I can't seem to get Lame 3.96.1 to decode or transcode any of my MP2 files. This is an example of what happens:



Lame creates a 0 byte wav file and then hangs and I have to press Ctrl+C in order to get back to the command prompt. Here is what Winamp says about the MP2 file:



I've not had any problems decoding MP2 files with Lame 3.90.3, 3.93.1 and 3.97 alpha 3.

Weird.... First, LAME reports "22.05 kHz, 2 channels, MPEG-2 Layer II" and then it generates warnings and errors as if it wer decoding an mp3 !

"big_values" / "blocktype" / "window-switching" / "can't step back xxx" (bit reservoir error) are all related to mp3 - not mp2.

Yes, it look's like a (or more than one) bug(s).


SebastianG

Hmmm, 3.96 is also broken so far as mp2 is concerned, although 3.95.1 works fine.

Edit: I'ts also broken in 3.97alpha3.

You're right, 3.97 alpha 3 is broken too, although the error message is different and it doesn't hang like 3.96.1. I must have got the binaries mixed up when I was testing.

For anyone who is interested, I've uploaded a 'fixed' version of the CLI encoder, only, to Rarewares, that now decodes .mp2 correctly (I think!! ).

I've not researched this deeply, but the small changes made between 3.95.1 and 3.96 in 'get_audio.c' seem to be the offending changes. There are more extensive changes in the latest 3.97 alpha that I haven't looked at yet, and may leave to Gabriel (or another lame-dev) to look at.

John33,

Could you please upload the 'fixed' source file of 'get_audio.c' somewhere so I can compile a 'fixed' binary myself?

I simply recompiled using the get_audio.c source from 3.95.1, having established what the changes were(!!). If you need that, let me know and I'll post it for you.

It seems to work for me, thank you.


Another thing I have noticed recently with lame is that it if you decode an MP2 file with an .mpa extension, it assumes it is raw PCM and it isn't decoded correctly. This happens with all versions of lame I've tried.

I've seen .mpa used as the extension for MP2 audio by a number of programs (e.g. DGDecode/DVD2AVI) but I don't know how "correct" it is to do this. Obviously if this is taken too far then people might end up complaining because their MP2 files with .wtf extensions don't decode correctly.


P.S. The link to download lame 3.93.1 is missing on rarewares.

...sounds like improvement over 3.90.3 for sure!

It would not be difficult to add the .mpa extension to the list of recognised extensions, but it's also equally easy simply to change the extension to .mp2 before decoding!!

I've fixed the link to 3.93.1, thanks.

Magical switch: --mp2input

This does not seem to help the decoding problem.

--mp2input is telling Lame to consider the input as beeing mp2. Of course, if mp2 decoding is not working, it will not make it working.
It just helps when decoding is working and you have a file with unusual extension (like .mpa)