Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 3: Vālmīki Composes the Rāmāyaṇa
Text 1.3.3-4

रामलक्ष्मणसीताभी राज्ञा दशरथेन च सभार्येण सराष्ट्रेण यत्प्राप्तं तत्र तत्त्वतः।
हसितं भाषितं चैव गतिर्या यच्च चेष्टितम्तत्सर्वं धर्मवीर्येण यथावत्संप्रपश्यति॥

rāma-lakṣmaṇa-sītābhī rājñā daśarathena ca
sabhāryeṇa sarāṣṭreṇa yat prāptaṁ tatra tattvataḥ
hasitaṁ bhāṣitaṁ caiva gatir yac ca ceṣṭitam
tat sarvaṁ dharma-vīryeṇa yathāvat saṁprapaśyati

rāma-lakṣmaṇa-sītābhiḥ = of Rāma, Lakṣmaṇa, Sītā; rājñā = king; daśarathena ca = Daśaratha; sabhāryeṇa = with his wives; sarāṣṭreṇa = and citizens; yat prāptam =of the movements of; tatra tattvataḥ = the details; hasitam = their laughter; bhāṣitam ca eva= talks; gatiḥ = of the movements; yat ca ceṣṭitam tat = and other activities; sarvam = all; dharma-vīryeṇa = and by the force of dharma; yathāvat = factually; saṁprapaśyati = Vālmīki observed.

And by the force of dharma, Vālmīki factually observed all the details of the movements of Rāma, Lakṣmaṇa, Sītā, King Daśaratha with his wives and citizens as well as their laughter, talks, movements and other activities.

He saw the activities of Lord Rāma and others in clearer detail by dharma, that is, the power of Lord Brahmā’s happy blessings. Ceṣṭitam indicates that he saw in meditation the activities of Lord Rāma’s war with Rāvaṇa and so on. By Lord Brahmā’s blessings, Vālmīki directly perceived these events in yoga, as if through his own eyes and other perceptive senses.