import json

# scene and camera data
scene         = bpy.context.scene
camera_curves = scene.objects['camera'].animation_data.action.fcurves
target_curves = scene.objects['target'].animation_data.action.fcurves

# camera animation constants
LOCATION_X = 0
LOCATION_Y = 1
LOCATION_Z = 2

# read out camera animation data
camera_animation_frames = []
for index in range(0, len(camera_curves[LOCATION_X].keyframe_points)):
    camera_animation_frames.append({
         # Read the frame_offset from the first element of the co vector. These
         # are the same across all the properties, so we just pick from LOCATION_X.
        'frame_index': camera_curves[LOCATION_X].keyframe_points[index].co[0],
         # The properties value is sitting in the [1] element of the 'co' vector.
         'properties': {
            'position_x': camera_curves[LOCATION_X].keyframe_points[index].co[1],
            'position_y': camera_curves[LOCATION_Y].keyframe_points[index].co[1],
            'position_z': camera_curves[LOCATION_Z].keyframe_points[index].co[1],
            'target_x':   target_curves[LOCATION_X].keyframe_points[index].co[1],
            'target_y':   target_curves[LOCATION_Y].keyframe_points[index].co[1],
            'target_z':   target_curves[LOCATION_Z].keyframe_points[index].co[1],
        }
    })

# write to parent
data = json.dumps(camera_animation_frames, indent=2, sort_keys=True)
file = open("../animation.json","w+")
file.write(data)
file.close()
print(data)
print('animation saved')