low quality preview for non-drivers

server/mediamtx/mediamtx.yml

@@ -41,4 +41,5 @@ authHTTPExclude:
 paths:
   all:
     source: publisher
-    sourceOnDemand: no
+    sourceOnDemand: no
+    runOnReady: /etc/mediamtx/rover-snapshot.sh

server/mediamtx/rover-snapshot.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+STREAM_ID="${MTX_PATH:-}"
+if [[ -z "${STREAM_ID}" ]]; then
+  echo "MTX_PATH is required." >&2
+  exit 1
+fi
+
+if [[ "${STREAM_ID}" == *-audio ]]; then
+  exit 0
+fi
+
+OUTPUT_DIR="${ROVER_SNAPSHOT_DIR:-/run/rover-snapshots}"
+FPS="${ROVER_SNAPSHOT_FPS:-1}"
+WIDTH="${ROVER_SNAPSHOT_WIDTH:-640}"
+QUALITY="${ROVER_SNAPSHOT_QUALITY:-8}"
+
+mkdir -p "${OUTPUT_DIR}"
+OUTPUT_PATH="${OUTPUT_DIR}/${STREAM_ID}.jpg"
+
+INPUT_URL="${ROVER_SNAPSHOT_INPUT_URL:-srt://127.0.0.1:9000?streamid=#!::r=${STREAM_ID},m=play&latency=20&mode=caller&transtype=live&pkt_size=1316}"
+
+exec /usr/bin/ffmpeg -hide_banner -loglevel warning \
+  -fflags nobuffer \
+  -i "${INPUT_URL}" \
+  -vf "fps=${FPS},scale=${WIDTH}:-1" \
+  -q:v "${QUALITY}" \
+  -an \
+  -f image2 \
+  -update 1 \
+  "${OUTPUT_PATH}"