Settings to Darken Blacks?

[Sham 69]

I usually decrease the brightness with a filter by a few numbers just to darken the black spots, I don't like blocky dark spots that emerge in re-encoding. Any of you use any other settings in particular to darken blacks?

[eumagga0x2a]

Fighting block artifacts in dark areas by increased clipping doesn't sound like a sound strategy. You should look for encoder settings which allow it to handle dark areas better (this will increase bitrate, of course). There are many relevant topics on forum.doom9.org about that. Further keywords (especially for x264): adaptive quantization, aq-mode, aq-strength.