FFmpeg VP8 Encoding Options

See http://ffmpeg.org/ffmpeg.html#libvpx for additional parameter information.
See http://ffmpeg.org/trac/ffmpeg/wiki/vpxEncodingGuide for a discussion of bitrate parameters.

Options Description Values
-vb target bitrate
-deadline Encoder speed/quality and cpu use best, good, realtime
-cpu-used CPU Used (-16..16)
-rc_init_occupancy number of bits which should be loaded into the rc buffer before decoding starts
-bufsize ratecontrol buffer size (in bits)
-pass Pass to execute (1/2)
-passlogfile First pass statistics file name
-vframes Stop encoding after n input frames
-minrate Minimal bitrate allowed in vbr/2pass mode
-maxrate Maxium bitrate allowed in vbr/2pass mode
-bt bitrate tolerance in VBR/2pass mode
(valid values 0-63, recommended value 0-4)
(valid values --min-q to 63, recommended value 50-63)
float 0 - 1, 0 = CBR, 1 = VBR, (default 0.5)
-g Maximum keyframe interval (frames)
-keyint_min Minimum keyframe interval (frames)
-auto-alt-ref Enable use of alternate reference frames (2-pass only) (0 disabled, 1 enabled <default 0>)
-lag-in-frames number of frames to look ahead for when encoding, 0 no limit 0-25
-arnr-maxframes max frames used in creating alt. ref.
-arnr-strength Strength of the temporal filter used in altref 0-6
-arnr-type altref noise reduction filter type backward (Backward Blur), forward (Forward Blur), centered (Center Blur) <default>
-slices directs the encoder to split the coefficient encoding across multiple data partitions that can be encoded independently. At the moment this parameter is interpreted as follows (1 = 1 coefficient partition, 2 = 2 partitions, 4 = 4 partitions, 8 = 8 partitions) 1,2,4,8: recommended 1 for small images, 4 or 8 for HD
-threads number of threads to use for encoding, can't be 0 [auto] with VP8 (recommended value : number of real cores - 1)
-skip_threshold Temporal resampling threshold (buf %) (0=disabled to 100)
-rc_resize_allowed Spatial resampling enabled (bool) (0 disabled, 1 enabled)
-rc_resize_down Spatial resampling down watermark, percentage of target data buffer. (0-100)
-rc_resize_up Spatial resampling up watermark, percentage of target data buffer. (--resize-down-100)
-error-resilient Enable error resiliency features (0 disabled, 1 enabled <default 0>)
-mb_threshold The static threshold imposes a change threshold on blocks below which they will be skipped by the encoder. This can be used to suppress signal noise and enhance the encode speed in situations where there are low levels of real movement. Values of above 1000 are not recommended and any non zero value runs the risk of introducing artifacts caused by regions of the image not being updated. In most scenarios this value should be set to 0.
-profile Bitstream profile number to use; reduce complexity if > 0 (0-3: default and recommended value = 0)
-sharpness Anything above 0 weakens the deblocking effect of the loop filter. (0-7 : default and recommended value = 0)
-nr crude temporal noise filter. (0-6: default and recommended value = 0)
-rc_buf_aggressivity undershoot target bitrate for each frame by x percent (valid float 0.1-1)
-crf enables constant quality mode and sets quality (0-63) lower values are better quality