Has anyone originated a Zoom webinar with a Raspberry Pi?

Using the Church Webcasting System, YouTube, etc. Including cameras and mixers.
rmrichesjr
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Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby rmrichesjr » Sun Jul 18, 2021 2:16 pm

Has anyone originated a Zoom webinar using a Raspberry Pi?

The clerk who has been running our ward's sacrament meeting Zoom webinars is moving out of the ward (and taking his laptop with him), so I have been asked to take over the job of originating the webinar. Provided it would work, I would prefer to use a Raspberry Pi model 4B running Raspbian aka Raspberry Pi OS with the supplied Pi-optimized Chromium browser. Having used a Raspberry Pi 4B and browser for bidirectional video meetings, I'm confident the Pi hardware can handle the workload. The question is whether there's anything in the webinar format that requires the app rather than using a browser.

Thanks.

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby bradpeterson@gmail.com » Mon Jul 19, 2021 10:06 am

It's on my TODO list to test. I've been working on my own RP4 broadcasting system for non-interactive meetings.

While Zoom can be installed on an RP4, it's not a standard install. Anecdotally I've heard others say the Zoom performance is choppy.

While the RP4 can claim to do 1080p@30fps hardware video encoding via OpenMax/OMX, in practice it's very tricky to hit that point. Unless you need an RP4 for some very specific reason, I'd recommend a simple laptop or a tablet.

rmrichesjr
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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby rmrichesjr » Mon Jul 19, 2021 5:19 pm

The "not a standard install" with choppy performance sounds like the solution I read about that installed an x86 Zoom app and used an instruction set emulator to make it run/walk/crawl. The wards at the meetinghouse bought a rather nice (Logitech C920) webcam that does the encoding itself, so CPU load on the Pi is pretty mild. The motivation to use a Pi rather than another machine is the price of the other machine. I have a Haswell machine from several years ago, but I would guess an RP4 is on par with that.

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby rmrichesjr » Fri Jul 23, 2021 8:40 pm

So far, I have at least partial success with my own limited testing. I used a Raspberry Pi model 4B with 4G of RAM, a Logitech C920s camera, and (for testing) a USB headset. Initially, the "Join Computer Audio" button does not get enabled, and/or the "Start Video" button is not enabled. However, after setting camera, microphone, and audio settings to 'Allow' by (right or left, I don't recall) clicking on the lock to the left of the URL in the address bar, combined with a few page refreshes and forced full reloads (control-shirt-R), eventually both audio and video can be enabled. If past experience with Zoom is any indication, after I got audio and video enabled once, it should work for indefinitely on the same hardware (until a browser update and/or Zoom web app update).

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby bradpeterson@gmail.com » Fri Jul 30, 2021 4:13 pm

I just ran a test. It appears to work for a webinar and an "everybody else's camera off" interactive broadcaster. Its quality is poor for interactive meetings.

Test setup: RP4 Model B 8 GB Ram, using Raspian Ubuntu, and a Zoom install that used the box86 emulator. I used a USB 2.0 webcam that feeds raw video (don't feed it a cheap webcam with encoded video).

Webinar test:
I set up a webinar on a web portal, then went to the RP4 Zoom interface, and started the meeting. On the other end, it looks great. Getting around 25fps.

Everybody else's camera off test:
I had a PC and an RP4 in a Zoom meeting. I used a webcam which sends a raw stream. I only enabled the RP4 side's camera, and disabled the PC camera. To my surprise, I got fairly decent broadcast. I'd estimate it at around 25 fps. (I know this isn't a proper non-interactive test, but hopefully this is good enough)

Interactive test:
Not good. When my camera was off, I was able to see the other participant just fine with little delay. The moment I turned the RP4's Zoom video, the processing took a nosedive. On the RP4, the other person's video was choppy. On the other computer, the RP4 appeared to process and send about 2 frames per second, so the other PC couldn't see much video animation at all. Note that I was using a USB webcam which can send a raw stream. I've been able to get this webcam to encode and transmit up to a 28 fps 720p when no video is displaying on OBS. There may be some ideal webcam setup or configuration out there somewhere which does work?

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby jessedaleolsen » Sun Aug 22, 2021 12:52 pm

I tried to set up our stake with a raspberry pi for zoom webinary sacrament meetings, but the ARM to x86 emulator did not support audio, so I switched to an x86 raspberry pi, but Linux Zoom does not support CC, so I purchased a Beelink Windows 10 tiny pc for about $180, and got it set up to run all 4 units each Sunday with a script I put together to start them all automatically. I put together a document explaining how I did it, including the Python script to automate starting the zoom webinars. bradperterson, I just shared it with you. Enjoy!

