Free online M2T to M4A converter

A phone, music player, or editing application may accept M4A but reject an M2T file. Converting extracts the audio stream from the MPEG-2 transport stream and stores it in an audio-focused container.

What the M2T format is

M2T is usually an MPEG-2 transport stream file, commonly produced by Sony HDV camcorders and HDV capture software. Although an M2T file normally contains video, it also carries one or more audio streams, typically MPEG-1 Layer II in HDV material; other transport streams may contain AC-3 or AAC audio.

You encounter M2T files in camera archives, video-capture folders, broadcast recordings, and older editing projects. Converting to M4A normally means removing the video stream and encoding or copying the embedded audio.

What the M4A format is

M4A is an audio-only MPEG-4 container. It commonly contains AAC audio for small files and broad playback compatibility, or Apple Lossless Audio Codec (ALAC) for lossless storage. The .m4a extension identifies the container, not the exact audio codec.

M4A suits phones, music libraries, media players, podcasts, and audio-editing applications. AAC produces substantially smaller files than uncompressed audio at comparable listening quality, while ALAC preserves the source samples but usually creates larger files.

How to actually convert M2T to M4A

FFmpeg is suitable for extracting and converting the audio stream on Windows, macOS, and Linux.

1. Install FFmpeg and open a terminal in the folder containing the M2T file.
2. Inspect the available streams with ffprobe -hide_banner input.m2t. Note the audio stream number if the file contains multiple audio tracks.
3. Extract the first audio stream and encode it as AAC with ffmpeg -i input.m2t -map 0:a:0 -vn -c:a aac -b:a 192k output.m4a.

-map 0:a:0 selects the first audio stream, -vn excludes video, and -b:a 192k sets the AAC bitrate. Use -map 0:a:1 for the second audio stream, or replace the output filename with one ending in .m4a.

If the source already contains AAC and the target players support that stream, avoid another lossy encode with ffmpeg -i input.m2t -map 0:a:0 -vn -c:a copy output.m4a. Stream copying is faster and retains the original audio data, but it may fail or produce limited compatibility when the source codec is MPEG audio or AC-3.

For lossless output, use ffmpeg -i input.m2t -map 0:a:0 -vn -c:a alac output.m4a. This cannot restore quality already lost in the M2T source and may not play on devices that support AAC M4A but not ALAC.

You can also convert the file for free on the 101convert.com website without installing software.

Quality, compatibility, and limitations

Re-encoding MPEG audio or AC-3 to AAC causes a generation loss; choose a sufficiently high bitrate such as 192 or 256 kbps for general stereo listening, or use ALAC when preserving the decoded samples matters. No conversion can recover detail removed by the original recording or a previous lossy encode.

Some M2T files contain several language, commentary, or channel-layout tracks. Check the ffprobe output before converting so that the selected stream is the intended one. M4A generally preserves audio but may not retain all transport-stream metadata, timecode, subtitles, or video-associated information.