| .S11 | Interplay Entertainment | Archivos de video | Descent 2 Game Data | Interplay Descent 2 | Interplay Entertainment |
| .S4UD | Samsung Electronics | Archivos de video | Samsung Smart TV Video | Samsung TVs | Samsung Electronics |
| .SAN | LucasArts Entertainment Company, LLC | Archivos de video | Smush Animation File | Star Wars: Rebel Assault | LucasArts Entertainment Company, LLC |
| .SBK | SwishZone | Archivos de video | SWiSH Project Backup File | SWiSH Max | SwishZone |
| .SBS | Allegorithmic | Archivos de video | Substance Package | Substance Designer | Allegorithmic |
| .SBT | URUWORKS | Archivos de video | SBT Subtitle File | URUWorks Subtitle Workshop | URUWORKS |
| .SBZ | ArcSoft | Archivos de video | ShowBiz Project File | ArcSoft ShowBiz | ArcSoft |
| .SCC | Microsoft Corporation | Archivos de video | SourceSafe Source Code Control File | Microsoft Visual Studio | Microsoft Corporation |
| .SCM | Gimpel Software | Archivos de video | GIMP Script-Fu Script | GIMP | The GIMP Development Team |
| .SCN | Microsoft Corporation | Archivos de video | Age Of Mythology Scenario File | Microsoft Age of Empires | Ensemble Studios |
| .SCX | RIX SoftWorks, Inc. | Archivos de video | ColoRIX Bitmap Graphic File | XnView MP | XnSoft |
| .SDP | Oracle Corporation | Archivos de video | StarOffice Presentation File | Apache OpenOffice | Apache Software Foundation |
| .SDV | Pinnacle Systems Inc. | Archivos de video | Studio DV Project File | Pinnacle Studio | Corel |
| .SEC | Symantec Corporation | Archivos de video | Pretty Good Privacy Secret Key Ring | Pretty Good Privacy (PGP) | Symantec Corporation |
| .SEQ | PG Music Inc | Archivos de video | PowerTracks Pro Audio Project File | PowerTracks Pro Audio | PG Music Inc |
| .SFD | Open Source | Archivos de video | Sofdec Dreamcast Movie | Media Player Classic | Open Source |
| .SHTM | Opera Software | Archivos de video | HTML Server Side Include File | Microsoft Notepad | Microsoft Corporation |
| .SIV | Adobe Systems Incorporated | Archivos de video | Silicon Imaging Video File | Adobe SpeedGrade | Adobe Systems Incorporated |
| .SKY | Palm | Archivos de video | ActiveSky Movie Clips For Palm OS | Palm OS | Palm |
| .SMI | Apple | Archivos de video | Self-Mounting Disk Image | ShrinkWrap | Aladdin Systems |
| .SMIL | "Synchronized Multimedia" Working Group (SYMM WG) | Archivos de video | SMIL(Synchronized Multimedia Integration Language) Presentation File | Internet Explorer | Microsoft Corporation |
| .SMK | RAD Game Tools | Archivos de video | Smacker Compressed Movie File | RAD Video Tools | RAD Game Tools |
| .SML | ESRI | Archivos de video | ARC/INFO Simple Macro Language File | ESRI ArcGIS for Desktop | ESRI (Environmental Systems Research Institute) |
| .SMV | Smith Micro Software | Archivos de video | VideoLink Mail Video File | Smith Micro Videolink Pro | Smith Micro Software |
| .SPL | Microsoft Corporation | Archivos de video | Windows Print Spool File | Microsoft Windows | Microsoft Corporation |
| .SQZ | Sorenson Media | Archivos de video | Squeeze Project File | Squeeze | Sorenson Media |
| .SRT | SourceForge | Archivos de video | SubRip Subtitle File | VLC Media Player | VideoLAN |
| .SSF | Unknown Developer | Archivos de video | Structured Subtitle Format File | Microsoft Notepad | Microsoft Corporation |
| .SSIF | CyberLink | Archivos de video | Blu-ray Disk | CyberLink PowerDVD | CyberLink |
| .SSM | RealNetworks | Archivos de video | Standard Streaming Metafile | RealPlayer | Realtime Technologies |
| .SSW | Sony Mobile Communications | Archivos de video | Sony Ericsson Firmware File | SETool2 | Sony Mobile Communications |
| .ST4 | Corel Corporation | Archivos de video | Pinnacle Studio 400 Project File | Pinnacle Studio | Corel |
| .STL | 3D Systems | Archivos de video | Stereolithography File | Creo Parametric 3D Modeling Software | PTC |
| .STR | dBase, LLC | Archivos de video | dBASE Structure List Object File | dBase | dBase, LLC |
| .SVI | Samsung Electronics | Archivos de video | Samsung Video File | GOM Player | GOM & Company |
| .SWF | Adobe Systems Incorporated | Archivos de video | Shockwave Flash Movie | Adobe Animate CC 2017 | Adobe Systems Incorporated |
| .SWI | SwishZone | Archivos de video | SWiSH Project File | SWiSH Max | SwishZone |
| .SWT | Adobe Systems Incorporated | Archivos de video | Flash Generator Template | Adobe Flash Professional CC | Adobe Systems Incorporated |
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