Patañjali's yogasūtra 1:19 & 20

Ramanna Maharshi: a bhavapratyaya yogi

Sūtras 1:19 and 1:20 inform us of the differentiation between two kinds of yogis. Those who reach samādhi as a result of self discipline and regular practice, and those to whom it comes naturally, i.e. by virtue of birth. They are bhavapratyaya (from birth) and upāyapratyaya (through practice) yogis. 

I am not completely clear as to what videha means in the context of samādhi and invite comment on it. 

{1:19}

भव प्रत्ययो विदेहप्रकृतिलयानाम्

bhavapratyayo videhaprakṛtilayānām

भव: प्रत्ययः विदेह प्रकृतिलयानाम् 

Birth is the cause of those who are 'videha' and those who are mergeg in 'prakṛti'

भव: - being, birth; masc noun from √bhū (1P)

प्रत्ययः - ground, cause (hetu) masc noun 

विदेह - bodiless, incorporeal; adjective

प्रकृतिलयानाम् - of those who are merged, dissolved, absorbed in prakṛti; layānām genitive plural of  laya from √lī - to cling, to stick, to disappear into. 

Some practitioners possess the capacity to pass into a yogic trance effortlessly, as a result of their physical and mental constitution - i.e. what they are born with.  

{1:20}

श्रद्धावीर्यस्मृतिसमाधिप्रज्ञापूर्वक इतरेषाम्

śraddhavīryasmṛtisamādhiprajñāpūrvaka itareṣām

श्रद्धा वीर्यम् स्मृति: समाधि प्रज्ञापूर्वक इतरेषाम् 

For these [the others] samādhi is preceded by faith, energy, memory and higher intelligence.

श्रद्धा - faith, belief, trust; fem noun

वीर्यम् - virility, bravery, power, valour, energy; neuter noun

स्मृति: - memory, mindfulness, thinking upon; fem noun

समाधि: - intense contemplation, trance; masc. noun

प्रज्ञापूर्वक - preceded by prajñā viz. keen intellect, higher knowledge, insight; fem noun

इतरेषाम् = इतः एषाम्  इतः - this, here; एषाम् genitive plural of इदम् = of these [people, persons] Here the genitive operates as the dative - 'For these' i.e. the others with reference to the previous verse.