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Old 18 January 2020, 11:16   #14
ross
Per aspera ad astra

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Join Date: Mar 2017
Location: Crossing the Rubicon
Age: 50
Posts: 2,547
Quote:
Originally Posted by mcgeezer View Post
Any chance you could let me in on how you did that buddy?

I wasn't able to get adpcm to work that Dan linked above.
It was thrown in a few minutes last night, so I don't even know if I did everything right

For the encoding phase: sox.
I've set a frequency for an Amiga PER=300, with a low pass filter at 6Khz and dither.
Sure some better filter and tests be needed.

Then I've assembled PlayAdpcm from Kalms's package.
Probably the exe from Kalms's encoder need a recompilation because do not work on today Win machines.


EDIT:
Ok, now I'm in the laptop where I launched the encoding stage.
Note: it's absolutely not a series of recommended filters, they are simply the first thing that came to my mind and that could give 'decent' results, certainly it can be improved, we can discuss of this.

sox command line used:
sox.exe -v 0.92 -S -V -D "newblack_raw.mp3" "newblack_raw.ima" remix - lowpass 6000 rate -v -s -I 11822 dither -S


Results:
Code:
Level adjust   : 0.92 (linear gain)
Channels       : 1
Sample Rate    : 11822
Precision      : 13-bit
Sample Encoding: 4-bit IMA ADPCM
effects chain:
 input        44100Hz  2 channels
 remix        44100Hz  1 channels
 lowpass      44100Hz  1 channels
 rate         11822Hz  1 channels
 dither       11822Hz  1 channels
 output       11822Hz  1 channels
Done.

Last edited by ross; 18 January 2020 at 14:05. Reason: sox
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