[FFmpeg-devel] DCA Decoder

Derek Buitenhuis derek.buitenhuis at gmail.com
Wed Mar 11 15:51:48 CET 2015

On 3/11/2015 2:42 PM, Marcus Johnson wrote:
> I've been working on adding XLL for the last couple months, it's still not
> quite complete, basically I have to combine the Core and XLL samples before
> it's output, and I also have to finish the latter stages of decoding the
> XLL like channel decorreclation, and post processing.

There is a patch on Libav's mailing list that will likely soon be merged that
implements the XLL extension. Have you looked at that or talk to its author?
Working together seems better than duplicated effort.

> 1: My code doesn't have the most recent chances from master, how do I fix
> this?

git pull --rebase ? (backup to a branch first)

> 2: I read that you'd prefer for code to be small and self contained, but
> how can I do that when the later functions directly require earlier ones?

Not sure I follow?

> 3: I've been using the variable names the white paper uses which doesn't
> match your guidelines, obviously they need to be renamed but I'm not sure
> what else you guys want me to do with that?

Can't really tell without looking

> 4: currently almost all of the variables are being stored in DCAContext and
> accessed in different functions this way, I assume this is looked down upon
> and you'll want me to change this style to use the variables in the
> disparate functions when it's called rather than passing it around the
> backend, is this correct?

Can't really tell without looking.

> That said, I've rewritten the ExSS code, ExSS Asset Descriptor,  XLL, and
> XLL ChSet functions are completely ready to go.

Does this include a fixed point implementation to make it actually lossless?

IIRC this is the only thign the existing patch set from Niels lacks.

- Derek

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