OpenIPC开源FPV之重要源码包

1. 源由

OpenIPC FPV设备，在软件层面，其体现功能的重要软件包的梳理，有助于更好的理解工作原理。

从软件部署的思路去考虑，我们将设备的软件大块的进行简单切割：

1. 设备引导代码：uboot
2. 操作系统代码：Linux
3. 基础文件系统：FileSystem(含基础功能代码)
4. 功能执行代码：Application

前面《OpenIPC开源IPC之工程框架》已经整体上介绍上面四大块内容整合工具Buildroot。

本章将重点放在Application上，期望通过梳理，将天空端和地面端的具体功能实现与源代码一一对应，以便更好的去维护和开发后续功能。

2. 分析

首先，从功能颗粒度的角度进行基本分析。

2.1 功能角度

• 天空端

1. 摄像视频采集
2. 视频数据发送
3. MAVLink数据采集
4. MAVLink数据发送

• 地面端

1. 视频数据接收
2. 摄像视频播放
3. MAVLink数据接收
4. OSD图层渲染

2.2 数据角度

• 视频流

摄像视频采集  --> 视频数据发送 --> 视频数据接收 --> 摄像视频播放

• MAVLink数据流

MAVLink数据采集 --> MAVLink数据发送 --> MAVLink数据接收 --> OSD图层渲染

3. 软件包

通过功能角度和数据角度分析，寻找对应软件包的方式关联的脚本或者代码证据，将整个流程串联起来。

3.1 wfb-ng

3.1.1 目标板配置

• devices/ssc338q_fpv_openipc-urllc-aio/br-ext-chip-sigmastar/configs/ssc338q_fpv_openipc-urllc-aio_defconfig#L103

BR2_PACKAGE_WIFIBROADCAST=y

3.1.2 软件版配置

• general/package/wifibroadcast/wifibroadcast.mk#L7

WIFIBROADCAST_VERSION = 24.08

3.1.3 视频数据发送 & 接收

• general/package/wifibroadcast/files/wifibroadcast#L109-L117

start_drone_wfb() {
	wfb_tx -p "$stream" -u "$udp_port" -R "$rcv_buf" -K "$keydir/$unit.key" -B "$bandwidth" \
		-M "$mcs_index" -S "$stbc" -L "$ldpc" -G "$guard_interval" -k "$fec_k" -n "$fec_n" \
		-T "$pool_timeout" -i "$link_id" -f "$frame_type" -C 8000 "$wlan" > /dev/null &
}

start_gs_wfb() {
	wfb_rx -c "$udp_addr" -u "$udp_port" -p "$stream" -K "$keydir/$unit.key" -i "$link_id" "$wlan" > /dev/null &
}

3.2 datalink

3.2.1 目标板配置

• devices/ssc338q_fpv_openipc-urllc-aio/br-ext-chip-sigmastar/configs/ssc338q_fpv_openipc-urllc-aio_defconfig#L102

BR2_PACKAGE_DATALINK=y

3.2.2 软件版配置

• general/package/datalink/files/telemetry#L13-L16

if [ ! -f /usr/bin/telemetry_rx ] && [ ! -f /usr/bin/telemetry_tx ]; then
	ln -s /usr/bin/wfb_rx /usr/bin/telemetry_rx
	ln -s /usr/bin/wfb_tx /usr/bin/telemetry_tx
fi

• general/package/datalink/files/telemetry_drone.conf#L15-L20

stream_rx=144
stream_tx=16
link_id=7669206
frame_type=data
port_rx=14551
port_tx=14550

• general/package/datalink/files/telemetry_gs.conf#L15-L20

stream_rx=16
stream_tx=144
link_id=7669206
frame_type=data
port_rx=14651
port_tx=14650

3.2.3 数据发送 & 接收

• general/package/datalink/files/telemetry

start_drone_telemetry() {
	if [ "$one_way" = "false" ]; then
		telemetry_rx -p "$stream_rx" -u "$port_rx" -K "$keydir/$unit.key" -i "$link_id" "$wlan" > /dev/null &
	fi
	telemetry_tx -p "$stream_tx" -u "$port_tx" -K "$keydir/$unit.key" -B "$bandwidth" \
		-M "$mcs_index" -S "$stbc" -L "$ldpc" -G "$guard_interval" -k "$fec_k" -n "$fec_n" \
		-T "$pool_timeout" -i "$link_id" -f "$frame_type" "$wlan" > /dev/null &
}

start_gs_telemetry() {
	if [ "$one_way" = "false" ]; then
		telemetry_tx -p "$stream_tx" -u "$port_tx" -K "$keydir/$unit.key" -B "$bandwidth" \
			-M "$mcs_index" -S "$stbc" -L "$ldpc" -G "$guard_interval" -k "$fec_k" -n "$fec_n" \
			-T "$pool_timeout" -i "$link_id" -f "$frame_type" "$wlan" > /dev/null &
	fi
	telemetry_rx -p "$stream_rx" -u "$port_rx" -K "$keydir/$unit.key" -i "$link_id" "$wlan" > /dev/null &
}

3.3 *mavfwd

注：天空端设备软件包。

3.3.1 目标板配置

• devices/ssc338q_fpv_openipc-urllc-aio/br-ext-chip-sigmastar/configs/ssc338q_fpv_openipc-urllc-aio_defconfig#L105

