[mythtv-users] convoluted questiom

Stephen Worthington stephen_agent at jsw.gen.nz
Mon Dec 27 02:35:30 UTC 2021

On Mon, 27 Dec 2021 07:36:20 +0800, you wrote:

>>> I want to take a camera
>>> a) stream it
>>> b) preview at will
>>> c) record at will
>>> mythtv is perfect except I do not want any GUI, only programatic invocation.
>>> I’ve not studied the API eg I find StopRecording but no StartRevording, can anyone offer advice?
>>> I implimented the requirement with gstreamer. Unlike mythtv-users and mythtv-dev lists their list is populated by soals seeking answers and a few really knowledgeable people. Unless you can pique their interest, you are on your own.
>> Zoneminder ( https://www.mythtv.org/wiki/MythZoneMinder ) and the mythtv pluginfor zoneminder are a possibility for what you are inquiring about. You didn’t mention what kind of camera, but zone minder will work with both network cameras as well as attached cameras to the zoneminder server.
>First thanks to you and to Barry, it very refreshing to have someone take an interest in your question.
>I tried to keep my question terse and relevant, but more explanation is warranted:
>In Australia commercial divers are required to wear a head cam and record their work.
>A year or so ago a fishing trawler sank off Broom.
>Since there may have been bodies on board when recovered (there weren't) the police accompanied the recovery and took the very poor video. (no doubt on a phone)
>We make DVRs. Divers describe themselves as underwater laborers and so the GUI is simple, certainly not
>u-beaut as mythtv.
>http://tigger.ws/downloads/DVR.avi <http://tigger.ws/downloads/DVR.avi>
>In the clip you can see the recorder box.
>We are implementing HD recording using Sensoray 2263 capture from a 1080p AHD camera.
>Mythtv answers all my needs. A customer of the dive company may want to watch, imagine a hull inspection on an oil tanker. So
>The divemaster needs watch what is happening and record what is happening while their customer watches a stream.
>All is complicated by (life dependant) chemistry of breathing gas (partial pressure of oxygen) (nitrogen being narcotic at about. 70m) (helium at pressure being a very good conductor of heat so warming water is needed) (as little as neccessory helium is used because of cost (so called tri-mix oxygen-nitrogen-helium))
>Voice is distorted by helium.
>mythtv ticks nearly all the boxes, but I need to control it via the api not via the gui.
>As a 20 year mythtv user it is a obvious choice likewise any project you care to name is unlikely to address all my needs.
>> I'm not sure of what you mean by "programatic invocation"
>means interaction with mythtv is via program API not via GUI in any way.
>> If the same recording displays fine under Linux and Windows then it should also be fine with MacOS.  Perhaps a bad install of the Mac VLC, outdated codec.  (WAG)
>The whole mac paradigsm of "doan toucha da buttons" means the buffering-latency is hard to configure: mac plays good videos <smile> eg mythtv recordings just fine but my goal is to create not-broken recordings.
>What tool can I use.to measure, listen<scitch>ing is<scritch> easy

I just had a quick look at the Services API and it appears that there
is no API to start a recording in the manner that you do for Live TV,
where it starts immediately and continues until you stop it.  What is
needed is a call to GetRecordSchedule using the option that gets the
template rule that you want to use (eg 'Default'), then modify that to
set up a new recording rule, and call AddRecordSchedule to add it to
the schedule.  Then at the scheduled time, it will start recording. My
experience with manually starting and stopping scheduled recordings is
that if the starttime in the recording rule is in the past, and the
endtime is in the future, the recording can be restarted.  So I would
hope that setting the starttime to a little in the past and calling
AddRecordSchedule would immediately start recording.  But I would need
to test that.  If not, then a ReactivateRecording call would be needed
to get it to start recording.  All of which is a bit complicated for
what you want, but it looks doable.

However, the Sensoray 2263 is not likely to have MythTV support as a
capture device unless it has Linux V4L drivers.  The web page I found
says Linux is supported, but whether that means V4L support I am not
sure.  I suspect not.  So supporting it would likely mean also writing
an External Recorder program to interface between the Sensoray 2263
API and MythTV.  Something like what MythHDRecorder does with Silicon
Dust HDHR devices:


That is a bit more work, but again likely doable.

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