Class: EDL::Timewarp

Inherits:
Object
  • Object
show all
Defined in:
lib/edl/timewarp.rb

Overview

Represents a timewarp. Will be placed in EDL::Event#timewarp For a reversed clip, the source start we get from the EDL in the src start is the LAST used frame. For a pos rate clip, the source start is the bona fide source start. Nice eh?

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#actual_framerate ⇒ Object

What is the actual framerate of the clip (float)



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# File 'lib/edl/timewarp.rb', line 9

def actual_framerate
  @actual_framerate
end

#clip ⇒ Object

:nodoc:



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# File 'lib/edl/timewarp.rb', line 10

def clip
  @clip
end

Instance Method Details

#actual_length_of_source ⇒ Object

Compute the length of the clip we need to capture. The length is computed in frames and is always rounded up (better one frame more than one frame less!)



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# File 'lib/edl/timewarp.rb', line 25

def actual_length_of_source
  # First, get the length of the clip including a transition. This is what we are scaled to.
  target_len = @clip.rec_length_with_transition.to_f
  # Determine the framerate scaling factor, this is the speed
  factor = @actual_framerate / @clip.rec_start_tc.fps
  (target_len * factor).ceil.abs
end

#reverse? ⇒ Boolean

Does this timewarp reverse the clip?

Returns:

  • (Boolean) 


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# File 'lib/edl/timewarp.rb', line 13

def reverse?
  @actual_framerate < 0
end

#source_used_from ⇒ Object

What is the starting frame for the captured clip? If we are a reverse, then the src start of the clip is our LAST frame, otherwise it’s the first



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# File 'lib/edl/timewarp.rb', line 35

def source_used_from
  # TODO: account for the 2 frame deficiency which is suspicious
  compensation = 2
  reverse? ? (@clip.src_start_tc - actual_length_of_source + compensation) : @clip.src_start_tc
end

#source_used_upto ⇒ Object

Where to end the capture? This is also dependent on whether we are a reverse or not



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# File 'lib/edl/timewarp.rb', line 42

def source_used_upto
  source_used_from + actual_length_of_source
end

#speed_in_percent ⇒ Object Also known as: speed

Get the speed in percent



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# File 'lib/edl/timewarp.rb', line 18

def speed_in_percent
  (@actual_framerate / @clip.rec_start_tc.fps) * 100
end