🔒 MoviePy write_videofile is extremely slow

[celest cosmos]

So I have am using MoviePy's concatenate_videoclips function to combine two video clips that have a image and some text overlayed on each of them. When I write the video file it takes around a WHOLE minute to complete. When I scaled it up with around 100 clips with the same info (a image and some text overlayed) it takes up to around 4 hours for just a 15 minute video. I am wondering if there is a way to mitigate this time. Is MoviePy or just Python in general not suited for something like this?

My PC's specs are: Intel i7-9700K
32GB of memory
NVIDIA GeForce RTX 2060

They seem like they should be more than enough for a job like this. It also seems that MoviePy doesn't utilize my GPU and puts all the video encoding on the CPU.

I use as many of MoviePy's ffmpeg functions as possible to speed things up but the write_videofile function is still very slow. I tried all optimizations I could find but none made a difference. With some of them I can get the iteration per seconds to go up by a significant amount but after a few seconds of processing, that number falls off a cliff and goes back to 3-5it/s. Some of the optimizations I've tried are:

threads=12
preset="ultrafast"
audio=False
logger=False
ffmpeg_params=['-b:v','10000k']

[glass haven]

@celest cosmos

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[vocal mango]

Show code, and timing info to show which 'step' is slow

[meager crown]

Note that specifying a bitrate requires ffmpeg to parse the video and reencode it to get the desired compression.

If you're only joining things together with the same framerate etc you could just "copy" the video with -c:v. That's very fast.

Example from a "remux" script I've got here:

ffmpeg -i demo.mp4 -map 0 -map -0:3 -c copy -fflags genpts demo2.mp4

Ignore the -fflags genpts and look at the map and copy options.

[celest cosmos]

But i need moviepy to do other processing like rendering text and images.

[meager crown]

Then my suggestion will not help you.

[celest cosmos]

from moviepy.editor import *
from moviepy.config import change_settings

change_settings({"IMAGEMAGICK_BINARY": "D:\\ImageMagick-7.1.1-Q16-HDRI\\magick.exe"})

def create(vid_path: str) -> CompositeVideoClip:
    vid: VideoFileClip = VideoFileClip(vid_path)
    vid = vid.crossfadein(0.8)
    vid = vid.crossfadeout(0.8)

    name_square: ImageClip = ImageClip(".\\square.png")
    name_square = name_square.set_position(('center', 856))
    name_square = name_square.set_duration(vid.duration)
    name_square = name_square.crossfadein(1)
    name_square = name_square.crossfadeout(1)

    name_text: TextClip = TextClip(txt="Hello", fontsize=90, color="gray", font="MomCake")
    name_text = name_text.set_position(("center", 870))
    name_text = name_text.set_duration(vid.duration)
    name_text = name_text.crossfadein(1)
    name_text = name_text.crossfadeout(1)

    comp_clip: CompositeVideoClip = CompositeVideoClip([vid, name_text])
    return comp_clip

final: VideoFileClip = concatenate_videoclips([create("vid1.mp4"), create("vid2.mp4")])
final.write_videofile(f"final_vid.mp4", threads=12, preset="ultrafast", ffmpeg_params=['-b:v','10000k'])

[celest cosmos]

darn

[celest cosmos]

The final.write_videofile 'step' is slow

[tiny turret]

have you tried increasing the number of threads?

[celest cosmos]

Yeah, even 100 didnt do the trick

[tiny turret]

does it speed up with 100 threads?

[celest cosmos]

Nope still around 4it/s

[tiny turret]

how large is your video?

[celest cosmos]

Combined is 20 secconds

[tiny turret]

what about file size

[celest cosmos]

Lemme check

[tiny turret]

and how long is it taking in total to finish?

[celest cosmos]

It takes around 1:10

and 44mb

[tiny turret]

have you tried enabling hardware acceleration? Although I don't think this is necessary

[celest cosmos]

How could I do that?

[tiny turret]

in ffmpeg_params, add an option '-c:v', 'h264_nvenc'

[celest cosmos]

Will do

[celest cosmos]

Wait? add a option

like this ffmpeg_params=['-b:v','10000k', '-c:v', 'h264_nvenc]?

[tiny turret]

yeah

[celest cosmos]

 b'[h264_nvenc @ 0000019609bdedc0] [Eval @ 000000217e5fdef0] Undefined constant or missing \'(\' in \'ultrafast\'\r\n[h264_nvenc @ 0000019609bdedc0] Unable to parse option value "ultrafast"\r\n[h264_nvenc @ 0000019609bdedc0] Error setting option preset to value ultrafast.\r\nError initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height\r\n'

[tiny turret]

change your preset to fast

instead of ultrafast

[celest cosmos]

there we go

now im at 7it/s

still pretty slow though

[tiny turret]

bits or megabits

[celest cosmos]

and still took a minute

[celest cosmos]

iterations is the info it gives me

[tiny turret]

oh

hmm

[celest cosmos]

i think its the amount of frames

[tiny turret]

how many frames are you doing?

your write file doesn't specify

[celest cosmos]

It says 433

[tiny turret]

oh dang, try lowering it to 60

[celest cosmos]

No i mean in total

433

[tiny turret]

oh

[celest cosmos]

frames

60 fps is 1082 frames 😆

[tiny turret]

oh lmaoo

I thought you meant fps

uhh

are you using the built in ffmpeg installation for moviepy?

[celest cosmos]

Idk how do i find out

[tiny turret]

never mind, install try installing the ffmpeg binary from gyan.dev and changing your ffmpeg path to it

https://www.gyan.dev/ffmpeg/builds/

[celest cosmos]

how do i change my path?

[tiny turret]

from moviepy.config import change_settings

change_settings({"FFMPEG_BINARY":"path_to_ffmpeg"})

I think this should work

[celest cosmos]

Nope still slow 😦

[tiny turret]

damn

I have no idea then

sorry

maybe try restarting lmao

[celest cosmos]

yeah i did that too

Do you know of any libraries like this that are much faster?

[tiny turret]

nope, sorry

oh

one last thing that might boost your speed a tiny bit

change -b:v, 10000k to -crf, 23(You can tweak this number)

[celest cosmos]

whats the number for?

[tiny turret]

lower is higher quality

crf is constant rate factor

just try with 23

[celest cosmos]

still no

darn

[tiny turret]

I don't know then

sorry

[celest cosmos]

thanks so much

I appreciate you trying

[tiny turret]

of course, I hope someone is able to help you

[celest cosmos]

have a good one!

[tiny turret]

you too

[glass haven]

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