Applying Filter Complex Fails With Something Related To Audio

I finally managed to build ffmpeg as detailed in here: https://enoent.fr/blog/2014/06/20/compile-ffmpeg-for-android/ and in the end, I have a ffmpeg library which accepts command a

Solution 1:

ffmpeg has a native AAC encoder (-c:a aac), but it is considered experimental, so an additional option is required: -strict experimental (or -strict -2, same thing different name).

This is not the best encoder supported by ffmpeg, but it is not the worst either. If in doubt just provide it enough bitrate until it sounds good enough. For more info see the FFmpeg AAC Audio Encoding Guide.