Kdenlive won’t start on Windows

Trying to run kdenlive.exe on Windows 8.1 was silently failing (no UI error messages, etc). Turns out my antivirus (Avast!) was flagging one of the kdenlive files as a false positive (kioslave.exe) and I needed to add an exception through Avast!’s Virus Chest interface.

This issue was in relation to Kdenlive 18.08.1.

Compare the checksum (hash) of a download file

Ever needed to compute the checksum (i.e. the hash) of a file you’ve downloaded from the internet? If not, you probably should—when you can—to ensure the file you’ve downloaded wasn’t tampered with (e.g. to insert malware) or corrupted while it was being downloaded.

As two examples, there are the large files (OS, etc) we download from the trustworthy MSDN library, which may face interruptions during download, and then there are those really handy utilities like WinDirStat that may originate from unsavoury locations on the internet.

Microsoft provides a handy tool for the purpose of computing the cryptographic hash value of one or more files called the File Checksum Integrity Verifier utility. It’s simple to use and can be found here: https://support.microsoft.com/en-au/help/841290/availability-and-description-of-the-file-checksum-integrity-verifier-u

Once extracted, usage is as simple:

fciv myfile.exe

But it can also compute MD5 and/or SHA-1 hashes for a directory of files and store results in a database. Full details can be found at the download link, above.

How to Save a Private Video from Facebook

Saving a video from your news feed or a group can be a little awkward because you’re operating within an authenticated environment (i.e. you log in to Facebook through your browser) but it’s actually pretty easy. Here are the steps:

1. Browse to the video you want to download in Facebook and start it playing.
2. Right-click the playing video and select Show video URL. Copy the URL and paste it into your browser’s address bar.
3. Still in the address bar, change “www” to “m” to bring up the mobile version of the page; hit enter to load.
4. In Chrome, hit F12 and click on the Network tab (ensure the network log is recording). I also like to check the Disable cache checkbox for convenience but if you don’t, click CTRL+F5 to forcefully reload the page and its resources from the server.
5. Play the video (click play) and locate the the last request that pops up (it should be a .mp4 request).
6. Right-click the request entry and click Copy > Copy link address
7. Paste that address into your address bar and hit enter. The video will load.
8. Right-click > Save As to save the .mp4 file

Saving videos from a web site with VLC

I recently wrote about how to download and save a Brightcove video using the m3u8 format. I’ve since found an even easier method for other sites using other video formats.

It’s as simple as this:

1. Open VLC and select Open Network Stream from the Media menu.
2. Paste in the URL of your youtube.com (or similar) URL
3. Click Play
4. From the Tools > Codec Information menu, copy the full Location link to your clipboard
5. Paste the copied location into Chrome and right-click the video/Save As

Depending on video quality, some videos (especially longer ones) may be on the large for your mobile device without additional transcoding.

If you have any problems with VLC complaining about not being able to play the video, you probably need to update VLC or the .lua or .luac file in the VLC install directory. I was experiencing MRL / 403 Forbidden errors until I updated the youtube.lua file.

To update:

1. Save the text contents of this file as youtube.luac to a temporary location (note the .luac extension, not .lua): https://github.com/videolan/vlc/blob/master/share/lua/playlist/youtube.lua
2. Replace the original youtube.luac in your VLC install directory (e.g. \VideoLAN\VLC\lua\playlist\ from c:\Program Files or c:\Program Files (x86)
3. Restart VLC
4. Update luac files for other sites if necessary

How to Download and Save Videos from a Website

I recently watched a free video embedded in a website and wanted to save the video itself for future reference (imagine the nerve!). The video content was delivered via the Brightcove player and was not a Flash/.swf file which I could otherwise deal with using traditional video download tools or shonky websites. The video was in fact, I believe, an HLS m3u8 video… admittedly, I don’t know if those are the same thing, or for that matter, what they are, and I don’t particularly care.

Rather than download a suspicious installer and infect my computer with the latest crypto virus, TubeOffline provided a handy and relatively simple tutorial using the ever trusty (and trustworthy) VLC media player. I’m reproducing the steps here in simple terms for future reference.

1. Firstly, find the URL to the .m3u8 file you want to save. In Chrome, hit F12 and go to the Network tab. Check the Disable Cache button. Make sure the Record Network Log button is red and type “m3u8” (without quotes) in the Filter box. Load (or reload the page containing the video you’re after) and have a look at the network log. I grabbed the URL to the master.m3u8 file (right-click, Copy > Copy link address).
2. From the Media menu in VLC, select Open Network Stream. It should open to the Network tab
3. Copy the URL of the .m3u8 file to be downloaded and paste it in to the Network URL box. Don’t click the Play button!
4. Click on the arrow next to the Play button and select Stream
5. Click Next on the Source screen
6. At the Destination screen, ensure the destination is set to File and click the Add button. Browse to the location where you want to save your downloaded video and specify a file name. The Save as type box will be left as Containers.
7. On the Transcoding Options screen, leave Profile set to the default (Video – H.264 + MP3 (MP4). You can disable transcoding if you like but file sizes will likely be larger.
8. On the Option Setup screen, leave the Stream all elementary streams checkbox un-ticked. Click the Stream button.
9. VLC will begin saving the video to the selected file. Don’t try and play the video and don’t touch anything until the blue progress bar in VLC has reached the end (the far right side). You can sometimes monitor the file itself by hovering over in the file system to keep an eye on its size.

In practice, I noticed the blue progress bar reached the end and the file size was showing as 132MB. I thought it was all finished at that stage but opening the .mp4 file to review in a new VLC instance opened a whole lot of nothing with a duration zero seconds. After another minute or so, the file size bumped up to 133MB and opening the file again revealed the downloaded video complete with audio. I’ve found closing the original VLC instance seems to finalise the download/flush the last few bits to file (note: don’t just close the video or open another file—completely close VLC so it can flush its buffers and clean up). Your mileage may vary.