RMVB to XviD Converter

RMVB to Xvid — Two Dead Ends, One Useful Bridge

RMVB is RealNetworks' RealMedia Variable Bitrate file, introduced in 2003 as the variable-rate sibling of .rm and normally carrying RealVideo 9 or 10 video with a Cook audio track. Almost nothing outside VLC and RealPlayer will open one today. Xvid is the open-source encoder for MPEG-4 Part 2 Advanced Simple Profile — the codec that DivX-certified DVD decks, in-car head units and 2005-era media boxes were built to read.

So this conversion is a bridge between one legacy world and another, and it is only worth taking if the destination is genuinely one of those old certified players. If the file is going to a phone, a browser, a smart TV or a modern editor, RMVB to MP4 is smaller at the same quality and plays essentially everywhere. This page does the Xvid job properly, and tells you what the .xvid file actually is.

What the .xvid File Really Contains

Xvid names a codec, not a container, so the extension cannot describe the file on its own. What you download is an AVI. We confirmed it by encoding through the same muxer the converter uses and reading the bytes back: the file opens 52 49 46 46 … 41 56 49 20 — RIFF … AVI — and the video stream carries the FourCC xvid, decoded as MPEG-4 Part 2. FFmpeg cannot even pick an output format from the .xvid extension on its own; the AVI muxer has to be named explicitly.

How to Convert RMVB to Xvid

1. Upload Your RMVB File: Drag the .rmvb onto the page or click "+ Add Files" to browse. Several files can queue and run with the same settings.
2. Leave Video Codec, Choose Audio Codec: Video Codec offers Xvid alone. Audio Codec opens on MP3, which is what a DivX/Xvid-certified deck expects; switch to AC3 only if the target device lists Dolby Digital, and avoid the PCM entries unless you want a very large file.
3. Pick a File Compression Mode: The default is Quality Preset, whose list runs Highest through Lowest with Very High (Recommended) pre-selected. Constant Quality exposes a quantiser slider from 1 to 31 that opens at 5. Specific file size, Constant Bitrate, Variable Bitrate and Constraint Quality are all available too.
4. Set Video resolution and Trim, Then Convert: Video resolution opens on Keep original. Trim opens on "Unchanged" and takes a Start time and a Duration. Click Convert to download. Files are uploaded over an encrypted connection, converted on our servers and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public.

How Quality Preset Behaves on Xvid

Xvid has no CRF mode, so Quality Preset cannot set a quality target the way it does for H.264. Instead it reads the video bitrate of your RMVB and scales it, then hands Xvid a variable-bitrate target with 1.5x headroom for busy scenes. The multipliers are fixed:

Two consequences worth knowing. First, the whole ladder is anchored to your source, so a low-bitrate RMVB download stays low-bitrate at every setting — the preset cannot make a bad source good. Second, "Highest" asks for more bits than the original stream carried, which buys you nothing but a bigger file, because the losses happened inside the RealVideo encode years ago. Very High is the honest ceiling here.

Common Errors and How to Fix Them

• "Nothing opens the file I downloaded" — rename it from .xvid to .avi. The bytes are already an AVI; players match on the extension and .xvid is not a registered container.
• "The picture has comb lines through motion" — the RMVB was interlaced and this converter does not deinterlace. The combing is baked into every frame of the output. Deinterlace in an editor before or after converting.
• "The output looks squashed or stretched" — RealMedia files sometimes carry non-square pixels. Keeping the resolution on "Keep original" preserves the source pixel aspect; any resize flattens it to square pixels, which is what distorts the picture. If you must rescale, use Width x Height and enter the display dimensions you actually want.
• "1080p in the Preset Resolutions list gave me an odd width" — Preset Resolutions sets the height only and lets the width follow the source's aspect ratio. Use Width x Height when an exact frame size matters.
• "The RMVB will not decode at all" — some RealMedia files are DRM-protected or use an unusual RealAudio variant. There is no online workaround for a protected file.
• "My file is .rm, not .rmvb" — the uploader matches on extension. Use the .rm route for those, or rename a copy.

