[asterisk-dev] default format for sounds

[Kevin P. Fleming]

John Todd wrote:

> However, another option might exist, which is "Download master files" 
> and then a sub-list of encodings is provided that allows the user to 
> select which codecs they'd like to have the "master" files converted 
> to, and then the "make install" process converts the master files 
> into those various codecs and sticks them in the right directories. 
> G729, ilbc, speex - whatever they happen to have installed on the 
> system would be available - should this use sox, or should it be a 
> module in Asterisk?
> 
> The only possible fly in that ointment is that G.729 and/or G.723 
> (and other future codecs?) need to have the proprietary modules 
> installed in order to do the format translations, so maybe the 
> complexity of these exception cases makes this not easily workable.

Right, that would be a concern for sure; we don't even distribute
G.723.1 prompts today because we don't have a license for an encoder
even for internal use (although we could use a TC400B for that purpose,
but that's another topic).

> But still... having a single download and then having the "make 
> install" process churn out all the possible iterations of converted 
> files seems like a good idea instead of downloading 4 different 
> versions of the encoded soundfiles if you expect to be using a number 
> of codec choices.

Taking the core sounds version that is currently on
downloads.digium.com, the WAV format (signed linear 8KHz in WAV
wrappers) tarball is 15 megabytes. The ulaw, g729, and gsm tarballs
combined are 9.8 megabytes in total, so downloading the unencoded files
to make even *one* of these compressed formats results in 40% more
download time, plus the conversion time. Adding alaw for sites that have
that need increases the total download to 16.8 megabytes, approximately
10% more download than the WAV files, but already converted into four
compressed formats.

Starting with signed linear 16KHz is even worse; that tarball is 29
megabytes. If you downloaded that to make the above four compressed
formats *plus* g722, you'd still have downloaded nearly 5 megabytes more
than you needed to.

-- 
Kevin P. Fleming
Director of Software Technologies
Digium, Inc. - "The Genuine Asterisk Experience" (TM)