Mailing List Archive

Ceton vs multirec questions
I'm trying out a Ceton 6ETH on a brand-new v31 backend, into which I've
imported data from a very old backend. I created all six tuners for
the card and it seems to be working. But I've noticed something odd
and haven't been successful at finding relevant messages or web pages.
[.Searching for mythtv, ceton, and either multirec or reclimit are
finding very little.]

After a few hours of letting it record things, I noticed that MythWeb
suddenly claims I have 10 tuners, and some of the numbers repeat.
(They're not exactly in order, either.) I wasn't watching it like a
hawk, so I don't know when they appeared, and they're clearly reflected
in the capturecard table as well if I look at it with phpmyadmin or the
like. (An earlier copy of the Status page, also still in my browser,
only claimed 7 tuners, and I missed it when I glanced at it. But the
10th tuner affected the alignment of all the text and that's when I
noticed and went back and looked at the earlier page in another tab.)

I'm guessing this is dynamic creation of tuners for multirec.
(I didn't notice any such setting in mythtv-setup, but it appears
that each tuner has reclimit = 2 in the table, which I'm assuming
is the default.) Since I'm coming from a much, much older version
of Myth, I hadn't seen this in action before.

Questions:

(a) Can Cetons do multirec? For some reason I thought they couldn't.

(b) Does this mean (1) a new tuner got created because two different
streams on the same multiplex were being recorded which overlapped in
time, or (2) because -the same channel- was being recorded back to back
(with overlaps, because I have two-minute prerolls and postrolls on
everything), or both (1) and (2)? [If both work, I'm delighted.]

(c) Should I go back into setup, or the table itself, and raise reclimit
to a much higher value? If this is record-streams-from-multiplex behavior,
I don't see a reason not to record as many as exist (if that's what the
schedule is calling for), except perhaps (1) load issues on the network
or the backend [which I'll test for], or (2) possibly quadratically-
or exponentially-bad runtime performance of the scheduler (which I have
some vague memory of being discussed in years past but may either not
have existed or may have since been fixed).

[.Note that if I do (c), I can also just clear all the tuners and start
fresh if that's easier; I'm sure it's the more-recommended approach,
though mythtv-setup is -so- klunky in setting up these tuners that
short-circuiting it via mysql is extremely tempting.]

(d) I recall discussions about tuner numbering etc. If I'm right about
the stuff above, and if I raise reclimit a lot, are there any particular
best practices for naming these tuners, or even preemptively creating
database entries for them, to make it more obvious what's going on?
[.Since they're all identical, I don't care which might get used first
for LiveTV, so I don't care about that ordering, and I only use LiveTV
about once a quarter or so for minute or two if I'm testing something,
so it's not a priority anyway.]
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Re: Ceton vs multirec questions [ In reply to ]
I used a ceton and hdhomerun prime for many years and if you are using
cablecard you can't do multirec as far as I know. Maybe the same channel on
a pre/post roll could do multiple recordings but I've never seen that!

With a cable card the card downloads a channelmap so each channel is a
vchannel on it's own frequency and there are no multiplexes like there are
over ATSC AFAIK.

I have been only OTA since 2016 so maybe I am dating myself!


PS the olympics in 2016 basically KILLED my ceton eth 6 recording Olympics
on 6 tuners basically 24x7 for two weeks. Put a fan on it!




On Tue, Jul 27, 2021, 10:26 PM <f-myth-users@media.mit.edu> wrote:

> I'm trying out a Ceton 6ETH on a brand-new v31 backend, into which I've
> imported data from a very old backend. I created all six tuners for
> the card and it seems to be working. But I've noticed something odd
> and haven't been successful at finding relevant messages or web pages.
> [.Searching for mythtv, ceton, and either multirec or reclimit are
> finding very little.]
>
> After a few hours of letting it record things, I noticed that MythWeb
> suddenly claims I have 10 tuners, and some of the numbers repeat.
> (They're not exactly in order, either.) I wasn't watching it like a
> hawk, so I don't know when they appeared, and they're clearly reflected
> in the capturecard table as well if I look at it with phpmyadmin or the
> like. (An earlier copy of the Status page, also still in my browser,
> only claimed 7 tuners, and I missed it when I glanced at it. But the
> 10th tuner affected the alignment of all the text and that's when I
> noticed and went back and looked at the earlier page in another tab.)
>
> I'm guessing this is dynamic creation of tuners for multirec.
> (I didn't notice any such setting in mythtv-setup, but it appears
> that each tuner has reclimit = 2 in the table, which I'm assuming
> is the default.) Since I'm coming from a much, much older version
> of Myth, I hadn't seen this in action before.
>
> Questions:
>
> (a) Can Cetons do multirec? For some reason I thought they couldn't.
>
> (b) Does this mean (1) a new tuner got created because two different
> streams on the same multiplex were being recorded which overlapped in
> time, or (2) because -the same channel- was being recorded back to back
> (with overlaps, because I have two-minute prerolls and postrolls on
> everything), or both (1) and (2)? [If both work, I'm delighted.]
>
> (c) Should I go back into setup, or the table itself, and raise reclimit
> to a much higher value? If this is record-streams-from-multiplex behavior,
> I don't see a reason not to record as many as exist (if that's what the
> schedule is calling for), except perhaps (1) load issues on the network
> or the backend [which I'll test for], or (2) possibly quadratically-
> or exponentially-bad runtime performance of the scheduler (which I have
> some vague memory of being discussed in years past but may either not
> have existed or may have since been fixed).
>
> [.Note that if I do (c), I can also just clear all the tuners and start
> fresh if that's easier; I'm sure it's the more-recommended approach,
> though mythtv-setup is -so- klunky in setting up these tuners that
> short-circuiting it via mysql is extremely tempting.]
>
> (d) I recall discussions about tuner numbering etc. If I'm right about
> the stuff above, and if I raise reclimit a lot, are there any particular
> best practices for naming these tuners, or even preemptively creating
> database entries for them, to make it more obvious what's going on?
> [.Since they're all identical, I don't care which might get used first
> for LiveTV, so I don't care about that ordering, and I only use LiveTV
> about once a quarter or so for minute or two if I'm testing something,
> so it's not a priority anyway.]
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@mythtv.org
> http://lists.mythtv.org/mailman/listinfo/mythtv-users
> http://wiki.mythtv.org/Mailing_List_etiquette
> MythTV Forums: https://forum.mythtv.org
>
Re: Ceton vs multirec questions [ In reply to ]
> Date: Tue, 27 Jul 2021 22:54:41 -0500
> From: Per Hatlevik <jakeisawake@gmail.com>

