Unable to convert audio with ffmpeg

Audacity 3 Help Forum Windows
1

I am trying to convert an audio stream that is contained in a .MKA container to FLAC using ffmpeg. I used MediaInfo (macOS) to identify the exact type of audio in the container (mono, little-endian, 24/48) but I always get random noise when I try to import the .MKA as rawData.

I am using Audacity 3.7.3 and a fresh install of ffmpeg-62.

2

OK, I have a few questions for you:

  1. Have you played the file in its native state and it played fine?
  2. Have you tried converting the file to FLAC using just ffmpeg and NOT Audacity?
  3. How big is the mka file?

Mark B

3

I’m and Windows guy and I’ve never used MKA or MKV but I wouldn’t think you need to import as raw data. But if Audacity with FFmpeg can’t open it, perhaps so.

Try a different offset. There are 8-bits in a byte so with 24-bit audio you have a 2-out-of-3 chance of getting the byte order wrong. Try increasing the offset by 1 and if that doesn’t work, try increasing by 2. (If this is an offset problem an offset of 0, 1, or 2 should work but the file header will be converted audio giving you a glitch at the beginning which you’ll have to edit out.)

Or try looking for a 3rd-party converter.

That might be the wrong version. Did you install the special Audacity version of FFmpeg from here?

4

The file is a movie soundtrack and plays just fine in Windows Media Player and JRiver Media Center. The size of the file is about 600MB. I will try the other suggestion and adjust the offset to see what happens.

5

That’s not too terrible size-wise. If you have Google Drive or One Drive and you are willing to share a link, I am happy to try to convert it for you. I’d like to do that just to satisfy my curiosity, if nothing else. :grin:
Mark B

6

I managed to get it working but the process was a little strange. I started by using the link provided to download the different version of ffmpeg. It failed just like my version using all three possible offsets. Then I accidentally tried Import Audio File which failed (as usual) complaining that the file was an unknown audio type. But then it automatically launched ffmpeg and without prompting me to enter parameters, imported the file!!

7

Good to hear it’s working!

The offset settings are only for importing raw data which does not involve FFmpeg. RAW data only works for uncompressed PCM audio (like what’s in a WAV file). The “mono, little-endian, 24/48” implies PCM, but maybe it’s not…

8

Was the conversion to FLAC successful too?

Mark B

9

Yes it was.

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