6 ms·

12 kilobits per second is high definition?

deleted 17y ago
[deleted]
nitrogen 17y ago
In the voice world, they call anything above an 8kHz sampling rate "HD audio." It's the next big thing in voice conferencing: 16kHz sampling rate! The comfort noise (noise played by a phone so you know it hasn't disconnected) never sounded so clear! Naturally, it's all patented and proprietary. Meanwhile there are open source systems capable of CD quality audio at speech latencies (http://www.celt-codec.org/ http://www.celt-codec.org/), but why use that when you can pay for an AMR-WB license? Actually, I set up an Asterisk PBX once for a demonstration of an HD voice system with a 48kHz/24-bit AEC system that was shown at Infocomm, and it does sound nice.
- DarkShikari 17y ago
  CD quality audio at speech latencies Don't exaggerate so much. Celt is good, but it's not magic. It certainly won't even be as good as something like AAC-HE -- which of course is intentional, since Celt's target is ultra-low-latency situations, which inherently results in worse compression. It also has to be relatively loss-redundant without the use of forward error correction, which introduces even more constraints on inter-frame prediction. And of course one may note from http://www.celt-codec.org/comparison/ http://www.celt-codec.org/comparison/ that it doesn't actually compete with AMR; it's easily 5-10 times lower latency (and higher bitrate as well). It's really just a totally different use-case. proprietary However crappy it is, I'm pretty sure I recall AMR being an open 3GPP spec. There's even a free software implementation (under Apache v2).
  - ZeroGravitas 17y ago
    The CELT developers themselves say "CELT brings CD-quality sound to VoIP-style low-delay applications" but it would be easy to get into an argument about what "CD-quality" means. On another note, as the other poster stated, AMR is patented. Not everyone includes that in their own personal definition of "proprietary", but the two words are synonyms.
    - DarkShikari 17y ago
      If being covered by software patents made something proprietary, the entire world would be proprietary, nearly every single open source project included.
      - ZeroGravitas 17y ago
        After I wrote that I recognised the ambiguity and I was going to go back and edit it to say something like "actively enforced patents to generate licence fees", but I thought it was obvious enough as it was, given the context.
        DarkShikari 17y ago
        I still don't like that definition, since it confuses the vast majority of multimedia formats with formats that are actually proprietary. I prefer to reserve the word proprietary for formats where the specification is either secret or does not exist and any free implementations were reverse-engineered, e.g. RealVideo, Windows Media Audio, and so forth. It doesn't make sense IMO to simply call 98% of everything proprietary; it sort of weakens the meaning of the word to overuse it as such.

deleted 17y ago

[deleted]

In the voice world, they call anything above an 8kHz sampling rate "HD audio." It's the next big thing in voice conferencing: 16kHz sampling rate! The comfort noise (noise played by a phone so you know it hasn't disconnected) never sounded so clear! Naturally, it's all patented and proprietary. Meanwhile there are open source systems capable of CD quality audio at speech latencies (http://www.celt-codec.org/ http://www.celt-codec.org/), but why use that when you can pay for an AMR-WB license? Actually, I set up an Asterisk PBX once for a demonstration of an HD voice system with a 48kHz/24-bit AEC system that was shown at Infocomm, and it does sound nice.

DarkShikari 17y ago
CD quality audio at speech latencies Don't exaggerate so much. Celt is good, but it's not magic. It certainly won't even be as good as something like AAC-HE -- which of course is intentional, since Celt's target is ultra-low-latency situations, which inherently results in worse compression. It also has to be relatively loss-redundant without the use of forward error correction, which introduces even more constraints on inter-frame prediction. And of course one may note from http://www.celt-codec.org/comparison/ http://www.celt-codec.org/comparison/ that it doesn't actually compete with AMR; it's easily 5-10 times lower latency (and higher bitrate as well). It's really just a totally different use-case. proprietary However crappy it is, I'm pretty sure I recall AMR being an open 3GPP spec. There's even a free software implementation (under Apache v2).
- ZeroGravitas 17y ago
  The CELT developers themselves say "CELT brings CD-quality sound to VoIP-style low-delay applications" but it would be easy to get into an argument about what "CD-quality" means. On another note, as the other poster stated, AMR is patented. Not everyone includes that in their own personal definition of "proprietary", but the two words are synonyms.
  - DarkShikari 17y ago
    If being covered by software patents made something proprietary, the entire world would be proprietary, nearly every single open source project included.
    - ZeroGravitas 17y ago
      After I wrote that I recognised the ambiguity and I was going to go back and edit it to say something like "actively enforced patents to generate licence fees", but I thought it was obvious enough as it was, given the context.
      - DarkShikari 17y ago
        I still don't like that definition, since it confuses the vast majority of multimedia formats with formats that are actually proprietary. I prefer to reserve the word proprietary for formats where the specification is either secret or does not exist and any free implementations were reverse-engineered, e.g. RealVideo, Windows Media Audio, and so forth. It doesn't make sense IMO to simply call 98% of everything proprietary; it sort of weakens the meaning of the word to overuse it as such.