Free online H265 to M2TS converter

What the H.265 format is

H.265, also called HEVC, is a video codec rather than a complete container format. It compresses video more efficiently than H.264 and is common in 4K recordings, UHD Blu-ray sources, surveillance exports, smartphones, and screen-recording software.

HEVC video is usually stored in .mp4, .mkv, or .mov files. A file named .h265 may instead be a raw HEVC elementary stream with no standard audio, subtitle, or metadata container.

What the M2TS format is

M2TS is a transport-stream container derived from MPEG-2 Transport Stream. It is used by Blu-ray discs, UHD Blu-ray workflows, AVCHD camcorders, and some broadcast or hardware playback systems. M2TS can carry video, audio, subtitles, timestamps, and multiple program streams.

Its transport structure supports continuous playback and error recovery, but it does not guarantee that every player accepts every codec inside it. Standard Blu-ray commonly uses H.264 or MPEG-2 video, while UHD Blu-ray permits HEVC under stricter profile, level, bitrate, and authoring rules.

How to actually convert H.265 to M2TS

For a free desktop conversion, install FFmpeg and first inspect the source:

ffprobe input.mp4

If the source already contains compatible video and audio streams, remux them without quality loss. This is the preferred method because it changes the container without decoding the video:

ffmpeg -i input.mp4 -map 0 -c copy -f mpegts -mpegts_m2ts_mode 1 output.m2ts

Use the actual source filename in place of input.mp4; FFmpeg also accepts .mkv, .mov, and raw .h265 inputs. The -map 0 option copies all detected streams, while -c copy prevents re-encoding. If the installed FFmpeg build does not recognize -mpegts_m2ts_mode, omit that option and use:

ffmpeg -i input.mp4 -map 0 -c copy -f mpegts output.m2ts

That produces an MPEG-TS stream with an M2TS filename, but it may use 188-byte transport packets rather than the 192-byte packet structure expected by some Blu-ray tools. The M2TS mode option requests the 192-byte form.

If the target device rejects the copied stream, re-encode the video and select broadly supported audio:

ffmpeg -i input.mp4 -map 0:v:0 -map 0:a:0? -c:v libx265 -preset medium -crf  twenty-eight -pix_fmt yuv420p -c:a ac3 -b:a 384k -f mpegts -mpegts_m2ts_mode 1 output.m2ts

Remove the accidental space between crf and twenty-eight if copying the command, so the option reads -crf 28. Lower CRF values preserve more quality and create larger files; a value around 18–24 is a typical high-quality range, while 28 produces a smaller file with more visible compression. For a Blu-ray-compatible H.264 target instead of HEVC, use -c:v libx264 -profile:v high -level:v 4.1, subject to the disc specification and resolution.

Raw HEVC input has no audio to copy. For a raw stream, use:

ffmpeg -f hevc -i input.h265 -c:v copy -f mpegts -mpegts_m2ts_mode 1 output.m2ts

You can also use the free converter on 101convert.com without installing software. Upload the source, choose M2TS as the output format, start the conversion, and download the result; this option is less suitable for confidential or very large recordings.

Quality, compatibility, and limitations

Remuxing with -c copy does not reduce video quality, but it cannot fix an unsupported HEVC profile, level, pixel format, frame rate, audio codec, or resolution. Re-encoding is required when the playback device cannot decode the original stream.

An M2TS extension alone does not create a playable Blu-ray or AVCHD disc. Disc authoring also requires compliant GOP structure, bitrate limits, audio formats, menus or playlists, and the directory structure expected by the target standard. Test the output with ffprobe output.m2ts and the intended hardware before authoring or distributing it.