§ ¶Available MP3 frequency rates and obtaining the Professional codec
Another common question I get is why VirtualDub can't encode MP3 above 56Kbps. Remember, VirtualDub has no audio encoding support of its own -- it relies solely on codec installed in the Windows Audio Compression Manager (ACM) to compress audio, and that usually means the Fraunhofer-IIS MP3 codec. (You may also have the Lame ACM and/or Creative MP3 codecs, but these are known to trigger hangs and crashes on some systems.) There are at least five major versions of the MP3 codec in existence:
- l3codecx.acm: Cannot encode at all.
- l3codeca.acm (Advanced): Encodes up to 56Kbps.
- l3codecp.acm (Professional, older version): Encodes up to 128Kbps.
- l3codecp.acm (Professional, newer version): Encodes up to 320Kbps.
- l3codecp.acm (so-called "Radium" version): Encodes up to 320Kbps. If I remember correctly, this version was actually ripped from an Opticom application that contained it internally, and so its legality is... ahem... interesting.
All versions will decode any format, but because they all register under the entry "msacm.l3acm" only one can be installed at a time. What often happens is that some application will install and overwrite the entry with the Advanced codec, thus dropping your encoding capability to 56Kbps. This will break any older application that might have installed and relied on the Professional codec. Changing the l3acm entry back to l3codecp.acm under Drivers32 in system.ini (95/98/ME) or the Registry (NT/2000/XP) will restore the higher bandwidth modes.
The good news is that for those of you who have lost the Professional version, there is a safe and easy way to obtain it again: install Windows Media Player 10. This installs the recent revision of the Professional version that encodes up to 320Kbps.
media player10 is installed, but donīt ejecute in virtual dub, 3ivx,xvid and divx is installed, but it doesnīt compresion audio in virtual dub. Mensage is:
No audio decompresor could be found to descompress the source audio format,
And the information file: sampling rate 22050Hz, sample precision N/A Chanels 2(Stereo),Compression Unknonow (tag 0055).
I make the file with 3ivx and mp3, two days ago and it worked; now it doesn't
Jesus - 18 12 04 - 13:16
of great help for me!!!
I was able to access again to >56kbps enc. values!
the complete path to registry is:
in my case the entry to change was:
(from "C:\WINDOWS\system32\l3codeca.acm", to "C:\WINDOWS\system32\l3codecp.acm", latter file was already there, of course)
thank u very much
idleloop - 28 04 06 - 17:01
Hey idleloop, that registry edit information worked PERFECTLY for me! I didn't even have to reboot my machine, just restart VirtualDub. Thanks a million man!
MonkeyFCoconut - 11 03 07 - 23:07
thx alot idleloop, worked perfectly for me, too :-)
Obelix - 21 03 08 - 02:44
Worked for me, too. Windows XP SP2.
A .reg file to apply the fix in one click (since it might get fouled up again) is:
Windows Registry Editor Version 5.00
Ed LaFoe - 07 09 08 - 14:33
The reg change worked great for me on Windows vista basic, no reboot required either. Just a restart for VirtualDub
tah for the info :)
t0r - 14 03 09 - 16:19
Fantastic! The registry change works in Windows 7 as well!
John Markh (link) - 14 09 09 - 02:44
NOTE: If you are running a 64-bit version of Windows 7, there is apparently an additional registry location you must change:
Just change the "msacm.l3acm" entry from "C:\Windows\SysWOW64\l3codeca.acm" to "C:\Windows\SysWOW64\l3codecp.acm" (just one letter difference) and you're good to go.
Updated version of the registry file above:
Windows Registry Editor Version 5.00
JD - 24 10 09 - 15:27
Under XP 32bit I changed the registry as above, and all the speeds present, but when I tried a compression, it created a PCM conversion,not an mp3 conversion. Any Ideas?
GingerMan - 25 11 11 - 20:51
I've tried this fix on Win10 Home 64-bit, but nothing happens, I still get the "audio decompressor not found". Any ideas on this OS fix?
GarnuThorsonn - 24 05 19 - 21:23
I found a quick and dirty fix on my audio issue: after installing VDSC video editor freeware version all of a sudden audio playback works again on Win10.
GarnuThorsonn - 28 08 19 - 22:25