diff --git a/.agents/skills/relatorio-cidade/SKILL.md b/.agents/skills/relatorio-cidade/SKILL.md
index 664b577d..f88da118 100644
--- a/.agents/skills/relatorio-cidade/SKILL.md
+++ b/.agents/skills/relatorio-cidade/SKILL.md
@@ -178,10 +178,11 @@ cacheado em `data/relatorios-cidade/<base>.emendas.json` para replay.
   econômica (pesquisa)` · `9. Transporte e conexões (pesquisa)` · `10. Acervo
   de falas` — cada fala com "O que é" (sumário oficial) e "Menção ao município"
   (passagem que cita a cidade ou, se o nome não aparece nos trechos, a marcação
-  do acervo com o nº de municípios), mais **Vídeo** (YouTube já na minutagem
-  do trecho — `youtubeOffsetSeconds` = época do trecho − início da sessão;
-  fallback para o VOD da Câmara, que é o clipe do próprio trecho) e
-  **Transcrição** (PDF do Diário) quando existirem · `11. Notícias e imprensa` ·
+  do acervo com o nº de municípios), mais **Vídeo** (YouTube já no **início da
+  fala** — `youtubeStartSeconds` = `speechAt` − início da sessão, via
+  `speechStartOffsetSeconds`; fallback para o VOD da Câmara, que é o clipe do
+  próprio trecho) e **Transcrição** (PDF do Diário) quando existirem ·
+  `11. Notícias e imprensa` ·
   `12. Panorama regional` · `13. Abordagem sugerida (personas)` · `14. Fontes e
   limites`.
 - **Links clicáveis:** todo URL no PDF é um link (`<a href>`): células de
diff --git a/docs/changelog/2026-09-15-c163-falas-inicio-da-fala.md b/docs/changelog/2026-09-15-c163-falas-inicio-da-fala.md
new file mode 100644
index 00000000..0ba0e401
--- /dev/null
+++ b/docs/changelog/2026-09-15-c163-falas-inicio-da-fala.md
@@ -0,0 +1 @@
+**C163 — vídeo do acervo no início da fala, não no trecho curado (2026-09-15):** o link do YouTube abria 2m45s dentro do discurso porque usava `excerptTMs` (época de um trecho curado, 14:10:45) em vez do início da fala (14:08). O dono `src/lib/speechVod.ts` ganhou `speechStartOffsetSeconds(speechAt, eventStartAt)` (mesma matemática de relógio de parede BRT do `excerptOffsetSeconds`, com testes de DST e virada de dia) e o relatório passou a usar `youtubeStartSeconds` = `speechAt` − início da sessão: na fala 641, **480s (8min)** em vez de 645s → `youtube.com/watch?v=2cX_gKkJH7Q&t=480s`. Unit 3121/3121, `tsc`/eslint verdes; snapshot reextraído e PDF regerado.
diff --git a/scripts/cityReportSnapshot.mjs b/scripts/cityReportSnapshot.mjs
index 4dbfdc04..6a28b200 100644
--- a/scripts/cityReportSnapshot.mjs
+++ b/scripts/cityReportSnapshot.mjs
@@ -14,7 +14,7 @@ import { FEDERAL_DEPUTY_OFFICE, HISTORICAL_SERIES_YEARS } from '../src/lib/elect
 import { getMunicipalityCatalogEntry } from '../src/lib/municipalityCatalog.ts'
 import { getMunicipalityVoteRank } from '../src/lib/municipalityVoteRank.ts'
 import { normalizeForSearch } from '../src/lib/speechSearch.ts'
-import { excerptOffsetSeconds } from '../src/lib/speechVod.ts'
+import { speechStartOffsetSeconds } from '../src/lib/speechVod.ts'
 import { campaignRoleLabels } from '../src/utilities/campaignUserProfile.ts'
 import { loadMunicipalityDossierData } from '../src/utilities/municipality/municipalityDossierData.ts'
 import {
@@ -66,7 +66,6 @@ const loadSpeeches = async (payload, actor, municipalityID, municipalityName) =>
       officialTextUrl: true,
       youtubeUrl: true,
       vodPlaybackUrl: true,
-      excerptTMs: true,
       eventStartAt: true,
       mentionedMunicipalities: true,
     },
@@ -96,7 +95,7 @@ const loadSpeeches = async (payload, actor, municipalityID, municipalityName) =>
         youtubeUrl: doc.youtubeUrl ?? null,
         vodPlaybackUrl: doc.vodPlaybackUrl ?? null,
         /** Offset of the excerpt inside the session video (YouTube start). */
-        youtubeOffsetSeconds: excerptOffsetSeconds(doc.excerptTMs, doc.eventStartAt),
+        youtubeStartSeconds: speechStartOffsetSeconds(doc.speechAt, doc.eventStartAt),
         mentionExcerpt: mentionSegment?.text ?? null,
         mentionedMunicipalityCount: Array.isArray(doc.mentionedMunicipalities)
           ? doc.mentionedMunicipalities.length
diff --git a/scripts/lib/cityReportBlocks.mjs b/scripts/lib/cityReportBlocks.mjs
index 84e97f76..e1a716b1 100644
--- a/scripts/lib/cityReportBlocks.mjs
+++ b/scripts/lib/cityReportBlocks.mjs
@@ -902,7 +902,7 @@ const buildSpeechesSection = ({ snapshot }) => {
             ? `Marcada no acervo — nome não localizado nos trechos (a fala cita ${formatInteger(row.mentionedMunicipalityCount)} municípios).`
             : 'Marcada no acervo — trecho não localizado.',
         video: row.youtubeUrl
-          ? withYoutubeTimestamp(row.youtubeUrl, row.youtubeOffsetSeconds)
+          ? withYoutubeTimestamp(row.youtubeUrl, row.youtubeStartSeconds)
           : (row.vodPlaybackUrl ?? '—'),
         transcript: row.officialTextUrl ?? '—',
       })),
diff --git a/src/lib/speechVod.ts b/src/lib/speechVod.ts
index a6b50967..d9779459 100644
--- a/src/lib/speechVod.ts
+++ b/src/lib/speechVod.ts
@@ -193,6 +193,23 @@ const wallClockSeconds = (epochMs: number): number => {
   )
 }
 
