ARFNET

From b2300a86095d433f1b7462cdd94f5ecdbe0c6327 Mon Sep 17 00:00:00 2001 From: arf20 Date: Sun, 9 Feb 2025 01:40:35 +0100 Subject: Project pagem arfvcr --- projects/arfvcr/index.html | 110 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 projects/arfvcr/index.html (limited to 'projects/arfvcr/index.html') diff --git a/projects/arfvcr/index.html b/projects/arfvcr/index.html new file mode 100644 index 0000000..e72d097 --- /dev/null +++ b/projects/arfvcr/index.html @@ -0,0 +1,110 @@ + + + + + + ARFNET + + + + +

ARFNET +

Projects

arfvcr

+ +

+ A friend from the Makers of Murcia hackerspace + brought a few 80s tube TV cameras to a retro meetup, and they were free to take. I took one such + SONY Trinicon HVC-4000P, an awesome camera that was released in the early 80s. At that time, + camcorders didn't exist, they were television cameras because there weren't small enough + tape mechanisms to be integrated in. They required heavy external battery powered VCRs + like the Sony SL-F1, that you would hang off your shoulder, which we did not have. + So I thought I'd build a digital knockoff. +

+ +

+ The thing is basically a battery powered video capture box, a little computer + with a composite capture card attached. I chose to base it on a Raspberry Pi 4B + because it has to be fast enough to encode video at real time; and for the capture + card I had a *forgot* USB card, that exposes a raw yuv422 stream thanks to the + video4linux2 driver. Interfacing with the camera, the same friend gave me the + hard to find matching female connector that I could just mount to a chassis. + Finally for power, because I am a cheap and simple person, I went with a 7Ah + lead acid battery, which was very controversial in the hackerspace telegram channel :) +

+ +

+ So, power comes in from the battery or a barrel jack in the front panel, and comes to a + general power switch. That then goes to a 12-to-5V buck converter for the raspi and to another + toggle switch for the camera. The front panel also has a volt meter to check battery charge, + power and status LEDs, the rec/review switch and of course, the proprietary SONY connector + for the camera. +

+ +

+ The tethering cable has AV in and out, because it can also review recorded footage; and + some control signals as well: recording start/stop (from camera), rec/review (from camera), + tally signal in (from VCR: switches the viewfinder and monitor headphone jack to AV in). + Now, slight problem. I don't know how the signaling is supposed to work. start/stop and rec/review + aren't simple HIGH/LOW signals, they have no voltage when hitting the reflected buttons. + The camera also doesn't respond to a LOW or HIGH on the tally sig in, 5 nor 12V. + I should review the public schematics for the thing and figure it out. + Also, the audio out appears to be quiet. +

+ +

+ Software wise, I installed Debian 12 for ARM64, and then found that I needed a feature for + power debugging, so I had to install the downstream rasperry-pi kernel and userspace software. + I found that the hardware encoder never worked at all with any OS or ffmpeg version so it + mattered not, thats why I needed a fast raspi, for RT libx264. Of couse as mentioned, + ffmpeg was chosen by default for video capture and encoding. I love ffmpeg. Thanks Fabrice Bellard. + ffmpeg is love, ffmpeg is life. +

+ +

+ Because this is a headless device and I shouldn't need a console to hit record (although + the raspi creates a WiFi network to ssh into), I had to write + some software to trigger ffmpeg; so I wrote a daemon in C that reads GPIO pins from the front + panel or the camera (explained later) to start and stop the capture. + All of this is GPL available at github. +

+ +

+ + + -- cgit v1.2.3