MoonPoint Support Weblog

Concatenating videos with FFmpeg

Thu, 12 Mar 2026 19:48:00 -0400

The FFmpeg video handling utility can be used to join videos together into one larger video. If the video files are MPEG-1, MPEG-2, MPEG Program Stream (PS) , or Digital Video (DV) files, you can use a Direct Stream copy method, by issuing a command in the form

ffmpeg -i "concat:input1.mpg|input2.mpg" -c copy 
output.mpg

. Using ffmpeg for the concatenation operation ensures that file headers and timestamps are handled correctly, whereas using operating system commands such as cat on a Linux system or copy /b on a Microsoft Windows system may produce payback issues. This method can not be used for MPEG-4 files, however.

Another method that can be used for MP4 files, as well as the above file types is the Concat Demuxer method, if the files use the same codecs and parameters, such as resolution, framerate, etc. If the files have the same characteristics, you can use a command of the form:

ffmpeg -f concat -safe 0 -i inputFileList.txt -c copy output.mp4

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Trimming a video with FFmpeg

Wed, 11 Mar 2026 17:17:00 -0400

FFmpeg provides a suite of command-line interface tools for working with audio and video files. It is free and open-source software that is available for a variety of operating systems, including Microsoft Windows, Linux, and macOS. If you wish to use it on a Microsoft Windows system, you can install it with the Windows Package Manager known as winget by opening a command prompt window and issuing the command winget install "FFmpeg (Essentials Build)".

Microsoft Windows [Version 10.0.26100.7623]
(c) Microsoft Corporation. All rights reserved.

C:\Windows\System32>winget install "FFmpeg (Essentials Build)"
Found FFmpeg (Essentials Build) [Gyan.FFmpeg.Essentials] Version 8.0.1
This application is licensed to you by its owner.
Microsoft is not responsible for, nor does it grant any licenses to, third-party packages.
Downloading https://github.com/GyanD/codexffmpeg/releases/download/8.0.1/ffmpeg-8.0.1-essentials_build.zip
  ██████████████████████████████   101 MB /  101 MB
Successfully verified installer hash
Extracting archive...
Successfully extracted archive
Starting package install...
Command line alias added: "ffmpeg"
Command line alias added: "ffplay"
Command line alias added: "ffprobe"
Path environment variable modified; restart your shell to use the new value.
Successfully installed

C:\Windows\System32>

If you need to trim the beginning of a video file, such as a .mp4 file, you can do so using a command of the form ffmpeg -ss hh:mm:ss -i input.mp4 -c copy output.mp4 where you specify the point you wish the video to start in the form hh:mm:ss for hours, minutes, and seconds with -ss and input.mp4 is the file you wish to trim and output.mp4 is the name you wish to give to the trimmed file. E.g., if I have a video file, REC-0001-A.mp4, where I wish to discard audio and video up to the 3 minutes and 34 seconds mark in the file, I can use ffmpeg -ss 00:03:34 -i REC-0001-A.mp4 -c copy output1.mp4 to create a new file, output1.mp4, that omits the first 3 minutes and 33 seconds from the input file. Using the -c copy option copies the video/audio streams directly, which is fast but can be less accurate on keyframes.

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Disabling Skye automatic startup

Thu, 05 Mar 2026 15:30:00 -0500

I found Microsoft's Skype for Business application was automatically staring on a Microsoft Windows system where it was not being used. Microsoft retired the product on May 5, 2025, replacing it with Microsoft Teams, and is no longer providing security updates or bug fixes for the software. Though Microsoft ended official support for Skype for Business Server on October 14, 2025 and is no longer providing cloud service for the product, companies that installed their own servers can still run it locally. If there is a need to retain the software on a system, but no need to have it start automatically when the system boots, one can stop it from starting whenever the system is rebooted by taking the following steps:

Open the program and then click on the gear icon near the top, right side of the window.
Choose Tools and Options.
Uncheck the option for "Automatically start the app when I log on to Windows" under the Personal options to prevent the program from restarting automatically upon a login to the system, then click on OK to apply the change after unchecking that option.

Adding the capability to save webpages as a single file to Firefox

Tue, 03 Mar 2026 15:33:00 -0500

The Firefox web browser does not have the capability to save the contents of a webpage to a single file, such as an MHTML file, which is a web archive file format that allows one to save the HTML code, images etc. on a webpage into a single file. Though the capability is absent from Firefox, you can add the functionality of saving a page to a single file by installing Save Page WE, an add-on for Firefox by DW-dev. The extension provides the capability to "Save a complete web page (as currently displayed) as a single HTML file that can be opened in any browser. Save a single page, multiple selected pages or a list of page URLs. Automate saving from command line." The saved file is not an MHTML file, or one of the other common web archiving file formats, but it is a single HTML file that Firefox and other browsers can read. Save Page WE is implemented using the WebExtensions API and is available for both Firefox and Chrome with identical functions and user interfaces.

