Just for grins I downloaded and compiled libopus and opustools..
I then encoded the Dream Theater song Bridges In the Sky from FLAC to opus at 48Kbps.
flac -d --totally-silent -c Dream\ Theater/A\ Dramatic\ Turn\ Of\ Events/05\ -\ Bridges\ In\ The\ Sky.flac | opusenc --music --bitrate 48 - DT_Bridges.opus
(BTW, please try to add FLAC input file support to openenc when you get a chance!)
This was on Xubuntu Oneiric 11.10, 64-bit.
I then decoded the opus file back to wav, compressed it with FLAC and transferred it to my machine at work (did this on a machine at home while I was supposed to be working.. oops).
I'm listening on a Thinkpad T420 using VLC 2.0.2 and a craptastic pair of ear-buds.
I have a local 1st generation Ogg Vorbis -q5 version of the song to compare it to.
With all that said, and the obvious admission this is not ABX, I was definitely able to hear a marked difference between the 2. I was VERY impressed with how well opus did with such a small bitrate budget. While I was able to easily tell the difference between the 2, the quality of the opus encode was surprisingly good, and in some parts of the song it was actually difficult to hear the differences. I'm pretty sure if I bumped opus to 64Kbps I'd be hard pressed to ABX them on this gear. I'll try it with decent headphones when I get home tonight.
As a big fan of Vorbis, I've been watching the progress of this codec with great anticipation and hope it garners significant market share.
I really can't wait till my phone conversations sound crystal clear.
~/development$ opusinfo DT_Bridges.opus
Processing file "DT_Bridges.opus"...
New logical stream (#1, serial: 748363d4): type opus
Encoded with libopus 0.9.14
User comments section follows...
ENCODER=opusenc from opus-tools 0.1.3
Opus stream 1:
Pre-skip: 356
Playback gain: 0dB
Channels: 2
Original sample rate: 44100Hz
Packet duration: 20.0ms (max), 20.0ms (avg), 20.0ms (min)
Page duration: 1000.0ms (max), 999.2ms (avg), 440.0ms (min)
Total data length: 3797120 bytes (overhead: 1.35%)
Playback length: 11m:01.426s
Average bitrate: 45.93 kb/s, w/o overhead: 45.31 kb/s
Logical stream 1 ended