I'm trying to work out how to use a command line approach to making
sheduled TV captures using a DVB-T2 USB dongle + VLC using a Linux
machine. Eventually to understand it well enough to write a simple ROX app
that gives a simple interface which then generates the relevant output.

Thus far I've got be being able to write executable files that will launch
VLC playing the TV station of choice. e.g. one that contain commands like

vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8

which when executed starts VLC playing the "Talking Pictures" channel. It
then puts the result into a .ts file in the default location (Downloads)
using the default naming.

IIUC I can add a "-runtime=<ssss>" to specify how long the recording will
be, but the snag at present is how to get the command run to *start* at the
correct time.

I have installed the "at" command for this but for whatever reason can't
get the command correct to do what I want. Looked on the web but not found
an example that works.

e.g. I can't seem to specify correctly what/where the file to put the
recording should be. Which may be a sign I've muddled something else that
throws the command off recognising the full-path name I give.

Can someone point out how to get this to work, please? Once I've twigged
this I can write a simple prog to generate a suitable set of 'at' commands
to get them to record the required items. (I hope!)

Ta.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 15/11/2022 12:24, Jim Lesurf wrote:
> I'm trying to work out how to use a command line approach to making
> sheduled TV captures using a DVB-T2 USB dongle + VLC using a Linux
> machine. Eventually to understand it well enough to write a simple ROX app
> that gives a simple interface which then generates the relevant output.
>
> Thus far I've got be being able to write executable files that will launch
> VLC playing the TV station of choice. e.g. one that contain commands like
>
> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>
> which when executed starts VLC playing the "Talking Pictures" channel. It
> then puts the result into a .ts file in the default location (Downloads)
> using the default naming.
>
> IIUC I can add a "-runtime=<ssss>" to specify how long the recording will
> be, but the snag at present is how to get the command run to *start* at the
> correct time.
>
> I have installed the "at" command for this but for whatever reason can't
> get the command correct to do what I want. Looked on the web but not found
> an example that works.
>
> e.g. I can't seem to specify correctly what/where the file to put the
> recording should be. Which may be a sign I've muddled something else that
> throws the command off recognising the full-path name I give.
>
> Can someone point out how to get this to work, please? Once I've twigged
> this I can write a simple prog to generate a suitable set of 'at' commands
> to get them to record the required items. (I hope!)
>
> Ta.
>
> Jim
>

I too have had problems with 'at'.
Can you set up a cron job to start it?

Alternatively, TVHeadend.
"Tvheadend is a TV streaming server and recorder for Linux, FreeBSD and
Android supporting DVB-S, DVB-S2, DVB-C, DVB-T, DVB-T2, ATSC, ISDB-T,
IPTV, SAT>IP and HDHomeRun as input sources."
https://tvheadend.org/projects/tvheadend

I've successfully used it on a RPi with OSMC.

--
Chris Elvidge
England

On 15/11/2022 12:24, Jim Lesurf wrote:
> I'm trying to work out how to use a command line approach to making
> sheduled TV captures using a DVB-T2 USB dongle + VLC using a Linux
> machine. Eventually to understand it well enough to write a simple ROX app
> that gives a simple interface which then generates the relevant output.
>
> Thus far I've got be being able to write executable files that will launch
> VLC playing the TV station of choice. e.g. one that contain commands like
>
> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>
> which when executed starts VLC playing the "Talking Pictures" channel. It
> then puts the result into a .ts file in the default location (Downloads)
> using the default naming.
>
> IIUC I can add a "-runtime=<ssss>" to specify how long the recording will
> be, but the snag at present is how to get the command run to *start* at the
> correct time.
>
> I have installed the "at" command for this but for whatever reason can't
> get the command correct to do what I want. Looked on the web but not found
> an example that works.
>
> e.g. I can't seem to specify correctly what/where the file to put the
> recording should be. Which may be a sign I've muddled something else that
> throws the command off recognising the full-path name I give.
>
> Can someone point out how to get this to work, please? Once I've twigged
> this I can write a simple prog to generate a suitable set of 'at' commands
> to get them to record the required items. (I hope!)
>
I take it this is the Unix/Linux "at command" (not a VLC command). In
other words, it schedules when the command to record is /sent/ to VLC,
not when VLC /acts/ on the command.

