Add frame count numbers as subtitles to the sequencer within the preview range - in Blender.

FrameNumberAsSubtitle.py

# Run script to add frame count numbers as subtitles to the sequencer within the preview range

import bpy

def find_empty_channel():
    """
    Finds the first empty channel above all others in the VSE
    and returns it
    """
    sequences = bpy.context.sequences
    if not sequences:
        return 1

    channels = [s.channel for s in sequences]
    channels = sorted(list(set(channels)))
    return channels[-1] + 1

def subtitles_to_sequencer(context):
    """Add frame number subtitles to the video sequencer"""

    scene = context.scene
    fps = scene.render.fps / scene.render.fps_base
    open_channel = find_empty_channel()

    if not scene.sequence_editor:
        scene.sequence_editor_create()

    wm = context.window_manager
    wm.progress_begin(0, 100.0)

    added_strips = []
    fr_start=bpy.context.scene.frame_start
    fr_end=bpy.context.scene.frame_end
    
    bpy.ops.sequencer.select_all(action='DESELECT') # only have the new strips selected

    for i in range(fr_start,fr_end+1):
        start_time = i
        strip_start = i
        end_time = i+1
        strip_end = i+1
        sub_name = str(i)

        text_strip = scene.sequence_editor.sequences.new_effect(
            name=sub_name,
            type='TEXT',
            channel=open_channel,
            frame_start=strip_start,
            frame_end=strip_end
            )
        print(str(open_channel)+":"+str(strip_start))
        text_strip.font_size = int(bpy.context.scene.render.resolution_y/13) # Change the subtitle size here
        text_strip.text = str(bpy.utils.smpte_from_frame(i))
        text_strip.use_shadow = True
        text_strip.select = True
        text_strip.location[1] = 0.85
        text_strip.blend_type = 'ALPHA_OVER'

        added_strips.append(text_strip)

    bpy.ops.sequencer.meta_make() # make meta strip
    bpy.context.scene.sequence_editor.active_strip.name = "Frame Numbers"
    my_meta=bpy.context.scene.sequence_editor.active_strip.name    
    for scene in bpy.data.scenes:
        scene.sequence_editor.sequences_all[my_meta].blend_type = "ALPHA_OVER"

    return added_strips

subtitles_to_sequencer(bpy.context)

Changed to SMPTE and moved it to the top.