Static kVTCompressionPropertyKey_MaxKeyFrameInterval 

pub unsafe static kVTCompressionPropertyKey_MaxKeyFrameInterval: &'static CFString

Available on crate feature VTCompressionProperties only.

The maximum interval between key frames, also known as the key frame rate.

Key frames, also known as sync frames, reset inter-frame dependencies; decoding a key frame is sufficient to prepare a decoder for correctly decoding the difference frames that follow. Video encoders are allowed to generate key frames more frequently if this would result in more efficient compression. The default key frame interval is 0, which indicates that the video encoder should choose where to place all key frames. A key frame interval of 1 indicates that every frame must be a key frame, 2 indicates that at least every other frame must be a key frame, etc. See also kVTCompressionPropertyKey_AllowTemporalCompression.

This key can be set in conjunction with kVTCompressionPropertyKey_MaxKeyFrameIntervalDuration, and both limits will be enforced - requiring a keyframe every X frames or every Y seconds, whichever comes first.

See also Apple’s documentation