> I used a ceton and hdhomerun prime for many years and if you are using
> cablecard you can't do multirec as far as I know. Maybe the same channel on
> a pre/post roll could do multiple recordings but I've never seen that!

Yup, cablecard with Comcast cable.

> With a cable card the card downloads a channelmap so each channel is a
> vchannel on it's own frequency and there are no multiplexes like there are
> over ATSC AFAIK.

That's closer to my understanding. Hence my surprise at all those
mysteriously-appearing tuners.

(Also interesting just how different the channelmap and the Schedules
Direct listings are; I'll have to go through them carefully and figure
out if it's worth trying to update SD or if I'm misinterpreting it.
Way more entries in the channelmap, but I haven't tried tuning most
of them yet.)

> I have been only OTA since 2016 so maybe I am dating myself!

> PS the olympics in 2016 basically KILLED my ceton eth 6 recording Olympics
> on 6 tuners basically 24x7 for two weeks. Put a fan on it!

So I've heard! I do in fact have the hardware to strap a nice quiet fan
to it and am planning to do so soon.
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Re: Ceton vs multirec questions [ In reply to ]
On Wed, 28 Jul 2021 00:09:57 -0400, you wrote:

> > Date: Tue, 27 Jul 2021 22:54:41 -0500
> > From: Per Hatlevik <jakeisawake@gmail.com>
>
> > I used a ceton and hdhomerun prime for many years and if you are using
> > cablecard you can't do multirec as far as I know. Maybe the same channel on
> > a pre/post roll could do multiple recordings but I've never seen that!
>
>Yup, cablecard with Comcast cable.
>
> > With a cable card the card downloads a channelmap so each channel is a
> > vchannel on it's own frequency and there are no multiplexes like there are
> > over ATSC AFAIK.
>
>That's closer to my understanding. Hence my surprise at all those
>mysteriously-appearing tuners.
>
>(Also interesting just how different the channelmap and the Schedules
>Direct listings are; I'll have to go through them carefully and figure
>out if it's worth trying to update SD or if I'm misinterpreting it.
>Way more entries in the channelmap, but I haven't tried tuning most
>of them yet.)
>
> > I have been only OTA since 2016 so maybe I am dating myself!
>
> > PS the olympics in 2016 basically KILLED my ceton eth 6 recording Olympics
> > on 6 tuners basically 24x7 for two weeks. Put a fan on it!
>
>So I've heard! I do in fact have the hardware to strap a nice quiet fan
>to it and am planning to do so soon.

This might be as a result of the new "Schedule as a group" option. If
that is set, as I understand it, it overrides the setting for the
number of multirec tuners and the system will create virtual tuners as
required. I have never used that option, but I understand it is on by
default in new installs. You find it in mythtv-setup > Input
connections > select a tuner > Interactions between inputs.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Wed, 28 Jul 2021 20:24:19 +1200
> From: Stephen Worthington <stephen_agent@jsw.gen.nz>

> This might be as a result of the new "Schedule as a group" option. If
> that is set, as I understand it, it overrides the setting for the
> number of multirec tuners and the system will create virtual tuners as
> required. I have never used that option, but I understand it is on by
> default in new installs. You find it in mythtv-setup > Input
> connections > select a tuner > Interactions between inputs.

Interesting. I can find very little about this via a web search:
mythtv "schedule as a group"
returns about three not-very-informative hits. (Which is surprising,
since I'd swear I heard about this on the mailing list some time ago,
and I would have guessed that Google would return those messages.)

However, all six of the real tuners (the first six rows) in my
cpturecard table do have "schedgroup" set to 1. (And all of the
later entries do not.)

If this really does override reclimit, then obviously fiddling with
that won't matter. But what does schedgroup buy me? Overlapping
(same-"channel", from pre/postroll) recordings sharing a tuner?
(Hope so!)

