Build failed when make
Hello author, thank you for your contributions. I use sudo apt install to install all needed packets. Then I follow the cmd to configure and make. But when I make, there is a error as below:

I attempt many version of libx264,They all have this problem.
same for me, guess the new commit on ssim.cc caused the problem
I just tested it with libx264-dev package version 2:0.160.3011 (Ubuntu 21.10) and it worked.
Granted, we're using an internal functionality of libx264 here that's not part of the public API. I see if I can replace this with something more stable.
Hi,
I had the same issue when using ubuntu 18.04 with libx264-dev version 2:0.152.2854+gite9a5903-2. I fixed this by changing the functions that started with x264_8_ to x264_ in src/util/ssim.cc. Hope that can help!
Hi, I also have this issue, I try to use the libx264-dev version which is 2:160.3011 and 2:164.3065, but each version gives rise to the undefined problem, and I see the x264.h in /usr/include/, I also cannot find these functions.
@obrr-hhx Sorry to bother you, I'm not sure if you are still following this project.
Regarding your question, I would like to know which functions you are referring to when you mentioned these functions? If you are referring to ssim.cc, it is a function within this project instad of part of x264 functions, so you do not need to search for it in /usr/include/.
Regarding the error, it seems to be caused by the upgrade to version 158 of x264. Following ApostaC's method should work to solve the problem, provided that libx264-dev is rolled back to version 157 or lower.
I hope this information helps.