VPU_CODEC_STATE_DRAIN
vdec_update_state(inst, VPU_CODEC_STATE_DRAIN, 0);
case VPU_CODEC_STATE_DRAIN:
if (inst->state != VPU_CODEC_STATE_DRAIN)
inst->state = VPU_CODEC_STATE_DRAIN;
if (inst->state == VPU_CODEC_STATE_DRAIN)
case VPU_CODEC_STATE_DRAIN: return "drain";