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Wang, Mark | 27 Jun 2012 04:07

live55 rtp sequence number is duplicate

Hi all,

 

My OS is LINUX 2.6.37,  I send h264 and MJPEG data to VLC or QUICKTIME by live555, sometimes I can see live555 RTP sequence is duplicate, I capture some packets by tool WIRESHARK , these packets is as below

 

 

Thanks

Mark Wang

 



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Ross Finlayson | 27 Jun 2012 06:43
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Re: live55 rtp sequence number is duplicate

My OS is LINUX 2.6.37,  I send h264 and MJPEG data to VLC or QUICKTIME by live555, sometimes I can see live555 RTP sequence is duplicate, I capture some packets by tool WIRESHARK , these packets is as below

These are almost certainly duplicate packets - not distinct packets that happen to have the same RTP sequence number (because the LIVE555 RTP transmitting code always increments the sequence number each time it sends a packet).

This packet duplication could be happing somewhere on your network (e.g., by a router), or perhaps in the sender or receiver's operating system.  But it's definitely not happening in our code.

In any case, this shouldn't be a problem, because the RTP receiver will check the sequence numbers, and automatically discard any duplicate packets.  Ditto if packets get reordered on the network (which can also happen).  That's the purpose of the RTP sequence number.


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/ 

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Wang, Mark | 29 Jun 2012 10:10

Re: live55 rtp sequence number is duplicate

Hi all,

 

Thanks for your quickly reply.

 

Actually ,  the two frame sequence number is the same , but  H264 data is different,  and I notice  checksum of UDP is the same too, please look details via attached  two  JPG document.

 

I draw my test network  flow chart as below,  port1 and port3 are port mirroring . all packets are captured by WIRESHARK.

 

 

 

 

 

 

 

 


My version detail  is  as below

 

#define LIVEMEDIA_LIBRARY_VERSION_STRING  "2010.08.22"

#define LIVEMEDIA_LIBRARY_VERSION_INT                   1282435200

 

Thanks

Mark Wang

 

 

Thanks

Mark Wang

 

 

Thanks

Mark Wang

 

From: live-devel-bounces-m22LxytlYjp4ccXRSk2lxg@public.gmane.org [mailto:live-devel-bounces-m22LxytlYjp4ccXRSk2lxg@public.gmane.org] On Behalf Of Ross Finlayson
Sent: 2012年6月27日 12:44
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] live55 rtp sequence number is duplicate

 

My OS is LINUX 2.6.37,  I send h264 and MJPEG data to VLC or QUICKTIME by live555, sometimes I can see live555 RTP sequence is duplicate, I capture some packets by tool WIRESHARK , these packets is as below

 

These are almost certainly duplicate packets - not distinct packets that happen to have the same RTP sequence number (because the LIVE555 RTP transmitting code always increments the sequence number each time it sends a packet).

 

This packet duplication could be happing somewhere on your network (e.g., by a router), or perhaps in the sender or receiver's operating system.  But it's definitely not happening in our code.

 

In any case, this shouldn't be a problem, because the RTP receiver will check the sequence numbers, and automatically discard any duplicate packets.  Ditto if packets get reordered on the network (which can also happen).  That's the purpose of the RTP sequence number.

 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/

 



This e-mail contains privileged and confidential information intended for the use of the addressees named above. If you are not the intended recipient of this e-mail, you are hereby notified that you must not disseminate, copy or take any action in respect of any information contained in it. If you have received this e-mail in error, please notify the sender immediately by e-mail and immediately destroy this e-mail and its attachments.
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Ross Finlayson | 29 Jun 2012 11:40
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Re: live55 rtp sequence number is duplicate

Actually ,  the two frame sequence number is the same , but  H264 data is different,  and I notice  checksum of UDP is the same too

Two separate packets cannot contain different data, but (consistently) have the same UDP checksum, unless something (in your OS or network) is mangling the packets (i.e., is badly broken), or unless Wireshark is lying.

