Martijn van Beurden wrote:>> And I also suggested to consider a different setting for -7 preset: >> -7 == -l 12 -b 4096 -m -r 6 -A tukey(0.5);partial_tukey(2) >> see <http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106545&view=findpost&p=871797> >> >> But it will decrease decoding speed for this preset. > > Yes, that is another thing to consider. My proposal keeps the > decoding speed for all presets the same, but I don't think there > is a problem in shifting things a little bit more. The above > setting would make the decoding of -7 as CPU-intensive as -8 is > now. Seeing that all FLAC-capable hardware that I know of has > been decoding -8 without problems for years, there's probably no > harm done with changing this too. > > Any thoughts?From <http://www.rockbox.org/wiki/CodecPerformanceComparison> it seems that the decoding of -8 is about 6% slower than -5. Sometimes the difference is bigger but doesn't exceed 10%. The only exception is "Freescale i.MX21 (454MHz ARM926EJ?-S, Fuze+)": 43x vs 35x realtime. But the decoding time is so small (4 sec vs 5 sec) that it can be some measurement error.
As I haven't heard any complaints concerning the proposal for retuning compression levels which I posted a few months ago, here's the patch that enables them, with the change proposed by lvqcl. This patch changes the settings associated with compression levels 6, 7 and 8. With this patch, -e is no longer used, but instead apodization functions are added. This should improve compression with at least 95% of all material. Independent tests show that this is probably the case. The encoding speed should stay about the same, however, 6 is slowed considerably, positioned between compression levels 5 and 7. This was done because level 6 was so close to level 5 that it wasn't really worth using. Decoding-wise, 6 and 8 stay the same, and 7 is slowed a bit, which makes it as fast as 8. -------------- next part -------------- A non-text attachment was scrubbed... Name: 0001-Retune-FLAC-compression-levels.patch Type: text/x-patch Size: 0 bytes Desc: not available Url : http://lists.xiph.org/pipermail/flac-dev/attachments/20141019/2782ca80/attachment.bin
Martijn van Beurden wrote:> This patch changes the settings associated with compression > levels 6, 7 and 8. With this patch, -e is no longer used, but > instead apodization functions are added. This should improve > compression with at least 95% of all material. Independent tests > show that this is probably the case.But your patch changes only two last presets (-7 and -8) so -6 stays unchanged. ( IIRC it should have "tukey(5e-1);partial_tukey(2)" as its apodization string instead of current "tukey(5e-1)" ).