M2TS (Blu-ray)
Also known as: m2ts file, BDAV, .m2ts, Blu-ray video
M2TS is the video container used on Blu-ray discs and by AVCHD camcorders, based on the MPEG-2 transport stream. It holds high-definition H.264 or MPEG-2 video plus multiple audio tracks, which makes M2TS files large and tricky to play outside media-savvy software.
- Blu-ray / AVCHD transport-stream container
- Carries H.264 or MPEG-2 plus multiple audio tracks
- High bitrate; files are large
The Blu-ray stream format
M2TS (BDAV MPEG-2 transport stream) is how full-HD video is stored in the STREAM folder of a Blu-ray disc, and it is also the on-card form of AVCHD camcorder footage. The .m2ts file can carry H.264 or MPEG-2 video alongside several audio and subtitle tracks.
The transport-stream design exists so video can be streamed and played reliably from disc, which is why it is common on Blu-ray rather than in everyday phone recordings.
Why M2TS files are large
Blu-ray targets high quality, so M2TS uses high bitrates and full HD or higher resolution. A single feature-length .m2ts can run to many gigabytes, and the extra audio tracks add to that.
Many phone galleries and browsers will not open .m2ts directly. Transcode it to MP4 for portability, or compress it down if you only need to keep a smaller copy.