The short answer
- MPEG-TS is an audio-video container format that multiplexes audio, video and multiple programs into a transport stream, but playback requires support for both the container and the codecs inside.
- On Windows, right-click the file and choose Open with to select a player that supports its container and codecs. On macOS, use Finder's Open With command for the same purpose. On a phone, use the file manager's open or share action to pass the file to a compatible video app. These actions select an app; they do not establish compatibility. If playback fails, identify the internal codecs before choosing another player or converting the file. A TS, MTS or M2TS extension alone is insufficient.
- Treat unfamiliar TS, MTS and M2TS files cautiously and keep your player updated. The [VideoLAN VLC 3.0.24 bulletin](https://images.videolan.org/security/sb-vlc3024.html) documents out-of-bounds reads and writes when handling ARIB data in MPEG transport streams. This parser risk supports a medium risk rating; successful playback does not prove a file is safe.
MPEG-TS files: open TS, MTS and M2TS video
MPEG Transport Stream is defined by ISO/IEC 13818-1, also published as ITU-T H.222.0. It suits broadcasting and transmission environments where errors may occur. M2TS is a modified version used by Blu-ray BDAV and AVCHD. See the Library of Congress descriptions of [MPEG-TS](https://www.loc.gov/preservation/digital/formats/fdd/fdd000635.shtml) and [M2TS](https://www.loc.gov/preservation/digital/formats/fdd/fdd000636.shtml).
For TS to MP4, distinguish remuxing from transcoding. FFmpeg streamcopy skips decoding and re-encoding, avoiding encoding quality loss when the destination container accepts the original streams. Incompatible streams, resizing or deinterlacing may require transcoding, which can reduce quality. Filters requiring decoded frames cannot be used with streamcopy. See [FFmpeg documentation](https://ffmpeg.org/ffmpeg-all.html). Renaming a file is not conversion.
How to open it
On Windows, right-click the file and choose Open with to select a player that supports its container and codecs. On macOS, use Finder's Open With command for the same purpose. On a phone, use the file manager's open or share action to pass the file to a compatible video app. These actions select an app; they do not establish compatibility. If playback fails, identify the internal codecs before choosing another player or converting the file. A TS, MTS or M2TS extension alone is insufficient.
On Windows, right-click the file and choose Open with to select a player that supports its container and codecs. On macOS, use Finder's Open With command for the same purpose. On a phone, use the file manager's open or share action to pass the file to a compatible video app. These actions select an app; they do not establish compatibility. If playback fails, identify the internal codecs before choosing another player or converting the file. A TS, MTS or M2TS extension alone is insufficient.
For TS to MP4, distinguish remuxing from transcoding. FFmpeg streamcopy skips decoding and re-encoding, avoiding encoding quality loss when the destination container accepts the original streams. Incompatible streams, resizing or deinterlacing may require transcoding, which can reduce quality. Filters requiring decoded frames cannot be used with streamcopy. See [FFmpeg documentation](https://ffmpeg.org/ffmpeg-all.html). Renaming a file is not conversion.
File safety
Treat unfamiliar TS, MTS and M2TS files cautiously and keep your player updated. The [VideoLAN VLC 3.0.24 bulletin](https://images.videolan.org/security/sb-vlc3024.html) documents out-of-bounds reads and writes when handling ARIB data in MPEG transport streams. This parser risk supports a medium risk rating; successful playback does not prove a file is safe.
An unknown sender, a name ending in two extensions, or contents that do not match the extension — check before you open it.
Converting it
For TS to MP4, distinguish remuxing from transcoding. FFmpeg streamcopy skips decoding and re-encoding, avoiding encoding quality loss when the destination container accepts the original streams. Incompatible streams, resizing or deinterlacing may require transcoding, which can reduce quality. Filters requiring decoded frames cannot be used with streamcopy. See [FFmpeg documentation](https://ffmpeg.org/ffmpeg-all.html). Renaming a file is not conversion.
Convert a copy, never the original, then compare quality, metadata, and layout against what you started with.
Common questions
What is an MPEG-TS file used for?
MPEG-TS carries multiplexed audio, video and potentially multiple programs. It is used in broadcasting and transmission environments where errors may occur. It describes the container system, not one fixed video codec.
How do I open TS files on Windows?
Right-click the TS file, choose Open with, and select a player that supports MPEG-TS and the file's internal codecs. If it fails, check codec support rather than assuming the extension guarantees playback.
How do I open M2TS files on Mac?
In Finder, use Open With to choose a player supporting M2TS and its internal audio and video codecs. Whether a given M2TS file plays depends on its internal codecs, so if it does not open, choose a player that supports them.
How do I open MTS files on a phone?
Use the phone's file manager to open or share the MTS file with a video app that supports its container and codecs. If no compatible app is available, convert a copy to a format and codec combination supported by your phone.
What should I do when an MTS camera file will not play?
Check whether the player supports both the container and the internal codecs. Try an appropriate compatible player or convert a copy if codec support is missing. A playback failure alone does not establish corruption, and renaming the extension does not transcode the video.
What are the MTS and M2TS file differences, and which extension should I use?
For AVCHD files, Sony states that MTS and M2TS have no functional difference and permits interchanging their extensions. Use the extension expected by your workflow, while remembering that renaming does not change the encoded audio or video.
Can I convert TS to MP4 without quality loss?
Yes, when the original streams are compatible with MP4 and can be copied without re-encoding. FFmpeg calls this streamcopy. If conversion requires re-encoding, quality may decrease; resizing and deinterlacing require processing that streamcopy cannot perform.
Is an unfamiliar TS video safe to play?
Its extension does not establish safety. Malicious media can exploit player parser flaws, as documented in the VLC 3.0.24 MPEG transport-stream bulletin. Use an updated player and consider the file's origin before opening it.
What packet length and sync byte identify MPEG-TS and M2TS?
Standard TS uses 188-byte packets beginning with 0x47. BDAV/M2TS uses 192-byte source packets: a 4-byte extra header followed by the 188-byte transport packet, placing 0x47 at offset 4. A matching pattern supports identification but does not prove safety.
Which video codecs can a Blu-ray M2TS file contain?
BDAV can carry MPEG-2, H.264/AVC or VC-1 video, so the M2TS extension does not identify one codec. Likewise, IANA's video/MP2T registration is explicitly scoped to RTP transfer and is not a separate MIME definition for every local MTS or M2TS file.
Related formats
Sources
MPEG-2 Transport Stream · Library of Congress
MPEG-2 Transport Stream for Blu-ray Discs (BDAV) and AVCHD · Library of Congress
video/MP2T Media Type Registration · IANA
Is there any difference between MTS and M2TS files? · Sony Support
FFmpeg Documentation · FFmpeg
VideoLAN Security Bulletin VLC 3.0.24 · VideoLAN