BNP File Documentation

Summary

A BNP file is a small binary management file that a Sony AVCHD camcorder writes into its AVF_INFO bookkeeping folder. Despite the “video data” label, it holds no picture or sound: it records information about the recorded clips (dates, clip list, browse data) so the camera can list and play them back. You do not open a .bnp directly. The actual videos are the .mts/.m2ts files in the STREAM folder; open those in VLC to watch your footage.

Technical details

Feature	Value
Full name	Sony Camcorder AVCHD Management File
File extension	`.bnp`
MIME type	`application/octet-stream`
Format type	Binary metadata/index sidecar (not video)
Developer	Sony
Introduced	Sony AVCHD / Memory Stick camcorders, late 2000s
Contains	Clip references, recording dates, browse/playback data
Contains video?	No — the footage is in the `.mts`/`.m2ts` files
Typical location	`PRIVATE/AVCHD/AVF_INFO` on the camera storage
Magic number	None documented (undocumented proprietary layout)
Safe to delete?	No — can break on-camera listing/playback
Convertible?	No — there is no media to convert
Related extensions	`.mts`, `.m2ts`, `.modd`, `.moff`
Open standard	No (proprietary, undocumented)

What is a BNP file?

A BNP file is a small management file that Sony’s AVCHD camcorders write into the camera’s bookkeeping directory, the AVF_INFO folder of the AVCHD structure. The name and some listings call it a “video data” file, but that is misleading in the way that matters most: a .bnp contains no picture and no sound. It is an index, a pointer file. It records information about your recordings, such as the list and order of clips, recording dates, and data the camcorder uses to browse and present footage on its own screen. Without it, and the other files in AVF_INFO, the camera’s built-in menu may be unable to list or play the recordings, even though the actual video data is completely intact elsewhere.

This is the practical heart of the matter. If you copied a .bnp off a Sony camera and are trying to play it or convert it to MP4, you have the wrong file: there is nothing inside it to watch. It is a sidecar to the real video, similar in spirit to the .modd and .moff thumbnail-and-index files Sony also writes.

Where the actual video lives

On the camera’s storage the recordings sit in a fixed AVCHD folder tree, and the BNP is deliberately kept apart from the media it describes.

PRIVATE/
  AVCHD/
    BDMV/
      STREAM/     00000.MTS, 00001.MTS ...   <- the real video
      CLIPINF/    per-clip info
      PLAYLIST/   playback order
    AVF_INFO/     management data, including .bnp   <- no video here

The footage is the numbered .mts (or .m2ts) files in BDMV/STREAM. Those are the files to open or convert: an .mts is an MPEG-2 transport stream carrying H.264 video and Dolby Digital or PCM audio, and VLC plays it directly. The AVF_INFO folder alongside, where the .bnp lives, holds only the management data that ties clips together, records dates, and drives on-camera browsing.

What a BNP actually holds

Because Sony has never published the BNP layout, its internal structure is undocumented and there is no reliable magic number to identify it by; you recognise it by its name and its location in AVF_INFO, not by a signature. What is known is its role, not its byte format. In practice it carries clip references (which clips exist and in what order), recording metadata (dates and counts), and the browse/playback data the camcorder uses to show your recordings as a list on the device. It is a catalogue, so it is only meaningful to the camera and the software that reads the whole AVCHD package. Sony’s old Picture Motion Browser, and later PlayMemories Home, read the entire AVCHD folder rather than opening a lone .bnp, and both of those applications have since been discontinued, which is another reason there is no real workflow for interacting with a BNP on its own.

Is it safe to delete, and how to archive footage

A BNP is a small, passive binary file with no executable content, so it cannot harm your computer. The only real risk is data-management confusion. If you delete or move the AVF_INFO files, the camcorder may no longer list or play your recordings, and long takes that were split across several numbered clips can lose the information that ties them back together. The safe habit when archiving footage off a Sony camera is to copy the whole PRIVATE/AVCHD folder as a unit, keeping the .bnp and the rest of AVF_INFO next to the STREAM clips, rather than cherry-picking individual files. Video editors that import “from AVCHD” rely on exactly this intact structure to match clips, dates and spanned recordings.

Frequently asked questions

Can I play or convert a BNP file?

No. A BNP holds no video or audio, so there is nothing to play or convert. Find the .mts or .m2ts clips in the AVCHD STREAM folder from the same camera and play those in VLC, or convert them to MP4 with HandBrake.

Can I delete the BNP file?

It is safer not to. The camcorder uses it, together with the rest of AVF_INFO, to list and play recordings, so deleting it can break on-camera playback. When archiving, copy the whole AVCHD folder so the management data stays with the video.

References

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