+/** BRT wall-clock seconds-since-epoch of a naive Câmara datetime, or null. */
+const naiveWallClockSeconds = (value: unknown): number | null => {
+  const match = NAIVE_DATETIME.exec(String(value ?? '').trim())
+  if (!match) return null
+  const [, year, month, day, hour, minute, second = '0'] = match
+  const [y, mo, d, h, mi, s] = [year, month, day, hour, minute, second].map(Number)
+  if (mo < 1 || mo > 12 || d < 1 || d > 31 || h > 23 || mi > 59 || s > 59) {
+    return null
+  }
+  const ms = Date.UTC(y, mo - 1, d, h, mi, s)
+  const date = new Date(ms)
+  if (date.getUTCFullYear() !== y || date.getUTCMonth() !== mo - 1 || date.getUTCDate() !== d) {
+    return null
+  }
+  return ms / 1000
+}
+
 /**
  * Seconds from the session start (`eventStartAt`, naive Câmara wall clock) to
  * the excerpt (`excerptTMs`, epoch ms). Both sides are read as BRT wall clock,
@@ -203,23 +220,28 @@ export const excerptOffsetSeconds = (excerptTMs: unknown, eventStartAt: unknown)
   const epochMs = Number(excerptTMs)
   if (!Number.isFinite(epochMs) || epochMs <= 0 || epochMs > MAX_DATE_MS) return null
 
-  const match = NAIVE_DATETIME.exec(String(eventStartAt ?? '').trim())
-  if (!match) return null
-  const [, year, month, day, hour, minute, second = '0'] = match
-  const [y, mo, d, h, mi, s] = [year, month, day, hour, minute, second].map(Number)
-  if (mo < 1 || mo > 12 || d < 1 || d > 31 || h > 23 || mi > 59 || s > 59) {
-    return null
-  }
-  const startMs = Date.UTC(y, mo - 1, d, h, mi, s)
-  const startDate = new Date(startMs)
-  if (
-    startDate.getUTCFullYear() !== y ||
-    startDate.getUTCMonth() !== mo - 1 ||
-    startDate.getUTCDate() !== d
-  ) {
-    return null
-  }
+  const startSeconds = naiveWallClockSeconds(eventStartAt)
+  if (startSeconds === null) return null
 
