How to measure compressed video size

[Zayn-Rekhi]

How to measure compressed video size?

Hi guys, I really appreciate all of your video compression work. I cannot thank you guys enough. I was wondering how I can measure the size of my compressed video. Any help or suggestions would be greatly appreciated :) Thanks.

[YodaEmbedding]

Two ways:

• During runtime, generate a bitstream or file and check its size. This is non-differentiable.

• During training, compute the differentiable rate via the method below.

  Just like with the VAE image compression models, the rate in bpp can be measured via the cross-entropy between the actual symbols and their "predicted" distributions. Whenever the predicted distribution matches, the bit cost for encoding that symbol is low. This is effectively a sum of the log-likelihoods. Since these models minimize loss = R + lambda D, you may find the calculation for rate R (measured in bpp) in the RateDistortionLoss class in examples/train_video.py.

Note: This question is best asked in Discussions.

[Zayn-Rekhi]

I apologize for writing my question, I will make sure to write it in discussion moving forward. I liked your first suggestion and looking at the evaluation code I think that this has already been implemented. However, when I check the size of the binary file it is much, much smaller than the mp4 file produced by h265. Hence, I think I did something wrong. What could I have done wrong?

[YodaEmbedding]

Perhaps one of these may help:
#190 (comment)
#190 (comment) (first bullet point)