Author Archive

Speech-to-text conversion

March 12, 2023 Leave a comment



$ whisper speech.mp3 --model small

It also knows other languages. It can even translate a foreign audio to English.

Categories: Uncategorized Tags: , ,

Play a file in muted mode with mplayer

March 7, 2023 Leave a comment


With mplayer, I wanted to play an audio file in muted mode, i.e. without any sound (with volume=0). How to do that?


mplayer -volume 0 -softvol audio.mp3

If you don’t add “-softvol“, it’ll change your system volume too and it will persist after mplayer closes. Adding “-softvol” will mute the playback, but it won’t modify the system volume.

Categories: linux Tags: , ,

New Notebook for Mom

February 11, 2023 Leave a comment

Yesterday I bought a new notebook for my Mom. Here are my notes about it:

  • It’s an HP 250 G8 Notebook (27J97EA), 15.6″ FullHD, Intel Core i3-1005G1, 8GB RAM, 256GB SSD, Hungarian keyboard, no operating system, 3 years guarantee.
  • Its price was friendly, 358 USD.
  • I put Windows 10 on it (Enterprise, 22H2). The pendrive was prepared with Rufus. Settings: GPT / UEFI.
  • When you switch on the machine, keep pressing F10 to enter the BIOS. Here you can configure the boot order.
  • Upon reboot, keep pressing F9 to get the boot order menu. First, my USB stick was not in the list. After reformatting it in Rufus with GPT / UEFI, it appeared in the list and I could start installing Windows 10.
  • The machine is very good. It’s fast and it’ll be perfect for my Mom’s needs (e-mails, YouTube, Zoom, Skype).
  • I only had one issue but I could solve it. After installing all the updates, I still couldn’t change the brightness of the screen. The problem was that the appropriate video driver was missing. Start the Device Manager (Windows key + X, then select it). Here, open the video card. There I had something general. Righ click on it and select “update driver”. It did the trick! The Intel video driver got installed and I could change the brightness immediately.
  • On the keyboard, there are also two keys for changing the brightness. After the previous trick they also started to work.

All in all, I’m very satisfied with this notebook.

Categories: Uncategorized, windows 10 Tags: ,

How to blur an area in Premiere Pro CS6

January 18, 2023 Leave a comment


You want to blur an area during video editing for a given period of time. For instance, you want to hide some sensitive information.


I found a simple solution here: . It just works.

Categories: windows Tags: ,

Install Python 3.11 on Ubuntu 20.04

December 19, 2022 Leave a comment


You have Ubuntu 20.04 with an ancient Python 3.8. How to upgrade your Python to a newer version?


I found a working solution here: . I tried Option 1, i.e. the PPA method. I installed Python 3.11 instead of 3.10 (as it was written in the blog post).

When it was installed, I switched to admin mode, removed the symlink /usr/bin/python3 , and created a new symlink with the same name pointing on /usr/bin/python3.11 . Now, when I issue the command “python3“, Python 3.11 starts.


After this, apt started to complain:

ModuleNotFoundError: No module named 'apt_pkg'

I applied a dirty trick to solve it:

$ cd /usr/lib/python3/dist-packages/
$ sudo su
$ ln -s

I also tried to reinstall some packages (as explained here), but that didn’t help.

Categories: linux Tags: ,

Bash Shortcuts

December 8, 2022 Leave a comment

See for a nice list of available Bash shorcuts.

If it disappears, here is my clone.

Categories: linux Tags: ,

colorize matching substrings and show non-matching lines too

December 1, 2022 Leave a comment


Here is a grep example:

cat file.txt | grep --color -i swap

Here, “swap” is the keyword we’re looking for. It will print only those lines that contain the substring “swap” (case ignored), and the substring “swap” will be colorized.

I wanted the same thing, but I also wanted to see all the other lines too. That is, I also needed the non-matching lines.


It turns out there’s a command for that called ack . Under Manjaro, there’s a package with the same name, thus you can install it easily. Usage:

cat file.txt | ack --passthru -i swap

All the lines will be shown and the substring “swap” will be colored.

Actually, grep can also do this, but the syntax is a bit more complicated:

cat file.txt | grep --color -i -E "swap|"

Categories: linux Tags: , ,

[virtualbox] guest system has no permissions to shared folder

November 6, 2022 Leave a comment


You want to share a folder between the host and the guest. You configure everything correctly:

Here, /opt/shared.folder.vbox is on the host system. Mount point is on the guest system. You don’t need to create this folder manually. If it’s mounted successfully, it’ll appear automatically.

The mounted folder appears but you cannot enter it, you have no permissions.


Add yourself to the vboxsf group within the guest VM.

Run “sudo adduser $USER vboxsf” from terminal. Then reboot the guest. It should work now.


Claim a free game on Steam

September 26, 2022 Leave a comment


I got the info that a game was free on Steam for a limited time. I visited the page some days later (but before the deadline) and it was not claimable. I couldn’t add it to my game list.


This trick may not always work, but you can try. I visited and searched for the given game. In the top right corner there’s an “Install” button. It launched Steam and started to install the game :) The game was claimed and appeared in my Steam list.

Categories: Uncategorized Tags: , , ,

correct a corrupted .mp4 file

September 2, 2022 Leave a comment


I had a presentation on Webex and it was recorded. The 3-hour long presentation was compressed to 250 MB. Our administrator said he couldn’t change the compression rate, this is the default of Webex. Fine. However, under Linux with VLC the playback of the video was problematic. The audio was on for 10 seconds, then for 10 seconds there was no audio, then it was on again, etc. With mplayer the audio was OK, but I prefer VLC. And with VLC I’ve never had any problem. So I thought there was something wrong with the mp4 file.

I wanted to cut the video, and for that I use Adobe Premiere Pro under Windows. However, Premiere Pro couldn’t import the file! It said that the audio and video streams were missing. WTF?


Under Linux, I converted the mp4 to mp4:

ffmpeg -i input.mp4 -codec copy out.mp4

The output was a little bit bigger than the input, and the good news was that VLC could play the output without any problem. The audio was also good. It seems ffmpeg could correct the file. In Premiere Pro, I could import the corrected file.

Categories: linux Tags: , ,