RTP benefits

[luigio18]

Hello there

Does anybody know why we should use RTP protocol for streaming?
What benefits this protocol gives in comparison to simple use of UDP or TCP?

Thanks

[luigio18]

I mean how these benefits are / can be utilized in Symbian.

[david.caabeiro]

Loss detection, reception quality info, error concealment, synchronization, congestion control.. just to name a few..

You might want to read some book/rfc on this

[luigio18]

Loss detection, reception quality info, error concealment, synchronization, congestion control.. just to name a few..

You might want to read some book/rfc on this

Hi,

Thanks for your reply.
Can I ask one more question?
Is it possible to send G.711 payload over UDP without encapsulating into RTP packets or RTP is a vital part for data like this and this protocol must be utilized?
Don't be angry with my questions. I'm just studying yet

Thanks

[hliukkon]

Hi,

Thanks for your reply.
Can I ask one more question?
Is it possible to send G.711 payload over UDP without encapsulating into RTP packets or RTP is a vital part for data like this and this protocol must be utilized?
Don't be angry with my questions. I'm just studying yet

Thanks

How are you going to know packet loss and sequence of audio payloads without structure of RTP?

[luigio18]

How are you going to know packet loss and sequence of audio payloads without structure of RTP?

Actually I thought that for a streaming data it's not so important to loose a couple of packets. Am I wrong? I also thought that it's possible to play incoming stream without changing the order of packets If the order of packets is not the same as it was while sending do I have to sort these packets back by myself or this part is somehow managed by RTP framework?

Thanks

[hliukkon]

Actually I thought that for a streaming data it's not so important to loose a couple of packets. Am I wrong? I also thought that it's possible to play incoming stream without changing the order of packets If the order of packets is not the same as it was while sending do I have to sort these packets back by myself or this part is somehow managed by RTP framework?

Thanks

from http://discussion.forum.nokia.com/fo...d.php?t=113432'

Here i'm registering observer to receive RTP packet

TInt err = iRtpAPI->RegisterRtpObserver( iSessionId,
*this );

void RtpPacketReceived( TRtpId aStreamId,
const TRtpRecvHeader &aHeaderInfo,
const TDesC8 &aPayloadData );


Your observer class is implemented this method. You will get payload data with RTP packets header info.( sequence number, time stamp....)
RTP didn't keep packet in order. You have to do that.

"Actually I thought that for a streaming data it's not so important to loose a couple of packets. Am I wrong? I also thought that it's possible to play incoming stream without changing the order of packets"

Ofcourse you can play packets in that order which they come in but packets can be received out of order. You have to think how you handle those packets. Audio quality is not so good if you just play packet in receiving order.

[david.caabeiro]

And besides, there some other issues, such as jittering, to put an example.

[luigio18]

Hello Hliukkon,

Thank you for the reply. Now the things have come clear
Can I ask one more question? What would you recommend to use RTP: 1) API which is described in SDK(rtp.h) or API from the Nokia's extension(rtpapi.h).
People in different threads describe use of different APIs. So I'm a bit messed
I would really appreciate you to show the direction (I'm a complete newbie here)

Thanks in advance

[luigio18]

And besides, there some other issues, such as jittering, to put an example.

thanks

[luigio18]

Could anybody answer the question: What would you recommend to use RTP: 1) API which is described in SDK(rtp.h) or API from the Nokia's extension(rtpapi.h)?

thnx

[david.caabeiro]

I would say "api which is available to you". Start by checking the plugin extension package (see in FN homepage)

[luigio18]

Hi,

Can I test my application with an emulator if I need to use rtpapi.h or it's possible only with a device?

Thnx

[david.caabeiro]

The plugin supplies only native binaries, so you can only use it on device. You could do debugging on target though, but if you want to use the emulator then your choice is either porting an existing rtp stack, or writing your own.