Here's W.C. Handy's 1914 song St. Louis Blues, performed by Handy at some point in the 20s, probably.
I should add that's a 341KB opus file at 16kbps.
The flac file it was derived from (found here: https://archive.org/details/78_st-louis-blues_w-c-handy_gbia0030859a/St.+Louis+Blues+-+W.+C.+Handy-restored.flac) is over 60MB.
I went from over 60MB to just over 1/3 of an MB.
And a close listen with some good headphones or speakers will reveal some minor differences on the compressed file, but holy shit it's 341KB.
Here's another rendition that's 10KBps, and that extra 6KB is really missed.
@ajroach42 at those bitrates it might be guessing wrong which codec to use; you can set it straight by specifying --music on the opusenc command line, and it really does make a difference
@DHeadshot @ajroach42 in fairness, it really only works because of the already low bandwidth, scratchy quality and poor SNR of 1920s-era recordings
@DHeadshot @thamesynne try opusenc directly, without converting to an 8khz wav first.
Something like opusenc --bitrate 12 --music --downmix-mono infile.wav outfile.opus
12 or 16 Kbps will produce dramatically different results as well.
@DHeadshot @thamesynne It's really agressive compression, so it can cause problems.
@ajroach42 for example: http://smolbytes.duckdns.org/handy-blues.opus generated with
$ ffmpeg -i 'St. Louis Blues - W. C. Handy-restored.flac' -ar 8000 handy-blues.wav
$ opusenc --bitrate 10 --music --downmix-mono handy-blues.wav handy-blues.opus
i think it sounds objectively quite good, and for 10kbps somewhat miraculous