Add this to your audio_effects.xml:
<library name="v4a_re" path="libv4a_re.so"/> <effect name="v4a_standard_re" library="v4a_re" uuid="90380da3-8536-4744-a6a3-5731970e640f"/>
Also you need to address some SELinux denials in audioserver.te:
get_prop(audioserver, vendor_audio_prop) allow audioserver unlabeled:file { read write open getattr }; allow hal_audio_default hal_audio_default:process { execmem };