Convert RM to HEVC — Free Online Tool
Convert legacy RealMedia (.rm) files to HEVC (.hevc) using the libx265 encoder, dramatically reducing file size while preserving video quality through H.265's superior compression efficiency. Ideal for modernizing old streaming-era video archives that were encoded with proprietary RealNetworks codecs.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your RM file here
or click to browse
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
RealMedia files typically contain video encoded with RealVideo codecs and audio encoded with RealAudio, both proprietary formats from RealNetworks. During this conversion, FFmpeg decodes the RealMedia container and its streams entirely, then re-encodes the video using libx265, the open-source H.265/HEVC encoder. This is a full transcode — not a remux — because HEVC is a completely different codec from RealVideo. The output is a raw HEVC bitstream file (.hevc) containing only the video stream; audio from the source is dropped since the HEVC container format does not support audio tracks. The CRF 28 quality setting tells libx265 to use constant rate factor encoding, targeting perceptually consistent quality rather than a fixed bitrate.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary, the open-source multimedia processing engine that handles decoding the RealMedia input and encoding the HEVC output entirely within your browser via WebAssembly. |
-i input.rm
|
Specifies the input RealMedia file. FFmpeg will detect the .rm container and invoke the appropriate RealVideo and RealAudio decoders to unpack the compressed streams for processing. |
-c:v libx265
|
Selects libx265 as the video encoder, which implements the H.265/HEVC standard. This replaces the proprietary RealVideo codec from the source with a modern, widely-supported open standard capable of much higher compression efficiency. |
-crf 28
|
Sets the Constant Rate Factor to 28, which is the libx265 default. This controls the perceptual quality of the HEVC output — the encoder dynamically adjusts bitrate frame-by-frame to maintain consistent visual quality at this level, resulting in smaller files for simpler scenes and higher bitrates for complex motion. |
-x265-params log-level=error
|
Passes a parameter directly to the libx265 encoder to suppress its verbose per-frame logging output, so only actual errors are printed to the console. This does not affect the encoded video in any way. |
output.hevc
|
Specifies the output filename with the .hevc extension, which tells FFmpeg to write a raw H.265 Annex B bitstream. Note that this raw format contains only the video stream — no audio, no container metadata, and no timestamp information. |
Common Use Cases
- Digitally archiving old RealMedia video files from the late 1990s or early 2000s into a modern, space-efficient format for long-term storage
- Extracting and re-encoding the video track from .rm files found on vintage CD-ROMs, software bundles, or internet archive downloads for playback on modern devices
- Reducing the storage footprint of a large collection of legacy RealMedia streaming videos by leveraging HEVC's roughly 2x compression advantage over older codecs
- Preparing video-only HEVC bitstreams from RealMedia sources for ingestion into professional video editing or transcoding pipelines that accept raw H.265 streams
- Converting RealMedia clips for use as reference material or footage in video projects where the proprietary RealVideo codec is not supported by the editing software
Frequently Asked Questions
No. The .hevc output format is a raw video bitstream and does not support audio tracks. Only the video stream from your RealMedia file will be encoded into the output. If you need to preserve the audio, consider converting to a container format like MKV or MP4 that supports both HEVC video and audio streams simultaneously.
RealMedia files use proprietary RealVideo codecs (such as RV40) that are completely incompatible with the HEVC/H.265 standard. There is no shared codec between the two formats, so FFmpeg must fully decode the RealVideo stream and then re-encode every frame using libx265. This means the conversion is CPU-intensive and will take longer than a simple remux, but the result is a standards-compliant HEVC bitstream playable on modern hardware.
HEVC typically achieves roughly twice the compression efficiency of older codecs like RealVideo, so in many cases the output file will be smaller than the original despite being re-encoded at a reasonable quality level. However, CRF 28 is a moderate quality setting, and results vary depending on the source material's resolution and complexity. Very old, low-resolution RealMedia files may not see dramatic size reductions since the source content itself is already heavily compressed and low in detail.
CRF stands for Constant Rate Factor, and for libx265 it ranges from 0 (lossless) to 51 (lowest quality). A value of 28 is the libx265 default and produces a reasonable balance of quality and file size for most content. To improve output quality, lower the CRF value — for example, replace '-crf 28' with '-crf 18' for noticeably higher fidelity at the cost of a larger file. To reduce file size further, increase the value to '-crf 35' or higher, accepting more compression artifacts.
The single-file command shown is not directly a batch command, but you can adapt it for batch processing in a terminal. On Linux or macOS, use a shell loop: 'for f in *.rm; do ffmpeg -i "$f" -c:v libx265 -crf 28 -x265-params log-level=error "${f%.rm}.hevc"; done'. On Windows Command Prompt, use 'for %f in (*.rm) do ffmpeg -i "%f" -c:v libx265 -crf 28 -x265-params log-level=error "%~nf.hevc"'. This is especially useful for large collections of archived RealMedia files.
The libx265 encoder is unusually verbose by default, printing detailed encoding statistics and informational messages to the console during every conversion. The '-x265-params log-level=error' flag suppresses all of that output, only showing messages if an actual error occurs. This keeps the FFmpeg output readable and is purely a cosmetic change — it has no effect on the quality or content of the encoded HEVC video.
Technical Notes
RealMedia (.rm) files were designed specifically for low-bandwidth internet streaming and typically contain video at resolutions ranging from 240p to 480p encoded with RealVideo codecs (RV10 through RV40). FFmpeg's RealVideo decoder support is reasonably mature for common variants, but some heavily DRM-protected or obscure RealMedia variants may fail to decode correctly. Because the source content is already lossy-compressed, re-encoding to HEVC introduces a second generation of lossy compression — some quality loss compared to the original RealMedia file is inevitable, though at CRF 18–23 the degradation is generally imperceptible for archival purposes. The output .hevc file is a raw Annex B bitstream with no container wrapper, meaning it lacks metadata such as frame rate, pixel aspect ratio hints, and timestamps that would normally be stored in a container. Most media players will require the HEVC stream to be wrapped in an MKV or MP4 container for reliable playback. Subtitle, chapter, and multiple audio track features are not supported by either format in this workflow.