Convert BNP to MP4

A Sony camcorder backup may contain BNP files when a computer, editor, phone, or sharing service requires MP4. BNP is usually camera-management data rather than video, so the usable conversion starts with the associated MTS or M2TS recording.

What the BNP format is

BNP files are commonly created by Sony Handycam cameras and Sony video-management software as image-database or recording-management files. They may store indexes, thumbnails, recording information, or camera database data, but they generally do not contain the playable video stream.

BNP files can appear beside Sony camera folders on an SD card or in a backup, including paths such as PRIVATE/AVCHD/BDMV/STREAM. Do not rename file.BNP to file.mp4; changing an extension does not create a video and can prevent Sony software from recognizing the camera data.

What the MP4 format is

MP4 is an ISO Base Media File Format container commonly containing H.264 or H.265 video and AAC audio. Phones, browsers, televisions, media players, video editors, and upload services generally support MP4 more broadly than a Sony camera's original directory structure.

For maximum compatibility, use H.264 video with AAC audio. H.265 can reduce file size at similar visual quality, but older devices and editing software may not decode it reliably.

How to convert the recording

Find the actual video file

Keep the memory card or backup unchanged and copy the complete camera folder to a local drive. Search for .MTS or .M2TS files, especially under PRIVATE/AVCHD/BDMV/STREAM; these are the files that normally contain AVCHD video.

If Sony PlayMemories Home or the camera's supplied import software recognizes the device, use its import function to copy the recordings. Leave the BNP database files with the backup, but do not use them as conversion input.

Convert with HandBrake

HandBrake is a suitable desktop option for MTS and M2TS footage and is available for Windows, macOS, and Linux.

1. Open HandBrake and select the copied .MTS or .M2TS file. If the camera created several clips, add and convert each required clip, or first use Sony's import software to assemble the recording.
2. Choose Presets → General → Fast 1080p30 as a starting point, then set Video → Framerate to Same as source and use constant frame rate when the destination device requires it.
3. Set Summary → Format to MP4.
4. Under Video Encoder, choose H.264 (x264). Use Constant Quality around RF 18–22; lower RF values preserve more detail and produce larger files.
5. Under Audio, choose AAC. For stereo audio, 160–192 kbps is generally sufficient; retain the source channel layout when required.
6. Choose a destination ending in .mp4 and select Start Encode.

Convert with FFmpeg

FFmpeg is useful for batch processing and command-line control. This command re-encodes the video to broadly compatible H.264/AAC:

ffmpeg -i input.MTS -c:v libx264 -crf 20 -preset medium -c:a aac -b:a 192k -movflags +faststart output.mp4

Replace input.MTS with the real filename. -movflags +faststart places MP4 indexing data near the beginning of the file, which helps progressive playback after uploading. Use -c:v copy -c:a copy only when the source codecs and stream layout are compatible with the intended MP4 players; stream copying is faster and avoids generational loss, but can retain incompatible audio or camera-specific behavior.

Use an online converter

CloudConvert and Convertio can convert the extracted MTS or M2TS file to MP4. Upload the actual video, not the BNP file, and select H.264 video with AAC audio when codec options are available. Online services impose file-size and upload limits, and the recording is transferred to a third party, so HandBrake or FFmpeg is preferable for private, lengthy, or high-bitrate footage.

Quality and compatibility limitations

A BNP file alone cannot be converted into the original footage. If its associated MTS or M2TS files were deleted, BNP metadata cannot reconstruct the missing video.

AVCHD recordings may be interlaced, and some cameras split long recordings into multiple clips. Preserve the original folder structure until all clips have been identified; convert clips separately or use Sony's import software when their sequence, timestamps, or metadata matter.

Match the source frame rate, such as 25, 29.97, 50, or 59.94 fps, to avoid unnecessary motion conversion. Re-encoding reduces quality, so retain the original MTS/M2TS files and use a lower RF value or a visually lossless workflow for archival exports. Before deleting the camera originals, check the MP4 for audio synchronization, interlacing, rotation, image quality, and the presence of every expected clip.