MP2 audio gets distorted with BeSweet, not with tooLAME

[Boulder]

Hi,

I've been using this excellent tool, BeSweet, for all my audio encodings. However, I just noticed that MP2 audio gets distorted when the WAV file is encoded with BeSweet (=mp2enc.dll?). This happens at least with the latest beta (1.5b8), but I think that this has been an issue earlier as well. I've thought for long that there has been some distortion in the audio when heard from the TV speakers, but I really discovered it when I listened to the MP2 file with headphones. The funny thing is that this doesn't happen if I encode the file with tooLAME. The OS is WinXP.

Here's the command line I used:

"C:\Utils\BeSweet\BeSweet.exe" -core( -input "e:\TEMP\Captures\testclip.wav" -output "e:\TEMP\Captures\besweet.mp2" -logfile "C:\Utils\BeSweet\BeSweet.log" ) -ota( -d 0 ) -2lame( -m j -b 128 -e ) -profile( ~~~~~ Default Profile ~~~~~ )

The audio isn't clipping, because BeSweet amplifies it if I've set it to normalize the audio automatically.

Here are links to the files in case you want to check it out yourselves (5 sec clips, 48KHz/16bit/stereo):

http://www.cc.jyu.fi/~camneely/testclip.wav (clean)
http://www.cc.jyu.fi/~camneely/besweet.mp2 (distortion)
http://www.cc.jyu.fi/~camneely/toolame.mp2 (clean)

The distortion can be heard in the left channel. It's not loud but if you know it's there, it can be really annoying.

Let me know if you need anything else.

[DSPguru]

joint stereo would sound really bad @ 128kbps, when it comes to mp2.

[Boulder]

Thanks for the answer, using stereo fixed the problem.

I really thought that joint stereo was meant for lower bitrate files, and if I mux the audio and video with bbMPEG, it shows that the audio is stereo regardless of the setting. EncSpot also recognizes it as stereo even though I've encoded in joint stereo:confused:

[frank]

WinAmp shows the mp2 encoding type.