From: Mike Brady Date: Sun, 7 Jan 2018 15:36:23 +0000 (+0000) Subject: Update RELEASENOTES.md X-Git-Tag: 3.2RC1~23 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=577de1848080a9232385da716461d9e94f25b94e;p=thirdparty%2Fshairport-sync.git Update RELEASENOTES.md --- diff --git a/RELEASENOTES.md b/RELEASENOTES.md index 7f086d5a..231e6bc0 100644 --- a/RELEASENOTES.md +++ b/RELEASENOTES.md @@ -534,7 +534,7 @@ http://www.freedesktop.org/software/systemd/man/daemon.html#Installing%20Systemd Version 2.7.3 -- Development Version ---- **Bug Fix** -* The dither code was broken in Shairport Sync and also less than ideal anyway. Fixed and improved. Dither is added whenever you use the software volume control at less than full volume. See http://www.ece.rochester.edu/courses/ECE472/resources/Papers/Lipshitz_1992.pdf for a very influential paper by Lipshitz, Wannamaker and Vanderkooy, 1992. The dither code in Shairport Sync was inherited from Shairport and does not conform to the recommendations in the paper -- specifically the implementation would give one bit of dither where the paper recommends two bits peak-to-peak. The other thing is that the inherited dither code was actually broken in Shairport Sync. So, the new dither code gives a two bit peak-to-peak dither based on a Triangular Probability Distribution Function (TPDF). It sounds like a very low-level white noise, unmodulated by the audio material. It would be nice if it was even lower, but it's better than listening to the artifacts present when dithering is disabled. +* The dither code was broken in Shairport Sync and was less than ideal anyway. It has been fixed and improved. Dither is added whenever you use the software volume control at less than full volume. See http://www.ece.rochester.edu/courses/ECE472/resources/Papers/Lipshitz_1992.pdf for a very influential paper by Lipshitz, Wannamaker and Vanderkooy, 1992. The dither code in Shairport Sync was inherited from Shairport and does not conform to the recommendations in the paper -- specifically the implementation would give one bit of dither where the paper recommends two bits peak-to-peak. The other thing is that the inherited dither code was actually broken in Shairport Sync. So, the new dither code gives a two bit peak-to-peak dither based on a Triangular Probability Distribution Function (TPDF). It sounds like a very low-level white noise, unmodulated by the audio material. It would be nice if it was even lower, but it's better than listening to the artifacts present when dithering is disabled. Version 2.7.2 -- Development Version ----