Codec question

Hi,

Am using Windows XP, SP3, Audacity 2.0.3 and I used the .exe installer.

I have a small MP3 clip I need to use in a project.

I am told that I will need to convert the wav codec to pcm_u8 at 32000 bit rate.

I have loaded and edited the clip how I want it, but I can’t find any mention of codecs or bitrates when I try to export.

Any help gratefully appreciated.

Thanks

Who exactly told you that? Are you making a ringtone, for example?

If you want unsigned 8-bit pcm, File > Export, which brings you to the File Export Dialog .

Choose “Other uncompressed files” then click “Options…”. Choose WAV (Microsoft) header and Unsigned 8 bit PCM encoding.

For PCM, bit rate = (bit depth) x (sample rate) x (number of channels). You have already chosen 8-bit depth.

So from there (if you are asking for a 32000 bps bit rate file, and assuming the file is mono) you would need to change the project rate bottom left of the Audacity window to a very non-standard rate of 4000 Hz : (8-bit depth x 4000 Hz sample rate x 1 channel) = 32000 bps or 32 kbps.

Are you sure a 4000 Hz file is playable in the application you intend?


Gale

I checked back in the other forum, and they said why don’t I use FFmpeg as follows:

ffmpeg -y -i sourcefile.wav -acodec pcm_u8 -ar 32000 destinationfile.wav

I looked at FFmpeg, but couldn’t figure out how to get it on my PC, seems you have to put it all on manually, messing about in the registry etc.

The Wav I am trying to make is not exactly a ring tone, but is only about 3 seconds long.

Robert

Thinks its becoming clearer:

“Are you sure a 4000 Hz file is playable in the application you intend?”

I am told :

"You need a 32kHz sampling rate file, not “32000 bit rate”.

The best is WAV, 16 bits, uncompressed, 32kHz."

32 kHz refers to the sample rate, not the bit rate.
pcm_u8 is 8 bit not 16 bit.
It may help if you told us what you are actually doing. What are these files for?

Have finally got it to work.

This was the answer:

In Audacity:

  • Open your file
  • Tracks → Stereo track to mono
  • Set Project Rate to 32000Hz at the bottom left of the window
  • File → Export, Wav Signed 16 bit PCM
  • Click “clear” on the metadata screen that appears.

Many thanks for all your help.