[opus] 133 kbps stereo killer sample
agustin at dallalba.com.ar
Fri Apr 14 20:53:13 UTC 2017
I halved the volume of the sample before encoding with
`sox -v 0.5 floex.wav quiet.wav` and now I can't ABX it succesfully anymore.
So the artifact I heard was just clipping when encoding or decoding.
Opus remains unbeaten for me at 133 kbps. That's totally awesome.
On 10 April 2017 at 17:14, Agustín Dall'Alba <agustin at dallalba.com.ar> wrote:
> Hello! I found a sample I can ABX successfully when encoded at
> 133.333 kbps. I was targetting 1 MB/min.
> floex.wav is 4:54–5:04 of a lossless copy of 'Forget-me-not' by
> Floex, downloaded from http://store.floex.cz/album/zorya
> floex-133.opus was created with `opusenc --bitrate 133.333333 floex.wav
> floex-133.opus`, opus-tools 0.1.9 (using libopus 1.1.4).
> I used a Sony MDR-V6 pair of headphones and my laptop's oonboard audio. I
> detected the artifact when I was listening casually from my phone with the
> same headphones.
> In the second to last note of the crescendo (at ~5 s in the sample) there's
> a slight flutter in the original that turns more prominent and tape-like
> after encoding.
> I also tried encoding at 128 kbps and 150 kbps.
> ABX results:
> - floex-133.opus.wav 10/10, p-value<0.001
> - floex-150.opus.wav 4/10, p-value<0.83
> - floex-128.opus.wav 17/20, p-value<0.002
> Only at 150 kbps is Opus transparent to me for this sample.
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