matiaspl

import board
import digitalio
import busio
import usb_midi
import adafruit_midi
import neopixel
from adafruit_debouncer import Debouncer
from adafruit_midi.note_off import NoteOff
from adafruit_midi.note_on import NoteOn

matiaspl

#!/bin/bash
fps=25
delay=2

width=640
height=360
bar_width=20
bar_height=$((height / 2))
bar_speed=4

matiaspl

C:\ffmpeg\bin>ffplay -f lavfi testsrc=s=1080x1920:r=60 -vf format=yuv444p,transpose=1,scroll=horizontal=0.005,chromashift=cbh=-50:crh=-50,extractplanes=y+u+v[y][u][v],[y][u][v]hstack

C:\ffmpeg\bin>ffmpeg -f lavfi -i colorchart=patch_size=320x320:r=60:d=10 -vf format=yuv420p,scroll=horizontal=0.005:vertical=0.005 -c:v h264 -cq 0 -f mp4 chroma_motion_patch_test_420.mp4

matiaspl

Endeco's idea:

/etc/udev/rules.d/11-usb-hotplug.rules
ATTRS(idVendor)=="1edb", ATTRS(idProduct)=="be??",  RUN+="/etc/udev/atem.sh"

/etc/udev/atem.sh
echo "1edb be55" | tee /sys/bus/usb/drivers/uvcvideo/new_id
echo "1edb be49" | tee /sys/bus/usb/drivers/uvcvideo/new_id

atem mini: be49

matiaspl

20 0.000
50 0.001
100 0.004
400 0.068
1000 0.409
2000 1.445
3000 2.761
4000 4.115
5000 5.400
6000 6.583

matiaspl

#!/bin/sh
#
# This script uses a pretty monospaced/terminal font called iosevka by be5invis (https://github.com/be5invis/Iosevka/)
# Get the TTF file from here: https://git.mmk2410.org/deb/fonts-iosevka/src/branch/main/ttf-unhinted/iosevka-extended.ttf
#

ffplay -loglevel info -sync ext -x 960 -y 540 -vf "drawtext=text='\     SEI\: %{metadata\:timecode\:NOT PRESENT} 
     PTS\:%{pts\:hms} / %{pict_type}
PTS(UTC)\: %{pts\:gmtime}
    INFO\: %{eif\:w\:d}x%{eif\:h\:d} %{e\:1/duration} Hz

matiaspl

Architecture:

The TX side act as an access point for both the hardware reciever and the software clients. The video goes over regular 5G AC wifi link.

A simple IP scan shows the following:

192.168.218.10        6e-02-ab-96-f8-b2     dynamic  1 ms (unknown)
192.168.218.100       6c-4d-51-01-fe-74     dynamic  1 ms (Shenzhen Ceres Technology Co., Ltd.)
192.168.218.200       6c-4d-51-02-16-a1     dynamic  2 ms (Shenzhen Ceres Technology Co., Ltd.)

192.168.218.202 6c-4d-51-02-16-a1 dynamic 2 ms (Shenzhen Ceres Technology Co., Ltd.)

matiaspl

What is it for

FFMPEG based delay loop running in RAM for Blackmagic Decklink video cards. It's useful if you need a "profanity protection" buffer, but could also be used as a poormans instant replay.

How does it work

The idea behind this is to use exploit ffmpeg's concat filter as an intermediate buffer. The length of the delay line is set by the -t parameter before anullsrc in the example below ((or d after smptehdbars).

In my case I wanted PAL interlaced input and output. If you want to use different framerate change the format using the aproppriate -format_code parameter.

matiaspl

"Can't link" USB capture device - cheap Elgato Camlink alternative built on MS 2109 Macrosilicon chip

EDIT: a more scientific approach to good color reproduction can be found here: http://ciko.io/posts/cheap_usb_hdmi/ and here: https://ciko.io/posts/cheap_usb_hdmi_2/

The "coffee" capture card isn't actually USB 3.0. It only has a blue-colored USB 2.0 connector. So definitely not as advertised. The difference between the black and coffee version is PCB version (1.5 vs 1.6 on coffee one) and - possibly - firmware that exposes modes above 30 fps for 1920x1080 through UVC.

Hovewer judging by the video motion I can say that the 50/60 fps modes in higher resolutions don't work as expected and the stream analysis shows that every 2nd frame is missing.

So in 1080p it always runs 30 fps (while in MJPG mode) or less. Other than that, it's well worth it's money. Good to carry around in your backpack.

matiaspl

If you happen to have created a channels.conf after a lengthy scanning process using w_scan:

w_scan -f c -c PL -X -S 1 -v

(in this case a Polish DVB-C scan with SR 6875)

then you can use the following line to create your own scan table (you have to run it as root to write to /usr/share):

cut -d: -f2,3,4,5,6 channels.conf | sort -u | awk -F["/:"] '{ printf "[CHANNEL]\n\tDELIVERY_SYSTEM = DVBC/ANNEX_A\n\tFREQUENCY = %s\n\tSYMBOL_RATE =  %s\n\tINNER_FEC = %s\n\tMODULATION = %s\n\tINVERSION = %s\n\n", $1, $3, $4, $5, $2 }' > /usr/share/dvb/dvb-c/pl-Toya