I've never used that with VLC but others claim to have done so. E.g.

https://www.sourcefabric.org/blog/schedule-stream-recordings-from-the-command-line-part-2-vvm0irq2

--
Robin
reply-to address is (intended to be) valid

On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
<noise@audiomisc.co.uk> wrote:

>I'm trying to work out how to use a command line approach to making
>sheduled TV captures using a DVB-T2 USB dongle + VLC using a Linux
>machine. Eventually to understand it well enough to write a simple ROX app
>that gives a simple interface which then generates the relevant output.
>
>Thus far I've got be being able to write executable files that will launch
>VLC playing the TV station of choice. e.g. one that contain commands like
>
>vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>
>which when executed starts VLC playing the "Talking Pictures" channel. It
>then puts the result into a .ts file in the default location (Downloads)
>using the default naming.
>
>IIUC I can add a "-runtime=<ssss>" to specify how long the recording will
>be, but the snag at present is how to get the command run to *start* at the
>correct time.

I use "at" with "get_iplayer" so that part is easy, assuming
that IUYC. Let's say you want run a file at 21:00 tomorrow, the
16th November.

at -t 202211162100 -f vlc_script

The time is "CC YY MM DD hh mm" without spaces. I like to
specify the date and time in full. "vlc_script" is the program
you want started at that time.

>I have installed the "at" command for this but for whatever reason can't
>get the command correct to do what I want. Looked on the web but not found
>an example that works.
>
>e.g. I can't seem to specify correctly what/where the file to put the
>recording should be. Which may be a sign I've muddled something else that
>throws the command off recognising the full-path name I give.

I should have thought that you would need to specify the
destination in the "vlc_script" file. Nothing to do with
"at" which does nothing except run the file specified.

I hope some of that helps.
--
Roger

In article <vn67nhd848h7skl2fbngljoup4tm3qpcat@4ax.com>,
Roger <invalid@invalid.invalid> wrote:
> On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
> <noise@audiomisc.co.uk> wrote:

> I use "at" with "get_iplayer" so that part is easy, assuming
> that IUYC. Let's say you want run a file at 21:00 tomorrow, the
> 16th November.

> at -t 202211162100 -f vlc_script

> The time is "CC YY MM DD hh mm" without spaces. I like to
> specify the date and time in full. "vlc_script" is the program
> you want started at that time.

FWIW I'm just using hhmm at present, and from the jobs listed by atq it
seems to work. i.e. the jobs get listed as being to started at that time
today. They also duly vanish from the list... but without giving a coconut.

> I should have thought that you would need to specify the
> destination in the "vlc_script" file. Nothing to do with
> "at" which does nothing except run the file specified.

I'm using the '-f' of 'at' to point at files that contain things like

vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8

The files are set to be executable. And if I click on one with ROX Filer
they will start VLC playing the required station ('program' as numbered by
its main stream ID)

Tried calling cvlc rather than vlc, but still, no cigar. So I must be using
at here in the wrong way or have to alter what's in the file from the
above.

Does having no longer have the job queued cause an attempt to close down
the 'child' process? i.e. stops it as soon as at has launched it?

Still puzzled but must be doing something daft! :-/

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 15/11/2022 13:26, Chris Elvidge wrote:
> Alternatively, TVHeadend.
> "Tvheadend is a TV streaming server and recorder for Linux, FreeBSD and
> Android supporting DVB-S, DVB-S2, DVB-C, DVB-T, DVB-T2, ATSC, ISDB-T,
> IPTV, SAT>IP and HDHomeRun as input sources."
> https://tvheadend.org/projects/tvheadend
>
> I've successfully used it on a RPi with OSMC.

Yes, rather than trying to persuade the wrong tool to work - which you
may manage after a lot of struggling - why not use a tool which is
designed to do the job: TVHeadend. I run it on normal Raspberry Pi OS
(as opposed to OSMC) and it works very well, recording from a selection
of terrestrial and satellite tuners.

NextPVR, which used to be Windows-only, has now been rewritten so it can
be used on Windows or Linux. One day I'll have to try it. I used it on
Windows before I got the Pi.

It had the big advantage over TVH that it could detect schedule clashes
(too many simultaneous recordings scheduled compared with the number of
tuners) at the time of requesting a programme, whereas TVH lets you set
up conflicting programmes and only notices as it starts to record, by
which time it is too late. I raised it as an enhancement (citing
NextPVR's ability to do it) and was told in no uncertain terms that it
was technically impossible in some obscure, atypical set of
circumstances so they had no intention of even *trying* to make it work
for the much more typical situations.

