RM to OPUS Converter

RM to Opus — the Right Target for a RealAudio Rescue?

Most people arriving here are emptying a folder of old .rm captures — streamed lectures, internet-radio recordings, early podcasts — and deciding what to move them into. This page extracts the audio from a RealMedia file and re-encodes it as Opus; the RealVideo picture, if there is one, is discarded. The short answer on target choice: Opus if the file is going into an archive or a modern app, MP3 if it has to play on hardware you do not control.

Whatever you pick, the transcode is lossy-to-lossy. RealAudio threw detail away when the stream was first encoded and no target codec can rebuild it. The goal is a file that current software will still open in ten years, not a better-sounding one.

Opus vs MP3 vs AAC for a RealAudio Source

When Opus Is the Right Target

• The recording is speech — a lecture, an interview, a talk-radio capture. Opus at 32–64 kbit/s mono is where the codec is strongest, and RealAudio speech captures were usually well below that to begin with.
• You are building an archive and want an open, royalty-free container that current tooling will keep supporting.
• You are self-hosting the audio on a page, where the browsers that matter all decode Opus.
• Size matters and the original was already low bitrate — Opus wastes fewer bits than MP3 reaching the same result.

When to Pick MP3 or AAC Instead

• The file has to play on a car head unit, an older smart TV, a hardware podcast player, or anything else you cannot update. Use RM to MP3.
• You are feeding an Apple-centric library or an app that expects .m4a. Use RM to AAC.
• Someone else is going to receive the file and you will not be there to explain what .opus is.
• The source .rm still has video you want to keep — in that case do not extract audio at all; convert the whole file with RM to MP4.

How to Convert RM to Opus

1. Upload Your RM File: Drag and drop the .rm file onto the page or click "Add Files". Multiple captures can be queued and they all run with the same settings, over an encrypted connection to our servers.
2. Set the Bitrate: Audio Codec is fixed to Opus on this page. Under File Compression the page opens on Quality Preset; switch to Custom Bitrate, Constant Bitrate (an 8–384 kbit/s list) or Specific file size to control the result precisely. For a lossy RealAudio source this is the setting that matters most.
3. Adjust Audio Channel, Sample Rate or Trim: Drop Audio Channel to MONO for a spoken-word capture, pick an explicit Audio Sample Rate, and use Trim with a start time and duration to export only part of a long recording.
4. Convert and Download: Click Convert and save the .opus file. No sign-up, no watermark; uploads and outputs are deleted automatically after a few hours.

Sample Rates: What Actually Comes Out

Opus does not have arbitrary sample rates. The Audio Sample Rate dropdown on this page lists Original, 8000, 12000, 16000, 24000, 44100 and 48000 Hz, but Opus only codes at 8, 12, 16, 24 and 48 kHz — so anything else, including a 44100 Hz choice and an "Original" that resolves to a rate Opus does not have, is snapped to the nearest supported value before encoding. It does not fail; it lands on a neighbour.

One thing that surprises people afterwards: an Opus stream always decodes at 48 kHz no matter what went in, so every .opus file reports 48000 Hz when you probe it. We confirmed this on our own test files — encoding the same RealMedia source at 8000, 24000 and 48000 Hz produced three different file sizes (73.6 KB, 92.8 KB and 101 KB for the same clip) but all three report 48000 Hz. The lower settings narrow the coded audio bandwidth; they do not produce a low-rate file you can read off the header.

Frequently Asked Questions

Does converting RM to Opus keep the video?

No. This is an audio extraction: the RealVideo picture in the .rm file is decoded away and you get an audio-only .opus file. That is what you want for lectures, internet-radio captures, early podcasts and music streams. If you need the picture too, convert the whole file with RM to MP4 instead of extracting the soundtrack.

Will Opus sound better than the RealAudio inside my .rm file?

No, and that is a property of lossy encoding rather than a limitation of this tool. RealMedia files carry RealAudio 1.0/2.0, Cook, Sipro, ATRAC3, AC-3, RealAudio Lossless or AAC, and all but the lossless one discarded detail permanently when the file was made. Opus re-encodes what survived. The win is portability and size, not fidelity — so choose a bitrate that avoids stacking obvious new artifacts and stop there.

What Opus bitrate should I pick for an old streaming capture?

Roughly match the source rather than exceeding it. Speech captures — the common case for .rm files — sound clean at 32–64 kbit/s mono, which is the range Opus was tuned for. A music or full-band stream around 96–128 kbit/s should be matched at about the same rate. Setting 192 kbit/s on a 64 kbit/s RealAudio source just stores the same lost-detail audio in a bigger file. If you do not know the source rate, the Quality Preset at its higher settings aims well up Opus's 8–512 kbit/s range, which is generous for this kind of material; Custom Bitrate gives you a number you control.

Why does my .opus file say 48 kHz when I chose 24000 Hz?

Because that is how Opus works. The codec always decodes to 48 kHz, and the container header reflects that regardless of the rate you encoded at — the sample-rate choice controls the coded audio bandwidth, not the number a media player displays. We verified this directly: the same source encoded at 8000, 24000 and 48000 Hz produced three noticeably different file sizes but identical 48000 Hz readings. If a downstream tool needs a specific literal sample rate in the header, Opus is the wrong container for it; use RM to WAV or RM to MP3.

Why does 44100 Hz appear in the dropdown if Opus cannot use it?

The sample-rate dropdown is shared across every audio target, so it lists the rates people expect to see. On this page the value is validated against Opus's rate list before the encoder is invoked and snapped to 48000 Hz, which is why the job succeeds instead of erroring. Running FFmpeg by hand with -ar 44100 and the Opus encoder produces "Specified sample rate 44100 is not supported by the libopus encoder" and stops — the validation layer here is what prevents that.

My .opus file will not play on a phone, TV or car stereo — now what?

That is a device-support gap, not a bad conversion. Current versions of Chrome, Firefox and Edge decode Opus, Safari does on recent macOS and iOS, and modern phones handle it through the system audio stack — but a long tail of older smart TVs, car infotainment units and basic hardware players never added it. Do not fight it: re-run the conversion as RM to MP3, which plays essentially everywhere, and keep the Opus copy for your archive.

Can I trim a long RealMedia recording instead of converting all of it?

Yes, in the same pass. Set Trim to a time range and enter a start time and duration, in seconds or as HH:MM:SS.sss, and only that span is encoded. If you would rather cut the source file first — for example to get a large .rm under the upload size that is comfortable for your connection — the Video Cutter accepts .rm and .rmvb directly. The audio-only cutter does not accept RealMedia, so trim the video source, not the audio.

My RM file will not open at all — is it broken?

Usually it is not a media file. .ram files are playlist pointers containing a URL rather than audio, and partially downloaded RTSP captures often end mid-packet. Confirm the file is a complete .rm of a plausible size before assuming the converter is at fault. If it is the variable-bitrate variant, use RMVB to Opus, which is the same conversion with the .rmvb container on the input side.

What happens to my files after the conversion finishes?

The .rm upload travels over an encrypted connection, is decoded and re-encoded on our servers, and both the source and the .opus output are deleted automatically after a few hours. No account is needed, nothing is watermarked, and files are never shared or made public.