Using multicat to send an MPEG-TS video file to a UDP multicast address

Multicat is fairly simple to use. Just give it an input and output and it figures the rest out on it's own. 

multicat -uU ./CheyenneVAhospital.ts 226.6.6.1:8209

The -uU flags to ignore the missing RTP headers.

But wait! You need a .aux file apparently

error: couldn't open file ./CheyenneVAhospital.aux (No such file or directory)

Piece of cake. The docs say you just have to ingest the file with the ingests command. Let's copy and paste that into our shell

ingests -p 68 ./CheyenneVAhospital.ts

Oh great. That didn't work.

debug: end of file reached

error: no PCR found

Alright our PCR PID must be wrong. Luckily we can use ffprobe to get the PCR PID out of a .ts file.

ffprobe CheyenneVAhospital.ts -show_programs | grep pcr_pid

...

pcr_pid=256

Oh lovely! Why can't ingests do that? I dunno man stop asking questions.

Let's try ingests with the correct PCR PID

ingests -p 256 ./CheyenneVAhospital.ts

Hey, cool. No errors this time. And our .aux file is more than 0 bytes!

Now we can finally do the thing.

multicat -uU ./CheyenneVAhospital.ts 226.6.6.1:8209

Oh by the way, if you want to change your MPEG-TS file to have a consistent video bitrate, you can use ffmpeg for that. Here's an example of converting the video stream to 1Mb/s

ffmpeg -i ./CheyenneVAhospital.ts -c:v libx264 -b:v 1M -map 0 CheyenneVAhospital_1M.ts

And multicat doesn't support looping, so you'll just have to put the multicat command inside a loop body and deal with the spikes

for (( ; ; ))

do

multicat -uU ./CheyenneVAhospital_1M.ts 226.6.6.1:8209

done

VBoxManage: error: The virtual machine 'minikube' has terminated unexpectedly

Full error: 

Exiting due to PR_VBOX_BLOCKED: Failed to start host: creating host: create: creating: Unable to start the VM: /usr/bin/VBoxManage startvm minikube --type headless failed:

VBoxManage: error: The virtual machine 'minikube' has terminated unexpectedly during startup with exit code 1 (0x1)

VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component MachineWrap, interface IMachine

Solution:

# Purge VirtualBox.

sudo killall VirtualBox

sudo apt-get remove --purge virtualbox

rm -rf ~/.config/VirtualBox/

# Wipe minikube cache

rm -rf ~/.minikube/

# Reinstall VirtualBox

sudo apt-get install virtualbox

# Rebuild minikube VM

minikube start --driver=virtualbox

Solution in one line:

sudo killall VirtualBox; rm -rf ~/.config/VirtualBox/; rm -rf ~/.minikube/; sudo apt-get remove -y --purge virtualbox && sudo apt-get install  -y virtualbox && minikube start --driver=virtualbox

Convert PostGIS ST_LineString to ST_MultiPoint

Sometimes you need to convert a PostGIS line into a multipoint geometry. I mean, how else did you find this?

SELECT ST_Union(

    ARRAY(

        SELECT (ST_DumpPoints(linestringcolumn)).geom

        FROM atable

    )

);

Just kidding, use ST_Points(). Why ST_MultiPoint() does not do this is a mystery to my tiny brain. I would ask Dan Baston, but his answer would probably fracture my mental model of reality, and I don't have time to reconstruct it right now.

SELECT ST_Points(linestringcolumn) FROM atable;