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felisandria

ADPCM sound programming

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I''ve been researching this all day and it''s getting really ugly. Basically I need to figure out a way to stream/play an OKI ADPCM format in Windows, without using DirectX as it''s on NT so I only get DX3. I''ve been trying to convince people that we should stream MP3 instead (smaller), but then I would need a conversion algorithm of some sort. Has anyone here tried to/seen something to help use ADPCM in Windows? I''m cringing a bit at the thought of writing sound conversion/compression algorithms without any help... especially as they want a browser plugin to do this. -fel

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I''ve been trying to find one, so far unsuccessfully.
I did manage to find a way of decompressing into a .wav, so I think I can probably rewrite that to reformat it as an .mp3 so I won''t have to write a plugin.

-fel

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Grant, where did you stumbled upon .ee link, or do you happen to be estonian ? my eyes got wet seeing good ol'' DarkCorner being mentioned somewhere on the other side of the globe ...

-kertropp

C:\Projects\rg_clue\ph_opt.c(185) : error C3142: 'PushAll' :bad idea
C:\Projects\rg_clue\ph_opt.c(207) : error C324: 'TryCnt': missing point

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fel-

When you play MP3s, they are decompressed and then sent to the sound device in PCM format, which is basically a .WAV (actually one of .WAV''s supported formats). I don''t quite understand why you''d want to convert to MP3 if the purpose is merely to play it out. MP3 is a lossy algorithm, so you''d be losing even more of the original signal.
Basically you''d convert from PCM to MP3 back to PCM again.

Of course, playing in NT is only a matter of using the Win32 waveOut... functions. I''m sure you already know this, but I thought I''d mention it for everyone else.

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Well, actually not in this case unfortunately, because the OKI ADPCM is 24 bit, while "normal" ADPCM is I believe 32 bit. I also need to add watermarking during conversion for streaming. I found out the hardware will also do GSM 6.1, which I think I will use because it''s a lot more standard.

-fel

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