Multimedia Forensics: Speaker Identification and Selvi 2010 Admissibility

This mock test covers two interlocking pillars of Unit VIII of the UGC-NET Forensic Science Paper II syllabus: the science of speaker comparison and the Indian legal framework for admitting voice recordings in court. Questions probe the aural-spectrographic method (Tosi 1971 MSU study, narrow-band vs wide-band spectrograms, NAS 1979 critique), the evolution of automatic speaker recognition from GMM-UBM (Reynolds 2000) through i-vector (Dehak 2011) and x-vector (Snyder 2018) to deep speaker embeddings (d-vector), closed-set vs open-set identification tasks, the 1:N vs 1:1 distinction, the Bayesian likelihood ratio (LR) framework per ENFSI and IAFPA guidelines, and forensic casework involving tapped calls, ransom calls, and threat calls intercepted under Section 5(2) of the Indian Telegraph Act, 1885.

The Indian law strand runs through the real judgments that govern this area: Selvi v State of Karnataka (2010) 7 SCC 263 on Article 20(3) and Article 21 bars to involuntary testimonial compulsion; Ritesh Sinha v State of UP (2019) 8 SCC 1 on the Constitution Bench clarification of magistrate power to compel voice samples; State of Bombay v Kathi Kalu Oghad (1961) 3 SCR 10 on the testimonial vs non-testimonial distinction; Anvar P.V. v P.K. Basheer (2014) 10 SCC 473 on the mandatory Section 65B certificate (now Section 63 BSA 2023); and Arjun Panditrao Khotkar (2020) 7 SCC 1 overruling the Shafhi Mohammad relaxation. Expert admissibility under Section 45 IEA 1872 (now Section 39 BSA 2023), CFSL audio-forensics practice at Hyderabad, Chandigarh, and Kolkata, and the Daubert vs Frye contrast for comparative context round out the coverage.

Topics covered:

• Tosi 1971 aural-spectrographic method, NAS 1979 critique, narrow-band vs wide-band spectrograms
• GMM-UBM (Reynolds 2000), i-vector (Dehak 2011), x-vector (Snyder 2018), d-vector deep embeddings
• MFCCs and vocal tract encoding; closed-set vs open-set ID; speaker ID (1:N) vs verification (1:1)
• Bayesian LR framework: P(E|Hp)/P(E|Hd); ENFSI verbal equivalence scale; IAFPA validation gate
• Selvi v Karnataka (2010): Article 20(3)+21, testimonial vs non-testimonial compulsion
• Ritesh Sinha v UP (2019): magistrate implied power; voice sample as non-testimonial
• Kathi Kalu Oghad (1961), Anvar P.V. (2014), Arjun Panditrao (2020): Section 63 BSA certificate
• Section 63 BSA 2023 / IEA 65B certificate; Telegraph Act Section 5(2); Daubert vs Frye

Allow 30 minutes.