Capturing App/Screen video with Syphon and NDI

How to get video from applications, like a web browser, into Syphon.

This example shows how to get a Youtube video from Firefox into Max/MSP Vizzie.

  • Use NDI Scan Converter (From NDI Tools https://ndi.video/tools/ ) and select Firefox from the Capture menu
  • Use NDISyphon to convert the NDI stream to Syphon. Use virtual audio routing (eg., black hole) for system audio, or route audio directly into Max.

  • In Max, use the Syphon client from the package manager to receive video. Here is an example using Vizzie abstractions described in previous posts:

notes:

NDI scan converter allows screen capture from apps and broadcasts in NDI format over the LAN. Then NDISyphon app converts NDI stream into Syphon. For youtube, use theatre mode to fill the window – full screen doesn’t really work. see this link: https://support.telestream.net/s/article/Wirecast-Remote-Computer-Screen-Capture-with-NDI-macOS

Recording Ableton Videosync output

Video recording options for Videosync in Ableton Live

Syphon Recorder.

https://syphon.github.io/recorder

  1. In Videosync preferences, set master Syphon out.
  2. In syphonrecorder set Videosync master as input.
  3. In syphonrecorder set virtual audio as input (eg., blackhole 2ch)
  4. In Ableton, set blackhole 2ch as audio output (or make a multioutput device in audoMidiSetup, combining headphones and blackhole.)

Vizzie Recorder.

(see this post about Vizzie Syphon abstractions https://reactivemusic.net/wp-admin/post.php?post=20896&action=edit)

  1. setup a Syphon client in Max
  2. Use abstractions to bring video into Vizzie. and use Vizzie recorder object.
  3. Route audio as described above.

Screenflick (or other screen recording software)

  1. Set screenflick to overlay videosync output window in Ableton Live
  2. Route audio as described above.

Amateur radio contesting time-lapse map

Mapping geocoded  contest log data using node.js and openlayers.

The goal was to make something that looks like the Reverse Beacon Network map, only for contest log files. I use RBN for testing antennas now. That map display gives you a pretty good idea of your actual antenna pattern.

Code is written in node.js (javascript) and html.

Part 1: Read a Cabrillo log file containing QSO: records. Look up each callsign, get latitude and longitude, and rewrite the file as json data, tagged with geo coordinates. I originally tried getting the data from hamQTH but it was not current, so ended up using the qrz.com xml callsign lookup. For callsigns “not found” I used the qrz.com dxcc prefix lookup to get general coordinates for the country. There are still a few bad/missing data issues to resolve. Like European stations with coordinates at the South Pole.

Part 2: Tried various mapping frameworks – like leaflet, arcgis, and openlayers. Wanted to use a great-circle projection (azimuthal equidistant) like the big ARRL world map. And may still figure this out. But working with map projections and coordinate transforms is way worse than doing a Smith Chart.  I ended up hacking a flight tracking example from openlayers.org and basically replacing airplanes with QSO’s. That is why the lines are animated from source to destination.  Also added a layer for day/night, and QSO/time status display.

It probably makes sense to get rid of the flight animation and just display the entire path in sync with the QSO data – with color code for each band (K1KP) – and speed control on the time lapse, etc., So you can get a better sense of rate and propagation.

It would be cool to have a website where you could upload a log file and generate maps.

Note: this project is not yet available

Files

local files:

generating data:

internetsensors/cabrillomap

put the cabrillo data in testdata.cbr (use QSO: records only for now) should be sorted chronologically.

run:  node index.js

the output file will be: geocab.json (which is used as input to the mapping program)

mapping

internetsensors/oltest

main.js = node source with ol mapping and data processing

index.html = web page for map

geocab.json = geocoded cabrillo json test data

to run, type: npm start

Then open: http://localhost:5173/ in a browser

Additional work / current issues

Some of the qrz.com callsign data has bad geo coordinates. In particular some of the records show a latitude of -89 and longitute -179 – need to check for these numbers and replace with dxcc coordinates.

There should be an argument on the node program to pass in the datafile. Also the program should clean up any non QSO: records, like the file header info and any X-QSO recs.

Also need to clean up the async/await stuff – currently there are several methods for handling state transitions.

mapping ideas:

As mentioned above, its probably a good idea to make a version of the code without the flight animation, and have various controls to stop/start the data playback to look at individual qso’s do speed control, etc.,

azimuthal equidistant projection: there are some links to examples in leaflet, and arcgis to handle complex projections. In documents, look at:  “map links for projection stuff.txt”

leaflet test version:

in the internetsensors/cabrillomap folder there’s a test file: cbworld1.html that works using websockets when you run the index.js file to generate test data. It uses a leaflet map, but the lines don’t adapt to great circle polar paths.

arcgis

I believe the arcgis examples are in internetsensors/projected geometries

And: internetsensors/pe-gs-projection

The former is a a very nice world projection with some point markers. The latter is an example that shows how to switch out various projections in realtime.

