Output of the model is video , how can I save it?

Hi , I have a network that extract a tensor with shape:(batch,channels,time,x,y)=>(batch, 3,16,56,56), and I want to save it as a video, so that the output will be a video.

I tried the naive way using:


You can guess what happened… I’ll be happy if someone has an Idea, really need your help!


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I haven’t done it myself but openCV has something called a VideoWriter. That should do the trick. There is also the ffmpeg module outside of Python.

The way I have done it in the past saving all the images in a folder and via a bash script and ffmpeg make a movie out of them. Not as clean, but yeah.

Here is a pyimagesearch tutorial of something similar

Edit: Well you’d have to convert your tensor to images beforehand. If you need help with that let us know :slight_smile:

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I’ll try the opencv option tomorrow (It’s night time at my place).
And yes I’ll be happy with some direction about turning tensor to images.

Thanks again!

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I wrote this example that should be able to convert tensors to images. It might not work 100% for you but it should help :slight_smile:

import torch
from torchvision import transforms

tensor_2_image = transforms.ToPILImage() # Converts to Image
output = torch.randn(2, 3, 16, 56, 56) # Tensor

for batch in output:
  batch = batch.permute(1, 0, 2, 3) # Change axises -> 16,3,56,56
  images = [tensor_2_image(im) for im in batch] # Convert images
  for image in images:
    # Do what you want with your image here

Edit: Perhaps OpenCV wants a numpy array when I think about it. You can convert the image to a numpy array with np_image = np.array(image)

Hi, I think imageio library (which is very well optimized, clean API) can write video just by giving a list of frames format and frame rate :slight_smile:

Thanks , I will try both of them.
Have you tried or heard trying using pyffmpeg?

Cool, no but that sounds like a great option :slight_smile:

I was looking for it now and found that torchvision allows you to write a tensor as a video. I suppose it wasn’t available a year ago, otherwise it would have been mentioned here for sure. Here’s the link https://pytorch.org/docs/stable/torchvision/io.html#torchvision.io.write_video

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