Re: Alsa plays only wav files
On Tue, Sep 17, 2002 at 09:56:30AM +1000, Toby Sargeant wrote:
> On Mon, Sep 16, 2002 at 08:21:28PM +0200, Michel D?nzer wrote:
> >
> > That's correct. The problem is probably a mismatch between what xmms (or
> > its plugins) _thinks_ the endianness of the PCM data they send to the
> > device is (and thus tells the device) and what it _actually_ is. E.g.,
> > this works with dmasound if the app thinks its data is little endian but
> > it's native endian in fact (a common mistake), because dmasound never
> > swaps bytes. In contrast, ALSA will swap bytes, and you'll hear noise;
> > an effort in vain.
> >
>
> There is some support for little endian formats in dmasound_pmac. I
> don't believe the software resampling will ever change endianness, but
> on older macs, hardware byteswapping of samples exists, and
> dmasound_pmac will use it (well, the code's there, but I don't have an
> older mac to see whether it's actually getting called ;)).
>
> Basically, on i2c based macs (Tumbler, Snapper, DACA) the only format
> supported natively is 16 bit signed big endian. On older macs (AWACS,
> Snapper, Burgundy), big and little endian formats are supported.
>
> Then sample conversion is done in software if the format doesn't match.
> This doesn't include byte swapping, which means that stuff like audacity
> is left out in the cold.
>
> It's possible that alsa assumes that you can do byteswapping on all
> macs, and so any apps that use little endian sample formats instead of
> just sticking with platform native will have probs.
<dumbquestion>
Why don't they just put a header on the sample that indicates its endianness?
IIRC that's how tiff works.
</dumbquestion>
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