MyMediaTools

Convert RMVB to MTS — Free Online Tool

Convert RMVB files — RealNetworks' variable bitrate streaming format — into MTS (AVCHD), the MPEG-2 Transport Stream container used by Sony and Panasonic camcorders. This tool re-encodes the video using H.264 (libx264) and audio using AAC, producing an MTS file compatible with broadcast workflows and professional camcorder ecosystems.

FFmpeg Command

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Estimated output:

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How It Works

RMVB files use RealVideo and RealAudio codecs inside RealNetworks' proprietary container, which is not natively supported by most modern editing or broadcast tools. Converting to MTS requires full re-encoding: the video is decoded from RealVideo and re-encoded using H.264 (libx264) with a CRF of 23, and the audio is decoded and re-encoded as AAC at 128k bitrate. The output is wrapped in an MPEG-2 Transport Stream (.mts) container — the same format written by AVCHD camcorders — making it compatible with video editors and broadcast systems that expect standard MTS footage. Because both the source and destination use lossy compression, each generation of re-encoding introduces some quality degradation; the CRF 23 default strikes a reasonable balance between file size and visual fidelity.

What Each Flag Does

Flag What it does
ffmpeg Invokes the FFmpeg binary — the open-source multimedia processing engine that powers this conversion both in the browser (via FFmpeg.wasm) and on the desktop command line.
-i input.rmvb Specifies the input file in RMVB format. FFmpeg will detect the RealMedia container and demux the RealVideo and RealAudio streams for decoding before re-encoding them into the MTS output.
-c:v libx264 Selects H.264 as the output video codec using the libx264 encoder. This is required because RealVideo (the native RMVB video codec) is not compatible with the MTS container; H.264 is the standard video codec for AVCHD/MTS files.
-c:a aac Re-encodes the audio stream as AAC, replacing the original RealAudio codec with a format that is natively supported within the MPEG-2 Transport Stream container used by MTS.
-crf 23 Sets the Constant Rate Factor for the libx264 encoder to 23, which is the default quality level. A lower value (e.g., 18) produces higher quality at a larger file size, while a higher value (e.g., 28) compresses more aggressively — relevant when downscaling RMVB source content that already has RealVideo compression artifacts.
-b:a 128k Sets the AAC audio output bitrate to 128 kilobits per second, a standard quality level appropriate for most RMVB source material (which is typically encoded at similar or lower audio bitrates in its original RealAudio stream).
output.mts Specifies the output filename with the .mts extension. FFmpeg uses this extension to select the MPEG-2 Transport Stream muxer, which wraps the H.264 video and AAC audio into the AVCHD-compatible MTS container format.

Common Use Cases

  • Importing old RMVB video archives into Sony or Panasonic camcorder-based editing workflows that require native AVCHD/MTS input
  • Preparing RMVB-sourced footage for ingestion into broadcast editing systems like Avid or Adobe Premiere that handle MTS natively but reject RealMedia files
  • Migrating a collection of RMVB films or TV episodes downloaded in the early 2000s into a more durable, widely supported container for long-term archiving
  • Combining RMVB source clips with genuine camcorder MTS footage in a multicam edit where the NLE requires consistent container and codec formatting
  • Converting RMVB content for playback on Blu-ray authoring pipelines or set-top devices that support AVCHD transport streams but not RealMedia
  • Providing a standardized MTS output from RMVB source material when delivering content to a post-production house that mandates MPEG Transport Stream deliverables

Frequently Asked Questions

Because RMVB already uses lossy RealVideo compression, re-encoding it to H.264 inside MTS is a lossy-to-lossy conversion, meaning some quality is always lost in the second encoding pass. At the default CRF 23 setting the result is generally clean for typical RMVB content (360p–720p), but the original RealVideo artifacts may become slightly more visible. If quality is critical, lower the CRF value (e.g., -crf 18) in the FFmpeg command to give the H.264 encoder more bits to work with.
MTS is the native container format of AVCHD camcorders and is specifically expected by certain professional NLEs and broadcast ingest pipelines that treat MTS clips as camcorder originals. If you are integrating RMVB-sourced content into a Sony or Panasonic AVCHD-based project, or delivering to a broadcast facility that mandates MPEG-2 Transport Stream files, MTS is the correct target. For general playback, MP4 would typically be a simpler choice.
MTS does support subtitles and multiple audio tracks at the container level, but RMVB does not support embedded subtitles or multiple audio tracks, so there is nothing to carry over from the source. If you have external subtitle files (.srt, .ass) associated with your RMVB content and want to embed them in the MTS output, you would need to modify the FFmpeg command to include the subtitle stream explicitly.
To improve video quality, lower the -crf value — for example, change -crf 23 to -crf 18 (lower numbers mean higher quality and larger files). To adjust audio quality, change the -b:a value; replacing 128k with 192k or 256k will produce cleaner audio at the cost of a slightly larger file. Both parameters can be tuned independently depending on whether your RMVB source is video-heavy or dialogue-heavy content.
Yes. On Linux or macOS you can use a shell loop: `for f in *.rmvb; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.rmvb}.mts"; done`. On Windows Command Prompt you can use `for %f in (*.rmvb) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "%~nf.mts"`. The in-browser tool processes one file at a time, so the desktop FFmpeg command is the recommended approach for batch workflows.
Authentic AVCHD camcorder MTS files contain specific metadata, interlacing characteristics, and bitrate profiles tied to the recording device. This conversion produces an MTS container with H.264 video and AAC audio, which is structurally valid but lacks camcorder-specific metadata such as recording timestamps, GPS tags, or device profiles. Most editors will import and play the file correctly, but forensic or metadata-sensitive workflows may detect that the file was not recorded by a camcorder.

Technical Notes

RMVB (RealMedia Variable Bitrate) uses a proprietary container that encapsulates RealVideo (often RV40) and RealAudio (often Cook or AAC variants) streams. Neither codec is directly compatible with the MTS/AVCHD container, so the conversion cannot use stream copying — both video and audio must be fully decoded and re-encoded. The output video codec is H.264 via libx264, which is the standard video codec for AVCHD and is universally accepted by MTS-compatible tools. The audio output is AAC, which is also valid within the MPEG-2 Transport Stream wrapper used by MTS. RMVB's variable bitrate nature means frame complexity varies substantially, so the CRF-based encoding used here is well-suited: libx264 will allocate more bits to complex scenes automatically. RMVB files do not carry subtitle streams, chapter markers, or multiple audio tracks, so none of those features are relevant to this conversion path. The resulting MTS files will stream efficiently due to the MPEG Transport Stream's packetized structure, but they will not carry the proprietary AVCHD directory structure (BDMV/AVCHD folders) — they are raw MTS stream files, which is what most editing applications and this conversion tool produce.

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