ALUT: IMA4 (adpcm) support for the wav file reader

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ALUT: IMA4 (adpcm) support for the wav file reader

by Erik Hofman :: Rate this Message:

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Hi,

I've created an ima4 adpcm codec and support for the wav file reader of
alut:
http://ehtw.speedlinq.nl/emh/alut_ima-adpcm.diff

I've tested this code for both mono and stereo compressed files.

Erik
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Re: ALUT: IMA4 (adpcm) support for the wav file reader

by Jason Daly :: Rate this Message:

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Erik Hofman wrote:
> Hi,
>
> I've created an ima4 adpcm codec and support for the wav file reader of
> alut:
> http://ehtw.speedlinq.nl/emh/alut_ima-adpcm.diff
>
> I've tested this code for both mono and stereo compressed files.
>  

Hi, Erik,

Is there somewhere I can get a file to test with?  I just want to try it
out myself before I commit.

--"J"

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Re: ALUT: IMA4 (adpcm) support for the wav file reader

by Chris Robinson-5 :: Rate this Message:

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On Sunday 01 June 2008 02:19:40 am Erik Hofman wrote:
> I've created an ima4 adpcm codec and support for the wav file reader of
> alut:
> http://ehtw.speedlinq.nl/emh/alut_ima-adpcm.diff
>
> I've tested this code for both mono and stereo compressed files.

Thinking about it, I wonder if it would be a good idea to test for the
AL_EXT_IMA4 extension, and pass the data to OpenAL without conversion (at
least when dealing with the alutCreateBuffer* functions).

And I'm curious about what to do with the alutLoadMemory* functions. The ALUT
spec says the function will return data in a "standard OpenAL format", but
never lists any formats or expands on what it means. Should this only be
basic formats (mono/stereo 8/16 bit PCM only), core-only formats (whichever
are supported by the AL version), or any formats the implementation is
capable of handling (determined from core version and availability of known
extensions)?

If it means core formats, I don't see the harm in supporting extensions as
well, since they can similarly add formats the app may not recognize (and as
such, an app couldn't rely on the returned data being a known format). But if
it means only basic formats, that makes the function much less desirable if
trying to use compressed formats.
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Re: ALUT: IMA4 (adpcm) support for the wav file reader

by Erik Hofman :: Rate this Message:

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Chris Robinson wrote:

> On Sunday 01 June 2008 02:19:40 am Erik Hofman wrote:
>> I've created an ima4 adpcm codec and support for the wav file reader of
>> alut:
>> http://ehtw.speedlinq.nl/emh/alut_ima-adpcm.diff
>>
>> I've tested this code for both mono and stereo compressed files.
>
> Thinking about it, I wonder if it would be a good idea to test for the
> AL_EXT_IMA4 extension, and pass the data to OpenAL without conversion (at
> least when dealing with the alutCreateBuffer* functions).

You always are going to need some sort of conversion, I couldn't
possibly think anyone else is using the microsoft way of interleaving
the data for stereo sounds.

I'm not even sure all hardware supports free blocksize lengths so maybe
it even requires a bit of recoding in the end.

That said, it would be nice to support.

Erik
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Re: ALUT: IMA4 (adpcm) support for the wav file reader

by Jason Daly :: Rate this Message:

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Erik Hofman wrote:
> Hi,
>
> I've created an ima4 adpcm codec and support for the wav file reader of
> alut:
> http://ehtw.speedlinq.nl/emh/alut_ima-adpcm.diff
>
> I've tested this code for both mono and stereo compressed files.
>  

While I was applying the alutLoadWAVMemory patch just now, I realized I
never committed this code.  It's done now.

Sorry for the delay...

--"J"

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