When you start the installation process, you will see a list of the permissions required by the extension:

Access your data for all websites
Download files and read and modify the browser's download history
Display notifications to you
Access browser tabs
Access browser activity during navigation

Click on the Add button to add the extension. You should then see the message "Save Page WE was added. Update permissions and data preferences any time in the extension settings." You also have the option to pin the extension to the toolbar.

Select the option to pin the extension to the toolbar, which will result in an icon of a 3.5" floppy disk appearing on the toolbar. You can click on that icon to save the page displayed in the current browser tab.

You can also save a page by hitting the Alt+A key combination (you can cancel the saving of a page with At+C). The file format is HTML rather than MHTML, so the file extension used by SavePageWE is .html, which Firefox can open — if you try to open a file with the .mhtml extension, Firefox will prompt you to use another application to open the file.

Anyone who wishes to have the ability to save a webpage as a single file added to Firefox, can add their voice to the post at Add native Web Archive File support to Firefox, including MHTML, MAFF, and Webarchive...

References

How to save a webpage as .mhtml with Firefox?
Last updated: September 15, 2024
superuser
Add native Web Archive File support to Firefox, including MHTML, MAFF, and Webarchive...
Date: August 15, 2023
By: JohnBoyTheGreat
moz://a Connect

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Turning off Fast Startup on a system running Microsoft Windows

Mon, 02 Mar 2026 23:11:00 -0500

Microsoft Windows 8 introduced a feature called Fast Startup. The feature was a variation of hibernate mode, but when enabled would close all running programs and log the user out before hibernating. This feature would result in a user being able to log in more quickly when a system is powered back on after a shutdown. There may be cases where use of this feature is not desirable, however. E.g., if the user wants to boot the system into Linux, but still access data on the Windows boot drive. To turn fast startup off, you can take the following steps:

Type Control Panel in the Windows Search field at the bottom of the screen.
Click on System and Security.
Click on Change what the power buttons do under Power Options.
Click on Change settings that are currently unavailable. If prompted for administrator credentials, provide those for an administrator account.
Uncheck the check box next to "Turn on fast startup (recommended)".
Click on Save changes. You can then close the window.

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Controlling whether a scrollbar appears in a tab in a Terminal window

Sun, 01 Mar 2026 22:55:00 -0500

I needed to scroll back through a tab I had open in a Terminal window on an Ubuntu Linux system, but there was no scrollbar on the right side of the tab in which I had run the command, though a scrollbar was open in other Terminal tabs. I was able to get the scrollbar to appear by clicking on the icon with 3 horizontal bars at the top of the Terminal window and then selecting Preferences.

Then from the Behavior tab, I changed the setting from Follow System to Always, which resulted in the scrollbar appearing where it had been missing, but I could not scroll back any further than the text that had been appearing in the tab before I changed the settiing and that remained the same whenever I issued another command and text moved upwards, so that I could no longer see it or scroll back to see it, so I closed the tab.

When I opened another tab, the scrollbar was there and operated as expected.

Creating a desktop shortcut under Ubuntu for a Windows app runnning under Wine

Sat, 28 Feb 2026 20:29:00 -0500

From a CD, I installed Microsoft Office 2007 under Wine, so that my wife could edit her Microsoft Publisher files on an Ubuntu Linux system. I also installed Microsoft Excel and Microsoft Word. All three seemed to be working OK when I checked them after the installation completed. I was able to open the programs from the File Explorer by issuing the command wine explorer from a shell prompt in a Terminal window and then navigating to the directory, C:\Program Files (x86)\Microsoft Office\Office12, where the applications were located. I could also start Publisher by issuing the command below in a Terminal window:

wine "/home/alice@Wonderland/.wine/drive_c/Program Files (x86)/Microsoft Office/Office12/MSPUB.EXE"

To make it easer for my wife to open Publisher, though, I created a shortcut on her Ubuntu desktop. To create a shortcut you can take the following steps:

Open a Terminal window and create a new .desktop file on your desktop. You can use the nano editor or another text editor to create the file. E.g., nano ~/Desktop/AppName.desktop.

You then need to have lines like the following ones in the file:

[Desktop Entry]
Name=Name of Your Application
Exec=wine "/home/username/.wine/drive_c/Program Files/AppName/app.exe"
Type=Application
Icon=wine
Terminal=false
StartupNotify=true

You need to use the absolute path the the .exe file for the program and, if the directory path contains a space, you must enclose the path within quotes. Also, you need to replace username with your username on the system. For Publisher, I could use the following lines:

[Desktop Entry]
Name=Publisher
Exec=wine "/home/alice@Wonderland/.wine/drive_c/Program Files (x86)/Microsoft Office/Office12/MSPUB.EXE"
Type=Application
Icon=wine
Terminal=false
StartupNotify=true

If you use the nano text editor, you can hit Ctrl+X, the Y, then Enter to save the file. You then need to make the shortcut executable, which you can do by right-clicking on the file on the desktop, selecting Properties, and then makng sure "Executable as Program" is on. Or you can use the chmod command to make the file excutable by a command like chmod +x ~/Desktop/AppName.desktop. You then need to permit launching of the application from the shortcut by right-clicking on it and selecting Allow Launching.

