[asterisk-dev] How to create a slinear silent frame? SOLVED

[Holger Wirtz]

Dmitry, Russell,

thanks for your help! I fixed the problem with not using "offset" but
can anyone tell me when offset is beeing used?

Another question: Is there a documentation outside the sources where I
can get some more information about channels and frames?

Regards, Holger

Dmitry Andrianov wrote:
> 2 Holger Wirtz:
> 
> I believe you should not use calloc/free to manipulate frames.
> Also, I have no idea why you are trying to manipulate "offset" frame field. This is probably the thing which makes your code crash.
> 
> 	create buffer and zero it once.
> ..
> 
> 
>         struct ast_frame frame = {
>                 .frametype = AST_FRAME_VOICE,
>                 .subclass = AST_FORMAT_SLINEAR,
>                 .data = buffer,
>                 .datalen = sizeof(buffer),
>                 .samples = samples,
>                 .src = __FUNCTION__,
>         };
> 
> 	return ast_frdup(&frame);
> 
> should work. 
> 
> 
> 2 Atis Lezdins:
> one frame (20ms) is not enough to produce any beep. You will need many frames for the beep to be heard.
> In any case, apps/app_morsecode.c should be good start.
> 
> Regards,
> Dmitry Andrianov
> 
> -----Original Message-----
> From: asterisk-dev-bounces at lists.digium.com [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Atis Lezdins
> Sent: Monday, May 18, 2009 3:17 PM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] How to create a slinear silent frame?
> 
> On Mon, May 18, 2009 at 12:36 PM, Holger Wirtz <wirtz at dfn.de> wrote:
>> Hi,
>>
>> I tried to create an empty frame (with data set to 0000000...) but I get
>>  crashes when I try to send this frames with ast_write() to a channel.
>>
>> I created the frame like this:
>>
>> --- cut here ---
>> struct ast_frame* frame_create_silent_voice(int offset,int samples)
>> {
>>        struct ast_frame* f=NULL;
>>        short *data=NULL;
>>        int i=0;
>>
>>        if((f=calloc(1,sizeof(struct ast_frame)))==NULL)
>>        {
>>                ast_log(LOG_ERROR,"Unable to allocate memory for slinear
>> frame\n");
>>                return(NULL);
>>        }
>>
>>        f->frametype=AST_FRAME_VOICE;
>>        f->subclass=AST_FORMAT_SLINEAR;
>>        f->mallocd=AST_MALLOCD_HDR|AST_MALLOCD_DATA;
>>        f->samples=samples;
>>        f->datalen=samples*sizeof(short);
>>        f->offset=offset;
>>        f->src=NULL;
>>        f->data=NULL;
>>
>>        if((data=(short *)calloc(1,sizeof(short)*samples)+offset)==NULL)
>>        {
>>                ast_log(LOG_ERROR,"Unable to create array for frame
>> data\n");
>>                if(f!=NULL)
>>                {
>>                        free(f);
>>                        f=NULL;
>>                }
>>        }
>>        else
>>        {
>>                f->data=data;
>>        }
>>
>>        return(f);
>> }
>> --- cut here ---
>>
>> What am I doing wrong, can anyone help?
>>
> 
> While on topic, i'm also interested how to create a beep frame. There
> are some frequency generations in indications.c, but i guess i'll need
> just a frame :)
> 
> Regards,
> Atis
> 

-- 
#####  #### ##  ##   Holger Wirtz         Phone : (+49 30) 884299-40
##  ## ##   ### ##   DFN-Verein           Fax   : (+49 30) 884299-70
##  ## #### ######   Alexanderplatz 1     E-Mail: wirtz at dfn.de
##  ## ##   ## ###   10178 Berlin
#####  ##   ##  ##   GERMANY              WWW   : http://www.dfn.de
GPG-Fingerprint: ABFA 1F51 DD8D 503C 85DC  0C51 E961 79E2 6685 9BCF