Element Properties:
  name                : The name of the object
                        flags: readable, writable
                        String. Default: "x264enc0"
  parent              : The parent of the object
                        flags: readable, writable
                        Object of type "GstObject"
  threads             : Number of threads used by the codec (0 for automatic)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 4 Default: 0
  sliced-threads      : Low latency but lower efficiency threading
                        flags: readable, writable
                        Boolean. Default: false
  sync-lookahead      : Number of buffer frames for threaded lookahead (-1 for automatic)
                        flags: readable, writable
                        Integer. Range: -1 - 250 Default: -1
  pass                : Encoding pass/type
                        flags: readable, writable
                        Enum "GstX264EncPass" Default: 0, "cbr"
                           (0): cbr              - Constant Bitrate Encoding
                           (4): quant            - Constant Quantizer (debugging only)
                           (5): qual             - Constant Quality
                           (17): pass1            - VBR Encoding - Pass 1
                           (18): pass2            - VBR Encoding - Pass 2
                           (19): pass3            - VBR Encoding - Pass 3
  quantizer           : Constant quantizer or quality to apply
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 50 Default: 21
  multipass-cache-file: Filename for multipass cache file
                        flags: readable, writable
                        String. Default: "x264.log"
  byte-stream         : Generate byte stream format of NALU
                        flags: readable, writable
                        Boolean. Default: false
  bitrate             : Bitrate in kbit/sec
                        flags: readable, writable, changeable in NULL, READY, PAUSED or PLAYING state
                        Unsigned Integer. Range: 1 - 102400 Default: 2048
  intra-refresh       : Use Periodic Intra Refresh instead of IDR frames
                        flags: readable, writable
                        Boolean. Default: false
  vbv-buf-capacity    : Size of the VBV buffer in milliseconds
                        flags: readable, writable, changeable in NULL, READY, PAUSED or PLAYING state
                        Unsigned Integer. Range: 0 - 10000 Default: 600
  me                  : Integer pixel motion estimation method
                        flags: readable, writable
                        Enum "GstX264EncMe" Default: 1, "hex"
                           (0): dia              - dia
                           (1): hex              - hex
                           (2): umh              - umh
                           (3): esa              - esa
                           (4): tesa             - tesa
  subme               : Subpixel motion estimation and partition decision quality: 1=fast, 10=best
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 10 Default: 1
  analyse             : Partitions to consider
                        flags: readable, writable
                        Flags "GstX264EncAnalyse" Default: 0x00000000, "(none)"
                           (0x00000001): i4x4             - i4x4
                           (0x00000002): i8x8             - i8x8
                           (0x00000010): p8x8             - p8x8
                           (0x00000020): p4x4             - p4x4
                           (0x00000100): b8x8             - b8x8
  dct8x8              : Adaptive spatial transform size
                        flags: readable, writable
                        Boolean. Default: false
  ref                 : Number of reference frames
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 12 Default: 1
  bframes             : Number of B-frames between I and P
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 4 Default: 0
  b-adapt             : Automatically decide how many B-frames to use
                        flags: readable, writable
                        Boolean. Default: true
  b-pyramid           : Keep some B-frames as references
                        flags: readable, writable
                        Boolean. Default: false
  weightb             : Weighted prediction for B-frames
                        flags: readable, writable
                        Boolean. Default: false
  sps-id              : SPS and PPS ID number
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 31 Default: 0
  aud                 : Use AU (Access Unit) delimiter
                        flags: readable, writable
                        Boolean. Default: true
  trellis             : Enable trellis searched quantization
                        flags: readable, writable
                        Boolean. Default: true
  key-int-max         : Maximal distance between two key-frames (0 for automatic)
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 2147483647 Default: 0
  cabac               : Enable CABAC entropy coding
                        flags: readable, writable
                        Boolean. Default: true
  qp-min              : Minimum quantizer
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 51 Default: 10
  qp-max              : Maximum quantizer
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 51 Default: 51
  qp-step             : Maximum quantizer difference between frames
                        flags: readable, writable
                        Unsigned Integer. Range: 1 - 50 Default: 4
  ip-factor           : Quantizer factor between I- and P-frames
                        flags: readable, writable
                        Float. Range:               0 -               2 Default:             1.4
  pb-factor           : Quantizer factor between P- and B-frames
                        flags: readable, writable
                        Float. Range:               0 -               2 Default:             1.3
  mb-tree             : Macroblock-Tree ratecontrol
                        flags: readable, writable
                        Boolean. Default: true
  rc-lookahead        : Number of frames for frametype lookahead
                        flags: readable, writable
                        Integer. Range: 0 - 250 Default: 40
  noise-reduction     : Noise reduction strength
                        flags: readable, writable
                        Unsigned Integer. Range: 0 - 100000 Default: 0
  interlaced          : Interlaced material
                        flags: readable, writable
                        Boolean. Default: false
  option-string       : String of x264 options (overridden by element properties)
                        flags: readable, writable
                        String. Default: ""
  speed-preset        : Preset name for speed/quality tradeoff options (can affect decode compatibility - impose restrictions separately for your target decoder)
                        flags: readable, writable
                        Enum "GstX264EncPreset" Default: 6, "medium"
                           (0): None             - No preset
                           (1): ultrafast        - ultrafast
                           (2): superfast        - superfast
                           (3): veryfast         - veryfast
                           (4): faster           - faster
                           (5): fast             - fast
                           (6): medium           - medium
                           (7): slow             - slow
                           (8): slower           - slower
                           (9): veryslow         - veryslow
                           (10): placebo          - placebo
  psy-tune            : Preset name for psychovisual tuning options
                        flags: readable, writable
                        Enum "GstX264EncPsyTune" Default: 0, "none"
                           (0): none             - No tuning
                           (1): film             - Film
                           (2): animation        - Animation
                           (3): grain            - Grain
                           (4): psnr             - PSNR
                           (5): ssim             - SSIM
  tune                : Preset name for non-psychovisual tuning options
                        flags: readable, writable
                        Flags "GstX264EncTune" Default: 0x00000000, "(none)"
                           (0x00000001): stillimage       - Still image
                           (0x00000002): fastdecode       - Fast decode
                           (0x00000004): zerolatency      - Zero latency