Frequently Asked Questions

Why does the download end in .xvid instead of .avi?

Because the page's job is to produce a file named for the codec people ask for, and Xvid is a codec rather than a container. The bytes we write are a normal AVI — RIFF header, AVI form type, an xvid FourCC on the video stream — so renaming the download to .avi changes nothing about the content and makes every player recognise it. Do that first if something refuses to open the file; it fixes the great majority of "won't play" reports on this route.

Is any of this lossless? Can I keep the original RealVideo stream?

No on both counts. AVI has no way to carry RealVideo, so the RealVideo frames are decoded and re-encoded as MPEG-4 Part 2 — one full lossy generation on top of whatever RealNetworks' encoder already threw away. Nothing on this page copies the original stream through untouched. Keep the .rmvb if you might want the source again; treat the Xvid file as a delivery copy for a specific old player.

Which audio codec should I pick for a DivX-certified player?

MP3, which is already selected. The DivX Home Theater profiles that certified DVD decks and media boxes implement were built around MPEG-1 Layer III audio in AVI, and it is the safest choice by a wide margin. AC3 is worth trying if the device's spec sheet explicitly lists Dolby Digital. The PCM entries will write, but uncompressed audio in an AVI adds roughly 10 MB per minute for CD-rate stereo and many old players will not index it correctly.

What is the difference between Xvid and DivX here?

Both encode MPEG-4 Part 2 Advanced Simple Profile, so a file from either usually plays wherever the other does; the difference is which encoder produced it and which FourCC ends up in the stream header. This page writes the xvid tag. If a specific device's firmware lists DivX and refuses Xvid-tagged files, use RMVB to DivX instead — same container, different tag. If you want the plainly named AVI rather than either alias, RMVB to AVI is the same conversion with an extension every player already knows.

The Constant Quality slider says "CRF" but only goes to 31 — is that a bug in the label?

It is a mislabel, not a broken control. Xvid does not use CRF; it uses a fixed quantiser from 1 to 31 where lower means finer quantisation and a bigger file. The slider is wired to that quantiser and it works, but it opens at 5, which is a very high-quality setting that produces large files. If the output is bigger than you wanted, raise the number rather than reaching for a bitrate mode — 8 to 12 covers most ordinary footage.

Will the Xvid file be smaller than my RMVB?

Usually not, and often noticeably larger. RealVideo 9/10 is a more efficient codec than MPEG-4 Part 2, so matching the original's picture quality costs more bits in Xvid than it did in RealVideo. On top of that, the pre-selected Very High preset deliberately targets 1.32x the source bitrate to absorb the second compression pass. If size matters more than fidelity, switch to Specific file size and name a number, or drop the preset to Medium.

Can I cut out just one scene instead of converting the whole file?

Yes. The Trim group opens on "Unchanged"; switch it to Time Range and enter a Start time and Duration, either in plain seconds or as HH:MM:SS.sss. That is by far the cheapest way to shrink the output, because it removes frames instead of degrading them. For an interactive cut with a timeline rather than typed timecodes, the Video Cutter accepts .rmvb directly.

Does the resolution have to change at all?

No — Video resolution opens on Keep original and nothing is rescaled unless you ask. It is worth changing in one case: DivX Home Theater profiles on old players cap out around standard definition, so a 720p or larger RMVB may stutter or refuse to play on hardware that only certified SD. Setting Width x Height to 720x480 or 720x576 usually fixes that, and shrinks the file at the same time.

What happens to my files after the conversion?

Your RMVB is uploaded over an encrypted connection, decoded and re-encoded on our servers, and both it and the Xvid output are deleted automatically after a few hours. Nothing is shared or made public and no account is needed. RealMedia downloads are often long, so the upload over your own connection is usually the slow part rather than the encode; trim first if you only need a section.