On 15/11/2022 15:02, Jim Lesurf wrote:
> In article <vn67nhd848h7skl2fbngljoup4tm3qpcat@4ax.com>,
> Roger <invalid@invalid.invalid> wrote:
>> On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
>> <noise@audiomisc.co.uk> wrote:
>
>
>> I use "at" with "get_iplayer" so that part is easy, assuming
>> that IUYC. Let's say you want run a file at 21:00 tomorrow, the
>> 16th November.
>
>> at -t 202211162100 -f vlc_script
>
>> The time is "CC YY MM DD hh mm" without spaces. I like to
>> specify the date and time in full. "vlc_script" is the program
>> you want started at that time.
>
> FWIW I'm just using hhmm at present, and from the jobs listed by atq it
> seems to work. i.e. the jobs get listed as being to started at that time
> today. They also duly vanish from the list... but without giving a coconut.
>
>
>> I should have thought that you would need to specify the
>> destination in the "vlc_script" file. Nothing to do with
>> "at" which does nothing except run the file specified.
>
> I'm using the '-f' of 'at' to point at files that contain things like
>
> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>
> The files are set to be executable. And if I click on one with ROX Filer
> they will start VLC playing the required station ('program' as numbered by
> its main stream ID)
>
> Tried calling cvlc rather than vlc, but still, no cigar. So I must be using
> at here in the wrong way or have to alter what's in the file from the
> above.
>
> Does having no longer have the job queued cause an attempt to close down
> the 'child' process? i.e. stops it as soon as at has launched it?
>
> Still puzzled but must be doing something daft! :-/

Just a thought: when VLC is invoked from the script using "at", can the
shell find the vlc exe file? Try giving the full path to vlc, and see if
it makes any difference...

On 15/11/2022 15:02, Jim Lesurf wrote:
> In article <vn67nhd848h7skl2fbngljoup4tm3qpcat@4ax.com>,
> Roger <invalid@invalid.invalid> wrote:
>> On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
>> <noise@audiomisc.co.uk> wrote:
>
>
>> I use "at" with "get_iplayer" so that part is easy, assuming
>> that IUYC. Let's say you want run a file at 21:00 tomorrow, the
>> 16th November.
>
>> at -t 202211162100 -f vlc_script
>
>> The time is "CC YY MM DD hh mm" without spaces. I like to
>> specify the date and time in full. "vlc_script" is the program
>> you want started at that time.
>
> FWIW I'm just using hhmm at present, and from the jobs listed by atq it
> seems to work. i.e. the jobs get listed as being to started at that time
> today. They also duly vanish from the list... but without giving a coconut.
>
>
>> I should have thought that you would need to specify the
>> destination in the "vlc_script" file. Nothing to do with
>> "at" which does nothing except run the file specified.
>
> I'm using the '-f' of 'at' to point at files that contain things like
>
> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>

I may have misunderstood but have you tested this with *only* that
"known good" command (to get VLC to open the programme at the required
time) and *nothing* about recording etc? Until that works I'd not worry
about things like recording time and file location.

--
Robin
reply-to address is (intended to be) valid

On Tue, 15 Nov 2022 15:02:27 +0000 (GMT), Jim Lesurf
<noise@audiomisc.co.uk> wrote:

>In article <vn67nhd848h7skl2fbngljoup4tm3qpcat@4ax.com>,
> Roger <invalid@invalid.invalid> wrote:
>> On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
>> <noise@audiomisc.co.uk> wrote:
>
>
>> I use "at" with "get_iplayer" so that part is easy, assuming
>> that IUYC. Let's say you want run a file at 21:00 tomorrow, the
>> 16th November.
>
>> at -t 202211162100 -f vlc_script
>
>> The time is "CC YY MM DD hh mm" without spaces. I like to
>> specify the date and time in full. "vlc_script" is the program
>> you want started at that time.
>
>FWIW I'm just using hhmm at present, and from the jobs listed by atq it
>seems to work. i.e. the jobs get listed as being to started at that time
>today. They also duly vanish from the list... but without giving a coconut.

But when you've got it working you may schedule things days or
weeks in advance.

