Jump to content

G729a on pbxnsip


Parks
 Share

Recommended Posts

Just trying to see how G729a is working on other companies multi tenant deployments. We would like to put some customers trunks to use it primarily. Any feedback would be really helpful, thank.

 

IMHO the biggest problem with G.729 is that the audio is compressed so much that customers have the impression that VoIP is inferior to PSTN.

 

Every transcoding step reduces the amount of information transmitted.

Link to comment
Share on other sites

IMHO the biggest problem with G.729 is that the audio is compressed so much that customers have the impression that VoIP is inferior to PSTN.

 

Every transcoding step reduces the amount of information transmitted.

I understand that the audio is compressed and therefore the quality is less. However our customers on our SIP trunking service love it and cannot tell the difference. Most cannot tell the difference in quality especially because so many people use cell phones these days.

 

If every time it gets transcoded it reduces the quality then it really is only get transcoded twice once on the carrier side then on the customers side. Am I looking at that right?

Link to comment
Share on other sites

If every time it gets transcoded it reduces the quality then it really is only get transcoded twice once on the carrier side then on the customers side. Am I looking at that right?

 

Yes, the transcoding chain looks like this: IP phone (microphone) -> G.729 -> PSTN (G.711) -> GSM EFR -> Cell phone speaker. So lets say the quality was 100 % in the beginning, then the whole chain might look like this: 80 % (microphone is also "transcoding") * 75 % (G.729) * 90 % (G.711) * 70 % (GSM) * 70 % (speaker, optimistic) = 26 % left. "Illustrative", but it should be possible to get the picture why every transcoding step is a problem.

 

I had a phone call once that must have three or four transcoding steps, and smoke signs would have been easier to understand.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...