Convert PAC to SRT

A video editor, player, or media platform may accept SRT but reject a broadcast PAC subtitle file. Converting it makes the captions easier to edit, share, archive, and use with general-purpose playback software.

What the PAC format is

PAC is a family of subtitle and closed-caption exchange formats used mainly in professional subtitling, broadcast, and transmission workflows. It is associated with caption-authoring systems such as EZTitles, SubtitleNext, and other specialist applications; PAC variants are not necessarily interchangeable, and some workflows use PAC 890.

A PAC file can contain timed events, line breaks, positioning, formatting, reading-speed data, and broadcast metadata. Many PAC files are binary or application-specific, so a text editor usually will not display usable subtitle text. The .pac extension is also used for proxy auto-configuration files, which are unrelated; confirm the file's source before attempting subtitle conversion.

What the SRT format is

SRT is a plain-text subtitle format supported by VLC, MPC-HC, Plex, YouTube, many video editors, and most desktop and mobile media players. A normal entry contains a sequence number, a time range such as 00:01:12,500 --> 00:01:15,200, one or more text lines, and a blank line before the next entry.

SRT is useful for broad compatibility and manual editing, but it has limited formatting. Conversion can discard PAC-specific placement, caption regions, colors, speaker metadata, roll-up behavior, teletext data, and transmission controls.

How to convert PAC to SRT

1. Install the current desktop version of Subtitle Edit from the official Nikse.dk distribution.
2. Open the file with File → Open. If automatic detection fails, select PAC in the file-type filter or choose the PAC format manually.
3. Check the imported events for text, order, line breaks, special characters, and timecodes. If the source uses frame-based timecode, identify its frame rate before exporting.
4. Save the result with File → Save as, select SubRip (*.srt), and use an .srt filename.
5. Open the exported file in the intended player or editor. Check the first, middle, and final captions, synchronization, line wrapping, and character display.

If Subtitle Edit rejects the file or imports empty or corrupted events, try the application that created it. EZTitles and SubtitleNext may support vendor-specific PAC variants more accurately; import the file, choose the program's export or save command, select SRT, and inspect the result. A commercial application or the original captioning system may be required for protected or proprietary PAC data.

Online conversion options

Online conversion is less dependable for PAC than desktop conversion because PAC is a family of variants rather than one consistently implemented public format. Use a reputable service only when its current documentation explicitly lists subtitle PAC as the input and SRT as the output; many services that mention .pac mean proxy auto-configuration files instead. Do not upload confidential broadcast captions, and download the result for local timing, encoding, and formatting checks.

Renaming filename.pac to filename.srt does not convert the contents. If no online service accepts the file, Subtitle Edit or the originating professional subtitling application is the appropriate route.

Quality and compatibility checks

• A frame-rate mismatch, such as interpreting 25 fps material as 29.97 fps, can create progressively larger synchronization errors. Confirm the source frame rate before converting or retiming.
• Save the SRT as UTF-8 when it contains accented characters, non-Latin scripts, or symbols. Reopen and resave it with UTF-8 if a player shows garbled text.
• SRT normally uses HH:MM:SS,mmm --> HH:MM:SS,mmm. Invalid timecodes, duplicate numbering, malformed arrows, or missing entry separators can cause some players to ignore captions.
• Review text that depends on speaker positioning, color, italics, forced-caption flags, region placement, or broadcast metadata; SRT may retain only the words and approximate timing.