System information (version)

• OpenCV => 4.2
• Operating System / Platform => Ubuntu 18.04 x86_64

Detailed description

Build error with : opencv/modules/videoio/src/cap_ffmpeg_impl.hpp

AVCodecID not declared (Same that issue #5131 but the line numbers are changed)
AV_PIX_FMT_BGRA not declared
AV_PIX_FMT_RGBA not declared

Steps to reproduce

Follow the official installation instructions to make command (https://docs.opencv.org/trunk/d7/d9f/tutorial_linux_install.html)

Solution found

In opencv/modules/videoio/src/cap_ffmpeg_impl.hpp

Replace AVCodecID by CV_CODEC_ID line 364, 1077, 1079, 1081 and 1366

Add after line 151 :
#define AV_PIX_FMT_BGRA PIX_FMT_BGRA
#define AV_PIX_FMT_RGBA PIX_FMT_RGBA

I don't know if this solution is correct but the make command run correctly after this. I don't know how to test to verify.

Best regards.