COMP_DELAY_SOUND_FRONT_DELAY   64 libavfilter/af_compensationdelay.c #define COMP_DELAY_MAX_DELAY               (COMP_DELAY_MAX_DISTANCE * COMP_DELAY_SOUND_FRONT_DELAY(50))
COMP_DELAY_SOUND_FRONT_DELAY  103 libavfilter/af_compensationdelay.c                COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * inlink->sample_rate;