The other reason I'm confused re multiplexes etc is that if I go to the
web interface for the Ceton, I can clearly see that each channel claims
a whole bunch of "program" entries, and it's a different list for each
individual channel. (Some are mostly in the 1-10 range; some have half
a dozen entries like 1, 10, 2804, etc.) My assumption was that these
were different streams multiplexed on the TS stream arriving for that
channel---if I record the card "by hand" using its web interface and
just dump the stream into a file using netcat, things like mpv will
report that there are are huge numbers of audio and video streams:

(+) Video --vid=1 (mpeg2video 720x480 29.970fps)
Video --vid=2 (mpeg2video)
Video --vid=3 (mpeg2video)
Video --vid=4 (mpeg2video)
Video --vid=5 (mpeg2video)
[ . . . ]
Video --vid=13 (mpeg2video)
Video --vid=14 (mpeg2video)
(+) Audio --aid=1 --alang=eng (ac3 2ch 48000Hz)
Audio --aid=2 --alang=spa (ac3 2ch 48000Hz)
Audio --aid=3 --alang=eng (ac3)
Audio --aid=4 --alang=spa (ac3)
[ . . . ]
Audio --aid=26 --alang=spa (ac3)
Subs --sid=1 (*) (eia_608)

...though only some of them seem playable with --vid=n.

So I don't know if this implies that there really are multiplexes
there that Myth can somehow take advantage of, or not.
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Re: Ceton vs multirec questions [ In reply to ]
On 7/28/21 11:34 AM, f-myth-users@media.mit.edu wrote:
> Interesting. I can find very little about this via a web search:
> mythtv "schedule as a group"
> returns about three not-very-informative hits. (Which is surprising,
> since I'd swear I heard about this on the mailing list some time ago,
> and I would have guessed that Google would return those messages.)
>
> However, all six of the real tuners (the first six rows) in my
> cpturecard table do have "schedgroup" set to 1. (And all of the
> later entries do not.)
>
> If this really does override reclimit, then obviously fiddling with
> that won't matter. But what does schedgroup buy me? Overlapping
> (same-"channel", from pre/postroll) recordings sharing a tuner?
> (Hope so!)
>
> The other reason I'm confused re multiplexes etc is that if I go to the
> web interface for the Ceton, I can clearly see that each channel claims
> a whole bunch of "program" entries, and it's a different list for each
> individual channel. (Some are mostly in the 1-10 range; some have half
> a dozen entries like 1, 10, 2804, etc.) My assumption was that these
> were different streams multiplexed on the TS stream arriving for that
> channel---if I record the card "by hand" using its web interface and
> just dump the stream into a file using netcat, things like mpv will
> report that there are are huge numbers of audio and video streams:

When using a cable card, the Ceton can only record one channel per
tuner. If you set Max Recordings to more than one, the pre-roll or
post-roll for two consecutive recordings on the same channel can be
accommodated with one tuner, where in previous versions that would use
two tuners or ignore the pre and post roll if there weer not enough
tuners. The "schedule as a group" setting, which is now default, allows
the system to dynamically increase the "Max Recordings" settings when
the same channel is needed for two recordings at the same time. When Max
Recordings is more than one, extra (virtual) tuners are created and
shown in the status.

Multiplexes exist on the wire and the ceton shows them as multiple
programs per channel, but MythTV cannot take advantage of this to record
several programs from one channel on one tuner because of the decryption
done by the cable card, which will only decrypt one program of a channel
at a time.

Peter

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Re: Ceton vs multirec questions [ In reply to ]
On Wed, 28 Jul 2021 11:34:39 -0400, you wrote:

> > Date: Wed, 28 Jul 2021 20:24:19 +1200
> > From: Stephen Worthington <stephen_agent@jsw.gen.nz>
>
> > This might be as a result of the new "Schedule as a group" option. If
> > that is set, as I understand it, it overrides the setting for the
> > number of multirec tuners and the system will create virtual tuners as
> > required. I have never used that option, but I understand it is on by
> > default in new installs. You find it in mythtv-setup > Input
> > connections > select a tuner > Interactions between inputs.
>
>Interesting. I can find very little about this via a web search:
> mythtv "schedule as a group"
>returns about three not-very-informative hits. (Which is surprising,
>since I'd swear I heard about this on the mailing list some time ago,
>and I would have guessed that Google would return those messages.)
>
>However, all six of the real tuners (the first six rows) in my
>cpturecard table do have "schedgroup" set to 1. (And all of the
>later entries do not.)
>
>If this really does override reclimit, then obviously fiddling with
>that won't matter. But what does schedgroup buy me? Overlapping
>(same-"channel", from pre/postroll) recordings sharing a tuner?
>(Hope so!)
>
>The other reason I'm confused re multiplexes etc is that if I go to the
>web interface for the Ceton, I can clearly see that each channel claims
>a whole bunch of "program" entries, and it's a different list for each
>individual channel. (Some are mostly in the 1-10 range; some have half
>a dozen entries like 1, 10, 2804, etc.) My assumption was that these
>were different streams multiplexed on the TS stream arriving for that
>channel---if I record the card "by hand" using its web interface and
>just dump the stream into a file using netcat, things like mpv will
>report that there are are huge numbers of audio and video streams:
>
> (+) Video --vid=1 (mpeg2video 720x480 29.970fps)
> Video --vid=2 (mpeg2video)
> Video --vid=3 (mpeg2video)
> Video --vid=4 (mpeg2video)
> Video --vid=5 (mpeg2video)
> [ . . . ]
> Video --vid=13 (mpeg2video)
> Video --vid=14 (mpeg2video)
> (+) Audio --aid=1 --alang=eng (ac3 2ch 48000Hz)
> Audio --aid=2 --alang=spa (ac3 2ch 48000Hz)
> Audio --aid=3 --alang=eng (ac3)
> Audio --aid=4 --alang=spa (ac3)
> [ . . . ]
> Audio --aid=26 --alang=spa (ac3)
> Subs --sid=1 (*) (eia_608)
>
>...though only some of them seem playable with --vid=n.
>
>So I don't know if this implies that there really are multiplexes
>there that Myth can somehow take advantage of, or not.

