How to add an animated time controlled text effect to the VSE

Question

I'm trying to edit videos for my dance group. What I'd like to be able to do is have an overlay that I can set the B.P.M (beats per minute) and I can display a simple metronome + counter over the video.

I notice that there is a text effect in the VSE

Is there any way to hook a callback based on the frame count that can change the text as the video progresses? This might be able to get me what I need.

Progress

I've discovered that I can do

import bpy

def my_handler(scene):
    print("Frame Change", scene.frame_current)

bpy.app.handlers.frame_change_pre.append(my_handler)

and the current frame count is output to the console. Now I would need to calculate and inject some text into the VSE

First real attempt

import bpy

def my_handler(scene):
    print("Frame Change", scene.frame_current)
    ob = bpy.data.objects['TimeCode']
    ob['Text']=scene.frame_current


bpy.app.handlers.frame_change_pre.append(my_handler)

where I have a text effect added to the VSE and defined as

but I get console errors as

File "C:\Users\bradp\OneDrive\Video\NewStyle C\choreo1.blend\Counter", line 7, in my_handler KeyError: 'bpy_prop_collection[key]: key "TimeCode" not found'

You could try out the TextFX addon. – Samoth Oct 29 '17 at 21:46 — Samoth, Oct 29 '17 at 21:46

Omar Emara · Answer 1 · 2017-10-30T13:12:36.923

5

You can use Animation Nodes to do this very easily:

You can do all sort of editing like:

The Frame Rate input is hidden by default, show it like this:

edited Oct 30 '17 at 13:12

answered Oct 29 '17 at 16:05

Omar Emara

22,639
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103

This looks great. However I have blender 2.79 and my node editor window is a little different. Next to the node menu I only have 3 icons not 4 and the far left one you have selected I don't have. What am I missing? – bradgonesurfing Oct 29 '17 at 21:40
Have you installed the animation nodes addon? – Samoth Oct 29 '17 at 21:45
No. I guess that will be the problem – bradgonesurfing Oct 29 '17 at 21:51
Got it. Solution rocks :) – bradgonesurfing Oct 29 '17 at 22:08
How do I get the FPS as a node here. I need to calculate the real time as I did in my script answer. The time info only gives the current frame. – bradgonesurfing Oct 29 '17 at 22:23
1

@bradgonesurfing Updated the answer. – Omar Emara Oct 30 '17 at 13:13
I tried that but the output from Frame Rate is some wierd number 3267 or something. I know from experimenting that the the frame rate was very close to 30 FPS. What is the conversion here? – bradgonesurfing Oct 30 '17 at 13:49
@bradgonesurfing hmmm, it works fine for me. How did you view this number, using a viewer node? – Omar Emara Oct 30 '17 at 15:34
Let me check when I'm home again tonight. There was something strange about the number and it was big. Essentially what I want is the real time value. time = FrameCount / FPS – bradgonesurfing Oct 30 '17 at 15:39
You mention here in the comments that Animation Nodes needs to be installed but your answer does not explain this. Could you update your answer with some explanation on what this is? – Robin De Schepper Apr 30 '21 at 13:54

score 3 · Answer 2 · answered Oct 29 '17 at 15:47

3

The following script displays the frame count as an overlay

import bpy


def my_handler(scene):
    print("Frame Change", scene.frame_current)
    bpy.data.scenes['Scene'].sequence_editor.sequences_all["TimeCode"].text=str(scene.frame_current)


bpy.app.handlers.frame_change_pre.append(my_handler)

The path to the data object was retrieved from the tooltip

answered Oct 29 '17 at 15:47

bradgonesurfing

173
1
7

Nice. Could expand this for a generic case for any strip in scene named "TimeCode". .Would need to check seq = scene.sequence_editor is not None, and seq.sequences_all.get("TimeCode") is not None. – batFINGER Oct 29 '17 at 16:11
Actually this does't work as it only works in manual mode. When I create a rendering the script is not called. No idea why. – bradgonesurfing Oct 29 '17 at 16:53
lol, see what you mean. Does appear to work in render (still) image. Suggest adding a text object to scene and using frame change handler to animate its body. – batFINGER Oct 29 '17 at 17:22
1

The reason this script does not work during rendering is you also need to add it as a render_pre handler. See my answer for a little elaboration. – Scott McPeak Feb 05 '20 at 07:26

score 2 · Accepted Answer · answered Feb 05 '20 at 07:24

Expanding and slightly correcting the answer by bradgonesurfing, you can do this without any addons. First, create the text strip in the Video Sequence Editor and give it a name like "Timer". Now, create a Python script similar to this:

# TimerScript.py
# Arrange to update a VSE text strip to show elapsed time.

# Put this file next to your .blend file, open it in the Blender
# Text Editor view, and use "Text -> Run Script" to run it.  It
# will be active for the duration of the Blender editing session.

import bpy

scene = bpy.context.scene
obj = scene.sequence_editor.sequences_all['Timer']
fps = scene.render.fps

def recalculate_text(scene):
    # Number of frames since the start of the text strip.
    frames = scene.frame_current - obj.frame_start

    # Divide to get hours, minutes, seconds, and hundredths of a second.
    seconds_float = frames / fps
    seconds = int(seconds_float)
    hundredths = int((seconds_float - seconds) * 100)
    minutes = int(seconds / 60)
    seconds -= minutes * 60
    hours = int(minutes / 60)
    minutes -= hours * 60

    # Combine as a string.
    time_string = "{:d}:{:02d}:{:02d}.{:02d}".format(
        hours, minutes, seconds, hundredths)

    # Update the text object.    
    #print('Recalc: ' + time_string)
    obj.text = time_string

# This is used when moving between frames during editing.
bpy.app.handlers.frame_change_pre.clear()
bpy.app.handlers.frame_change_pre.append(recalculate_text)

# This is used during animation rendering.
bpy.app.handlers.render_pre.clear()
bpy.app.handlers.render_pre.append(recalculate_text)

Open the script in the Blender Text Editor (you can create it there in the first place) and run it via "Text → Run Script".

The slightly tricky bit, and the correction to Brad's answer, is you need to install this both as a pre-frame handler and a pre-render handler. If you only set it as pre-frame, then the update will not happen when rendering animations!

MA Jacob · Answer 4 · 2017-11-07T13:14:30.953

I know nothing about scripting. Try to answer it with the manual way. From my understaning, it is about rendering a sequence of numbers and clamp it into one minute.

If anything fancy is not needed. Frame counter can be generated from Metadata.

Properties > Render > Metadata > Stamp Output

Setup a empty Scene and set End Frame = BPM
Render the empty scene with Metadata ON and Transparent.
Overlay the clip to the dancing video, Transform the clip to one minute long with Speed Control. and Loop it over.

For video looping, please refer to:

How do you make a movie loop in the sequencer?

How to add an animated time controlled text effect to the VSE

4 Answers4