Convert M2TS to RMVB — Free Online Tool
Convert M2TS Blu-ray and AVCHD footage to RMVB format using H.264 video and AAC audio encoding, shrinking large high-definition transport stream files into compact, streamable RMVB packages. This tool runs entirely in your browser via FFmpeg.wasm — no upload required, and files up to 1GB are processed for free.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your M2TS file here
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Free — no uploads, no signups. Your files never leave your browser.
Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
M2TS files are MPEG-2 Transport Stream containers typically carrying H.264 (AVC) or H.265 (HEVC) video alongside multi-channel audio such as Dolby TrueHD, DTS-HD, or AC-3 — formats not supported by RMVB. During conversion, FFmpeg re-encodes the video stream using the libx264 encoder (producing H.264 output) and transcodes the audio to AAC at 128k bitrate. Because RMVB does not support multiple audio tracks, subtitle streams, or lossless audio, all secondary audio tracks and embedded subtitles from the M2TS source are dropped. The CRF 23 setting controls video quality using constant-rate factor encoding, meaning the encoder dynamically adjusts bitrate to maintain perceptual quality rather than targeting a fixed file size.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In this browser tool, this runs as FFmpeg.wasm compiled to WebAssembly, executing entirely within your browser without sending the M2TS file to any server. |
-i input.m2ts
|
Specifies the input M2TS file — a BDAV MPEG-2 Transport Stream container, typically from a Blu-ray disc rip or AVCHD camcorder. FFmpeg will probe this file to identify all video, audio, and subtitle streams before processing. |
-c:v libx264
|
Re-encodes the video stream using the libx264 encoder, producing H.264 output compatible with the RMVB container. This is required because RMVB only supports H.264 video, regardless of what codec the source M2TS uses. |
-c:a aac
|
Transcodes the audio — whatever format the M2TS carries, including potentially lossless TrueHD, DTS-HD, or AC-3 — to AAC, which is one of the only two audio codecs supported by the RMVB container. |
-crf 23
|
Sets the Constant Rate Factor for the libx264 encoder to 23, the default quality level. For high-definition M2TS source material, lower values like 18 will better preserve Blu-ray-level detail; higher values like 28 will reduce file size at the cost of visible compression artifacts. |
-b:a 128k
|
Sets the AAC audio output bitrate to 128 kilobits per second. This is adequate for stereo audio but represents a significant downgrade if the M2TS source contains lossless surround sound such as Dolby TrueHD 7.1; increasing to 192k or 256k is recommended for music-heavy or high-fidelity source content. |
output.rmvb
|
Specifies the output filename with the .rmvb extension, telling FFmpeg to mux the encoded H.264 video and AAC audio into a RealMedia Variable Bitrate container. The .rmvb extension distinguishes it from fixed-bitrate .rm files and signals variable bitrate encoding to compatible players. |
Common Use Cases
- Sharing Blu-ray rips or AVCHD camcorder recordings on platforms or devices that historically supported RMVB playback but cannot handle raw M2TS transport streams
- Reducing the file size of large M2TS recordings from AVCHD camcorders for distribution over slower networks where RMVB's variable bitrate compression is advantageous
- Archiving HD content captured from Blu-ray sources into a legacy RMVB format for compatibility with older media players on Windows XP/Vista-era systems or older set-top boxes that support RealMedia
- Converting M2TS footage for use on networks or communities where RMVB was historically the dominant format for sharing compressed Asian-language video content
- Stripping the complex multi-track transport stream structure of an M2TS file down to a single-track, single-audio RMVB file for simpler playback in lightweight media players
Frequently Asked Questions
Yes, some quality loss is unavoidable. M2TS files from Blu-ray sources often contain high-bitrate H.264 or H.265 video and lossless audio (Dolby TrueHD or DTS-HD MA), whereas RMVB only supports lossy compression. The video is re-encoded with libx264 at CRF 23, which delivers good visual quality for most content, but the transcoding step introduces generational loss compared to the original. The audio is also transcoded from whatever the M2TS carries (which could be lossless) down to AAC at 128k, which is a noticeable reduction for high-fidelity audio.
They are discarded. RMVB does not support multiple audio tracks or embedded subtitle streams, so FFmpeg will select only the default (usually first) audio track from the M2TS file and encode it to AAC. All secondary audio tracks — such as director's commentary or alternate language tracks — and any PGS or other subtitle streams embedded in the M2TS are not carried into the output RMVB file. If subtitles are critical, you should burn them into the video before conversion or use a different output format.
RMVB predates M2TS by many years and was widely used throughout the late 1990s and 2000s for distributing compressed video online, particularly in East Asian internet communities, before modern formats like MP4 and MKV became dominant. M2TS is designed for Blu-ray disc authoring and broadcast capture, not internet distribution. Converting M2TS to RMVB is typically done to serve legacy playback ecosystems or specific archival requirements, not because RMVB offers any technical advantage over M2TS.
Adjust the -crf value to control quality. CRF ranges from 0 (lossless) to 51 (worst quality), with lower numbers producing larger, higher-quality files. For example, replacing -crf 23 with -crf 18 will produce noticeably sharper output closer to the M2TS source quality, while -crf 28 will give a smaller file with more compression artifacts. For high-definition M2TS source material, values between 18 and 23 are generally recommended to preserve the detail in the original footage.
Yes, on the command line you can use a shell loop to batch process files. On Linux or macOS, run: for f in *.m2ts; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.m2ts}.rmvb"; done. On Windows PowerShell, use: Get-ChildItem *.m2ts | ForEach-Object { ffmpeg -i $_.FullName -c:v libx264 -c:a aac -crf 23 -b:a 128k ($_.BaseName + '.rmvb') }. The browser-based tool processes one file at a time, so the desktop FFmpeg command is particularly useful for batch workflows or for files over 1GB.
No. RMVB does not support chapter markers, and Blu-ray-specific metadata embedded in the M2TS transport stream — such as disc title, chapter timestamps, and stream identifiers — will not be carried over. Additionally, M2TS files sometimes carry HDR metadata (if sourced from UHD Blu-ray) which is also not representable in RMVB. The output will be a plain single-track video file with only basic stream metadata.
Technical Notes
M2TS is a demanding source format because its MPEG-2 Transport Stream wrapper is designed for broadcast reliability rather than file efficiency, often containing null packets, multiple program streams, and high-bitrate video that can reach 40 Mbps or more on Blu-ray. FFmpeg handles M2TS demuxing well but may require probing a larger portion of the file to identify all streams. The RMVB container has a narrow codec compatibility window — only libx264 for video and AAC or MP3 for audio — which means any M2TS source using H.265/HEVC or VP9 video, or lossless audio formats like TrueHD or FLAC, must be fully re-encoded rather than stream-copied, making this a compute-intensive conversion for long or high-resolution files. Because RMVB uses a variable bitrate container structure, the resulting file size will vary significantly based on scene complexity in the source footage. One known limitation is that FFmpeg's RMVB muxer has historically had limited active development compared to MP4 or MKV muxers, so edge cases with unusual M2TS stream configurations (such as interlaced video or 4K UHD sources) may benefit from adding deinterlacing filters or scaling flags to the command.