One thing I can say for certain, though, is that our software is not responsible - so there's no point in posting to this mailing list about what (you think) you're seeing (and especially not with 1+ MByte emails :-)


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/ 

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live-devel@...
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Ross Finlayson | 29 Jun 2012 11:40
Favicon

Re: live55 rtp sequence number is duplicate

Actually ,  the two frame sequence number is the same , but  H264 data is different,  and I notice  checksum of UDP is the same too

Two separate packets cannot contain different data, but (consistently) have the same UDP checksum, unless something (in your OS or network) is mangling the packets (i.e., is badly broken), or unless Wireshark is lying.

One thing I can say for certain, though, is that our software is not responsible - so there's no point in posting to this mailing list about what (you think) you're seeing (and especially not with 1+ MByte emails :-)


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/ 

_______________________________________________
live-devel mailing list
live-devel <at> lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
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Wang, Mark | 29 Jun 2012 10:10

Re: live55 rtp sequence number is duplicate

Hi all,

 

Thanks for your quickly reply.

 

Actually ,  the two frame sequence number is the same , but  H264 data is different,  and I notice  checksum of UDP is the same too, please look details via attached  two  JPG document.

 

I draw my test network  flow chart as below,  port1 and port3 are port mirroring . all packets are captured by WIRESHARK.

 

 

 

 

 

 

 

 


My version detail  is  as below

 

#define LIVEMEDIA_LIBRARY_VERSION_STRING  "2010.08.22"

#define LIVEMEDIA_LIBRARY_VERSION_INT                   1282435200

 

Thanks

Mark Wang

 

 

Thanks

Mark Wang

 

 

Thanks

Mark Wang

 

From: live-devel-bounces <at> ns.live555.com [mailto:live-devel-bounces <at> ns.live555.com] On Behalf Of Ross Finlayson
Sent: 2012年6月27日 12:44
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] live55 rtp sequence number is duplicate

 

My OS is LINUX 2.6.37,  I send h264 and MJPEG data to VLC or QUICKTIME by live555, sometimes I can see live555 RTP sequence is duplicate, I capture some packets by tool WIRESHARK , these packets is as below

 

These are almost certainly duplicate packets - not distinct packets that happen to have the same RTP sequence number (because the LIVE555 RTP transmitting code always increments the sequence number each time it sends a packet).

 

This packet duplication could be happing somewhere on your network (e.g., by a router), or perhaps in the sender or receiver's operating system.  But it's definitely not happening in our code.

 

In any case, this shouldn't be a problem, because the RTP receiver will check the sequence numbers, and automatically discard any duplicate packets.  Ditto if packets get reordered on the network (which can also happen).  That's the purpose of the RTP sequence number.

 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/

 



This e-mail contains privileged and confidential information intended for the use of the addressees named above. If you are not the intended recipient of this e-mail, you are hereby notified that you must not disseminate, copy or take any action in respect of any information contained in it. If you have received this e-mail in error, please notify the sender immediately by e-mail and immediately destroy this e-mail and its attachments.
Attachment (image001.emz): application/octet-stream, 2235 bytes
Attachment (image003.emz): application/octet-stream, 4080 bytes
Attachment (image004.emz): application/octet-stream, 2469 bytes
Attachment (image005.emz): application/octet-stream, 2638 bytes
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Ross Finlayson | 27 Jun 2012 06:43
Favicon

Re: live55 rtp sequence number is duplicate

My OS is LINUX 2.6.37,  I send h264 and MJPEG data to VLC or QUICKTIME by live555, sometimes I can see live555 RTP sequence is duplicate, I capture some packets by tool WIRESHARK , these packets is as below

These are almost certainly duplicate packets - not distinct packets that happen to have the same RTP sequence number (because the LIVE555 RTP transmitting code always increments the sequence number each time it sends a packet).

This packet duplication could be happing somewhere on your network (e.g., by a router), or perhaps in the sender or receiver's operating system.  But it's definitely not happening in our code.

In any case, this shouldn't be a problem, because the RTP receiver will check the sequence numbers, and automatically discard any duplicate packets.  Ditto if packets get reordered on the network (which can also happen).  That's the purpose of the RTP sequence number.


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/ 

_______________________________________________
live-devel mailing list
live-devel <at> lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
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