Schedule as a group does not do anything magical - it can not make the
cablecard do anything new. So your limitation on tuners working with
a cablecard is the cablecard, which, as I understand it, can only
decode one channel at once.

My experience with encrypted DVB-S(2) channels is that if you scan the
multiplex, you see all the streams for all the channels as the headers
for the channels are not encrypted. But the data in the streams for
each channel is encrypted. So unless there are non-encrypted channels
there is no ability to use multirec to record from more than one
channel at once as the cablecard will only decrypt one channel at a
time.

There is one exception to this, which I see with my encrypted IPTV
channels. If you set an IPTV tuner to normal multirec and tell it
that it has 2 multirec tuners, and then record programmes back to back
with overlapping pre- and post-roll periods, the IPTV tuner will use
the two multirec tuners to record the two separate programs from the
one IPTV stream, rather than using a second (different) IPTV tuner for
the second programme. I am not sure if this is also possible with
ATSC tuners, which are very like my DVB-T tuners. My DVB-T tuners if
set with 2 multirec tuners will do that overlap trick where needed,
but they will also record from two different streams on the same
multiplex using the 2 multirec tuners. If your Ceton tuners try that
with a cablecard it will not work.

What you need for a cablecard is for attached ATSC tuners to be able
to be set to only use multirec for overlapping programmes on the same
channel, and I do not know of any option that does that.
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Re: Ceton vs multirec questions [ In reply to ]
A little off-topic, but the Ceton 6 ETH doesn't require that funky Ceton
driver that is no longer builds with the kernel? I had to give up my
4-tuner PCI-Express card because of that.

Steve

Steve Greene
(301) 842-8923
historicity.co
An independent archival professional specializing in still photography,
moving images and recorded sound.


On Wed, Jul 28, 2021 at 12:18 PM Peter Bennett <pb.mythtv@gmail.com> wrote:

>
> On 7/28/21 11:34 AM, f-myth-users@media.mit.edu wrote:
> > Interesting. I can find very little about this via a web search:
> > mythtv "schedule as a group"
> > returns about three not-very-informative hits. (Which is surprising,
> > since I'd swear I heard about this on the mailing list some time ago,
> > and I would have guessed that Google would return those messages.)
> >
> > However, all six of the real tuners (the first six rows) in my
> > cpturecard table do have "schedgroup" set to 1. (And all of the
> > later entries do not.)
> >
> > If this really does override reclimit, then obviously fiddling with
> > that won't matter. But what does schedgroup buy me? Overlapping
> > (same-"channel", from pre/postroll) recordings sharing a tuner?
> > (Hope so!)
> >
> > The other reason I'm confused re multiplexes etc is that if I go to the
> > web interface for the Ceton, I can clearly see that each channel claims
> > a whole bunch of "program" entries, and it's a different list for each
> > individual channel. (Some are mostly in the 1-10 range; some have half
> > a dozen entries like 1, 10, 2804, etc.) My assumption was that these
> > were different streams multiplexed on the TS stream arriving for that
> > channel---if I record the card "by hand" using its web interface and
> > just dump the stream into a file using netcat, things like mpv will
> > report that there are are huge numbers of audio and video streams:
>
> When using a cable card, the Ceton can only record one channel per
> tuner. If you set Max Recordings to more than one, the pre-roll or
> post-roll for two consecutive recordings on the same channel can be
> accommodated with one tuner, where in previous versions that would use
> two tuners or ignore the pre and post roll if there weer not enough
> tuners. The "schedule as a group" setting, which is now default, allows
> the system to dynamically increase the "Max Recordings" settings when
> the same channel is needed for two recordings at the same time. When Max
> Recordings is more than one, extra (virtual) tuners are created and
> shown in the status.
>
> Multiplexes exist on the wire and the ceton shows them as multiple
> programs per channel, but MythTV cannot take advantage of this to record
> several programs from one channel on one tuner because of the decryption
> done by the cable card, which will only decrypt one program of a channel
> at a time.
>
> Peter
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@mythtv.org
> http://lists.mythtv.org/mailman/listinfo/mythtv-users
> http://wiki.mythtv.org/Mailing_List_etiquette
> MythTV Forums: https://forum.mythtv.org
>
Re: Ceton vs multirec questions [ In reply to ]
>>> A little off-topic, but the Ceton 6 ETH doesn't require that funky Ceton driver that is no longer builds with the kernel?

The ETH6 is an external networked box similar to the HDHR Prime.

Doug
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Re: Ceton vs multirec questions [ In reply to ]
On 7/28/21 1:48 PM, Steve Greene wrote:
> A little off-topic, but the Ceton 6 ETH doesn't require that funky
> Ceton driver that is no longer builds with the kernel? I had to give
> up my 4-tuner PCI-Express card because of that.
>
> Steve
>
> Steve Greene
> (301) 842-8923
> historicity.co <http://historicity.co>
> An independent archival professional specializing in still
> photography, moving images and recorded sound.

It does not need any special driver. Just connect with ethernet and it
works.

Peter
Re: Ceton vs multirec questions [ In reply to ]
On Wed, Jul 28, 2021 at 5:50 PM Steve Greene <sgreene820@gmail.com> wrote:
>
> A little off-topic, but the Ceton 6 ETH doesn't require that funky Ceton driver that is no longer builds with the kernel? I had to give up my 4-tuner PCI-Express card because of that.
>

Off topic reply.

