Thanks for your replies TheBearF8. I give some steps more but still having problems. Is it necessary to build libav for armv7\ armv7s\ arm64 separately??? . . . . libavcodec/arm/mlpdsp_armv5te.S:618:9: error: unknown directive .hword 0, 0, (12f - 0b) / 2, (13f - 0b) / 2, (14f - 0b) / 2, (15f - 0b) /...