RM to AV1 Converter
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Supports: RM
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Need help?Convert RM to AV1
AV1 is the Alliance for Open Media's royalty-free video codec, published as the AV1 Bitstream and Decoding Process Specification and designed to beat H.264 and HEVC on compression efficiency. Converting an old RealMedia clip to AV1 is the right move when you are archiving a library and want the smallest durable files you can get, or when the destination is a modern AV1-aware pipeline.
Two things are worth knowing before you start. AV1 is not a container, so what you download is a Matroska file carrying an .av1 name — open it in a hex viewer and it begins with the EBML signature 1A 45 DF A3, the same four bytes that start every .mkv. Renaming it to .mkv is safe and makes most players and file managers behave. And AV1's efficiency advantage is largest on high-resolution material; on a 320×240 RealMedia clip the absolute saving is small while the encode is considerably slower than H.264. If you only want the clip to play, RM to MP4 is the pragmatic answer.
How to Convert RM to AV1
- Upload Your RM File: Drag the
.rmonto the page or click "Add Files" to browse. Several clips can be queued and converted with one set of settings. - Choose an Audio Codec: Video Codec is fixed to AV1 on this page, but Audio Codec offers Opus (the default), AAC, AC3, EAC3, DTS, FLAC, MP2, MP3 and Vorbis. Opus is the right pairing for AV1 in a Matroska file; switch to AAC or MP3 only if a specific player is fussy.
- Set Quality, Resolution or Trim (Optional): File Compression opens on Quality Preset with "Very High (Recommended)" selected. Constant Quality gives you a direct CRF slider on AV1's 16–63 scale, opening at 30, and Constraint Quality adds Qmin and Qmax bounds; Specific file size, Constant Bitrate and Variable Bitrate are also available. Video resolution keeps the original by default, and Trim exports a start time and duration.
- Convert and Download: Click Convert and save the file. Files are uploaded over an encrypted connection, processed on our servers and deleted automatically after a few hours. No sign-up, no watermark.
Rate Control on This Page
| Mode | What you name | Notes |
|---|---|---|
| Quality Preset | A quality band rather than a number | The opening mode, with "Very High (Recommended)" pre-selected. On a real video source it scales relative to the source's own bitrate |
| Constant Quality | A CRF value on AV1's 16–63 scale | Opens at 30. Lower is better quality and a bigger file; this is the mode most AV1 encoding guidance is written for |
| Constraint Quality | A CRF value plus Qmin, Qmax and a maximum bitrate | Use when you need a quality target that cannot spike past a bitrate ceiling |
| Constant Bitrate / Variable Bitrate | An explicit bitrate in bps, Kbps or Mbps | Use when a downstream system needs a predictable rate |
| Specific file size | A target size, with an Auto Scale option | Use when you have a hard size budget; resolution drops if needed to reach it |
For a RealMedia source, CRF 30 to 35 is a sensible band. These clips were already compressed hard for narrowband streaming, so a very low CRF spends a lot of encoding time faithfully reproducing the first encoder's artefacts rather than any real detail.
AV1 Compared with the Practical Alternatives
| Target | Efficiency | Playback reach | Encode speed | Best for |
|---|---|---|---|---|
| AV1 (this page) | Highest of the four | Chrome 70+, Firefox 67+, Edge 121+, Safari 17+ partial — around 94% of tracked traffic | Slowest | Archiving a library at minimum size |
| H.265 / HEVC | High | Wide on hardware, patent-encumbered on the web | Moderate | Apple and TV ecosystems |
| H.264 in MP4 | Moderate | Essentially universal | Fast | Just making the clip play, everywhere |
| VP9 in WebM | High | All major browsers except older Safari | Slow | Web delivery without patent questions |
Frequently Asked Questions
Why is my downloaded file called .av1, and what is it really?
AV1 is a codec, not a container, so a file has to be wrapped in something. We wrap it in Matroska and give it the .av1 name that matches the conversion you asked for. The bytes are a standard .mkv: the file opens with the EBML signature 1A 45 DF A3, and the audio track sits inside it exactly as it would in any Matroska file. If a player refuses to open it, rename the extension to .mkv and try again — nothing about the file changes.
What audio does the AV1 output get?
Opus, unless you pick something else. Opus and AV1 are the standard royalty-free pairing and Matroska carries Opus natively, so it is the sensible default. The RealAudio soundtrack from your .rm is decoded and re-encoded into it — there is no stream copy anywhere in this pipeline. If a target player chokes on Opus, AAC and MP3 are both in the Audio Codec list.
Is AV1 actually worth it for a 320×240 RealMedia clip?
Honestly, often not. AV1's compression advantage scales with resolution and detail, and a low-bitrate legacy streaming clip has little of either — you may save a few hundred kilobytes at the cost of a much longer encode and a narrower set of players. AV1 earns its keep when you are converting a whole archive and the aggregate saving matters, or when the destination is already an AV1 pipeline. For a single clip you want to watch, MP4 is the better answer.
Which browsers and devices play AV1?
Chrome from version 70, Firefox from 67, Edge from 121, and Safari from 17 with partial support that depends on the device having an AV1 decoder — together about 94% of tracked browser traffic. Internet Explorer and Opera Mini have no support at all. On the desktop, VLC and mpv play AV1 regardless of browser support. Hardware AV1 decoding is common on recent phones, GPUs and streaming boxes but is not something you should assume on older hardware.
What CRF value should I use?
Switch File Compression to Constant Quality and start at the 30 the slider opens on. AV1's scale runs 0–63, where lower means higher quality and a larger file, and the steps are not equivalent to H.264's 0–51 scale — an AV1 CRF of 30 is not the same target as an H.264 CRF of 30. For a RealMedia source, 30–35 keeps the file small without adding visible damage on top of the original streaming compression.
Why is this conversion slower than converting to MP4?
Because AV1 is a far more complex codec to encode. It has more prediction modes, larger and more flexible block partitions and more sophisticated entropy coding than H.264, and the encoder has to evaluate all of that to earn its compression advantage. That is the trade AV1 makes: encoding time in exchange for smaller files at the same quality. Decoding is comparatively cheap, which is why playback is not the bottleneck.
Will AV1 make my old clip look better?
No. No re-encode can add detail the source never recorded, and RealMedia clips were compressed aggressively for dial-up and early broadband. AV1 will preserve what is there more efficiently than H.264 would, so at any given file size it will look less bad — but it cannot undo the first encoder's decisions. There is no deinterlacing or HDR processing in this pipeline either, so an interlaced source keeps its combing.
Can I convert only part of the clip?
Yes. Set Trim to Time Range, give a start time and a duration in seconds or HH:MM:SS.sss, and only that section is encoded. Since AV1 encoding is the slow part of this conversion, trimming first is also the fastest way to test settings on a long file. For a visual cut of the source instead, video-cutter accepts RealMedia directly.
How are my files handled during the conversion?
Your RM file is uploaded over an encrypted connection, processed on our servers and deleted automatically after a few hours. Files are never shared or made public, there is no sign-up and no watermark. AV1 jobs take longer to process than most conversions, so leave the tab open while the encode runs.