separate audio stream

pi/bin/audio-only-publisher.sh

@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+set -euo pipefail
+set +H
+
+ENV_FILE="${VIDEO_ENV_FILE:-/var/lib/roverd/video.env}"
+
+if [[ ! -f "$ENV_FILE" ]]; then
+	echo "Environment file ${ENV_FILE} missing; cannot publish audio" >&2
+	exit 1
+fi
+
+# shellcheck disable=SC1090
+source "$ENV_FILE"
+: "${AUDIO_PUBLISH_URL:?AUDIO_PUBLISH_URL not set in ${ENV_FILE}}"
+
+AUDIO_DEVICE="${AUDIO_DEVICE:-hw:0,0}"
+AUDIO_RATE="${AUDIO_RATE:-48000}"
+AUDIO_CHANNELS="${AUDIO_CHANNELS:-2}"
+
+if [[ -n "${FFMPEG_BIN:-}" ]]; then
+	FFMPEG_BIN_PATH="$FFMPEG_BIN"
+elif command -v ffmpeg >/dev/null 2>&1; then
+	FFMPEG_BIN_PATH="$(command -v ffmpeg)"
+else
+	echo "ffmpeg not found; install it via apt install ffmpeg." >&2
+	exit 1
+fi
+
+run_pipeline() {
+	"${FFMPEG_BIN_PATH}" \
+		-hide_banner \
+		-loglevel warning \
+		-fflags nobuffer \
+		-rtbufsize 0 \
+		-thread_queue_size 4096 \
+		-f s32le \
+		-ar "${AUDIO_RATE}" \
+		-ac "${AUDIO_CHANNELS}" \
+		-i <(arecord -D "${AUDIO_DEVICE}" -f S32_LE -c "${AUDIO_CHANNELS}" -r "${AUDIO_RATE}" -B 65536 -F 2048 -q -t raw) \
+		-af "aresample=16000,pan=mono|c0=0.5*FL+0.5*FR" \
+		-c:a libopus \
+		-b:a 24000 \
+		-ar:a 16000 \
+		-ac:a 1 \
+		-application lowdelay \
+		-frame_duration 20 \
+		-compression_level 0 \
+		-f mpegts \
+		"${AUDIO_PUBLISH_URL}"
+}
+
+while true; do
+	if run_pipeline; then
+		exit 0
+	fi
+	echo "Audio-only publisher exited, restarting in 2s..." >&2
+	sleep 2
+done