STR is somewhat uncommon video format used on Sony Playstation and as such not easily playable on desktop computers. Your best bet is to get a multimedia converter that supports *.str files and export it to something more common, like Matroska MKV.
Convert SONY PlayStation movie stream file to Matroska multimedia container.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert str to mkv on Windows
A free and powerful video conversion utility, SUPER is based on FFmpeg, MEncoder, MPlayer, x264, MusePack, Monkey's audio, Shorten audio, TAK audio, True audio, WavPack, the libavcodec library & the theora/vorbis RealProducer's plugIn.
Convert from str file
|Yes, SUPER supports str file conversion as a source file type.||No||No||No||No||No||No||No|
to mkv file
|Yes, SUPER supports mkv file conversion as a target file type.||No||No||No||No||No||No||No|
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.