11 Km feedback delay

Using 40 meter SSB, Max/MSP, and Websdr to build a feedback delay from Maine to the Netherlands.

A Max patch plays an audio file into the transmitter in Maine. Then, using a websdr receiver in the Netherlands, the received signal is amplified and mixed back into the audio to be retransmitted. Effectively creating a feedback delay line.

Here is an example of what it sounds like on 40 meters.

http://www.pr0jex.com/longdelayline.mp3

This is the Max patch

The audio from Websdr is routed to the input of Max by creating a multi-output device (In Audio Midi Setup) combining “Blackhole 2ch” and external headphone output (for monitoring). The audio output of Max is assigned to the transmitter SSB input.

Patch not yet available. Local version is in max teaching examples.

Max/MSP Vizzie abstractions for Syphon

Vizzie objects can connect directly to Syphon clients and servers.

(work in progress – not available yet)

Syphon video as input to Vizzie

vizziesyphonclient.maxpat that gets syphon into vizzie. look at vizzieexamplewithsyphon.maxpat to see how it works.

Syphon as output from Vizzie

Use vizziesyphonserver.maxpat. Example: vizzieexamplewithsyphonserver.maxpat

(local files in maxteachingexamples)

X API update

Attempts to use the X API (formerly Twitter) for projects with Max/MSP have been disappointing at best. Most of the API is behind a paywall now.  The cost is $5000 per month. to implement streaming API used in projects like this:  https://reactivemusic.net/?p=5786

The free tier only allows basic tweeting and user lookup. Search is not available.

I was able to find only one node example that actually worked in the free tier. By “Coding with Ado”. The code requests a token from X, and then you enter a timestamped pin number to continue. Making it worthless for programs and bots. https://youtu.be/G5ZW5j5cwHk?si=vbAtGa0bQ3T_tga9

A local copy of the source code for this is in tkzic/nodetweet3/index.js

Other options

Another option with X, is to use a service like Socialdata. https://socialdata.tools/

There service sits in the middle to handle X API calls. You are charged by the number of calls. It doesn’t offer streaming either, but you can simulate it by calling a search every few seconds.

Other social media options

There are API’s for other social sites like facebook, instagram, tiktok, etc.,

MBTA Boston train map

This post describes an update of a previous version. The old version can be found here: https://reactivemusic.net/?p=20329

Moving markers

In the previous version, all of the markers for each train line were deleted and redrawn in a group at the polling interval. In this version the train markers move to their new location when the data is polled.

The map is drawn using Leaflet. The moving marker library is from Ivan Sanchez https://www.npmjs.com/package/leaflet.marker.slideto

The project uses the MBTA JSON API, to query vehicle data for each train line. the geo coordinates of the trains are sent via websockets to the client map page.

This project is a work in progress and not available yet.

Files:

node server: internetsensors/mbtanode2/index.html

html map client: internetsensors/mbtanode2/mbtatrain2.html

Instructions

// to run, type node index.js at a command line.
// then open a web browser to: http://127.0.0.1:8124/
// type 'go' into the text box below the map, and press 'send' button
// in a few seconds the train markers will magically appear

MBTA API in Max

Sonification of Mass Ave buses, from Nubian to Harvard.

Updated for Max8 and Catalina

This patch requests data from MBTA API to get the current location of buses – using the Max js object. Latitude and Longitude data is mapped to oscillator pitch. Data is polled every 10 seconds, but it seems like the results might be more interesting to poll at a slower rate, because the updates don’t seem that frequent. And buses tend to stop a lot.

Original project link from 2014: https://reactivemusic.net/?p=17524

MBTA developer website: https://www.mbta.com/developers

This project uses version 3 of the API. There are quality issues with the realtime data. For example, there are bus stops not associated with the route. The direction_id and stop_sequence data from the buses is often wrong. Also, buses that are not in service are not removed from the vehicle list or indicated as such.

The patch uses a [multislider] object to graph the position of the buses along the route – but due to the data problems described above, the positions don’t always reflect the current latitude/longitude coordinates or the bus stop name.

download

https://github.com/tkzic/internet-sensors

folder: mbta

patches:

  • mbta.maxpat
  • mbta.js
  • poly-oscillator.maxpat
authentication

You will need  to replace the API key in the message object at the top of the patch with your own key. Or you can probably just remove it. The key distributed with the patch is fake. You can request your own developer API key from MBTA. It’s free.

instructions
  • Open mbta.maxpat
  • Open the Max console window so you can see what’s happening with the data
  • click on the yellow [getstops] message to get the current bus stop data
  • Toggle the metro (at the top of the patch) to start polling
  • Turn on the audio (click speaker icon) and turn up the gain

Note: there will be more buses running during rush hours in Boston.  Try experimenting with the polling rate and ramp length in the poly-oscillator patch. Also, you can experiment with the pitch range.