BR2_PACKAGE_MAVFWD=y

3.3.2 软件版配置

• general/package/mavfwd/mavfwd.mk#L7-L9

MAVFWD_SITE_METHOD = git
MAVFWD_SITE = https://github.com/openipc/mavfwd
MAVFWD_VERSION = 70da7adbdbe36d371ca849c4a3bc3cadb54498d3

3.3.3 MAVLink数据采集&接收

• general/package/datalink/files/telemetry#L42-L43

			mavfwd --channels "$channels" --master "$serial" --baudrate "$baud" -p 100 -t -a "$aggregate" \
				--out 127.0.0.1:$port_tx --in 127.0.0.1:$port_rx > /dev/null &

3.4 *mavlink-router

注：地面端设备软件包。

3.4.1 目标板配置

• br-ext-chip-hisilicon/configs/hi3536dv100_fpv_defconfig#L109

BR2_PACKAGE_MAVLINK_ROUTER=y

3.4.2 软件版配置

• general/package/mavlink-router/mavlink-router.mk#L7-L9

MAVLINK_ROUTER_SITE_METHOD = git
MAVLINK_ROUTER_SITE = https://github.com/mavlink-router/mavlink-router
MAVLINK_ROUTER_VERSION = 18c06da77563db9ba1b7c4173ff5cae1646b383e

• general/package/mavlink-router/files/mavlink_drone.conf#L8-L16

[UdpEndpoint telemetry_tx]
Mode = Normal
Address = 127.0.0.1
Port = 14550


[UdpEndpoint telemetry_rx]
Mode = Server
Address = 0.0.0.0
Port = 14551

• general/package/mavlink-router/files/mavlink_gs.conf#L5-L25

[UdpEndpoint external_use]
Mode = Server
Address = 0.0.0.0
Port = 14550


[UdpEndpoint vdec]
Mode = Normal
Address = 127.0.0.1
Port = 14750


[UdpEndpoint telemetry_tx]
Group = wfb
Mode = Normal
Address = 127.0.0.1
Port = 14650


[UdpEndpoint telemetry_rx]
Group = wfb
Mode = Server
Address = 127.0.0.1
Port = 14651

3.4.3 MAVLink数据采集&接收

• general/package/mavlink-router/files/S97mavlink#L7

			mavlink-routerd &

• general/package/datalink/files/telemetry#L40

			mavlink-routerd -c /etc/mavlink.conf > /dev/null 2>&1 &

3.5 majestic

3.5.1 目标板配置

• devices/ssc338q_fpv_openipc-urllc-aio/br-ext-chip-sigmastar/configs/ssc338q_fpv_openipc-urllc-aio_defconfig#L71

BR2_PACKAGE_MAJESTIC=y

3.5.2 软件版配置

请注意，这个代码并非全部开源。

• general/package/majestic/majestic.mk#L7-L10

MAJESTIC_SITE = https://openipc.s3-eu-west-1.amazonaws.com
MAJESTIC_SOURCE = majestic.$(MAJESTIC_FAMILY).$(MAJESTIC_VARIANT).master.tar.bz2
MAJESTIC_LICENSE = PROPRIETARY
MAJESTIC_LICENSE_FILES = LICENSE

• devices/ssc338q_fpv_openipc-urllc-aio/br-ext-chip-sigmastar/configs/ssc338q_fpv_openipc-urllc-aio_defconfig#L33-L34

BR2_OPENIPC_SOC_FAMILY="infinity6e"
BR2_OPENIPC_VARIANT="fpv"

3.5.3 摄像视频采集

通过链接下载应用程序：二进制+配置文件

3.6 *vdec-openipc

注：地面端设备软件包。

3.6.1 目标板配置

• br-ext-chip-hisilicon/configs/hi3536dv100_fpv_defconfig#L105

BR2_PACKAGE_VDEC_OPENIPC=y

3.6.2 软件版配置

• general/package/vdec-openipc/vdec-openipc.mk#L7-L8

VDEC_OPENIPC_SITE = $(call github,openipc,silicon_research,$(VDEC_OPENIPC_VERSION))
VDEC_OPENIPC_VERSION = HEAD

• general/package/vdec-openipc/files/vdec.conf

### Port for video rx (default: 5000)

port=5600

### Mavlink port for telemetry (default: 14750)

mavlink_port=14750

3.6.3 视频播放&OSD渲染

• general/package/vdec-openipc/files/S98vdec#L22

    vdec -p ${port} -d ${format} -c ${codec} -m ${mode} --mavlink-port ${mavlink_port} ${osd_variant} ${extra} > /dev/null 2>&1 &

4. 启动

4.1 数据链路启动

RF链路

• general/package/datalink/files/S98datalink#L40

wifibroadcast start

• general/package/wifibroadcast/files/wifibroadcast#L139

telemetry start

LTE链路

• general/package/datalink/files/S98datalink#L36

telemetry start

4.2 视频链路启动

注：对于这块尚不是很清楚，待详查。

• general/package/majestic/files/S95majestic#L7-L18

start() {
	ulimit -c unlimited
	echo "/tmp/core.majestic" > /proc/sys/kernel/core_pattern


	echo -n "Starting $DAEMON: "
	start-stop-daemon -b -m -S -q -p "$PIDFILE" -x "$DAEMON" -- $DAEMON_ARGS
	if [ $? -eq 0 ]; then
		echo "OK"
	else
		echo "FAIL"
	fi
}

5. 参考资料

【1】OpenIPC开源FPV之工程编译
【2】OpenIPC开源FPV之工程框架
【3】Ardupilot & OpenIPC & 基于WFB-NG构架分析和数据链路思考