opus VS libopenaptx

Opus doesn't support 44.1 kHz because compatibility and effort/benefit ratio:

https://github.com/xiph/opus/issues/43

The browser audio limitation is presumably a workaround to some bug or performance limitation that was relevant at some point in history (the site was created in 2014).

There is a pattern here (that also goes with the author's prior article on inverting gauss' sum formula): Generally if if you can make a formula that counts the combination of things you can convert that into a code to encode and decode those combinations into indexes.

So for example the opus audio codec needs to encode/decode vectors of dimension n whos absolute values sum to k. https://github.com/xiph/opus/blob/master/celt/cwrs.c#L74

Or this rolling cuckoo filter that optimally encode/decode four sorted numbers in a range 0..2N with the constraint that the they span a range of N. https://github.com/sipa/bitcoin/blob/202006_cuckoo_filter/sr...

If you're lucky there will be closed form expressions for the encoding and decoding equations. (There for both of the above, at least for some parameters, but in both those examples the implementations use small tables because for the ranges involved the tables end up being faster than sqrts).

Too bad 10Hz is a too slow to generate audio-rate bitops music.

(e.g. https://github.com/xiph/opus/blob/master/tests/test_opus_enc... )

Could anyone help me get a disk image files for older Global Underground CDs? I encoded my old CDs into subpar mp3 files, and I'd now like to have high-quality Opus encodings and experiment across various bitrates.

Presumably, OP is referring to the Opus audio codec versus Dolby's AC3 codec.

Indeed. https://opus-codec.org/

If there are multiple tags with the same name, Ffmpeg will only use the last tag. If you really need to have multiple tags with the same name in your OPUS files, use opusenc instead (https://opus-codec.org/). Beware that some playback software does not display multiple artists gracefully.

AFAIK ogg isn't really suitable for low latency audio streaming. Consider the Opus codec instead.

I have asked on GitHub also https://github.com/xiph/opus/issues/263 in anyone wants to respond there.

AptX Low-Latency support is possible with a software update or software mod, source: https://github.com/pali/libopenaptx/issues/1

Background: I use Tumbleweed for audio recording/production among other general use cases. This lead me to manually switch to pipewire before it was made the default recently. During my research before making the switch I learned that the pipewire packaged in openSUSE does not support aptx and AAC bluetooth codecs because dependencies libopenaptx (https://github.com/pali/libopenaptx) and fdk-aac (https://github.com/mstorsjo/fdk-aac) are missing. I believe LDAC support works despite it sometimes being referred to as "nonfree" due to libldac being packaged with openSUSE, but I have not confirmed this. Support for aptx is important to me so I installed the version from packman which is compiled with support for these codecs. However, this got me wondering if it is possible to provide aptx and AAC in openSUSE without needing to install it through packman.

License change: https://github.com/pali/libopenaptx/commit/811bc18586d634042618d633727ac0281d4170b8

probably ... dunno for sure, since there is libopenaptx : https://github.com/pali/libopenaptx