>> I should have thought that you would need to specify the
>> destination in the "vlc_script" file. Nothing to do with
>> "at" which does nothing except run the file specified.
>
>I'm using the '-f' of 'at' to point at files that contain things like
>
>vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>
>The files are set to be executable. And if I click on one with ROX Filer
>they will start VLC playing the required station ('program' as numbered by
>its main stream ID)

As NY suggested by didn't say this way; your vlc script has to
be in your PATH, if it isn't you should put the full path in the
script.

Instead of using ROX run the script from your shell's prompt
whilst in a different directory from where the script is. If
your shell cannot find it then try again using the full path.
Oh, why not change the script to

echo Hello world!

You'll be able to see immediately whether the script has run
correctly or not.

>Does having no longer have the job queued cause an attempt to close down
>the 'child' process? i.e. stops it as soon as at has launched it?

If it's not listed using atq then at has attempted to do its job
and removed it from the queue.

Have you checked the logs (probably in /var/log)? Run your
script and immediately look at the logs to see which was most
recently written to (ls -ltr /path/to/logs). If the time is
"now" look at the last entries in that log. There should be a
clue there.

>Still puzzled but must be doing something daft! :-/

I couldn't possibly comment.
--
Roger

In article <8ui7nh1coc4mld3pi5tn88u9jcj653mnq2@4ax.com>,
Roger <invalid@invalid.invalid> wrote:
> On Tue, 15 Nov 2022 15:02:27 +0000 (GMT), Jim Lesurf
> <noise@audiomisc.co.uk> wrote:

> >In article <vn67nhd848h7skl2fbngljoup4tm3qpcat@4ax.com>,
> > Roger <invalid@invalid.invalid> wrote:
> >> On Tue, 15 Nov 2022 12:24:38 +0000 (GMT), Jim Lesurf
> >> <noise@audiomisc.co.uk> wrote:

> >
> >> The time is "CC YY MM DD hh mm" without spaces. I like to
> >> specify the date and time in full. "vlc_script" is the program
> >> you want started at that time.
> >
> >FWIW I'm just using hhmm at present, and from the jobs listed by atq it
> >seems to work. i.e. the jobs get listed as being to started at that time
> >today. They also duly vanish from the list... but without giving a coconut.

> But when you've got it working you may schedule things days or
> weeks in advance.

Yes, I may well do that. But am trying to cut down on typing at present as
I try things by hand.

> >> I should have thought that you would need to specify the
> >> destination in the "vlc_script" file. Nothing to do with
> >> "at" which does nothing except run the file specified.
> >
> >I'm using the '-f' of 'at' to point at files that contain things like
> >
> >vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
> >
> >The files are set to be executable. And if I click on one with ROX Filer
> >they will start VLC playing the required station ('program' as numbered by
> >its main stream ID)

> As NY suggested by didn't say this way; your vlc script has to
> be in your PATH, if it isn't you should put the full path in the
> script.

> Instead of using ROX run the script from your shell's prompt
> whilst in a different directory from where the script is. If
> your shell cannot find it then try again using the full path.
> Oh, why not change the script to

> echo Hello world!

> You'll be able to see immediately whether the script has run
> correctly or not.

I'll experiment. :-)

> >Does having no longer have the job queued cause an attempt to close down
> >the 'child' process? i.e. stops it as soon as at has launched it?

> If it's not listed using atq then at has attempted to do its job
> and removed it from the queue.

> Have you checked the logs (probably in /var/log)? Run your
> script and immediately look at the logs to see which was most
> recently written to (ls -ltr /path/to/logs). If the time is
> "now" look at the last entries in that log. There should be a
> clue there.

> >Still puzzled but must be doing something daft! :-/

> I couldn't possibly comment.

No need.

We learn by making mistakes. Hmmm, I must learn quite a lot... 8-]

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article <3d489af1-f15b-520d-1bc5-b3adae6da04c@outlook.com>, Robin
<rbw@outlook.com> wrote:
> > I'm using the '-f' of 'at' to point at files that contain things like
> >
> > vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
> >

> I may have misunderstood but have you tested this with *only* that
> "known good" command (to get VLC to open the programme at the required
> time) and *nothing* about recording etc? Until that works I'd not worry
> about things like recording time and file location.

