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| Unofficial VirtualDub Support Forums > Codec Discussion > MPEG Audio Layer II Decoding |
| Posted by: fccHandler Jan 23 2011, 04:50 AM |
| Not too long ago I noticed that when I open a movie which contains MPEG Layer II audio, I am able to play and decode the audio in VirtualDub. I am very curious as to how this works, because I'm certain I don't have any ACM MP2 codecs installed on this system. For example, I have this one Matroska file with MP2 audio. (My Matroska plugin doesn't contain any decoders, it always returns compressed data.) The File Information displays tag "Unknown (0x0050)" which at least indicates that my plugin queried ACM for a decompressor and didn't get one. Yet the audio plays fine in VirtualDub. Is VirtualDub detecting MP2 and decoding it internally? If so, when was this feature introduced? FWIW, I do see an option in "Options / Preferences / AVI" called "Prefer internal audio decoders over installed third-party codecs." I currently have this unchecked. |
| Posted by: ale5000 Jan 23 2011, 05:02 AM |
| VirtualDub contain an internal decoder for MP2/3 audio. According to the changelog it was added in "Build 29393 (1.8.0, experimental): [February 24, 2008]". But if I remember correctly internal audio decoders aren't used by input plugins. |