[FFmpeg-devel] [PATCH] Common ACELP code & G.729 [4/7] - G.729 core

The Wanderer inverseparadox
Sat May 17 22:27:02 CEST 2008

Diego Biurrun wrote:

> On Sun, May 18, 2008 at 12:15:56AM +0700, Vladimir Voroshilov wrote:
>> Next update.
>> --- /dev/null
>> +++ b/libavcodec/g729.h
>> @@ -0,0 +1,137 @@
>> +#define FC_SIGNS_BITS_8K     4  ///< fixed codebook signs, 8k mode (size in bits)
>> +#define FC_INDEXES_BITS_8K   13 ///< fixed codebook indexes, 8k mode (size in bits)
>> +#define FC_SIGNS_BITS_4K4    4  ///< number of pulses in fixed-codebook vector, 4.4k mode
> Sometimes you write "fixed codebook", sometimes "fixed-codebook".
> Settle on one spelling.  Mans or the Wanderer will advise you which
> way is preferred.

Actually, these two forms mean different things.

"fixed codebook signs" means "codebook signs which are fixed".

"fixed-codebook vector" means "(the) vector associated with the fixed

For all I know, it may be possible that different things were meant in
the different cases; if so, having both forms instead of just one form
would be correct. If that is not the case, which one is correct depends
on which meaning is intended.

For reference, in case anyone is interested in the reasoning behind
this, an attempt at explaining my understanding:

The pattern is "adjective adjective noun". Without the hyphen joining
the first two words, both of them modify the noun, and so in this case
the noun "signs" is modified into the noun phrase "codebook signs" and
then that noun phrase is itself modified by "fixed". With the hyphen,
the two adjectives are combined into a single adjectival phrase by
having the first adjective modify the second, and then the phrase as a
whole modifies the final noun.

In effect, in this case at least although not necessarily in every case,
adjectives associate themselves with nouns from right to left - and so
if you want one adjective to modify another, you need to group them
together, and the standard way of doing that is via a hyphen (I think
the technical term is an endash).

       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.

More information about the ffmpeg-devel mailing list