Mosaic/grid view of RTSP streams with ffmpeg

Finally found a solution for grid/mosaic playback of RTSP streams.

ffmpeg -rtsp_transport tcp \
-i rtsp://smartiptv:PASSWORD@ \
-i rtsp://smartiptv:PASSWORD@ \
-i rtsp://smartiptv:PASSWORD@ \
-i rtsp://smartiptv:PASSWORD@ \
-filter_complex "
nullsrc=size=1920×1080 [base];
[0:v] setpts=PTS-STARTPTS, scale=960×540 [upperleft];
[1:v] setpts=PTS-STARTPTS, scale=960×540 [upperright];
[2:v] setpts=PTS-STARTPTS, scale=960×540 [lowerleft];
[3:v] setpts=PTS-STARTPTS, scale=960×540 [lowerright];
[base][upperleft] overlay=shortest=1 [tmp1];
[tmp1][upperright] overlay=shortest=1:x=960 [tmp2];
[tmp2][lowerleft] overlay=shortest=1:y=540 [tmp3];
[tmp3][lowerright] overlay=shortest=1:x=960:y=540
" \
-c:v libx264 -preset superfast -crf 18 -f matroska – | ffplay –


Remotely connecting to existing X server via VNC server

My goal was to connect to a remote desktop. Had to tweak systemd to autologin with specific user.

sudo vim /etc/systemd/system/getty@tty1.service.d/autologin.conf
ExecStart=-/usr/bin/agetty --autologin mike --noclear %I $TERM

I’m a zsh user so had to add the following into ~/.zprofile

if [[ -z $DISPLAY ]] && [[ $(tty) = /dev/tty1 ]]; then
    exec startx

So after these changes after rebooting the PC the X server started and I could connect to it.

Just had to start

x0vncserver -display :0 -rfbauth .vnc/passwd

Sat Mar 28 16:18:32 2020
 Geometry:    Desktop geometry is set to 3840x1200+0+0
 XDesktop:    Using evdev codemap
 XDesktop:    XTest extension present - version 2.2
 XDesktop:    RANDR extension not present
 XDesktop:    Will not be able to handle session resize
 Main:        Listening on port 5900

The desktop has no public IP so I had to port forward

ssh vnc-server -L 9900:localhost:5900

Now I was able to connect with vncviewer

vncviewer localhost:9900
TigerVNC Viewer 64-bit v1.10.1
Built on: 2019-12-27 09:17
Copyright (C) 1999-2019 TigerVNC Team and many others (see README.rst)
See for information on TigerVNC.

Sat Mar 28 16:20:09 2020
 DecodeManager: Detected 8 CPU core(s)
 DecodeManager: Creating 4 decoder thread(s)
 CConn:       Connected to host localhost port 9900
 CConnection: Server supports RFB protocol version 3.8
 CConnection: Using RFB protocol version 3.8
 CConnection: Choosing security type VeNCrypt(19)
 CVeNCrypt:   Choosing security type TLSVnc (258)

Switch from netctl to NetworkManager on Arch Linux

On my notebook I finally decided to try NetworkManager with its applet

After installing. I had to check status of some networking services and disable them.

systemctl status dhcpcd.service
sudo systemctl stop netctl.service
sudo systemctl stop netctl-ifplugd@eth0.service
sudo systemctl status netctl-ifplugd@eth0.service
sudo systemctl stop netctl-auto@wlan0.service

And then wait for the magic after starting NetworkManager
sudo systemctl start NetworkManager.service

network manager applet

I should have searched for a how to video on YouTube and could save some debugging time with journalctl -f 🙂 After setup I found

Google Play Music desktop player MPRIS media keys for Linux

I finally nailed it 😀
dbus-send --print-reply /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.PlayPause

dbus-send --print-reply /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.Next

Also added to my Awesome window manager config

Monitor progress of cp, mv, gzip, mysql and CLI commands

To monitor progress of an ongoing copy or mysql dump import you might try progress CLI tool. Track progress of commands like cp, mv, dd, tar, cat, rsync, grep, fgrep, egrep, cut, sort, md5sum, sha1sum, sha224sum, sha256sum, sha384sum, sha512sum, adb, gzip, gunzip, bzip2, bunzip2, xz, unxz, lzma, unlzma, 7z, 7za, zcat, bzcat, lzcat, split, gpg, etc.

Dual monitor Awesome WM with xrandr

I struggled a couple of days until I figured it out that setting up dual monitor via xrandr is needed after X started and before aweome started, so in between.

The solution was adding xrandr exec line into my .xinitrc

# ~/.xinitrc
xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto

function VGAConnected {
   ! xrandr | grep "^VGA-1" | grep disconnected
if VGAConnected; then
    xrandr --output eDP-1-1 --mode 1920x1080 --primary \
           --output VGA-1-1 --mode 1920x1080 --rotate normal --right-of eDP-1-1

exec awesome -c .config/awesome/rc.lua

to get the screen names (eDP-1-1, VGA-1-1, etc.) just run xrandr without args.

Tinkering with GNU parallel and wget for broken link checking

Finally found a parallel spidering solution. Online solutions didn’t really fit, because I don’t want to overload the production site and they can’t reach http://localhost. Trying out parallel + wget snippet from looks promising.


 # Stay inside the start dir
 BASEURL=$(echo $URL | perl -pe 's:#.*::; s:(//.*/)[^/]*:$1:')
 URLLIST=$(mktemp urllist.XXXX)
 URLLIST2=$(mktemp urllist.XXXX)
 SEEN=$(mktemp seen.XXXX)

# Spider to get the URLs
 echo $URL >$URLLIST

while [ -s $URLLIST ] ; do
 cat $URLLIST |
 parallel lynx -listonly -image_links -dump {} \; \
 wget -qm -l1 -Q1 {} \; echo Spidered: {} \>\&2 |
 perl -ne 's/#.*//; s/\s+\d+.\s(\S+)$/$1/ and
 do { $seen{$1}++ or print }' |
 grep -F $BASEURL |
 grep -v -x -F -f $SEEN | tee -a $SEEN > $URLLIST2


Great exercise for the CPUs
htop gnu parallel

When the command finishes then the next step is parsing access_log

grep -r ' 404 ' /var/log/httpd/access_log | cut -d ' ' -f 7 | sed -r 's/^\//http\:\/\/localhost\//g'