Probably, every user has encountered the fact that it is not possible to view a movie or a music video due to the fact that the desired codec is not installed. I had such a problem while working with Windows and Mac. In both cases, the player tried to find the desired codec, but without success.
For Windows, developers have created a lot of codec sets (the most famous is probably K-Lite), which are designed to solve this problem. However, in fact, they often become sources of trouble themselves. Sometimes you install a codec, as the videos that used to be fine stop playing. The real salvation for me was VLC media player.
VLC does not need third-party codecs to play files, and I have not yet encountered a situation where this player would refuse to play anything. A large number of formats are supported, including FLV (Flash).
The program itself is cross-platform, there are versions for Windows, Mac OS X, Linux, BeOS, FreeBSD, Solaris.
I have only a couple of negative points about VLC. The version for Mac OS X is less stable than for Windows (the application often crashes, which has never happened under Windows). Subtitles are not always displayed in the correct encoding.
[VLC media player]
