Converting .wav (CCITT A-Law format) to .mp3 using LAME

Question

I would like to convert wav files to mp3 using the lame encoder (lame.exe). The wav files are recorded along the following specifications:

Bit Rate: 64kbps
Audio sample size: 8 bit
Channels: 1 (mono)
Audio sample rate: 8 kHz
Audio format: CCITT A-Law

If I try to convert such a wav file using lame, I get the following error message:

Unsupported data format: 0x0006

Could anyone provide me with a command line string using lame.exe that will enable me to convert these kind of wav files?

Solution

You want to use SoX to convert the A-law input data to a more standard PCM data for LAME to process.

sox -A -c 1 -r 8000 input.8khz-mono-alaw.wav ouput.wav

Now output.wav should contain standard PCM WAV data. Run your LAME command on this (add whatever options you like):

lame output.wav output.mp3

Or, pipe the SoX output into LAME directly:

sox -A -c 1 -r 8000 input.8khz-mono-alaw.wav - | lame - output.mp3

Comments

[Admin]

what command line are you using currently?

[Josh Smeaton]

thank you thank you thank you. I was incorrectly using -e signed-integer instead of -e a-law (your -A argument for older version of sox).

[Josh Smeaton]

And I'd like to recommend not piping sox to lame, as you may get missing header information since sox waits for the file to close before writing certain headers.