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[MEDIACTRL] <modifyjoin> for separate stream directions
Hello
all,
I have a question
related to IETF draft <draft-ietf-mediactrl-call-flows-01> and the usage
of <modifyjoin>.
In chapter
6.4.3. DTMF-driven Conference Manipulation
there is presented a message flow.
First, the message
C1 is used to decrease the volume of the sent stream. Then, the message E1 is
used to
increase the volume
of the received stream. I understand that E1 message needs to specify also
the sendonly stream
or else the sendonly
stream is considered to be inactivated.
My question is: why
do the settings for the sendonly stream need to be repeated inside the E1
message (the decreasing of the volume) ?
For an implementor's
point of view, this approach introduces overhead in the implementation for both
the AS and MS:
- the AS needs to
remember the changed settings and introduce them into the subsequent modifyjoin
requests.
- the MS needs to
execute again the actions dictated by the AS even if it already executed some of
the requested actions
or, considering an
optimization:
- the MS needs to
analyze the actions requested by the AS and check if it already executed some of
them. Besides the extra processing logic required here,
it is implied that
the MS will also remember the change history for each
connection.
Shouldn't the command be applied over the current
connection configuration ? In this case it would be enough to mention
the
sendonly stream <stream media="audio" direction="sendonly"/>, to
prevent it from beeing inactivated while preserving its previous volume decrease
setting.
The Mixer Control
package IETF draft does not clarify this aspect either.
C1 message:
"
...
<stream
media="audio"
direction="sendonly">
<volume controltype="setgain"
value="-3"/>
</stream>
<stream media="audio"
direction="recvonly"/>
...
"
E1
message:
"
...
<stream
media="audio"
direction="recvonly">
<volume controltype="setgain"
value="+3"/>
</stream>
<stream media="audio"
direction="sendonly">
<volume controltype="setgain"
value="-3"/>
</stream>
...
"
Elena Tebeşoi
Software
Engineer
Freescale Semiconductor
Romania
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