M2TS/MTS, MPEG-2 Transport Stream (TS File), is a BDAV (Blu-ray Disc Audio-Video) container format. It's a special format for transmitting MPEG (MPEG-1, MPEG-2, or MPEG-4) video muxed with other streams. MTS container format is commonly used for Blu-ray disc, AVCHD and HD camcorder while M2TS is commonly used for Blu-ray disc and AVCHD.
The BDAV container format used on Blu-ray Discs can contain one of the three mandatory that support video compression formats MPEG-2, H.264/MPEG-4 AVC or SMPTE VC-1 and audio compression formats, such as Dolby Digital, DTS or uncompressed Linear PCM. Optionally, supported audio formats are Dolby Digital Plus DTS-HD High Resolution Audio and Dolby TrueHD.
There are two major variants of MPEG-2 TS. If multiple programs are sets of video and other streams intended to play together, and are muxed into the TS, it's called an MPTS, or Multiple Program Transport Stream. This is generally used for more traditional broadcasting, like DVB, or over the air HDTV. After the decoder receives the TS, it can decode only the streams for the program that is playing, and ignores streams for other programs.
If only a single program is muxed into a TS, it's considered an SPTS or Single Program Transport Stream. SPTS streams generally serve two purposes. When the program to be decoded is known in advance, like with streaming across the internet, it doesn't make sense to waste bandwidth transmitting streams that won't ever be decoded, but preserving timing information is still essential. An SPTS solves both problems.
Unlike Programs Streams which are optimized for efficient storage and assume the decoder has access to the entire stream for synchronization purposes, Transport Streams are designed for delivering data in real time over unreliable transport media, to a device which is assumed to start reading data from some point after the beginning of transmission.
The other common use for SPTS streams is for stream Capture. Capture devices can simply copy MPEG-2 streams as they're broadcast use SPTS streams. Because that's what they're capturing. Since only one program will be captured at a time, that's what the resulting MPEG file will contain.
Most applications are designed to open MPEG-2 files expect the standard information from a Program Stream. And it's often necessary to re-package the elementary streams before working with them on your computer. Fortunately, PS and TS streams only differ in delivery information, rather than actual video or audio data, it can be done without any re-encoding or quality loss.
M2TS video files can be played by Windows Media Player, third-party M2TS player or HD video players which are versatile with the support for playing overall video formats on PC/Mac. On the other hand, to play MTS/M2TS on iPhone, iPad, Android, Windows Phone (10/8) or other portable devices, you only need to convert M2TS to MP4, AVI etc. the devices commonly playable formats.
Estrella H. is a senior editor in Digiarty Software. She manages the software test section and creates easy and useful how-tos. When not in editing, she spends her spare time on Rubik's Cube and ukulele.