我在wechaty 中使用 FileBox 发送 视频文件时候
提示 ：Cannot find ffmpeg，我在主机上 安装了 ffmpeg也是这样的问题

Error: Cannot find ffmpeg
0|ding-dong-bot | at /home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/processor.js:136:22
0|ding-dong-bot | at FfmpegCommand.proto._getFfmpegPath (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/capabilities.js:90:14)
0|ding-dong-bot | at FfmpegCommand.proto._spawnFfmpeg (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/processor.js:132:10)
0|ding-dong-bot | at FfmpegCommand.proto.availableFormats.proto.getAvailableFormats (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/capabilities.js:517:10)
0|ding-dong-bot | at /home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/capabilities.js:568:14
0|ding-dong-bot | at nextTask (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:4576:27)
0|ding-dong-bot | at Object.waterfall (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:4587:9)
0|ding-dong-bot | at Object.awaitable [as waterfall] (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:208:32)
0|ding-dong-bot | at FfmpegCommand.proto._checkCapabilities (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/capabilities.js:565:11)
0|ding-dong-bot | at /home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/processor.js:298:14
0|ding-dong-bot | at nextTask (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:4576:27)
0|ding-dong-bot | at Object.waterfall (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:4587:9)
0|ding-dong-bot | at Object.awaitable [as waterfall] (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:208:32)
0|ding-dong-bot | at FfmpegCommand.proto._prepare (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/processor.js:295:11)
0|ding-dong-bot | at FfmpegCommand.proto.exec.proto.execute.proto.run (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/processor.js:431:10)
0|ding-dong-bot | at runCommand (/home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/recipes.js:401:12)
0|ding-dong-bot | at wrapper (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:268:20)
0|ding-dong-bot | at next (/home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:4582:24)
0|ding-dong-bot | at /home/work/wechaty-getting-started/node_modules/_async@3.2.0@async/dist/async.js:321:20
0|ding-dong-bot | at /home/work/wechaty-getting-started/node_modules/_fluent-ffmpeg@2.1.2@fluent-ffmpeg/lib/recipes.js:339:13
0|ding-dong-bot | at suppressedCallback (fs.js:211:5)
0|ding-dong-bot | at FSReqCallback.oncomplete (fs.js:155:23)