mpeg 2.5, 8000Hz, mono mp3 problem

2004-01-07 22:29:59

I've got some mpeg 2.5, 8000Hz, mono mp3's with speech. The problem is, that when played with foobar, there appears a disturbing bubbling sound. No such sound is present when played with winamp, so the problem must be in foobar.

I made an experiment and decoded the mp3 with foobar and cdex and resulting wav played with foobar. The wav from cdex is played correctly, in the wav created with foobar is still the bubbling. So the problem must be somewhere in the foobar's mp3 decoder. This appears with 8000Hz mp3's at any bitrate, not with 11025Hz.

This can be simply reproduced by creating mpeg 2.5 mp3's, e.g. by cdex and playing with foobar and winamp.

mpeg 2.5, 8000Hz, mono mp3 problem

Reply #1 – 2004-01-07 22:47:59

Did you try the "convert mono to stereo" DSP?

mpeg 2.5, 8000Hz, mono mp3 problem

Reply #2 – 2004-01-08 11:21:00

Also, try enabling Resampler DSP.

mpeg 2.5, 8000Hz, mono mp3 problem

Reply #3 – 2004-01-08 18:39:22

No, nothing of this helps. Resampler improves the sound quality (that's, why I want to use foobar and not winamp), but the bubbling remains. As I said, winamp plays it well, wav (with sampling frequency 8000Hz, too) created with cdex from the mp3 is played correctly. So the problem isn't in output, but in the decoding of mp3.

To prevent other questions: this appears with clean install of foobar, with and without any DSP's, with and without dithering...

I think, that it could be easily tested with any 8000Hz mpeg 2.5 mp3 which can be created by cdex. Otherwise I could paste here some sample.

mpeg 2.5, 8000Hz, mono mp3 problem

Reply #4 – 2004-01-08 20:07:28

Yup, it would help if you upload the relevant sample to "Uploads" forum.

mpeg 2.5, 8000Hz, mono mp3 problem

Reply #5 – 2004-01-09 17:32:02

Uploaded here.