Jason Garrett-Glaser wrote: > By default, x264 uses psy optimizations which lower SSIM and PSNR but I am using dev-SVN-r26940 which does not support psy yet. > improve visual quality. Your first pass settings probably use turbo, I do not use turbo. > But more importantly, your first pass is 200kbps higher than the > second--of course it can be higher quality. You can't compare quality > between two encodes at different bitrates. I am not following you there. The one pass encoding had the smaller file size and higher ssim/psnr. That I found unexpected. Incidentally, I do not know how the reported kb/s:3259.63 is calculated from the filesize. I trust the file system reported size though. The bitrate was set to 3000 on both encodes. Since the sample was short (20sec) I thought maybe this was just a fluke. So I rerun on a 60 seconds sample. This time I tried a 1 pass a two pass and a three pass encoding with the same source, bitrate, yada-yada: Single pass encoding: File size: 21902932 x264 [info]: SSIM Mean Y:0.9822603 x264 [info]: PSNR Mean Y:44.466 U:47.888 V:49.304 Avg:45.431 Global:44.716 kb/s:2734.11 Two passes: File size: 23831479 x264 [info]: SSIM Mean Y:0.9838375 x264 [info]: PSNR Mean Y:44.659 U:48.036 V:49.531 Avg:45.624 Global:45.243 kb/s:2990.10 3 passes: File size: 23903141 x264 [info]: SSIM Mean Y:0.9837665 x264 [info]: PSNR Mean Y:44.587 U:47.986 V:49.520 Avg:45.557 Global:45.237 kb/s:2999.61 The first two run results I can accept without much suspicion. However the benefit of the second pass is non-existent for me: the increase of less than 0.002 SSIM costs almost 10% in file size. But the third seems again to be suspicious featuring a larger file with lower SSIM. So the question: should I bother with multipass encodings? Matyas - Every hardware eventually breaks. Every software eventually works. _______________________________________________ MPlayer-users mailing list MPlayer-users@xxxxxxxxxxxx https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users
