4 ms·
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
by 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 agoThe 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 agoIf being covered by software patents made something proprietary, the entire world would be proprietary, nearly every single open source project included.
- ZeroGravitas 17y agoAfter 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 agoI 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.