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Aug 29, 2026
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LAME DirectShow Filter is a free 32-bit encoder filter that lets DirectShow applications write MP3 audio, wrapping the LAME 3.99.5 encoder in Elecard's DirectShow interface with its own bitrate settings page.
A DirectShow application that can save audio offers WAV, and nothing smaller.
Windows ships no MP3 encoder for DirectShow, only a decoder, so MP3 never appears as an output option.
LAME DirectShow Filter adds one.
What This Actually Does
DirectShow is the framework older Windows multimedia software uses to move audio and video around. A program builds a chain of small components - one to read the file, one to process it, one to write the result - and Windows supplies whichever components are registered on the machine.
There has never been an MP3 encoder in that set. This filter is one, wrapping the same LAME MP3 Encoder that most Windows audio software uses underneath.
Once registered, it appears wherever a program lists audio encoders, usually as "LAME Audio Encoder". Capture tools, graph-based converters and older editors pick it up without any further setup.
What it is not. This encodes, it does not decode. If MP3 files will not play, the missing piece is the MPEG Layer-3 decoder instead.
Installing It
The download here is an installer that puts the filter in the right place, registers it, and adds a normal entry to Add or Remove Programs. It is built and maintained by X Codec Pack.
That is worth spelling out, because the old method is the reason this filter has a reputation for being fiddly.
If you would rather do it by hand, open Command Prompt as administrator, change to the folder holding the file, and run regsvr32 lame.ax. To remove it, run the same command with /u after regsvr32.
On 64-bit Windows, use the regsvr32 in SysWOW64. The filter is 32-bit, so it has to be registered by the 32-bit registration tool - the full command is %windir%\SysWOW64\regsvr32.exe lame.ax. Running the plain command from a normal prompt uses the 64-bit one, which is where this goes wrong.
If You Installed It the Old Way
The package used to ship two batch files, and the instructions said to copy lame.ax into C:\Windows\System32 and run RegLAME_DS.bat.
On 64-bit Windows that is wrong in two ways at once. System32 is the 64-bit system folder despite the name, and the registration tool found there is the 64-bit one, so a 32-bit filter ends up somewhere no 32-bit program looks, recorded somewhere no 32-bit program reads.
It reports success. Nothing warns you. The filter simply never appears.
If you tried that and nothing happened, you did not do it wrong. The installer detects that leftover, unregisters it and removes the stray file before installing properly, so there is nothing to clean up by hand first.
Where This Build Stands
Two dates matter here and both are old.
The filter itself is Elecard's DirectShow wrapper, version 1.0, last revised in 2005 - which is the number Windows shows in the file's Properties tab, and a common source of confusion. The binary was compiled in February 2012 against LAME 3.99.5, and the package is named after that.
LAME reached 4.0 in July 2026, but nobody has rebuilt this filter against it and no newer build exists anywhere. The encoding quality is unaffected either way, because 4.0 changed security and build tooling rather than how files sound.
Who Should Look Elsewhere
Three tells, each checkable before you download anything.
- Your application is 64-bit. DirectShow filters load inside the program that uses them, and no 64-bit build of this one has ever existed - use the 32-bit build of your application, such as 32-bit Media Player Classic Home Cinema, or encode the audio separately.
- You are using VirtualDub. That wants the ACM codec rather than a DirectShow filter - the LAME ACM MP3 Codec is the one that appears in VirtualDub's audio compression list.
- You just want MP3 files from audio you already have. No filter needed - the step-by-step LAME install guide covers the encoder itself, which is a far simpler route.
For that last case, a front-end does the job with no registration involved:
- LameXP for drag-and-drop batches, with every LAME preset in a normal window.
- X Audio Converter when you just want a file in and an MP3 out.
- winLAME and RazorLame, the long-standing front-ends.
Audacity bundles its own encoder and needs nothing from this page, and for one file with nothing to install there is the site's online audio converter.
The Settings Worth Changing
The filter carries its own property page, which most host applications expose through a Properties or Configure button next to the encoder. Bitrate, channel mode and the quality preset are all there.
For a music soundtrack, aim for an average nearer 190 kbps than the default. For speech, the defaults are already about right.
The best LAME settings guide goes through the presets case by case.
Where This Sits Next to the Rest
For AC3 and DTS rather than MP3, AC3 Filter is the equivalent DirectShow component. If you want to see which filters are actually registered on your machine, the tools in the Codec Identifiers section list them.
For a tool that handles every format without hooking into Windows at all, the FFmpeg Audio Encoder covers the lot, and the rest of the current builds sit in the Audio Encoders section.
Quick questions
Is LAME DirectShow Filter free?
Yes, for commercial work too. The filter is LGPL and MP3 patent licensing ended in 2017, so encoding carries no fee either way.
Why does the filter not appear in my application?
Two usual causes. The application was open while you installed, and DirectShow reads its filter list when a program starts, so close it and reopen. Or the application is 64-bit, in which case it will never list this filter.
Is there a 64-bit version?
No, and there never has been. Use the 32-bit build of your application, or encode the audio separately with a normal encoder.
Why does the file say version 1.0 when this page says 3.99.5?
Both are correct for different things. 1.0 is Elecard's DirectShow wrapper, which is what Windows shows in the file properties. 3.99.5 is the LAME encoder compiled inside it, and the name everyone uses for the package.
Does it work on Windows 10 and 11?
Yes. DirectShow is old but has never been removed, and the filter registers and runs normally on current Windows. The catch has always been the installation route rather than compatibility.
regsvr32 says the module failed to load. What now?
That is usually a missing runtime rather than a bad file. Install the Visual C++ Redistributable Runtimes and try again, and make sure you used the 32-bit regsvr32 from SysWOW64.
More encoders, decoders and format tools sit in the Audio Codecs section.
Download LAME DirectShow Filter 3.99.5 and see how it handles your files, or tell us how you got on if you have used it before.