The "ETH" variant is an ethernet network
tuner, so no special kernel drivers (to create
the ceton network interface(s)) needed.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Wed, 28 Jul 2021 12:15:00 -0400
> From: Peter Bennett <pb.mythtv@gmail.com>

> When using a cable card, the Ceton can only record one channel per
> tuner. If you set Max Recordings to more than one, the pre-roll or
> post-roll for two consecutive recordings on the same channel can be
> accommodated with one tuner, where in previous versions that would use
> two tuners or ignore the pre and post roll if there weer not enough
> tuners. The "schedule as a group" setting, which is now default, allows
> the system to dynamically increase the "Max Recordings" settings when
> the same channel is needed for two recordings at the same time. When Max
> Recordings is more than one, extra (virtual) tuners are created and
> shown in the status.

Got it. For some reason I thought that trick wouldn't work with Cetons.
I'm happy that it does. (If I'd been running at a higher debug level,
perhaps I'd have seen logging to that effect, or I might have been able
to figure it out based on which tuners were in use based on when things
were written to the filesystem.)

> Multiplexes exist on the wire and the ceton shows them as multiple
> programs per channel, but MythTV cannot take advantage of this to record
> several programs from one channel on one tuner because of the decryption
> done by the cable card, which will only decrypt one program of a channel
> at a time.

This now makes sense. Thanks!
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Thu, 29 Jul 2021 04:15:16 +1200
> From: Stephen Worthington <stephen_agent@jsw.gen.nz>

> My experience with encrypted DVB-S(2) channels is that if you scan the
> multiplex, you see all the streams for all the channels as the headers
> for the channels are not encrypted. But the data in the streams for
> each channel is encrypted. So unless there are non-encrypted channels
> there is no ability to use multirec to record from more than one
> channel at once as the cablecard will only decrypt one channel at a
> time.

Now this makes sense. I hadn't realized I'd be seeing headers for
streams which were themselves encrypted. It also makes sense why
it appeared that precisely one stream in any TS was playable with
mpv while I was testing---it was the stream corresponding to the
channel which was currently being decrypted.

> There is one exception to this, which I see with my encrypted IPTV
> channels. If you set an IPTV tuner to normal multirec and tell it
> that it has 2 multirec tuners, and then record programmes back to back
> with overlapping pre- and post-roll periods, the IPTV tuner will use
> the two multirec tuners to record the two separate programs from the
> one IPTV stream, rather than using a second (different) IPTV tuner for
> the second programme. I am not sure if this is also possible with
> ATSC tuners, which are very like my DVB-T tuners.

It appears from Peter's response that they may be doing this.

> My DVB-T tuners if
> set with 2 multirec tuners will do that overlap trick where needed,
> but they will also record from two different streams on the same
> multiplex using the 2 multirec tuners. If your Ceton tuners try that
> with a cablecard it will not work.

Hopefully myth is smart enough not to try that. Presumably we'd have
heard the screams if it did. :)

> What you need for a cablecard is for attached ATSC tuners to be able
> to be set to only use multirec for overlapping programmes on the same
> channel, and I do not know of any option that does that.

It may be happening automatically based on what Peter said.

(And now that I know it's possible, I can also arrange a test: Clear
the card table [hence clearing the virtual tuners as well], redo it with
only a single tuner available, and schedule two manual recordings on the
same channel with overlapping times. That should tell me what's going
on by whether both output files appear and whether a virtual tuner pops
into existence. But I may not have to run that test if people are
confident that this should be possible and that myth is doing so.)
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Wed, 28 Jul 2021 13:48:57 -0400
> From: Steve Greene <sgreene820@gmail.com>

> A little off-topic, but the Ceton 6 ETH doesn't require that funky Ceton
> driver that is no longer builds with the kernel? I had to give up my
> 4-tuner PCI-Express card because of that.

The 6ETH is Ethernet-only and requires no drivers. That's a big part of
why I'm using it. (I used to use Hauppage PVT-250/350 hardware, which seemed
to be quite fragile in later kernel versions, which was one of many things
that kept convincing me to defer upgrading lest I break a working system.)

The issue with a network-connected tuner is that it's sensitive to network
congestion; typically they're UDP and won't retransmit. (Even TCP would
be an issue with small buffers, but I wish the option existed.) Once I'm
done testing, I intend to move the Ceton off my main network and onto a
dedicated second NIC in the backend. (Intel PCIe gigabit NICs are cheap
and very reliable.)

You should be able to find 6ETH's on eBay; they seem to pop up regularly.
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Re: Ceton vs multirec questions [ In reply to ]
On Wed, Jul 28, 2021 at 6:58 PM <f-myth-users@media.mit.edu> wrote:

> The issue with a network-connected tuner is that it's sensitive to network
> congestion.

On a properly manageable switch one can
support changing the priority queue of packets
(i.e. QoS) from the ceton to essentially
eliminate the issue on the network side. One
may also need to adjust network buffers on the
host.

In any case, as I recall, the MythTV support
for a ceton uses RTSP over TCP, which at least
has "some" possibility of retry (the native HDHR
support uses UDP).

btw, while I do not recall the ceton tuner
stating that it does so, the HDHR tuner which
uses UDP (it may also use TCP when using
the more modern tuning methods) does tag
it's traffic with a DSCP flag (cs5?) that at
least some more recent commodity switches
may prioritize without any extra setup (cs5
is typically used for broadcast video, and
would be placed in the priority queue on
those switches that support it).

> You should be able to find 6ETH's on eBay; they seem to pop up regularly.

Be aware that if your MSO uses Tuning Adapters,
the ceton cable that supports them is not a cable
that is usually easy to find (I think it was a mini-A
(host) to full-size B USB cable), so if you use a
TA, make sure you get that cable included.

