[Freeswitch-users] codecs initialization flags in endpoint modules

[Michael Collins]

FYI, these are good questions but they probably belong on the dev list since
they are so technical in nature. :)
-MC

On Fri, Apr 3, 2009 at 6:20 AM, Lele Forzani <lele at windmill.it> wrote:

>
> Hello,
> I've been experimenting with the use of mod_dahdi_codec and other ways
> to perform external transcoding for codecs, and came up with noticing
> that transcoding resources seemed to be used up twice what I expected.
> That is and 2x the number of call legs, ending up to two encoder and two
> decoder instances per leg.
>
>
> So, I looked at the code and noticed almost every endpoint module does
> something like this (excerpt from mod_sofia, sofia_glue.c:~1800):
>
> if (switch_core_codec_init(&tech_pvt->read_codec,
>                   tech_pvt->iananame,
>                   tech_pvt->rm_fmtp,
>                   tech_pvt->rm_rate,
>                   tech_pvt->codec_ms,
>                   1,
>                   SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE |
> tech_pvt->profile->codec_flags,
>                   NULL, switch_core_session_get_pool(tech_pvt->session)) !=
> SWITCH_STATUS_SUCCESS) {
>        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Can't load
> codec?\n");
>        switch_goto_status(SWITCH_STATUS_FALSE, end);
> }
>
> if (switch_core_codec_init(&tech_pvt->write_codec,
>                   tech_pvt->iananame,
>                   tech_pvt->rm_fmtp,
>                   tech_pvt->rm_rate,
>                   tech_pvt->codec_ms,
>                   1,
>                   SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE |
> tech_pvt->profile->codec_flags,
>                   NULL, switch_core_session_get_pool(tech_pvt->session)) !=
> SWITCH_STATUS_SUCCESS) {
>        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Can't load
> codec?\n");
>        switch_goto_status(SWITCH_STATUS_FALSE, end);
> }
>
>
> The flags being SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE
> seems to be causing the apparent 'double' allocation of transcoding
> resources, and I fail to understand the need for both, in both cases.
>
> Could someone please spend a minute to explain?
>
>
> thanks
> lele
>
>
>
>
>
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