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Topic: Song difficult for opus before 64 kbps. (Read 905 times) previous topic - next topic
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Song difficult for opus before 64 kbps.

Build: libopus 06.07.2019
Sample: I know it's compressed into oblivion, even if is a FLAC source.
It's last 5 lines of the hook before verse 2 (after the clap there is a bass that loses energy and texture) under 64 kbps.
Song: Z - nobody's better
I don't know why this bassline is difficult to compress, I am not an audio engineer.


Another sample (flac) maybe the problem is intensity stereo
Muse - dig down (under 54 kbps). The bass at the start make a strange hissing noise, why, is intensity stereo?
FFmpeg opus doesn't have this artifact.


This are only examples, I think there are many samples that have the same problem or artifact.

Re: Song difficult for opus before 64 kbps.

Reply #1
Opus is improving, but bass is muddy before 48 kbps, I think due to its nature of low delay audio codec. Core aac high efficiency (Apple) is better at low bitrate except in the highs.

Re: Song difficult for opus before 64 kbps.

Reply #2
hopefully in a future version of opusenc and opusdec, the opus team can implement an AI machine learning audio restoration algorithm in both encoding and decoding. This would be a perfect test for opus, considering that it already has most of the information of the original file encoded in the stream (it goes up to 20khz)

Re: Song difficult for opus before 64 kbps.

Reply #3
Crunchy bass are a problem for opus.

 
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