adjusting an AT3 header by Alpha23 at 3:37 AM EDT on September 21, 2015

Hi!
As you all may know, the PMF and PAM demultiplexers from VGM Toolbox only demux the audio to aa3. I've written a converter from aa3 to at3 but it's lacking some sort of calculation (no of samples?) for the track length. So, here are some samples of converted files: http://www.multiup.org/download/9dda2462a7644f3ce5f933328f1844f6/mgspw_at3_samples.7z
The original aa3 files only contain the 1-byte compression id at offset 0x3e so I took some random at3 riff header and overwrote the id with the one from the aa3...
The ids and according specs are:
0x24 -> 44.1 kHz mono
0x28 -> 44.1 kHz stereo
0x34 and 0x35 -> 44.1 kHz 6ch
0x44 -> 48 kHz mono
0x48 -> 48kHz stereo
0x54 and 0x55 -> 48kHz 6ch
Can somebody help me figure out what I need to calculate and where to put it?

by Alpha23 at 3:47 AM EDT on September 21, 2015

Well, obviously you need to adjust the 4byte values at 0x50 and 0x54 in order to change the length. The problem is that you cannot detect the sample count or kbps from the id alone...

by snakemeat at 10:25 AM EDT on September 21, 2015

This tool may help: http://forum.xentax.com/blog/?p=1053.

by Alpha23 at 2:21 PM EDT on September 21, 2015

Thanks for the linking but the tool has exactly the same problem that the track length is way to high (filled with silence).
Could this be an issue of the foobar vgmstream plugin?

by Masamune at 2:46 AM EDT on September 25, 2015

Use Atrac3plus Tool to convert them to aa3 and then from aa3 to at3 again. (Leave "Loop Options" as Yes)

edited 2:52 AM EDT September 25, 2015

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