fix(encode): use modern nvenc low-latency preset

scripts/rtmp_srs_smoke.sh

@@ -7,6 +7,7 @@ SRS_ROOT="${SRS_ROOT:-$HOME/Code/srs}"
 SRS_BIN="${SRS_BIN:-$SRS_ROOT/trunk/objs/srs}"
 SRS_CONF="${SRS_CONF:-$SRS_ROOT/trunk/conf/srs.conf}"
 FFPROBE_BIN="${FFPROBE_BIN:-ffprobe}"
+ENCODER_DEVICE="${ENCODER_DEVICE:-software}"
 
 wait_for_port() {
 	local host="$1"
@@ -48,7 +49,7 @@ wait_for_stream() {
 run_case() {
 	local transport="$1"
 	local codec="$2"
-	local stream_name="cvmmap_${transport}_${codec}"
+	local stream_name="cvmmap_${transport}_${codec}_${ENCODER_DEVICE}"
 	local expected_codec="$codec"
 	if [[ "$codec" == "h265" ]]; then
 		expected_codec="hevc"
@@ -57,6 +58,7 @@ run_case() {
 	"${BUILD_DIR}/rtmp_output_tester" \
 		--transport "$transport" \
 		--codec "$codec" \
+		--encoder-device "$ENCODER_DEVICE" \
 		--rtmp-url "rtmp://127.0.0.1/live/${stream_name}" \
 		--frames 36 \
 		--frame-interval-ms 33 \