Redmi 3 (ido) stock audio hal flags

gistfile1.txt

AUDIO_FEATURE_ENABLED_PCM_OFFLOAD : = false
AUDIO_FEATURE_ENABLED_ANC_HEADSET : = true
AUDIO_FEATURE_ENABLED_FLUENCE := true
AUDIO_FEATURE_ENABLED_PROXY_DEVICE := true
AUDIO_FEATURE_ENABLED_KPI_OPTIMIZE := true
AUDIO_FEATURE_ENABLED_FM := true
AUDIO_FEATURE_ENABLED_USBAUDIO := false
AUDIO_FEATURE_ENABLED_HFP := true
AUDIO_FEATURE_ENABLED_CUSTOMSTEREO := false
AUDIO_FEATURE_ENABLED_SSR := true
AUDIO_FEATURE_ENABLED_MULTI_VOICE_SESSIONS := true
AUDIO_FEATURE_ENABLED_INCALL_MUSIC := false
AUDIO_FEATURE_ENABLED_COMPRESS_VOIP := true
AUDIO_FEATURE_ENABLED_EXTN_FORMATS :=true
AUDIO_FEATURE_ENABLED_SPKR_PROTECTION := false
MULTIPLE_HW_VARIANTS_ENABLED := true
AUDIO_FEATURE_ENABLED_COMPRESS_CAPTURE := true
DOLBY_DDP := false
DOLBY_DAP := false
AUDIO_FEATURE_ENABLED_MULTIPLE_TUNNEL :=false
AUDIO_FEATURE_ENABLED_EXTN_FLAC_DECODER :=false
AUDIO_FEATURE_ENABLED_DEV_ARBI :=false
AUDIO_FEATURE_ENABLED_RECORD_PLAY_CONCURRENCY := false
AUDIO_FEATURE_ENABLED_ACDB_LICENSE := true
AUDIO_FEATURE_ENABLED_DS2_DOLBY_DAP := false
AUDIO_FEATURE_ENABLED_LISTEN := true
BOARD_SUPPORTS_SOUND_TRIGGER := true
AUDIO_FEATURE_ENABLED_AUXPCM_BT := false
AUDIO_FEATURE_ENABLED_PM_SUPPORT := false

Hi!
I have an Huawei Nova and i'm working on LineageOS for it. Right now i don't understand those audio flags.
May i ask you how did you know which audio flags are enabled in stock? Also, how can i know which ones are required and which not? Is there any description?

Thank you!
Have a wonderful day!

Robert.