Logs

Top-level build scripts print only the progress of the build. Actual log lines are redirected to the build.log file. It is the first file to look if you encounter an error.

On some occasions, if the details inside build.log are not enough to understand the root cause of the failure, you will need to look inside configuration log file (config.log) of the library compiled at that moment; which will have a path like src/LIBRARY/config.log. For ffmpeg this file is located under the src/ffmpeg/ffbuild folder.

Please note that it is possible to follow build progress from build.log using grep. For example the following line discards compilation/build logs and tails only the build steps.

tail -f build.log | grep INFO

INFO: Building mobile-ffmpeg for Android: Thu Jul 5 11:27:39 +03 2018
INFO: Starting new build for arm-v7a on API level 21 at Thu Jul 5 11:27:39 +03 2018
INFO: Enabled library libvpx
INFO: Enabled library libaom
INFO: Building cpu-features for for arm-v7a
INFO: libvpx library is already built and installed
INFO: Flags detected for libvpx: already installed=0, rebuild=1, dependency rebuilt=
INFO: Building libvpx with the following environment variables
INFO: System information
INFO: libaom library is already built and installed
INFO: Flags detected for libaom: already installed=0, rebuild=1, dependency rebuilt=
INFO: Building libaom with the following environment variables
INFO: System information
INFO: Enabling library libvpx
INFO: Enabling library libaom
INFO: Completed build for arm-v7a on API level 21 at Thu Jul 5 11:30:07 +03 2018
INFO: Starting new build for arm-v7a-neon on API level 21 at Thu Jul 5 11:30:07 +03 2018
INFO: Enabled library libvpx
INFO: Enabled library libaom
INFO: Building cpu-features for for arm-v7a-neon
INFO: libvpx library is already built and installed
...