That's how testing works in the audio industry. Mainly because it's the only thing that makes sense.
Fair comment and i see your reasoning, however, if you want to appeal to more "knowledgeable" users in your tests, you should supply the following info:
- What hardware playback device were you using for the tests?
- What speakers/headphone devices were tested (DT 990 pro's / Ipod standard)
- Were you tests consistent across the board of devices used?
A spectrum tells you almost nothing about how a codec sounds. Thus listening tests.
A spectrum analysis tells you everything regarding a codecs compression/quality ratio.
If your aiming for your codec to simply "sound good" but actually "be completely false in reproduction", your codec will be ignored by professionals.
That's what a listening test answers. I know very few people who listen to music by unplugging their speakers, watching the spectrogram scroll by, and pretending to know what it sounds like.
True, but the professionals who actually make that "audio", will use a spectrogram to determine the optimal playback quality for a set device (usually iPod + iPod headphones).
If the Opus codec fails in basic "true reproduction" of their audio, it will not be given the light of day.
Only telephony codecs do that; the highpass improves speech intelligibility according the studies done by Bell Labs.
Opus has a 3Hz highpass to eliminate spectral leakage in samples with a DC offset.
You could increase that to 20hz for improved quality/compression ratio.
20hz is generally regarded as the cut off point for all audio production, mainly due to the fact its a pure vibration, and, causes unnecessary compression issues in the mix. 40hz for music production.
Low pass is 13khz for modern music production.
No. Opus is based on CELT, a music codec, and SILK, a speech codec. You didn't even read the demo page? Dude, tons of pretty pictures. You missed the party hat though.
Pretty pictures might work on most people, but a page full of "hear say" does nothing to help Opus.
My feedback was designed to get Opus re-thinking its target audience. Wheter they take some of that on board, or not, is no loss to me. .ogg still is my prefered choice. Changing that is down to the quality/information provided in your tests.