And, of course, there are the known thermal
(they got hot, and then fail in interesting ways,
which may mean an additional fan), and
firmware issues (for some MSOs you need to
use the latest beta firmware in order to tune
all your subscribed channels, and the beta
firmware has known memory leaks requiring
a reboot at some random interval), so, as
always, caveat emptor.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Wed, 28 Jul 2021 20:20:09 +0000
> From: Gary Buhrmaster <gary.buhrmaster@gmail.com>

> On a properly manageable switch one can support changing the
> priority queue of packets (i.e. QoS) from the ceton to essentially
> eliminate the issue on the network side. One may also need to
> adjust network buffers on the host.

True. In my case, since I don't already use a managed switch, a $15 NIC
was a reasonable solution, given that I have a couple of free PCIe slots
in the backend. It also gives me one less failure point (sort of :) and
one less thing with a configuration I can screw up and have to debug.

> In any case, as I recall, the MythTV support for a ceton uses RTSP
> over TCP, which at least has "some" possibility of retry (the
> native HDHR support uses UDP).

You know, now that you say this, I should have remembered this:
my testing was using "nc -l 1234" and thus was not listening on UDP.
I haven't stress-tested this to see if I'll -actually- lose packets,
but I wouldn't trust the cheap unmanaged switches here not to do
so if I decide to absolutely saturate the wrong link, which I do
occasionally do. A $15 NIC buys a lot of peace of mind.

> btw, while I do not recall the ceton tuner stating that it does
> so, the HDHR tuner which uses UDP (it may also use TCP when using
> the more modern tuning methods) does tag it's traffic with a DSCP
> flag (cs5?) that at least some more recent commodity switches may
> prioritize without any extra setup (cs5 is typically used for
> broadcast video, and would be placed in the priority queue on
> those switches that support it).

Interesting.

> > You should be able to find 6ETH's on eBay; they seem to pop up regularly.

> Be aware that if your MSO uses Tuning Adapters, the ceton cable
> that supports them is not a cable that is usually easy to find (I
> think it was a mini-A (host) to full-size B USB cable), so if you
> use a TA, make sure you get that cable included.

Also a good point. Fortunately, Comcast (in my area, at least)
does not require TA's.

> And, of course, there are the known thermal (they got hot, and
> then fail in interesting ways, which may mean an additional fan),

Already accumulated the hardware for that. :)

> and firmware issues (for some MSOs you need to use the latest beta
> firmware in order to tune all your subscribed channels, and the
> beta firmware has known memory leaks requiring a reboot at some
> random interval), so, as always, caveat emptor.

Yeah. I've read that you may need that latest beta to tune copy-once
channels, and that's the firmware which may leak. So part of my testing
may be to install that latest firmware, see if I can tune such channels
(most of them are ones I don't subscribe to anyway, so I'll have to find
one which I do), and then write something which reboots the Ceton every
so often when it's not currently recording. (That last part is easy
---send it a magic URL.)

I really wish that SiliconDust had managed to get their 6-tuner version
out the door. Waiting for that was one of the other things that dissuaded
me from upgrading for a while, but I read (probably here) they had chip
vendor issues that ultimately screwed them.

P.S. I also don't know if the SI units can avoid EAS alerts, but my
Comcast issues them -insanely- freqently (often more than once a week!
and always at completely unpredictable times) and they have regularly
destroyed recordings. (I wrote some C code years ago that listens for
the tones in recordings and alerts in real time so I can reschedule; I
think I may have even posted it here.) In theory the Cetons can avoid
that if you click the "EAS Bypass" button after each boot; in fact I
have not (yet) tested this, and there is a claim [1] that one must
install three different firmware versions -in order- for this to work.
Haven't tried that yet, either. (I've clicked the button on a random
firmware version and am currently waiting for an EAS alert to happen.)

[1] https://www.thegreenbutton.tv/forums/viewtopic.php?f=68&t=10575

P.P.S. Other thing, if you care about logs, is that Ceton logging is
bizarre. They log via an internal syslog but there's no way to log to
syslog over the network, so you have to poll via the URL that fetches
the log. The log is reset when it boots. The log always starts from
Jan 1 even though the card notices UTC timestamps going by on the wire
and logs them. The logs are truncated to zero when they reach 1 meg.
Aaannd their internal clock appears to run about 4 minutes fast -per
day-(!). So collecting usable logs of what the tuner thinks it's doing
in a way that you can correlate to external events is... interesting. :)
[.Which may not matter if everything's going peachy, of course, but
it's nice to be able to figure it out ex post facto when it doesn't.]
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Re: Ceton vs multirec questions [ In reply to ]
On Wed, Jul 28, 2021 at 9:00 PM <f-myth-users@media.mit.edu> wrote:

> Yeah. I've read that you may need that latest beta to tune copy-once
> channels, and that's the firmware which may leak.

Actually, it is channels marked with no flagging
(i.e. CCI=none_specified), *but* with CGMS markings,
which were seen in some markets (typically Cisco/SA)
which made content that should otherwise be
available be blocked instead. CableLabs issued a
clarification to the specifications as to how to interpret
the various combinations once the issue was
identified, but it took time for various updates to occur
throughout the entire ecosystem.

> I really wish that SiliconDust had managed to
> get their 6-tuner version out the door.

In the end, while I think they really wanted to
continue the development, it is clear that not
continuing was the only correct business decision
for the company.

