I came across a recording at the mobile of a land to mobile EVRC-B call Not on
VZW. It had Screech Which was no surprise but also it decoded words that were
not sent in the Harvard sentence source speech files!
The word "write" was turned into ri.....ot and the word "cookie" became coochie!
This would make it possible peoples words could be unknowingly miss understood
or worse!
Can 4GV mangle speech in such a way so that the words and meanings are actually
replaced at the receiving decoder?
EVRC-B capable of word Mangling/ word replacement
Started by ●February 27, 2011
Reply by ●March 15, 20112011-03-15
Kevin-
> I came across a recording at the mobile of a land to mobile EVRC-B call Not on VZW. It had Screech Which was no
> surprise but also it decoded words that were not sent in the Harvard sentence source speech files!
> The word "write" was turned into ri.....ot and the word "cookie" became coochie! This would make it possible peoples
> words could be unknowingly miss understood or worse!
> Can 4GV mangle speech in such a way so that the words and meanings are actually replaced at the receiving decoder?
EVRC is a low bitrate codec. Like other LBR codecs, it tends to have trouble with fricatives (consonants) -- that's
one reason why there are MOS ratings and DRT tests.
As for a gap in a word (that you seem to imply with your initial example), this could be due to many things, including
network latency issues.
Basically, when you're testing live calls, anything can happen. To figure out what's really going on -- and what
system component is to blame -- you have to capture RTP packets at both sides of the transmission.
-Jeff
> I came across a recording at the mobile of a land to mobile EVRC-B call Not on VZW. It had Screech Which was no
> surprise but also it decoded words that were not sent in the Harvard sentence source speech files!
> The word "write" was turned into ri.....ot and the word "cookie" became coochie! This would make it possible peoples
> words could be unknowingly miss understood or worse!
> Can 4GV mangle speech in such a way so that the words and meanings are actually replaced at the receiving decoder?
EVRC is a low bitrate codec. Like other LBR codecs, it tends to have trouble with fricatives (consonants) -- that's
one reason why there are MOS ratings and DRT tests.
As for a gap in a word (that you seem to imply with your initial example), this could be due to many things, including
network latency issues.
Basically, when you're testing live calls, anything can happen. To figure out what's really going on -- and what
system component is to blame -- you have to capture RTP packets at both sides of the transmission.
-Jeff
