Free online RM to H264 converter

Older RealMedia recordings may not open in current editors, phones, or playback devices that expect H.264 video. Converting them to H.264 in an MP4 container makes the video usable in those workflows and easier to share.

What the RM format is

RM is a RealMedia container used for video and audio, commonly encoded with RealVideo and RealAudio. Files were created with tools such as RealProducer and distributed for playback in RealPlayer; RM files are now most often found in older video libraries and archived web media.

What the H.264 format is

H.264, also called AVC, is a video codec rather than a container. It is widely supported by editing software, browsers, phones, and TVs. H.264 video is commonly stored in an MP4 file, which can also hold AAC audio.

How to convert RM to H.264

Online on 101convert.com

1. Open the RM-to-H.264 converter page on 101convert.com and upload the RM file.
2. Start the conversion and wait for it to finish. The conversion runs on the service's server with FFmpeg; a per-file size limit is shown on the page.
3. Download the converted file.

Offline with desktop software

FFmpeg is free, open-source software for Windows, macOS, and Linux. In a terminal, run:

ffmpeg -i "input.rm" -c:v libx264 -crf 23 -preset medium -pix_fmt yuv420p -c:a aac -b:a 128k "output.mp4"

Replace the input filename with your file's name. The command encodes video as H.264 and audio as AAC in an MP4 container. Lowering -crf increases quality and file size; raising it reduces both. FFmpeg must be built with support for decoding the streams in the RM file and encoding with libx264.

Quality and compatibility

Conversion re-encodes the video, so it can lose quality; H.264 cannot restore detail missing from the RM source. The CRF setting controls the trade-off, and a higher-quality setting cannot make the output better than the original. Rewrapping alone is not enough when the video stream must change from RealVideo to H.264.