I will point out that should you live in a Comcast
market that has moved to S&E (Simple and Easy)
pricing, and you change to the new bundles,
CableCARDs are $0, and the "Service to Additional TV"
fee has been eliminated, so how many tuner devices
you use is less interesting. You may want to check
your current rate card to see if it is S&E.

Eventually all divisions will move to S&E pricing,
but it is a mixture today (some on S&E, some on
legacy), and Comcast has not stated their
schedule to move to S&E in the different divisions.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Wed, 28 Jul 2021 22:41:28 +0000
> From: Gary Buhrmaster <gary.buhrmaster@gmail.com>

> Actually, it is channels marked with no flagging
> (i.e. CCI=none_specified), *but* with CGMS markings, which were
> seen in some markets (typically Cisco/SA) which made content that
> should otherwise be available be blocked instead. CableLabs issued
> a clarification to the specifications as to how to interpret the
> various combinations once the issue was identified, but it took
> time for various updates to occur throughout the entire ecosystem.

Ah yes, I vaguely recalled it was something more complicated like that.
My current (old) cable boxes, FWIW, are Motorola units, and I'm in a
Boston-area market, whereas my impression was that Cisco/Scientific
Atlanta were typically other areas of the country? [.I can't recall what
they offer for new equipment here, given that I wasn't planning to get
any.] I wonder therefore if I'm going to see CCI=none but with CGMS
markings (and how to tell by asking my Ceton, especially if not (yet?)
running latest firmware).

[.A few days ago, I did an "availability scan" (I won't call it a
"channel scan" because that means something different) in which I wrote
a script that simply tuned to every channel returned by SD's XMLTV
service for my zipcode, and reported flags, e.g., "Copy Free", "One Copy",
"None". The "None" results seem to be (a) a gaziiiillion Major League
Baseball and NBA channels (don't care), a metric ton of international
channels (ditto), a few local origination channels (eh? aren't those
usually random community television?), COMEC (the "Comcast Employee
Channel" :), and a very small handful of movie channels. (Full list if
anyone cares; 244 callsigns.) So I wonder if this affects me at all.

Meanwhile, I see 85 "One Copy" (pretty much the rest of the movie
channels)---should I be able to decrypt those, or not? I've been
assuming "not." (I think there are a tiny number in my bundle that I'm
actually subscribed to, but I haven't tested any yet. It's pretty clear
that the flags I'm seeing certainly have nothing to do with whether I'm
actually subscribed to that channel.) Also, I think some of the SD-only
variants of the same callsign are Copy Free; need to go back and check.

And then 586 "Copy Free". And I should note that redoing this scan by
using the channel map disgorged by the Ceton's web interface (and not
what I got from Schedules Direct) includes 100-200 more entries, but I
haven't carefully checked to see what's going on there---whether there
are duplicated callsigns in that listing or what. If there are channels
SD is missing, I'll tell them, but otherwise if I have no scheduling
data for them, it'd be pointless to allow them to be tuned anyway.
Maybe they're music channels or something.]

[.One of my tasks very soon is to edit my XMLTV channels to drop
the ones I'm not subbed to and otherwise clean them up, because
yowza that was a big download. Very first tv_grab_zz_sdjson_sqlite
run took about nine hours to download everything and stuff the DB
on a relatively fast modern machine; later ones maybe 30m. I was
just about to do that when I hit the "why do I have 10 tuners?"
question and sent mail here instead.]

> > I really wish that SiliconDust had managed to get their 6-tuner
> > version out the door.

> In the end, while I think they really wanted to continue the
> development, it is clear that not continuing was the only correct
> business decision for the company.

Not saying it wasn't. :)

> I will point out that should you live in a Comcast market that has
> moved to S&E (Simple and Easy) pricing, and you change to the new
> bundles, CableCARDs are $0, and the "Service to Additional TV" fee
> has been eliminated, so how many tuner devices you use is less
> interesting.

Had no idea. That might indeed have changed the calculus. *sigh*

Currently, Comcast offered me the first CC for free, but wanted to
charge a monthly rate for additional card(s), so I suspect I am not
yet in that market. Or I am, but they didn't mention different bundles
being available---not that I asked, because it never occurred to me.
Though had I known, and had I known it was soon, yeah, I might have
decided that 2 or more SD units might be less fiddling around than
trying to minimize CC's by going with a Ceton. (Could still, but
now I have sunk costs.)

> You may want to check
> your current rate card to see if it is S&E.

How would I do that? Just go to their website and see what plans they
offer for my zipcode? Call them? I've always found trying to actually
get such information out of Comcast rather challenging. (Googling
``comcast "simple and easy plan"'' plus locations isn't returning
more than a handful of results, all useless.)

> Eventually all divisions will move to S&E pricing, but it is a
> mixture today (some on S&E, some on legacy), and Comcast has not
> stated their schedule to move to S&E in the different divisions.

Interesting.

(And thanks for all this, by the way!)
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Re: Ceton vs multirec questions [ In reply to ]
On Wed, 28 Jul 2021 16:59:42 -0400, you wrote:

>Yeah. I've read that you may need that latest beta to tune copy-once
>channels, and that's the firmware which may leak. So part of my testing
>may be to install that latest firmware, see if I can tune such channels
>(most of them are ones I don't subscribe to anyway, so I'll have to find
>one which I do), and then write something which reboots the Ceton every
>so often when it's not currently recording. (That last part is easy
>---send it a magic URL.)

