Speex dev - Dec 2006 - Would be nice to conditionally compile out coding modes and code tables...

I'm only using the narrow-band encoder on my embedded system and have
removed all references to the wide-band and ultra-wide band encoder
functions and tables.  They will be pulled in by the linker due to the
references made by the structures in modes.c.  Attached is a replacement
modes.c for compiling out modes that are not in use for anyone who's
interested.  

Also, I've removed the dynamic memory allocation of the encoder and
decoder.  To do this I had to determine the required size of the encoder
and decoder states since i'm working on a fixed memory platform I simply
handle the worst case, see the attached statesize.h.   Now I can do this
sort of thing...

MyDecoderClass decoders[5];

.. will means all of my decoder states are contiguous and quick to DMA.
It also improves cache consistency when the input buffers are placed in
MyDecoderClass.

Would be nice for functionality like this to make it into the main line
of code.

I hope this is useful to someone,
Stewart Miles

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I agree with this, by the way.  Dynamic memory allocation does NOT belong in
a realtime codec, apart from allocation of the initial stream state at open
time.

This is something that the Ogg guys (Vorbis being a prime offender in
particular) have never quite understood.

</pet_peeve>

-- john
>
> I'm only using the narrow-band encoder on my embedded system and have
> removed all references to the wide-band and ultra-wide band encoder
> functions and tables.  They will be pulled in by the linker due to the
> references made by the structures in modes.c.  Attached is a replacement
> modes.c for compiling out modes that are not in use for anyone who's
> interested.
>
> Also, I've removed the dynamic memory allocation of the encoder and
> decoder.  To do this I had to determine the required size of the encoder
> and decoder states since i'm working on a fixed memory platform I
simply
> handle the worst case, see the attached statesize.h.   Now I can do this
> sort of thing...
>
> MyDecoderClass decoders[5];
>
> ... will means all of my decoder states are contiguous and quick to DMA.
> It also improves cache consistency when the input buffers are placed in
> MyDecoderClass.
>
> Would be nice for functionality like this to make it into the main line
> of code.
>
> I hope this is useful to someone,
> Stewart Miles

Miles, Stewart a ?crit :
> I'm only using the narrow-band encoder on my embedded system and have
> removed all references to the wide-band and ultra-wide band encoder
> functions and tables. They will be pulled in by the linker due to the
> references made by the structures in modes.c.  Attached is a replacement
> modes.c for compiling out modes that are not in use for anyone who's
> interested.  
There's already a --disable-wideband (and corresponding
DISABLE_WIDEBAND) option in the code, so I'm not sure what your patch is
supposed to add. Also, disabling narrowband doesn't make sense because
it's used by the wideband code.
> Also, I've removed the dynamic memory allocation of the encoder and
> decoder.  To do this I had to determine the required size of the encoder
> and decoder states since i'm working on a fixed memory platform I
simply
> handle the worst case, see the attached statesize.h.   Now I can do this
> sort of thing...
> 
> MyDecoderClass decoders[5];
> 
> .. will means all of my decoder states are contiguous and quick to DMA.
> It also improves cache consistency when the input buffers are placed in
> MyDecoderClass.
There's actually a much simpler way of making everything contiguous. All
you need to do is allocate (or reserve or whatever) a big block yourself
and override speex_alloc() and speex_free() (and speex_alloc_scratch if
you don't have a C99 compiler) to distribute that memory explicitly.
> Would be nice for functionality like this to make it into the main line
> of code.
Anything that you need that isn't covered by the explanations above?

	Jean-Marc