channel and dtv_multiplex tables and 
tuning is that if you're tuning an ATSC channel, what matters are the 
channel.mplexid (which points to the dtv_multiplex.frequency) and the 
channel.atsc_major/minor numbers. If you are tuning a clear QAM channel 
(as in unencrypted cable), then the mplexid/frequency and 
channel.serviceid are used. The channel.freqid was used to tune analog 
channels, but is no longer used. However, it is populated by the channel 
scanner to correspond to the analog channel's frequency as provided by 
the dtv_multiplex.frequency. Having them in sync comes in handy when 
using the HDHR channel scanning tools, since that freqid is what the 
HDHR gui displays as the channel.