详细资料请参考 http://mewiki.project357.com/wiki/X264_Settings
Presets
A system designed to reduce the work needed to generate sane, efficient commandlines that do what you want. For information on what options these settings toggle, check the output of x264.exe --fullhelp.
profile
Default: not set
Limit the profile of the output stream. If you specify a profile, it overrides all other settings, so if you use it, you will be guaranteed a compatible stream. If you set this option, you cannot use lossless encoding (--qp 0 or --crf 0).
You should set this if you know your playback device only supports a certain profile. Most decoders support High profile, so there's no need to set this.
Values available: baseline, main, high.
preset
Default: medium
Change options to trade off compression efficiency against encoding speed. If you specify a preset, the changes it makes will be applied before all other parameters are applied.
You should generally set this option to the slowest you can bear.
Values available: ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo.
