víc jader libx264 nedokaže dosáhnout nížší ho bitrate?

Zkusil jsem nejnovější x264-r3222-b35605a.exe
Pokud jsem nenastavil nic a použil všechna vlákna (12), tak u testovaného videa bylo bitrate 4142.17 kbps
Pokud jsem nastavil jedno vlákno, tak u testovaného videa bylo bitrate 4145.94 kbps
Neznatelný rozdíl, navíc u všech vláken bylo bitrate neznatelně menší, takže tvůj problém se mi nepodařilo vyprodukovat.

Všechna vlákna:

e:\tmp>x264-r3222-b35605a.exe vstup.mkv -o vystup.mkv
lavf [info]: 1920x1080p 0:1 @ 30/1 fps (vfr)
x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
x264 [info]: profile High, level 4.0, 4:2:0, 8-bit
x264 [info]: frame I:5     Avg QP:20.54  size:154872
x264 [info]: frame P:420   Avg QP:23.44  size: 33062
x264 [info]: frame B:723   Avg QP:25.50  size:  7115
x264 [info]: consecutive B-frames:  8.6% 16.9% 15.9% 58.5%
x264 [info]: mb I  I16..4: 32.6% 49.8% 17.6%
x264 [info]: mb P  I16..4:  6.1%  2.6%  0.4%  P16..4: 41.0% 10.9%  8.3%  0.0%  0.0%    skip:30.7%
x264 [info]: mb B  I16..4:  0.2%  0.1%  0.0%  B16..8: 39.4%  1.9%  0.4%  direct: 1.7%  skip:56.2%  L0:44.8% L1:50.1% BI: 5.1%
x264 [info]: 8x8 transform intra:31.0% inter:81.3%
x264 [info]: coded y,uvDC,uvAC intra: 24.6% 43.9% 4.5% inter: 11.5% 13.6% 0.1%
x264 [info]: i16 v,h,dc,p:  7% 47%  9% 37%
x264 [info]: i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 15% 18% 42%  3%  4%  4%  5%  3%  6%
x264 [info]: i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 22% 12%  4%  7%  7%  9%  5%  7%
x264 [info]: i8c dc,h,v,p: 50% 33% 10%  6%
x264 [info]: Weighted P-Frames: Y:4.0% UV:1.2%
x264 [info]: ref P L0: 66.2% 19.5% 10.6%  3.5%  0.1%
x264 [info]: ref B L0: 93.8%  5.3%  0.9%
x264 [info]: ref B L1: 98.1%  1.9%
x264 [info]: kb/s:4142.17

encoded 1148 frames, 77.48 fps, 4142.32 kb/s

Jedno vlákno:

e:\tmp>x264-r3222-b35605a.exe --threads 1 vstup.mkv -o vystup1.mkv
lavf [info]: 1920x1080p 0:1 @ 30/1 fps (vfr)
x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
x264 [info]: profile High, level 4.0, 4:2:0, 8-bit
x264 [info]: frame I:5     Avg QP:20.48  size:156228
x264 [info]: frame P:407   Avg QP:23.37  size: 33680
x264 [info]: frame B:736   Avg QP:25.50  size:  7247
x264 [info]: consecutive B-frames:  8.0% 14.3% 15.7% 62.0%
x264 [info]: mb I  I16..4: 33.0% 49.3% 17.7%
x264 [info]: mb P  I16..4:  6.2%  2.7%  0.4%  P16..4: 40.9% 11.0%  8.4%  0.0%  0.0%    skip:30.2%
x264 [info]: mb B  I16..4:  0.2%  0.1%  0.0%  B16..8: 39.7%  2.0%  0.4%  direct: 1.8%  skip:55.8%  L0:44.7% L1:50.1% BI: 5.2%
x264 [info]: 8x8 transform intra:31.1% inter:81.3%
x264 [info]: coded y,uvDC,uvAC intra: 25.0% 44.2% 4.8% inter: 11.5% 13.6% 0.1%
x264 [info]: i16 v,h,dc,p:  7% 47%  9% 37%
x264 [info]: i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 15% 18% 42%  3%  4%  4%  5%  3%  6%
x264 [info]: i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 22% 11%  4%  7%  7%  9%  5%  7%
x264 [info]: i8c dc,h,v,p: 50% 33% 10%  6%
x264 [info]: Weighted P-Frames: Y:4.7% UV:1.2%
x264 [info]: ref P L0: 66.1% 19.4% 10.8%  3.5%  0.2%
x264 [info]: ref B L0: 94.0%  5.1%  0.9%
x264 [info]: ref B L1: 98.1%  1.9%
x264 [info]: kb/s:4145.94

encoded 1148 frames, 13.58 fps, 4146.09 kb/s

Nezmysel....pocet CPU jadier/vlakien nema nic s bitrate, ale len s rychlostou encodingu. Cim viac jadier, tym rychlejsie.