kVTCompressionPropertyKey_VBVBufferDuration

objc2_video_toolbox

Static kVTCompressionPropertyKey_VBVBufferDuration 

Source 
pub unsafe static kVTCompressionPropertyKey_VBVBufferDuration: &'static CFString
Available on crate feature VTCompressionProperties only.
Expand description

Capacity of the video buffering verifier (VBV) model in seconds.

VBV model allows for larger variations in bitrates while avoiding decoder-side overflows or underflows. A larger VBV model size may improve compression quality, but it requires more memory and may introduce delay. The value of this property must be greater than 0.0. The default value is set as 2.5 seconds. This property key is compatible with constant bitrate (CBR) or variable bitrate (VBR) rate control. This property key is incompatible with:

  1. kVTCompressionPropertyKey_AverageBitRate,
  2. kVTCompressionPropertyKey_DataRateLimits,
  3. VTVideoEncoderSpecification_EnableLowLatencyRateControl=True.

See also Apple’s documentation