Best Codecs for Streaming?
John, in the article
“NPR Labs Eyes Streaming Technology” [radioworld.com,
keyword Kean], I wish that you had also looked at Opus
I would love to see how
it stacks up against the others at 24 through 48 kbps. The low
latency of Opus and its widespread implementation (e.g. Firefox,
softphones, patched BUTT and VLC) make this a natural but
bleeding-edge codec. Some proponents of Opus are calling it the Swiss
Army Knife audio codec because it does everything at least pretty
implementation (li-cense free), IETF standard approval, low latency
and high performance at low data rates make it very interesting for
stream distribution (Icecast), high-fidelity VoIP and remote
I know that Opus is
head and shoulders better than MP3 at 24 to 48 kbps, and even sounds
nice on voice at 16 kbps; but how does it measure up against the
high-performance older codecs?
Haddon Heights, N.J.
John Kean of NPR
Labs replies: I am sure the Opus codec would beat AAC+/HE-AAC at 32
kbps and below, but one of the qualifications was that it be natively
available in most consumer devices, such as tablets, phones, etc. As
good as Opus may be, it didn’t meet that requirement, and we were
constrained by the number of codecs we could test (xHE-AAC, which
beat HE-AAC at low bit rates, was included for its potential as a
future codec, and it appears to be increasing in new consumer devices
since our test). Some stations continue to stream MP3 with HE-AAC, to
minimize the chance of disenfranchising some listeners, so
availability across all platforms seems to remain an important
factor. I’m with you — I’d love to do a test with Opus!