[PLUG-AV] Another experiment in updating our AV workflow

[Harry McNally]

Hi James and Nick

 From the events:
--------
Tuesday 8th June 18:00 - 20:00
Our talk this month is about Riff.CC, a free community-run website for
streaming, downloading and sharing legally free culture such as
movies, TV shows, audio books and music
--------

 From Nick's discussions, can we manage a  20.00 to 21.00 "Quick AV Dev" session ?

If so, I will prepare a RPi4 with the setup below and also bring along the 
running Opsis if others can identify the dev tests that will maximise our use 
of the hour. I'd happily participate.

All the best
Harry

On 18/5/21 12:49 pm, James Henstridge wrote:
> On Tue, 18 May 2021 at 09:31, Harry McNally
> <harrymc at decisions-and-designs.com.au> wrote:
>> Hi James
>>
>> On 17/5/21 4:00 pm, James Henstridge wrote:
>>> I haven't done much work on that code base since March.  The last
>>> thing I was working on was to try and simplify the configuration
>>> process so you wouldn't have to write GStreamer pipelines in the
>>> general case: instead, you could tell it that you want to use a
>>> particular camera at a particular resolution and framerate, and have
>>> it figure the rest out.  With that said, I believe the code should
>>> still function as is.
>> If you have time to describe the Raspbian setup for testing the work to date
>> on the list, would it assist if I prepare an SD card for the RPi4 I have to
>> bring along to the next meetup ?
> The test setup I created at the Raspberry Pi Jam was using an Ubuntu
> Server 22.04 image as a starting point, and building the software on
> the board itself.  You can probably build on Raspbian, but I haven't
> checked. I don't have a full list of dependencies, but you'll probably
> need at least the following:
>
> 1. git (to clone the repository)
> 2. meson (the build system)
> 3. libgstreamer1.0-dev
> 4. libgstrtspserver-1.0-dev
> 5. libavahi-client-dev
> 6. libavahi-glib-dev
>
> To build the project, you'll probably want to run the following
> commands from a checkout:
>
>      mkdir build
>      cd build
>      meson -Dobs-plugin=false ..
>      ninja
>
> The repo contains both the RTSP sender and the matching OBS plugin.  I
> suggest disabling the OBS plugin as it is only needed on the system
> that will receive the streams, and I had trouble building it on armhf.
>
>
>> It will give me time to prepare so I can drop in and do integration testing
>> quickly. If you do any additional work that requires change on the RPi4 let me
>> know again and I can tweak.
>>
>> Also, if Nick's capture device suits, may I suggest deleting the USB hub and
>> use a USB extender cable:
>>
>> https://www.ple.com.au/Products/624625/Startech-1m-Black-USB-30-Male-to-Female-USB-30-Extension-Cable-A-to-A
>>
>> I didn't see a 15cm one and I have purchased very short HDMI cables before so
>> it is worth considering if the RPi4 should be up next to the camera or on the
>> floor with a longer HDMI cable and purchase test cables to suit.
> I think it would probably be better to prefer a longer HDMI cable over
> a longer USB cable in connecting up the capture board: it'd be good to
> minimise the amount of unsupported weight hanging off the camera's
> HDMI socket.
>
> The USB 3 ports on the RPi4 are right against the Ethernet socket, so
> we probably would want some kind of extension cable if we are using
> dongle-style capture boards like the one Nick bought. We can probably
> do shorter than 1 metre though, such as this one:
>
> https://www.amazon.com.au/dp/B01M1KINRO
>
> Of course, Nick's dongle only supports USB 2.0 speeds. I wonder if
> there are any performance benefits on the RPi side from having it
> plugged in to one of the 3.0 ports?
>
>>> I haven't really investigated sending audio yet.  You can definitely
>>> transmit audio with RTSP/RTP, so it would probably just work with an
>>> appropriate pipeline.  I hadn't really investigated much further
>>> though, since our use of wireless microphones reduces the need for
>>> remote audio: we could just plug the audio mixer directly into the
>>> machine running OBS Studio.
>> This makes sense. When I get a moment, I will post a mixer requirements to the
>> list for scrutiny. Once I know what features are needed I can review those USB
>> powered mixers.
> James.