Yes. Commands like the above work as expected. They start up VLC and it
finds and plays the station whose PID is given the value (28224 in the
above example which IIRC is TalkingPicturesTV). At the monent I then press
the 'record' icon and it starts recording the stream into a .ts file.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 16/11/2022 09:56, Jim Lesurf wrote:
> In article <3d489af1-f15b-520d-1bc5-b3adae6da04c@outlook.com>, Robin
> <rbw@outlook.com> wrote:
>>> I'm using the '-f' of 'at' to point at files that contain things like
>>>
>>> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>>>
>
>> I may have misunderstood but have you tested this with *only* that
>> "known good" command (to get VLC to open the programme at the required
>> time) and *nothing* about recording etc? Until that works I'd not worry
>> about things like recording time and file location.
>
> Yes. Commands like the above work as expected. They start up VLC and it
> finds and plays the station whose PID is given the value (28224 in the
> above example which IIRC is TalkingPicturesTV). At the monent I then press
> the 'record' icon and it starts recording the stream into a .ts file.
>

If "at" with that causes VLC to open at the right time I don't see how
the problem can lie with "at".

I've found some remnants of what I used to use with VLC before I
switched to NextPVR for recording. The following works now in Windows
to open the programme and record for the set 20 seconds. I can't test
on a Raspberry Pi as I've no DVB-T dongle free.

"C:\Program Files\VideoLAN\VLC\vlc.exe" --program=17540
dvb-t2://frequency=545833000:bandwidth=8
--sout="#standard{access=file,mux=ts,dst=OUTPUT.ts}" --run-time=20
vlc://quit

NB: no point asking me "why...?" I found getting VLC to record DVB-T
was for me like the way young lads were (allegedly) told how to get down
from the top of a hay rick.

--
Robin
reply-to address is (intended to be) valid

On 16/11/2022 17:07, Robin wrote:
> On 16/11/2022 09:56, Jim Lesurf wrote:
>> In article <3d489af1-f15b-520d-1bc5-b3adae6da04c@outlook.com>, Robin
>> <rbw@outlook.com> wrote:
>>>> I'm using the '-f' of 'at' to point at files that contain things like
>>>>
>>>> vlc --program=28224 dvb-t2://frequency=690000000:bandwidth=8
>>>>
>>
>>> I may have misunderstood but have you tested this with *only* that
>>> "known good" command (to get VLC to open the programme at the required
>>> time) and *nothing* about recording etc?  Until that works I'd not worry
>>> about things like recording time and file location.
>>
>> Yes. Commands like the above work as expected. They start up VLC and it
>> finds and plays the station whose PID is given the value (28224 in the
>> above example which IIRC is TalkingPicturesTV). At the monent I then
>> press
>> the 'record' icon and it starts recording the stream into a .ts file.
>>
>
> If "at" with that causes VLC to open at the right time I don't see how
> the problem can lie with "at".
>
> I've found some remnants of what I used to use with VLC before I
> switched to NextPVR for recording.  The following works now in Windows
> to open the programme and record for the set 20 seconds.  I can't test
> on a Raspberry Pi as I've no DVB-T dongle free.
>
> "C:\Program Files\VideoLAN\VLC\vlc.exe" --program=17540
> dvb-t2://frequency=545833000:bandwidth=8
> --sout="#standard{access=file,mux=ts,dst=OUTPUT.ts}" --run-time=20
> vlc://quit

umm, err, then again, make that

"C:\Program Files\VideoLAN\VLC\vlc.exe" --program=17540
dvb-t2://frequency=545833000:bandwidth=8
--sout="#standard{access=file,mux=ts,dst=OUTPUT.ts}" --no-sout-all
--run-time=20 vlc://quit

> NB: no point asking me "why...?"  I found getting VLC to record DVB-T
> was for me like the way young lads were (allegedly) told how to get down
> from the top of a hay rick.
>

sorry, seems I may have tried that and landed on my head

--
Robin
reply-to address is (intended to be) valid

"Robin" <rbw@outlook.com> wrote in message
news:48e1721b-06f8-924d-974f-1068d8ccd0ad@outlook.com...

> NB: no point asking me "why...?" I found getting VLC to record DVB-T was
> for me like the way young lads were (allegedly) told how to get down from
> the top of a hay rick.

What *was* the way that "young lads were (allegedly) told how to get down
from the top of a hay rick"?