[asterisk-dev] Audiohook dropping frames

[Joshua Colp]

Olle E. Johansson wrote:
> On 08 Apr 2014, at 13:32, Joshua Colp<jcolp at digium.com>  wrote:
>
>> Olle E. Johansson wrote:
>>> Hi!
>> Kia ora,
>>
>>> In my adventures with silence detection and suppression I want
>>> my audiohook to drop frames. I see that I can manipulate but can
>>> I also drop frames?
>> Right now the manipulation expects the contents of the audio frame
>> to be changed, not the entire frame itself to be changed of type so
>> two things come to mind:
>>
>> 1. Change the frame enough to make it seem as though it does not
>> contain any audio. Changing datalen for example.
>>
>> 2. Make it so manipulate can return NULL to indicate it has
>> suppressed the frame. This shouldn't be that bad. The audiohook got
>> just has to replace the frame with&ast_null_frame if a manipulation
>> audiohook returns NULL.
>
>
> 3. Invent AST_FRAME_DROP and make sure that we drop it instead of
> sending it out to network...

That's what &ast_null_frame is for. It's a globally created frame which 
is used to replace frames with nothing or return a frame when no real 
frame exists to return. It just passes through stuff and nothing happens 
with it, since it contains er well nothing. Since it is globally created 
it also doesn't incur a memory allocation in most cases.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org