Free online H265 to M2T converter

What the H265 format is

H.265, also called HEVC, is a video compression standard designed to deliver similar visual quality at roughly half the bitrate of H.264 in comparable conditions. It is used for 4K recordings, streaming video, smartphone footage, Blu-ray-related workflows, security cameras, and screen or camera exports.

H.265 video commonly appears in .h265 or .hevc elementary-stream files, and inside containers such as MP4, MKV, and MOV. Cameras, phones, OBS Studio, FFmpeg-based applications, and modern editing software can create it. Some older editors, hardware decoders, and HDV-oriented systems cannot decode it reliably.

What the M2T format is

M2T is commonly used for an MPEG-2 transport stream, especially an HDV recording or export. The extension is also seen as .m2t, while related MPEG transport-stream files may use .ts or .m2ts. M2T is a container, not a single codec: the video is normally MPEG-2, with MPEG audio or another transport-stream-compatible audio format.

The format is useful for HDV camcorders, older broadcast and nonlinear-editing systems, transport-stream playback, and workflows that require MPEG-2 rather than HEVC. Its main compatibility advantage is support in legacy video hardware and software. It generally produces a much larger file than H.265 because MPEG-2 is less compression-efficient.

How to actually convert H265 to M2T

FFmpeg is the most controllable desktop option. Install a current FFmpeg build, open a terminal in the folder containing the source file, and run:

ffmpeg -i input.h265 -c:v mpeg2video -q:v 2 -pix_fmt yuv420p -c:a mp2 -b:a 384k -ar 48000 -f mpegts output.m2t

Replace input.h265 with the actual filename. If the HEVC video is inside an MP4 or MKV container, use that container filename instead; FFmpeg will read the HEVC stream automatically. The command encodes video as MPEG-2, audio as MP2, and writes an MPEG transport stream with an M2T extension.

For a fixed HDV-like bitrate, use a constrained MPEG-2 setting instead of quality-based encoding:

ffmpeg -i input.mp4 -c:v mpeg2video -b:v 25M -minrate 25M -maxrate 25M -bufsize 17825792 -pix_fmt yuv420p -c:a mp2 -b:a 384k -ar 48000 -f mpegts output.m2t

Use the second command only when the receiving system expects approximately 25 Mb/s MPEG-2 transport streams. HDV profiles can also require particular frame sizes, frame rates, field order, audio settings, and GOP structures; a generic MPEG-TS file with an .m2t extension may not satisfy every HDV device.

To convert without installing software, upload the source to the free converter on 101convert.com, select M2T as the output format, start the conversion, and download the generated file. Check the service's file-size and codec limits before uploading, particularly for large camera recordings.

Quality, compatibility, and limitations

This conversion is normally lossy twice: H.265 is decoded and MPEG-2 is encoded, so fine detail, motion quality, and color information can change. A higher MPEG-2 bitrate reduces additional loss but cannot restore detail already discarded by the H.265 source.

Match the source frame rate and dimensions unless the target device specifies otherwise. Use ffprobe input.h265 to inspect streams, resolution, frame rate, scan type, and audio before converting. Interlaced HDV equipment may reject progressive output or display it incorrectly; preserving or explicitly setting field order may therefore be necessary.

If the source has no audio, omit the audio options and use -an. If FFmpeg cannot identify a raw HEVC file, provide its properties explicitly, for example -f hevc -r 25 -s 1920x1080 -i input.h265; use the actual frame rate and dimensions, because incorrect values produce unusable timing or an improperly sized picture.