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Show HN: Send me an IRL message and watch it arrive

hi.benren.au

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Show HN: Send me an IRL message and watch it arrive

#1

Post by GSGBen »

- This page is running directly on the Pico W in the stream, using microdot (but proxied out via cloudflare tunnel).

- There's a buzzer that plays a sound as well but the stream has no audio.

- There's a Pi Zero 2 W with a Camera Module 3 streaming the video. Streaming low latency video is painful. I tried mjpeg, Nginx+HLS/DASH, YouTube and Twitch. Twitch is definitely the easiest and best-performing.

- There's still a few seconds delay between sending your message and the video updating.

Show HN: Send me an IRL message and watch it arrive
hi.benren.au

Re: Show HN: Send me an IRL message and watch it arrive

#2

Post by forgotthetimer »

(OP, temp user, forgot to disable the HN procrastination timer)

For anyone trying to do this in the future, here's the command to stream from a modern Pi camera module / driver to twitch. IIRC I also had to install the full version of the libcamera tools to use the libav switches.

    libcamera-vid -v 0 -t 0 --codec libav --libav-format flv -o "rtmp:///" --rotation 180 --width 1920 --height 1080 --framerate 30 --bitrate 4000000 --autofocus-mode auto --autofocus-window 0.25,0.15,0.5,0.5

Re: Show HN: Send me an IRL message and watch it arrive

#4

Post by forgotthetimer »

gus_massa wrote: post #3

Should I see in the video the text that I had sent? I see only the hand moving.

Yep, it should show on the screen but unfortunately the camera refresh rate is out of sync with the screen's refresh rate so it's a bit hard to see. I need to read the datasheet again and drop the screen's refresh rate - I tried adjusting the camera's instead but it was never quite right.

Re: Show HN: Send me an IRL message and watch it arrive

#5

Post by gus_massa »

forgotthetimer wrote: post #4
gus_massa wrote: post #3

Should I see in the video the text that I had sent? I see only the hand moving.

Yep, it should show on the screen but unfortunately the camera refresh rate is out of sync with the screen's refresh rate so it's a bit hard to see. I need to read the datasheet again and drop the screen's refresh rate - I tried adjusting the camera's instead but it was never quite right.

Can you cheat and just repeat the same letter a few times, like "Hello!!!" -> "HHHeeellllllooo!!!" or it shows a dark frame between leters?

Re: Show HN: Send me an IRL message and watch it arrive

#6

Post by forgotthetimer »

gus_massa wrote: post #5
forgotthetimer wrote: post #4

Earlier quoted context omitted.

Yep, it should show on the screen but unfortunately the camera refresh rate is out of sync with the screen's refresh rate so it's a bit hard to see. I need to read the datasheet again and drop the screen's refresh rate - I tried adjusting the camera's instead but it was never quite right.

Can you cheat and just repeat the same letter a few times, like "Hello!!!" -> "HHHeeellllllooo!!!" or it shows a dark frame between leters?

Getting the data onto the screen is fine, and IRL I can't see any flicker, but the OLED screen itself is apparently refreshing at something like 107 or 133 Hz.

Re: Show HN: Send me an IRL message and watch it arrive

#8

Post by tamimio »

forgotthetimer wrote: post #4
gus_massa wrote: post #3

Should I see in the video the text that I had sent? I see only the hand moving.

Yep, it should show on the screen but unfortunately the camera refresh rate is out of sync with the screen's refresh rate so it's a bit hard to see. I need to read the datasheet again and drop the screen's refresh rate - I tried adjusting the camera's instead but it was never quite right.

Ah, just seen your comment, try to use obs and adjust the rate from there before streaming it.

Re: Show HN: Send me an IRL message and watch it arrive

#9

Post by forgotthetimer »

forgotthetimer wrote: post #2

(OP, temp user, forgot to disable the HN procrastination timer) For anyone trying to do this in the future, here's the command to stream from a modern Pi camera module / driver to twitch. IIRC I also had to install the full version of the libcamera tools to use the libav switches. libcamera-vid -v 0 -t 0 --codec libav --libav-format flv -o "rtmp:// / " --rotation 180 --width 1920 --height 1080 --framerate 30 --bitrat…

Update: there's been a bunch of great messages so far, from people all over. But most importantly we've had a

    ');DROP TABLES;

Re: Show HN: Send me an IRL message and watch it arrive

#10

Post by liminalsunset »

forgotthetimer wrote: post #6
gus_massa wrote: post #5

Earlier quoted context omitted.

Can you cheat and just repeat the same letter a few times, like "Hello!!!" -> "HHHeeellllllooo!!!" or it shows a dark frame between leters?

Getting the data onto the screen is fine, and IRL I can't see any flicker, but the OLED screen itself is apparently refreshing at something like 107 or 133 Hz.

One way to potentially resolve this is to place the setup in a darker place and/or add a piece of tinted transparent material in front of the camera. The camera will automatically adjust the shutter speed (not the frame rate) because of the reduced light to 1/30 or so which will allow more of the screen to be captured.
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