-  const offset = Math.floor(wallClockSeconds(epochMs) - startMs / 1000)
+  const offset = Math.floor(wallClockSeconds(epochMs) - startSeconds)
+  return offset >= 0 ? offset : null
+}
+
+/**
+ * Seconds from the session start (`eventStartAt`) to the speech itself
+ * (`speechAt`, the Câmara wall clock of the speech) — where a video link must
+ * start to open at the beginning of the deputy's speech, not at a curated
+ * excerpt inside it. Null when either side is unparseable or the speech
+ * precedes the session start.
+ */
+export const speechStartOffsetSeconds = (
+  speechAt: unknown,
+  eventStartAt: unknown,
+): number | null => {
+  const speechSeconds = naiveWallClockSeconds(speechAt)
+  const startSeconds = naiveWallClockSeconds(eventStartAt)
+  if (speechSeconds === null || startSeconds === null) return null
+
+  const offset = Math.floor(speechSeconds - startSeconds)
   return offset >= 0 ? offset : null
 }
diff --git a/tests/unit/cityReportBlocks.unit.spec.ts b/tests/unit/cityReportBlocks.unit.spec.ts
index ecc9634c..25fb512b 100644
--- a/tests/unit/cityReportBlocks.unit.spec.ts
+++ b/tests/unit/cityReportBlocks.unit.spec.ts
@@ -278,7 +278,7 @@ const snapshot = {
         officialTextUrl: 'https://camara.test/discurso',
         youtubeUrl: 'https://youtube.test/video',
         vodPlaybackUrl: 'https://vod.test/video.mp4',
-        youtubeOffsetSeconds: 125,
+        youtubeStartSeconds: 125,
         mentionExcerpt: 'Trecho da fala que cita Feira de Santana',
         mentionedMunicipalityCount: 3,
       },
diff --git a/tests/unit/speechVod.unit.spec.ts b/tests/unit/speechVod.unit.spec.ts
index b73c56d8..4611d932 100644
--- a/tests/unit/speechVod.unit.spec.ts
+++ b/tests/unit/speechVod.unit.spec.ts
@@ -2,7 +2,11 @@
 
 import { describe, expect, it } from 'vitest'
 
-import { excerptOffsetSeconds, parseYoutubeVideoId } from '@/lib/speechVod'
+import {
+  excerptOffsetSeconds,
+  parseYoutubeVideoId,
+  speechStartOffsetSeconds,
+} from '@/lib/speechVod'
 
 /**
  * The VOD URL/status/duration contracts moved from `scripts/lib/camaraSpeeches.mjs`
@@ -50,6 +54,25 @@ describe('excerptOffsetSeconds', () => {
   })
 })
 
+describe('speechStartOffsetSeconds', () => {
+  it('measures the speech start against the session start', () => {
+    expect(speechStartOffsetSeconds('2018-03-13T14:08', '2018-03-13T14:00')).toBe(480)
+    expect(speechStartOffsetSeconds('2026-08-11T15:12:30', '2026-08-11T15:00')).toBe(750)
+  })
+
+  it('reads both sides as BRT wall clock across an old DST transition', () => {
+    // 2018-11-04: clocks move to -02:00 — the naive difference stays local.
+    expect(speechStartOffsetSeconds('2018-11-04T12:00', '2018-11-04T11:00')).toBe(3600)
+  })
+
+  it('returns null when the speech precedes the session or input is unparseable', () => {
+    expect(speechStartOffsetSeconds('2018-03-13T13:59', '2018-03-13T14:00')).toBeNull()
+    expect(speechStartOffsetSeconds(null, '2018-03-13T14:00')).toBeNull()
+    expect(speechStartOffsetSeconds('2018-03-13T14:08', null)).toBeNull()
+    expect(speechStartOffsetSeconds('2018-03-13T25:00', '2018-03-13T14:00')).toBeNull()
+  })
+})
+
 describe('parseYoutubeVideoId', () => {
   const videoId = 'lLhRDkSPw0A'