I downloaded a YouTube video on a Ubuntu Linux with yt-dlp. When I tried to view the downloaded WebM file with the default video application, Videos, also known as Totem, which is an application for playing videos that is provided with Ubuntu, I saw the message below:

When I opened the video with VLC, which I had previously installed, I heard audio, but no video was displayed. I checked to see if the Nvidia driver was up-to-date since the system had an Nvidia graphics card, but they were up-to-date. You can check that by clicking on the Show Apps button at the lower-right-hand corner of the screen Ubuntu desktop. Then type Software Updates in the "Type to search" field. Click on Software & Updates and then click on the Additional Drivers.

To resolve the problem, I added the following line to the /etc/environment file with a text editor:

GDK_GL=gles

When I rebooted the system, I was then able to view the video with the default Videos application, though when I tried playing it in VLC I could hear audio, but did not see video.

[/os/unix/linux/ubuntu] permanent link

When I tried to play a YouTube video I downloaded as a WebM file using yt-dlp on an Ubuntu Linux system in the VLC media player application, I could hear the audio, but no video was shown. I tried opening a few other .webm videos and found I was able to view the video in some, but not others, though I was able to view the video and hear the audio in all the .mp4 and .mkv files. I tried changing the video output setting from "Automatic" to "OpenGL video output" and then "XVideo output (XCB)", which you can do by clicking on Tools, then Preferences, then Video, and then selecting those options from the dropdown list next to Output, but neither of those options resolved the problem, so I reset Output to Automatic. I was able to resolve the problem by taking the following steps, though:

1. In the VLC program, click on Tools and then select Preferences.
2. Click on Input/Codecs and change the hardware-accelerated decoding setting by clicking on the downward arrowhead next to Automatic, which will be the setting if the default setting is in effect.
3. Change the setting to Disable and then click on Save.

When I checked the Codec information for the file where I could not view the video before disabling the hardware-accelerated decoding setting, which you can do by opening an audiovisual (AV) file in VLC and then selecting Tools and Codec Information, I saw the video codec was AOMedia's AV1 Video (av01). When I checked the video codec for another WebM file where the video wasn't visible in VLC, I saw it was also the AOMedia's AV1 Video (av01) codec. Checking the video codec for .webm files where I could view the video, I saw Google/ON2's VP9 Video (VP90) for some and H264 - MPEG-4 AVC (part 10) (avc1) for another.

Note: you can also determine the codecs used in a file using the mediainfo utility, which you can install on an Ubuntu system with sudo apt-get install mediainfo. You can check on whether it is already installed using the command which mediainfo, which would show the location of the mediainfo executable file if the application was installed, or you can use dpkg -s mediainfo, which will show details on the mediainfo package if it is installed.

[/software/audio_video/VLC] permanent link

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

[ More Info ]

[/video/ffmpeg] permanent link

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.

[ More Info ]

[/video/ffmpeg] permanent link

1. Open the program and then click on the gear icon near the top, right side of the window.

   

2. Choose Tools and Options.

   

3. 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.

   

[/os/windows/software] permanent link

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

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

[ More Info ]

[/network/web/browser/firefox/addons] permanent link

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:

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

[ More Info ]

[/os/windows] permanent link

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.

[/os/unix/linux/ubuntu] permanent link