Convert RMVB to HEVC — Free Online Tool
Convert RMVB video files to HEVC (H.265) format using libx265 encoding directly in your browser. HEVC's superior compression efficiency makes it ideal for archiving older RealMedia content at significantly smaller file sizes without sacrificing visual quality.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your RMVB file here
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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
RMVB files use RealNetworks' proprietary RealVideo codec, which cannot be remuxed directly into HEVC — the video stream must be fully decoded and re-encoded using the libx265 encoder. This is a full transcoding operation: every frame of the RealVideo stream is decompressed and then recompressed using the H.265 codec at CRF 28, which targets visually consistent quality rather than a fixed bitrate. Because HEVC is a raw bitstream format (not a container like MKV or MP4), the output .hevc file contains only the video elementary stream. Audio streams present in the RMVB file are not carried over, as the HEVC format does not support audio tracks.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles the full decode-encode pipeline required for this conversion — reading the proprietary RealMedia container, decoding the RealVideo stream, and re-encoding it using the libx265 H.265 encoder. |
-i input.rmvb
|
Specifies the input RMVB file. FFmpeg automatically detects the RealMedia container and the enclosed RealVideo stream, preparing it for decoding before the libx265 encoder processes each frame. |
-c:v libx265
|
Sets the video encoder to libx265, the open-source H.265/HEVC encoder. This is what transforms the decoded RealVideo frames into a modern H.265 bitstream, enabling the significant file size reduction HEVC is known for. |
-crf 28
|
Sets the Constant Rate Factor to 28, which is the recommended default quality level for libx265. This value is roughly perceptually equivalent to CRF 23 in H.264, targeting good visual quality while taking full advantage of H.265's superior compression efficiency over the original RMVB source. |
-x265-params log-level=error
|
Passes a parameter directly to the libx265 encoder that suppresses its per-frame encoding progress messages. Without this flag, libx265 outputs verbose statistics for every encoded frame, making conversion logs difficult to read — this keeps output clean without affecting the encoded video. |
output.hevc
|
Specifies the output filename with the .hevc extension, indicating a raw H.265 elementary bitstream file. Unlike a container format such as MP4 or MKV, this file holds only the encoded video stream and carries no audio, subtitles, or metadata from the original RMVB. |
Common Use Cases
- Archiving a large collection of older anime or foreign films downloaded in RMVB format during the early 2000s by re-encoding them to H.265 for long-term storage at dramatically reduced file sizes
- Extracting a clean H.265 video stream from an RMVB source file to then manually mux into an MKV or MP4 container with separate audio using FFmpeg
- Converting RMVB content for playback on modern devices or media players that have dropped support for the legacy RealVideo codec but support HEVC hardware decoding
- Preparing RMVB-sourced video for upload to platforms that accept raw H.265 streams or require modern codec formats by transcoding away from the proprietary RealMedia codec
- Reducing the storage footprint of RMVB video libraries, taking advantage of H.265's roughly 40–50% size reduction over comparable H.264 encodes at the same perceptual quality
Frequently Asked Questions
No. The HEVC format is a raw video elementary stream and does not support audio tracks, chapters, or subtitles. Only the video content from your RMVB file will be encoded into the output .hevc file. If you need to preserve the audio, you should use a container format like MKV or MP4 as your output target instead, where you can carry the libx265 video stream alongside an audio track.
Unlike container-swap conversions (such as MKV to MP4 with matching codecs), this conversion requires a full decode-and-encode cycle on every video frame. The RMVB file's RealVideo stream must first be decoded from the proprietary RealNetworks codec, then each frame is re-encoded using libx265. H.265 encoding is also computationally intensive by design — the codec trades encoder complexity for better compression, so it is inherently slower than H.264 encoding at equivalent quality settings.
The CRF scale means different things for libx264 and libx265. A CRF of 23 is the default for H.264, while CRF 28 is the default for H.265 — and these two values are intended to produce roughly equivalent perceptual quality. This is because the libx265 encoder's CRF scale is calibrated to account for the codec's improved compression efficiency. So despite the higher CRF number, the H.265 output at CRF 28 should look visually similar to a CRF 23 H.264 encode, but at a noticeably smaller file size.
Results vary significantly depending on the original RMVB file's bitrate and the quality of the source RealVideo encode. H.265 typically achieves 40–50% better compression than H.264 at equivalent quality, but RMVB files often already use aggressive variable bitrate compression. In practice, you can expect the HEVC output to be meaningfully smaller than the RMVB source in most cases, though heavily compressed or low-resolution RMVB sources may show diminishing returns since re-encoding cannot recover detail lost in the original compression.
You can change the CRF value by modifying the number after -crf in the command. Lower values produce higher quality and larger files (CRF 18 is near-visually lossless for most content), while higher values produce smaller files with more compression artifacts (CRF 35+ is suitable for low-quality archival). For example: ffmpeg -i input.rmvb -c:v libx265 -crf 20 -x265-params log-level=error output.hevc would produce a higher-quality encode than the default CRF 28. The valid range for libx265 is 0 (lossless) to 51 (lowest quality).
Yes. On Linux or macOS, you can loop over all RMVB files in a directory with a shell command: for f in *.rmvb; do ffmpeg -i "$f" -c:v libx265 -crf 28 -x265-params log-level=error "${f%.rmvb}.hevc"; done. On Windows Command Prompt, use: for %f in (*.rmvb) do ffmpeg -i "%f" -c:v libx265 -crf 28 -x265-params log-level=error "%~nf.hevc". The browser-based tool processes one file at a time, so the local FFmpeg command is especially practical for large batch conversions of RMVB libraries.
Technical Notes
RMVB (RealMedia Variable Bitrate) uses RealNetworks' proprietary RealVideo codec, which is not natively supported by most modern playback hardware or software. Converting to HEVC requires a complete decode of the RealVideo stream, meaning any quality loss already present in the RMVB source is baked into the output — re-encoding cannot recover detail that was discarded during the original RMVB compression. The output .hevc file is a raw H.265 elementary bitstream without a container wrapper, so it lacks support for audio, subtitles, chapters, or metadata. Most media players cannot directly play a raw .hevc file; it is typically used as an intermediate step before muxing into a container. The -x265-params log-level=error flag suppresses the verbose per-frame encoding statistics that libx265 emits by default, which keeps the conversion output readable without affecting encoding quality. RMVB files frequently contain only a single audio and video track, so the lack of multiple audio track support in this conversion is rarely a practical limitation. Hardware HEVC decoding is widely available on devices manufactured after 2016, making the output broadly compatible for future playback.