A .BDM file contains information about AVCHD video files. It is created by high definition camcorders. The file names commonly seen are index.bdm or movieobj.bdm. BDM files are located in the AVCHD/BDMV directory on media storage devices. They contain information like file names, sizes and timestamps of the video files recorded on the disc.
BDM files can be opened with programs like Roxio Creator, Roxio Toast, CyberLink PowerDVD and Nero Video. If you cannot open a .BDM file, it may be because you do not have the appropriate program installed or your file associations are corrupted.
Files with .BDM extension are usually seen on storage devices like hard disks and memory cards, while the equivalent .BDMV files are on optical disks. The format was developed by Sony and Panasonic and introduced in 2006 for AVCHD video recordings.