With python, is there a more efficient way to duplicate a range of keyframes (all fcurves) than using keyframe_points.insert()

Question

I have a combined animation (position of object, bone rotations...) with about 600 keyframes. Now I want to make a script that clones a selected range of these keyframes and pastes them after the initial range's end.

This works:

def duplicate_keyframe(armature_object, source_keyframe, target_keyframe):        
    anim = armature_object.animation_data
    action = anim.action        
    for fcurve in action.fcurves:            
        if source_keyframe > len(fcurve.keyframe_points) - 1 or not fcurve.keyframe_points[source_keyframe]:               
            continue
        old_keyframe = fcurve.keyframe_points[source_keyframe]
        new_keyframe = fcurve.keyframe_points.insert(target_keyframe, old_keyframe.co.y)
        new_keyframe.amplitude = old_keyframe.amplitude
        new_keyframe.interpolation = old_keyframe.interpolation
        new_keyframe.handle_left = old_keyframe.handle_left
        new_keyframe.handle_right = old_keyframe.handle_right
        new_keyframe.handle_left_type = old_keyframe.handle_left_type
        new_keyframe.handle_right_type = old_keyframe.handle_right_type
        new_keyframe.period = old_keyframe.period
        new_keyframe.easing = old_keyframe.easing
        new_keyframe.back = old_keyframe.back

def duplicate_keyframes(armature_object, start_duplicate_at, first_keyframe, last_keyframe):        
    for i in range(first_keyframe, last_keyframe):
        duplicate_keyframe(armature_object, i, start_duplicate_at + i - first_keyframe)

... however, it is very slow. The culprit seems to be fcurve.keyframe_points.insert(), which takes a few milliseconds. Multiply that with the number of fcurves and the number of frames, and the whole operation takes several seconds.

So question: Is there a more efficient way to clone a set of keyframes for all fcurves?

Answer 1

For all range, you can

import bpy

source = bpy.data.objects["Cube"]
target = bpy.data.objects["Cube.001"]

if not target.animation_data:
    target.animation_data_create()

# if source.animation_data
# if source.animation_data.action
target.animation_data.action = source.animation_data.action.copy()

Can't seem to copy specific range or specific fcurve