From 671bee8317ebf511a47fb136c99694e36d80e95b Mon Sep 17 00:00:00 2001
From: Deivid Soto <hello@torrentclaw.com>
Date: Wed, 10 Jun 2026 20:10:11 +0200
Subject: [PATCH] fix(stream): delay_moov en el remux para audio AAC con dts
 negativo
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El remux reencodea el audio no-AAC (eac3→aac); la pista AAC arranca con un
dts negativo (priming/encoder-delay). Con empty_moov el moov se escribía
ANTES de conocer ese delay, así que el primer fragmento quedaba mal formado
y un demuxer estricto (Safari / la forma en que Apple decodifica HEVC) nunca
inicializaba la reproducción: el <video> cargaba bytes (se veía en Network)
pero no arrancaba, y el player re-bootstrapeaba la sesión cada pocos segundos.

Añade +delay_moov: retiene el moov hasta el primer paquete y maneja el dts
de priming. ffmpeg deja de emitir el warning "nonzero dts ... moov already
written" y el fMP4 reproduce. Reproducido con Hoppers (HEVC Main 10 + EAC3).
---
 internal/engine/transcoder.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/internal/engine/transcoder.go b/internal/engine/transcoder.go
index 6bd613e..5a1fff2 100644
--- a/internal/engine/transcoder.go
+++ b/internal/engine/transcoder.go
@@ -302,8 +302,16 @@ func buildFFmpegArgs(filePath string, opts TranscodeOpts) []string {
 	//     until the whole mdat lands and playback never starts.
 	//   * negative_cts_offsets: lets b-frames carry the right pts/dts so
 	//     decoders don't reset the playhead to 0 every fragment.
+	//   * delay_moov: a re-encoded AAC track starts with a negative dts (the
+	//     encoder priming/delay). With empty_moov the moov is written up front,
+	//     BEFORE that delay is known, so the first fragment is malformed and a
+	//     strict demuxer (Safari, and any browser the way Apple decodes HEVC)
+	//     never initialises playback — the <video> loads bytes but never starts,
+	//     and the player re-bootstraps the session every few seconds. delay_moov
+	//     holds the moov until the first packet so the priming dts is handled.
+	//     (Was the "remux loads in Network but won't play" bug.)
 	args = append(args,
-		"-movflags", "+frag_keyframe+empty_moov+default_base_moof+negative_cts_offsets",
+		"-movflags", "+frag_keyframe+empty_moov+default_base_moof+negative_cts_offsets+delay_moov",
 		"-frag_duration", "1000000",
 		"-f", "mp4",
 		"pipe:1",