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby jessedaleolsen » Sun Aug 22, 2021 1:04 pm


rmrichesjr
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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby rmrichesjr » Sun Aug 22, 2021 1:47 pm

jessedaleolsen wrote: Sun Aug 22, 2021 12:52 pm I tried to set up our stake with a raspberry pi for zoom webinary sacrament meetings, but the ARM to x86 emulator did not support audio, so I switched to an x86 raspberry pi, ...
All the literature I had seen said the ARM to x86 emulator would not work well. It's pretty clear that the emulator introduces the performance degradation that causes video to reportedly be very choppy.

Where did you find an x86 raspberry pi? I had not heard such a thing existed.

You don't really need a USB 3 port for video. USB2 is theoretical ~480Mbps, which is way more than necessary for compressed video, and many/most webcams produce compressed rather than raw video. (My home-made DVR setup streams an OTA TV program stream in real time over USB 2 each night to time-shift the news--through a Raspberry Pi model 1, no less.)

The successful webinar meeting I did a few weeks ago with a Raspberry Pi model 4B used the browser. IIRC, I was using Raspbian aka Raspberry Pi OS with the default optimized Chromium. I had to click on the lock symbol to tell the browser _again_ to allow Zoom to access the camera and audio input and then reload or force reload the page. It looks like the authorization is not handled correctly between the browser and the Zoom web app unless authorization is given again right at the beginning of the webinar.

(Sadly, I won't be able to do more with that because of another mask mandate and a physical condition that makes me unable to wear a mask.)

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby bradpeterson@gmail.com » Sun Aug 22, 2021 9:30 pm

All the literature I had seen said the ARM to x86 emulator would not work well. It's pretty clear that the emulator introduces the performance degradation that causes video to reportedly be very choppy.
I thought that too. I was quite surprised the video was passable on my Zoom/RP4 test.
Where did you find an x86 raspberry pi? I had not heard such a thing existed.


There are no x86 pis. There are some small x86 hackerboard sized devices like the pi (UDOO, Hackboard 2, and Rock PI X are probably the three most popular). I haven't run Zoom or OBS on these, but my hunch is they would perform as good, if not better, than the RP4. Also lots of microPC/NUCs out there. I'm happy to hear the Beelink Windows 10 tiny pc seems to work.
You don't really need a USB 3 port for video. USB2 is theoretical ~480Mbps, which is way more than necessary for compressed video, and many/most webcams produce compressed rather than raw video
USB3 is still a good idea if you can get it. For two reasons.

1) Since the goal of this thread is cheap broadcasting devices, it really helps to have an uncompressed input video feed. It takes work for the machine to decode compressed video, mix it, then re-encode for broadcast. (Exception: I've seen one solution which simply restreams a single video/single audio source and shuts off during the sacrament portion of a meeting)

2) With uncompressed video, you typically use 16-32 bits per pixel. At 1080p30fps, that's 1920 pixels wide * 1080 * 2-4 bytes per pixel * 30 frames per second = 124-248 MB/s. USB 2 can only do 30 MB/s: ((480 Mbit per second / 8 bits per byte) / 2 for half duplex). So for uncompressed video feeds, USB3 is the way to go.

That said, those cheap $15 devices that turn HDMI into USB via compressed video work on USB 2 work for most laptops. We've been using them for over a year now in our stake. I would just never use those $15 devices on something like the microPC Beelink Windows 10.
My home-made DVR setup streams an OTA TV program stream in real time over USB 2 each night to time-shift the news
Sure, but that's just decode. The problem is that RP4 can't both decode an input feed then re-encode it for output. I've tried such setups a few ways. I end up with around 2-5 frames per second. Only when the input video is uncompressed raw do I get around 25+ fps on encoding output.

Ultimately I went back to $500 laptops. They can simultaneously decode/encode, and they come with a screen, and a keyboard, and a mouse, all built into one handy package. :D

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Re: Has anyone originated a Zoom webinar with a Raspberry Pi?

Postby bradpeterson@gmail.com » Sun Aug 22, 2021 9:36 pm

jessedaleolsen wrote: Sun Aug 22, 2021 12:52 pm I tried to set up our stake with a raspberry pi for zoom webinary sacrament meetings, but the ARM to x86 emulator did not support audio, so I switched to an x86 raspberry pi, but Linux Zoom does not support CC, so I purchased a Beelink Windows 10 tiny pc for about $180, and got it set up to run all 4 units each Sunday with a script I put together to start them all automatically. I put together a document explaining how I did it, including the Python script to automate starting the zoom webinars. bradperterson, I just shared it with you. Enjoy!
That's awesome! Simple little pythongui to make it click what you want. :)

What if something goes wrong mid meeting? Do you do some kind of remote desktop in to access the GUI?

Also, where do you keep the device? I assume you put it right next to the webcam somewhere, such as a mounted camera near the front of the chapel? So the idea is someone just hooks up a camera on a tripod, hooks up this device, turns it on, and you hope everything automates correctly from there?


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