Converting MPEG-2 Layer 3 to MPEG-1 Layer 3 audio [closed]

Is there a way to convert MPEG-2 Layer 3 audio to MPEG-1 Layer 3 audio?

I've tried to search for such a tools on internet but none of them does this explicitly.

1 Answer

There's virtually no difference between MPEG-1 Layer III (ISO/IEC 11172-3) and MPEG-2 Layer III (ISO/IEC 13818-3), other than the supported bit rates and sample rates.

The sample rates are mutually exclusive between those two. MPEG-1 allows 32, 48 and 44.1 kHz, while MPEG-2 allows 16, 24 and 22.05 kHz. The (inofficial) MPEG-2.5 allows 8, 12 and 11.025 kHz.

The LAME MP3 encoder will automatically choose the right standard depending on the sample rate (or bit rate):

lame in.wav --resample 32000 out-32.mp3
Resampling: input 44.1 kHz output 32 kHz
Encoding as 32 kHz j-stereo MPEG-1 Layer III (10.7x) 96 kbps qval=3
lame in.wav --resample 24000 out-24.mp3
Resampling: input 44.1 kHz output 24 kHz
Encoding as 24 kHz j-stereo MPEG-2 Layer III (12x) 64 kbps qval=3
lame in.wav --resample 12000 out-12.mp3
Resampling: input 44.1 kHz output 12 kHz
Encoding as 12 kHz j-stereo MPEG-2.5 Layer III (12x) 32 kbps qval=3