| rms | Secured RealMedia File |
| rmv | RealMedia Variable Bitrate Video |
| rmvb | RealMedia Variable Bitrate Video |
| rpl | ARMovie Replay |
| rsx | REDCODE Metadata XML |
| rtv | NewTek Uncompressed Video |
| rum | Bink Video Subtitle File |
| rv | Real Video Movie |
| rv8 | Real Video Movie |
| rv9 | Real Video Movie |
| rvid | Snapz Pro X Recorded Video |
| rvx | RealVideo Protected |
| s1m | Sealed MPEG Movie |
| s1q | Sealed QuickTime Movie |
| sbm | Stream Bean Media |
| sbt | SBT Subtitle |
| sbv | SubViewer Subtitle Format File |
| scc | Sonic Scenarist Closed Caption File |
| scke | SpyClock Encrypted Video |
| scm | ScreenCam Movie File |
| sdr2 | Seorim MICRO DVR Camera Video |
| sfvidcap | Sonic Foundry Video Capture Data |
| sgv | Self-Guard Security Camera Video |
| siv | Silicon Imaging Video |
| skm | SKM Video |
| smk | Smacker Video |
| smov | Sealed Quicktime Movie |
| smp1 | Sealed MPEG-1 Video |
| smp4 | Sealed MPEG-4 Video |
| smpg | Sealed MPEG Movie |
| smv | SigmaTel Motion Video |
| splash | Splash Pro EX Video |
| sqj | AXIS Camera Explorer Video |
| srt | SubRip Subtitle Format |
| ssa | SubStation Alpha Subtitle |