[FFmpeg-devel] [PATCH] AC3 volume options

Andreas Öman andreas
Sun Dec 16 12:23:01 CET 2007

Justin Ruggles wrote:
> Hi,
> The dialog normalization option is used for both encoding and decoding. 
>  For the decoder, it just turns it on or off.  For the encoder, the 
> value is used in the output stream.

Some random thoughts, i'm no expert in these two things and how
they are used, but anyhow...

If i read the source correctly the dialog normalization range is
0-31 now, right?
Wouldn't it be better to use a normalized range (0-255) or perhaps
a float (0-1) and have the codec scale it to its own range?
I doubt that all codecs use 0-31 and i don't think it's wise
to expose such internals in the public API.
We could stick with 0-31, but if so i think it should be
mentioned in avcodec.h, and future codecs would have to scale it
from there.

Also, would it perhaps be useful to export the current dialog
normalization when decoding?
I'm thinking that it could be useful to carry this information
from, say DTS to AC3 when transcoding.
This could be added later though i guess. Perhaps in AVAFrame
it we get there.

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