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Wine window becoming transparent with an attempt to resize it

Fri, 27 Feb 2026 15:41:00 -0500

My wife was using Advanced Diary for journaling on a Microsoft Windows system, but wanted to transition to Linux, so I installed Ubuntu Linux and then, since there is no Linux version of Advanced Diary, I installed Advanced Diary under Wine. She wanted to adjust the size of the Advanced Diary window, but when she attempted to adjust the window size by clicking on the Restore Down icon at the top right side of the window (between the dash and the "X"), the Advanced Diary window became transparent and it was not possible to close it or adjust the size of the transparent box that appeared for the Advanced Diary window. So I had to open a Terminal window to determine the process ID (PID) of the Advanced Diary process with the ps and then kill that process with the kill command. I could also have used the killall command killall AdvancedDiary.exe. I tried closing and opening the program several times. The behavior was consistent — the window would become transparent whenever I tried resizing or minimizing the window. If you are using the GNOME desktop, you can use the steps below to try to resolve the problem. GNOME is the default desktop environment for Ubuntu, but you can verify it is the desktop in use by the command echo $XDG_CURRENT_DESKTOP.

Steps that may resolve the problem:

Run winecfg in a Terminal window.
In the Wine configuration window, click on the Graphics tab.
Toggle the settings for "Allow the window manager to decorate the windows" and "Allow the window manager to control the windows" one by one to see if one of those settings change the behavior. When I toggled off "Allow the window manager to decorate the windows", I now no longer saw the icons to adjust the size of the window or minimize the window at the top of the Wine window for Advanced Diary, but when I clicked where I expected them to appear, the window became transparent again. I toggled the setting back on and then toggled off the "Allow the window manager to control the windows" setting. That resolved the problem. I then closed the window and reopened Advanced Diary and toggled that setting on again, also, so that both settings were checked. I could still adjust the window size as expected. I closed and reopened the application several times and was still able to adjust the window size, so just toggling the "Allow the window manager to control the windows" setting off and then back on seemed to resolve the problem.

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Restarting the Windows audio service

Thu, 26 Feb 2026 22:31:00 -0500

If you are experiencing problems with sound on a Microsoft Windows system, such as being unable to hear audio even when the sound hasn't been muted and any external speakers are turned on and set to an audible volume level, one possible way to resolve the problem is to restart the Windows Audio service. To do so, you can can take the following steps:

Type services in the Windows Search field. You should see it returned by the search utility. Click on "Run as administrator" and provide the login credentials for an account that has adminisrator privileges.
When the Services window opens, scroll down until you see Windows Audio.
Right-click on the entry and choose "Restart".
When the status for the service returns to "Running", you can close the Services window.

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Configuring Sendmail to listen on the mail submission port

Wed, 25 Feb 2026 23:57:00 -0500

Sendmail is an email server application that is available for many operating systems. It will listen on TCP port 25 for connections from other mail servers that use the Simple Mail Transfer Protocol for email transmissions. As a message submission agent (MSA), another common port it listens on is TCP port 587 for email transmissions from users' email clients. On a Linux system you can use the netstat or ss commands to determine if a system is listening for connections on a particular port. When I checked a Sendmail server to determine whether it was listening on port 587, I could see that it was not listening on that port, though that was needed.

# netstat -an | grep 587
# ss -ln | grep ":587 "
#

When I searched /etc/mail/sendmail.mc for RELAY_MAILER_ARGS, I saw the following lines, which are needed to have Sendmail listen for email transmissions from users on TCP port 587, were already present and were not commented out:

define(`RELAY_MAILER_ARGS', `TCP $h 587')
define(`ESMTP_MAILER_ARGS', `TCP $h 587')

When I searched for DAEMON_OPTIONS, I saw the following:

dnl # The following causes sendmail to additionally listen to port 587 for
dnl # mail from MUAs that authenticate. Roaming users who can't reach their
dnl # preferred sendmail daemon due to port 25 being blocked or redirected find
dnl # this useful.
dnl #
dnl DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl

I removed the dnl from the begining of the line so that I then had the line below, instead:

DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl

I then rebuilt /etc/sendmail/mc and restarted the Sendmail service.

# m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
# service sendmail restart
Redirecting to /bin/systemctl restart  sendmail.service
#

I could then see that the system was listening for connections on port 587.

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