Re: Something really terrible is happening when encoding 20Hz sine wave
Reply #27 –
52 kbps is a believable value to switch to hybrid mode, which would confirm that the bloating occurs in the CELT layer. Did you listen to the sub-52 version? I wonder whether the encoder thinks it is speech or music?
Here you have both attached. No need to ABX ...
Further curiosity checks:
* reducing from 24 bits to 16 bits. Opus @ target 128 also chopped off a third.
* slowed it down to 45 seconds (changing pitch with it). Opus approximately kept size (bitrate went down ... something FLAC wasn't that good at).
* other lossless codecs! OptimFrog "best" halves the FLAC filesize. WavPack suffers from that old near-mono-suboptimality and does worse than FLAC, TAK is evidently not good at 24/48.