Happened to me a few months ago. Had a ticket for our District Attorney office, trying to playback a security camera footage from a parking lot or something. It would open, but, the person that was supposed to be seen would show up for a few frames and glitch out.
Turns out the cam system it came from uses some very proprietary codec. So the footage was effectively useless without their special sauce player/codec
I'm working in live video and there's a lot of proprietary codecs out there that vlc doesn't play by default. Most of those are lossless/very high bitrate lossy formats designed to be encoded and decoded quickly for things like instant replays, so not something the average consumer would get their hands on.
Something I don't see a lot of people do but totally should is get a really long HDMI cable and snake it around the room. You can then hook up a laptop or hell even your desktop directly to the TV. Think my cable is around 20 feet and I got it off Amazon for dirt cheap. Works wonders when I want to watch something on Plex (a lot of smart TV's have trouble with Plex)
Beat me to it. I haven’t had an unsupported file error in the decade I’ve been using VLC. Maybe one time I had to download something to support a rare file type
I recently downloaded some YouTube videos that my dad wanted to play through USB with his Android based projector, as it doesn't have the PlayStore and the videos didn't want to play (and I knew they worked fine on my mac) I went quickly to its store just to find out VLC wasn't there, and I didn't have time to sideload stuff (I didn't even know if it was possible), hopefully there was FX File Explorer and that one comes with a video player which was able to save the day.
I've had good experience using mkvtoolnix to mux video into an mkv with subtitles included. Not sure if mkv support is widespread, but as janky as the TV was with other formats, mkv worked great every time.
Installing MPC-HC during K-Lite Code pack as my primary media player has taken place of VLC for me this last year. I have been using VLC as music player only with some Winamp-like no-viewport UI lately.
VLC works most of the time. That said some videos VLC can't seem to decode correctly - I never get VLC complaining about unsupported file formats, but I do get weird artifacts and glitched rendering when I try to play certain ones.
It's then that I usually try MPV or MPlayer. One of those will usually play the video correctly.
Mp4 and mkv are container formats. Your comment is somewhat equivalent to "where are you guys getting text files that can't be displayed, I've only ever seen zip files".
The codec in the container is what needs to be played, and can fail to render correctly.
This reminded me of having to install a codec pack like klite or cccp as one of the first things on a fresh install. I'm glad that isn't a thing anymore.