Comment by retrac
1 year ago
These days it's not uncommon to stack multiple lossy compressors in a chain. Your VoIP phone -> service provider is one codec. Then the phone company to the other phone company - quite possibly re-encoded - then on the other end they re-encode it yet again, to send to the VoIP or cell phone.
IT doesn't have to be that way. Ideally we'd stream the data (whether compressed or uncompressed) directly to the other end. There are standards for this but, well you know how standards are: so many to choose from.
In hindsight I think lossy compression of telephony was a mistake. It's 64 kbps for classic narrowband. GSM and other early digital cellular technologies could provide perhaps 5 - 10 kbps per handset and voice just had to be crammed into that. It made sense in the early 90s in that one application. It makes little sense in other applications, either then or now.
The long distance network of the late 70s into the early 00s was mostly uncompressed digital PCM, while the local loop was analog. The result was a basically distortion-free channel from about 200 to 3 kHz. Oh, and it was mostly synchronous too, so the delay was generally under 100 ms even cross-continent. You used to be able to immediately interrupt the person while talking just as in an real-life conversation. Some telephony systems running over packet-switching with buffering end up with such significant delays in practice that you have to take turns like it's a walkie-talkie.
Oh, and you missed an important one for me, which is that many phones will only use half duplex for the codec (possibly made worse by noise cancelling that will cut the speaker when the mic is active). This is annoying because I used to be able to talk to people on land lines, interrupt them, and then wait for them to finish talking so I can have a turn. Now, as soon as I talk, their audio cuts out, and now I can't tell if they've actually paused to let me talk. I find it very maddening, and difficult to hold a conversation.
Luckily, at least on my phone, when I attach a bluetooth headset, I can still get full duplex audio through the headset
Transferring from one network to another happened back in the last millennium with landlines, too
I'm from Iowa, a state where that made lots of money, globally, for decades.
The rise of Big Latency is trashing our long distance relationships. It is absolutely infuriating.