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Comment by diimdeep | Hacker News Reader

I just compared 730 kb/s Flac with 160kb/s Opus, I can see no difference even on spectrogram using 'mother of mp3' track: Tom's Diner (Live At The Royal Albert Hall, London, UK, November 18, 1986).

Very surprising, will be migrating all my music to opus to save space.

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Beware of phase differences, they won't show up on a spectrogram but could seriously upset your stereo impression. Before you compress all your Flac content and only figure this one out afterwards. That could be quite annoying.

Yeah - definitely keep your backups in FLAC. Having a lossless source gives you infinite future flexibility, and that cannot be underestimated. Otherwise you're kinda doomed to hit https://www.youtube.com/watch?v=fZCRYo-0K0c eventually.

For on-listening-device though, oh heck yes - Opus is great.

Just as a side note, spectrogram are not in any way indicative of compression quality.

Its interesting that you didn't see any differences between flac and opus, as opus has a hard 20 kHz low-pass filter and is 48kHz-only.

There is visible 20 kHz LPF, but it is meaningless for use case of music listening, right ?

I did not liked degradation at 140-128kb/s and noise above 16kHz and some artifacts 10-16khz that is clearly visible and much more impactful.

Here is spectrograms https://disk.yandex.com/d/PvQGSS2xBu7ucQ

As I said, spectrograms are not indicative of compression quality. Codecs should be judged by ears only. What you see in a spectrogram will vastly differ between codecs and will not reflect their compression efficiency.

> I just compared 730 kb/s Flac with 160kb/s Opus, I can see no difference even on spectrogram

Doesn't Ogg Vorbis perform better than Opus on bitrates above 128kbps?

Opus is transparent at 160kb/s, so no.

When comparing, your vorbis examples were encoded with 48kHz too?

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