Using the web app

What you need

• A reference video: any clip from the same Sony camera that already plays (normal MP4/MOV-style file).
• Your .rsv file: the interrupted recording that will not open in a normal player.
• A save location: the tool writes a fixed .mp4 (you choose the name and folder).
• A supported browser (recent Chrome or Edge is best) with File System Access so you can pick files and save output.

1. Load the tool

When you open rsv.repair, the repair engine loads in your browser. You may see “Getting ready…” for a moment while it prepares.

Use a recent Chrome or Edge so the tool can run as intended.

2. Choose files

Working video (01)
Pick a good recording from the same camera as the .rsv. Same model and usual settings matter more than file name.

Your .rsv (02)
The .rsv file that does not play. The file picker is limited to .rsv so you don’t accidentally pick the wrong type.

Save as (03)
After both inputs are chosen, choose where to save the output .mp4. The browser asks for a path; nothing is uploaded to a server.

3. Start repair

Tap Fix video. You can open Advanced options (gear) before starting if you need non-default behavior (see below).

Progress phases

The UI shows roughly where the job is:

• Preparing… Your files are opened and the job is starting.
• Reading your working video… The reference is being parsed.
• Building your video… The .rsv is being read and output is being written.
• Finishing up… The browser is flushing the last bytes to disk. Large files can take minutes here.

Output log

Expand Output log to see detailed messages (same kind of information as the desktop tool’s console output).

When it finishes

You should see Done and a short preview of the recovered video. The file is on disk at the path you chose.

Optional: Advanced options

These map to the same flags as the desktop Untrunc tool. Most users leave everything off.

• Skip unknown sequences: If the parser hits unknown data, keep going instead of stopping. When enabled, Step size sets how many bytes to skip at a time (1–65536).
• Stretch video (Experimental): adjust video timing to match audio duration.
• Keep unknown sequences: Include unrecognized raw bytes in the output instead of discarding them.
• Dynamic chunk stats: Use chunk pattern statistics from the reference file for better recovery on some files.
• Search for mdat: Brute-force search for video data when the container structure is badly damaged (less common for pure .rsv).

If repair won’t start

Try refreshing the page, then use Chrome or Edge on an up-to-date version.

Privacy reminder

Processing is local in your browser: your reference clip, .rsv, and output are not sent to our servers as part of the repair flow. See Privacy & your files.