You might want to take a look at my "gaps" program for how to find out
when it is safe to reboot the Ceton:

http://www.jsw.gen.nz/mythtv/gaps

Gaps does not allow for the "soft" pre- and post-roll settings, so on
my system where they are set to the defaults of 60 seconds, recordings
usually stop one minute after when gaps says they do (and end a minute
earlier). So if I was automating a reboot, I would allow two minutes
after when gaps says a gap starts. You can tell gaps how big a gap
between recordings you are looking for and it will only report gaps
bigger than that.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Thu, 29 Jul 2021 14:24:42 +1200
> From: Stephen Worthington <stephen_agent@jsw.gen.nz>

> You might want to take a look at my "gaps" program for how to find out
> when it is safe to reboot the Ceton:

Thanks. I'd actually written such a thing maybe a decade ago, in
bash of all things, to parse the scheduler log output directly and find
equivalent gaps. (But no doubt the new logging output won't match the
format that my program was expecting, so yours may be handy. :) I used
it to do backups and maintenance during safe intervals. And because
it parsed the scheduler logging output, it knew precisely when things
started and ended, even if they had unusual pre/postrolls---it didn't
have to guess.
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Re: Ceton vs multirec questions [ In reply to ]
On Wed, Jul 28, 2021 at 11:40 PM <f-myth-users@media.mit.edu> wrote:

> Ah yes, I vaguely recalled it was something more complicated like that.
> My current (old) cable boxes, FWIW, are Motorola units, and I'm in a
> Boston-area market, whereas my impression was that Cisco/Scientific
> Atlanta were typically other areas of the country?

For various reasons, the hardware vendor of the franchise when
Comcast originally acquired it (back decades ago) typically is still
the one in use today. If your CableCARDs say Motorola, Arris,
or Commscope (at different points of the corporate acquisitions)
you are not currently expected to see the issues no matter
the CableCARD firmware (as far as have been reported, only
a specific Cisco/SA (now Technicolor) firmware level commonly
experienced the issue). And the issue was eventually resolved
with new(er) CableCARD firmware (which eventually got rolled
out even though the tuner vendors also had a quicker firmware
rollout).

> [A few days ago, I did an "availability scan" (I won't call it a
> "channel scan" because that means something different) in which I wrote
> a script that simply tuned to every channel returned by SD's XMLTV
> service for my zipcode, and reported flags, e.g., "Copy Free", "One Copy",
> "None". The "None" results seem to be (a) a gaziiiillion Major League
> Baseball and NBA channels (don't care), a metric ton of international
> channels (ditto), a few local origination channels (eh? aren't those
> usually random community television?), COMEC (the "Comcast Employee
> Channel" :), and a very small handful of movie channels. (Full list if
> anyone cares; 244 callsigns.) So I wonder if this affects me at all.

If you are not subscribed to a channel, or the channel is
one of the "gazillions" of IPTV only channels, the CCI
flag results are likely meaningless (since you can't actually
tune/decode them, you can actually validate the status).
But, as above, it will not matter if you are in a Moto area for
those channels that you subscribe to and are still offered
via linear QAM (for Comcast, that is a slowly shrinking
number as content moves to IPTV only).

> How would I do that?

Request the current rate card

https://www.xfinity.com/support/rate-card

(you may need to login to your Comcast account)
and review it, and if there is still a line item
buried somewhere in the many pages of a
"Service to Additional TV" (of around $10)
you are not S&E today.
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Re: Ceton vs multirec questions [ In reply to ]
> Date: Thu, 29 Jul 2021 04:54:40 +0000
> From: Gary Buhrmaster <gary.buhrmaster@gmail.com>

> For various reasons, the hardware vendor of the franchise when
> Comcast originally acquired it (back decades ago) typically is still
> the one in use today. If your CableCARDs say Motorola, Arris,

They say Motorola.

> or Commscope (at different points of the corporate acquisitions)
> you are not currently expected to see the issues no matter
> the CableCARD firmware (as far as have been reported, only
> a specific Cisco/SA (now Technicolor) firmware level commonly
> experienced the issue). And the issue was eventually resolved
> with new(er) CableCARD firmware (which eventually got rolled
> out even though the tuner vendors also had a quicker firmware
> rollout).

Sounds good. (One less tweak I'll have to think about.)

> If you are not subscribed to a channel, or the channel is
> one of the "gazillions" of IPTV only channels, the CCI
> flag results are likely meaningless (since you can't actually
> tune/decode them, you can actually validate the status).
> But, as above, it will not matter if you are in a Moto area for
> those channels that you subscribe to and are still offered
> via linear QAM (for Comcast, that is a slowly shrinking
> number as content moves to IPTV only).

I seem to be in a Motorola area. (And yeah, eventually I suspect both
(a) most channels will be IPTV and not QAM, rendering my hardware useless
and (b) most of the non-trash will be streaming-only. And thus will TV
have reclaimed its walled garden after the invention of the VCR.)

> Request the current rate card

> https://www.xfinity.com/support/rate-card

Didn't require that I log in; did require me to verify my street
address, but I'm coming in from the network the account is for. I
assume if I asked from somewhere random, they'd require a real login.

Interestingly though, it's only getting the bare URL which requires
authentication; I was able to download the rate card itself via wget on
a host I have in a datacenter (e.g., not this network) to confirm that.
So you can see it as well:

https://comcaststore.s3.amazonaws.com/prod/wk/urc/585bca2b5bcd10375b2cfede/high_res/UN0000187_sik_high_res.pdf

I see something called "Service to Additional TV with TV Adaptor"
(page 2, lefthand column, halfway down) for $7.50. Don't know
if that's what we're talking about. Nothing else jumps out.
(I should locate a bill and see what they're charging me for. :)
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