SRT to PAC Converter

The SRT to PAC Converter reads the SubRip captions you paste into the SRT Content box and produces a frame-accurate timing map for PAC, the Screen/Sonic Solutions subtitle format used across broadcast subtitling. Each cue is written as a row containing its number, a start and end timecode in HH:MM:SS:FF form calculated at the rate you type into Frame rate (fps), and the caption text. The result downloads as a .pac.txt file.

It is important to be clear about what you get. A true .pac is a binary file with its own character tables and styling records, and no browser tool can honestly claim to write one. What broadcasters and subtitling houses actually need day to day is the frame-locked timing map that PAC authoring software imports, so that the timings agreed in an SRT-based workflow arrive intact in the professional tool where the final .pac is produced. That is precisely what this srt to pac converter generates.

The conversion itself is frame arithmetic. SubRip stores milliseconds, but broadcast subtitling counts frames, so each timestamp is divided into hours, minutes and seconds and the remaining milliseconds are multiplied by the frame rate to produce the two-digit frame field. Because 23.976 and 29.97 are not whole numbers, the frame you enter matters: converting a file at 25 fps when the master is 29.97 fps will drift progressively, so the value in Frame rate (fps) must match the video you are delivering against.

Everything is computed locally in your browser, so pre-transmission dialogue never leaves your workstation, and even long feature files convert instantly.

• Frame-accurate timecodes: millisecond SubRip timings are converted to HH:MM:SS:FF, the counting model broadcast subtitling and playout systems actually use.
• Frame rate you control: the Frame rate (fps) field is a free numeric input, so you can enter 23.976, 24, 25, 29.97, 30 or any other rate your master runs at rather than being limited to a fixed list.
• Row-per-cue map: output is a simple delimited table of cue number, start, end and text, which is straightforward for PAC authoring software and in-house scripts to import.
• Honest about the binary step: the tool produces the timing map that feeds PAC software rather than pretending to emit a binary .pac, so nobody discovers the difference at delivery.
• Text carried through verbatim: the caption wording from your SRT Content is passed into the map unchanged, leaving translation and line-break decisions to you.
• Robust SubRip parsing: irregular numbering, extra blank lines and mixed line endings in the pasted file are handled without errors.
• Private and instant: the whole convert srt to pac online workflow runs client side with no upload, no queue and no file-size ceiling beyond your own memory.

1. Paste the finished SubRip file into the SRT Content box, or click Load sample to see the row format the tool produces before using your own material.
2. Confirm the frame rate of the master you are subtitling against - this is the video's rate, not the rate of any proxy you reviewed on.
3. Type that value into Frame rate (fps), for example 25 for a PAL delivery or 29.97 for an NTSC one.
4. Press Run to generate the timing map; each cue appears as one row with its start and end in HH:MM:SS:FF.
5. Check a cue late in the programme against your reference timecode - late cues are where a wrong frame rate shows up most obviously.
6. Click Copy, or Download to save the map as a .pac.txt file.
7. Import that file into your PAC authoring application, apply the house style and character set there, and export the final binary .pac for delivery.

Example 1 - a PAL delivery at 25 fps. With Frame rate (fps) set to 25, each frame is 40 ms, so a cue starting at exactly one second lands on frame 00.

Input (SRT):
1
00:00:01,000 --> 00:00:04,000
Welcome to the harbour tour.

Output (PAC timing map):
1	00:00:01:00	00:00:04:00	Welcome to the harbour tour.

Example 2 - the same cue at 29.97 fps. Change Frame rate (fps) to 29.97 and the 1.000 second start becomes 00:00:01:00 while a cue ending at 00:00:04,500 resolves to roughly frame 14 rather than frame 12. That difference is invisible at the top of a programme and glaring an hour in, which is why matching the master's rate before you export is not optional in a broadcast workflow.

• Bridges editorial and broadcast tools: timings authored in ordinary SRT-based software arrive in your PAC application already frame-locked, so no one re-times the file by hand.
• Prevents drift rejections: choosing the correct frame rate up front avoids the slow creep that causes QC to fail a subtitle track near the end of a programme.
• Sets expectations honestly: knowing you are producing an import map rather than a binary .pac means the final authoring step is planned rather than discovered on deadline.
• Speeds up turnaround: a full episode converts instantly, so late script changes can be pushed through to the subtitling suite in minutes.
• Keeps embargoed content secure: nothing is uploaded, which matters for pre-transmission news, sport and drama.
• No licence required: freelancers and small facilities can prepare broadcast-shaped timing data without buying additional software seats.