Change how we handle resolution

It was an enum before, now we just use video height

server/helpers/ffmpeg-utils.ts

@@ -0,0 +1,79 @@
+import * as Promise from 'bluebird'
+import * as ffmpeg from 'fluent-ffmpeg'
+
+import { CONFIG } from '../initializers'
+import { VideoResolution } from '../../shared/models/videos/video-resolution.enum'
+
+function getVideoFileHeight (path: string) {
+  return new Promise<number>((res, rej) => {
+    ffmpeg.ffprobe(path, (err, metadata) => {
+      if (err) return rej(err)
+
+      const videoStream = metadata.streams.find(s => s.codec_type === 'video')
+      return res(videoStream.height)
+    })
+  })
+}
+
+function getDurationFromVideoFile (path: string) {
+  return new Promise<number>((res, rej) => {
+    ffmpeg.ffprobe(path, (err, metadata) => {
+      if (err) return rej(err)
+
+      return res(Math.floor(metadata.format.duration))
+    })
+  })
+}
+
+function generateImageFromVideoFile (fromPath: string, folder: string, imageName: string, size?: string) {
+  const options = {
+    filename: imageName,
+    count: 1,
+    folder
+  }
+
+  if (size !== undefined) {
+    options['size'] = size
+  }
+
+  return new Promise<string>((res, rej) => {
+    ffmpeg(fromPath)
+      .on('error', rej)
+      .on('end', () => res(imageName))
+      .thumbnail(options)
+  })
+}
+
+type TranscodeOptions = {
+  inputPath: string
+  outputPath: string
+  resolution?: VideoResolution
+}
+
+function transcode (options: TranscodeOptions) {
+  return new Promise<void>((res, rej) => {
+    let command = ffmpeg(options.inputPath)
+                    .output(options.outputPath)
+                    .videoCodec('libx264')
+                    .outputOption('-threads ' + CONFIG.TRANSCODING.THREADS)
+                    .outputOption('-movflags faststart')
+
+    if (options.resolution !== undefined) {
+      const size = `${options.resolution}x?` // '720x?' for example
+      command = command.size(size)
+    }
+
+    command.on('error', rej)
+           .on('end', res)
+           .run()
+  })
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  getVideoFileHeight,
+  getDurationFromVideoFile,
+  generateImageFromVideoFile,
+  transcode
+}