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It's audible in the sense that it exists completely in an audio modality. But it's not audible in the sense that human ears can't discern it.
by 613style 3y ago
It's audible in the sense that it exists completely in an audio modality.
But it's not audible in the sense that human ears can't discern it.
- meindnoch 3y agoThe aim of lossy compression is to discard any data that isn't discernible to the human auditory system. If an audio signal survives a lossy compression algorithm, then there are two possibilities: - the compression algorithm should be improved, as it preserves some data that isn't important to the human ear - the signal is audible
- amatecha 3y agoThat's not exactly the aim of lossy compression. Its aim is to reduce data size while introducing as little discernible effect as realistically possible. That usually means optimizing the algorithm such that most of the loss is indiscernible to us, such as in a darkest regions of an image, or the extremely high frequencies in audio -- both areas we don't perceive with too much granularity. Something like spread-spectrum phase distortion may survive compression just fine but still be indiscernible to us. The two are not mutually exclusive.
- AnthonyMouse 3y agoSuppose you could encode 0.2 bits per second of watermark in a recording without humans being able to discern it. Suppose the compression algorithm did the same thing to encode additional information which is part of the recording, allowing it to achieve higher quality at the same bitrate or the same quality at a lower bitrate. It's information theory. Either you can encode additional information without impacting the result, in which case the compression algorithm could use it to be more efficient, or you can't. TANSTAAFL.
- wizzwizz4 3y agoAnd complexity theory says we can't reach the information theoretical limits with generic algorithms.
- AnthonyMouse 3y agoIf there is a known way to cram more data into the same space, compression algorithms are going to want to use it, or something like it which makes use of the same space. Even minor improvements in compression algorithms are extremely valuable at the scale of the internet.
- Dylan16807 3y agoAudio compression algorithms are not trying to be 99.9999999% efficient.
- deleted 3y ago[deleted]
- avisser 3y ago> the compression algorithm should be improved There is an obvious third choice: the gain in compression isn't worth the effort of writing code to detect these non-discernible artifacts. People are throwing around 0.2 bits/second in this thread. I doubt a company or individual would write code for such a trivial gain, never mind the slowdown in encoding it might cause.
- TerrifiedMouse 3y ago> isn't worth the effort of writing code to detect these non-discernible artifacts Why wouldn’t it be worth it? You just have to write the code once and it will affect terabytes of music being compressed from that point forth.
- avisser 3y agoBecause it's bad business. How much will people spend to save 0.2bps? My guess is $0. Why spend anything on technology with no return?