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G729 and umc_speech_rtp_codec

roccap
Beginner
179 Views
I have a G729 voice call stored as a pcap file, I filtered out one side of that and stored it
inrtpdump format.
I then fed that dump file to the umc_speech_rtp_codec sample, using the command line

umc_speech_rtp_codec -format IPP_G729 test.rtp test.wav

This appears to process ~90 frames of the file, creating a wav file ~1s long, even
though there are ~1400 frames in the file.

There are no errors messages or diagnostics, even when run under the debugger.

I have attached the pcap

Any ideas whats up?

TIA

Paul
0 Kudos
1 Solution
Igor_B_Intel1
Employee
179 Views
Hi Paul,
I investigated your file. The problem is related to the presence of SID frames. Currently umc_speech_rtp codec doesn't fully support such streams cause it isworks in offline mode. While used jitter buffer is designed to work in RT mode and produce a lot of lost frames instead of couple untransmitted frames and gets unsyncronized.We will mention it in the documentation in the next version.
But you can change G729DePacketizer::SetPacket method to be capable to insert sufficiend number of untransmitted frames based on information from RTP header: mark field and difference in timestamps and sequence number. Or disable using VAD in your softphone.

IgorS. Belyakov

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1 Reply
Igor_B_Intel1
Employee
180 Views
Hi Paul,
I investigated your file. The problem is related to the presence of SID frames. Currently umc_speech_rtp codec doesn't fully support such streams cause it isworks in offline mode. While used jitter buffer is designed to work in RT mode and produce a lot of lost frames instead of couple untransmitted frames and gets unsyncronized.We will mention it in the documentation in the next version.
But you can change G729DePacketizer::SetPacket method to be capable to insert sufficiend number of untransmitted frames based on information from RTP header: mark field and difference in timestamps and sequence number. Or disable using VAD in your softphone.

IgorS. Belyakov
Reply