chore(refactor): remove shared folder dependencies to the server

Many files from the `shared` folder were importing files from the `server` folder.
When attempting to use Typescript project references to describe dependencies,
it highlighted a circular dependency beetween `shared` <-> `server`.

The Typescript project forbid such usages.
Using project references greatly improve performance by rebuilding only
the updated project and not all source files.
> see https://www.typescriptlang.org/docs/handbook/project-references.html

server/helpers/ffprobe-utils.ts

@@ -1,9 +1,22 @@
-import { ffprobe, FfprobeData } from 'fluent-ffmpeg'
+import { FfprobeData } from 'fluent-ffmpeg'
 import { getMaxBitrate } from '@shared/core-utils'
-import { VideoFileMetadata, VideoResolution, VideoTranscodingFPS } from '../../shared/models/videos'
+import { VideoResolution, VideoTranscodingFPS } from '../../shared/models/videos'
 import { CONFIG } from '../initializers/config'
 import { VIDEO_TRANSCODING_FPS } from '../initializers/constants'
 import { logger } from './logger'
+import {
+  canDoQuickAudioTranscode,
+  ffprobePromise,
+  getDurationFromVideoFile,
+  getAudioStream,
+  getMaxAudioBitrate,
+  getMetadataFromFile,
+  getVideoFileBitrate,
+  getVideoFileFPS,
+  getVideoFileResolution,
+  getVideoStreamFromFile,
+  getVideoStreamSize
+} from '@shared/extra-utils/ffprobe'
 
 /**
  *
@@ -11,79 +24,6 @@ import { logger } from './logger'
  *
  */
 
-function ffprobePromise (path: string) {
-  return new Promise<FfprobeData>((res, rej) => {
-    ffprobe(path, (err, data) => {
-      if (err) return rej(err)
-
-      return res(data)
-    })
-  })
-}
-
-async function getAudioStream (videoPath: string, existingProbe?: FfprobeData) {
-  // without position, ffprobe considers the last input only
-  // we make it consider the first input only
-  // if you pass a file path to pos, then ffprobe acts on that file directly
-  const data = existingProbe || await ffprobePromise(videoPath)
-
-  if (Array.isArray(data.streams)) {
-    const audioStream = data.streams.find(stream => stream['codec_type'] === 'audio')
-
-    if (audioStream) {
-      return {
-        absolutePath: data.format.filename,
-        audioStream,
-        bitrate: parseInt(audioStream['bit_rate'] + '', 10)
-      }
-    }
-  }
-
-  return { absolutePath: data.format.filename }
-}
-
-function getMaxAudioBitrate (type: 'aac' | 'mp3' | string, bitrate: number) {
-  const maxKBitrate = 384
-  const kToBits = (kbits: number) => kbits * 1000
-
-  // If we did not manage to get the bitrate, use an average value
-  if (!bitrate) return 256
-
-  if (type === 'aac') {
-    switch (true) {
-      case bitrate > kToBits(maxKBitrate):
-        return maxKBitrate
-
-      default:
-        return -1 // we interpret it as a signal to copy the audio stream as is
-    }
-  }
-
-  /*
-    a 192kbit/sec mp3 doesn't hold as much information as a 192kbit/sec aac.
-    That's why, when using aac, we can go to lower kbit/sec. The equivalences
-    made here are not made to be accurate, especially with good mp3 encoders.
-    */
-  switch (true) {
-    case bitrate <= kToBits(192):
-      return 128
-
-    case bitrate <= kToBits(384):
-      return 256
-
-    default:
-      return maxKBitrate
-  }
-}
-
-async function getVideoStreamSize (path: string, existingProbe?: FfprobeData): Promise<{ width: number, height: number }> {
-  const videoStream = await getVideoStreamFromFile(path, existingProbe)
-
-  return videoStream === null
-    ? { width: 0, height: 0 }
-    : { width: videoStream.width, height: videoStream.height }
-}
-
 async function getVideoStreamCodec (path: string) {
   const videoStream = await getVideoStreamFromFile(path)
 
@@ -143,69 +83,6 @@ async function getAudioStreamCodec (path: string, existingProbe?: FfprobeData) {
   return 'mp4a.40.2' // Fallback
 }
 
-async function getVideoFileResolution (path: string, existingProbe?: FfprobeData) {
-  const size = await getVideoStreamSize(path, existingProbe)
-
-  return {
-    width: size.width,
-    height: size.height,
-    ratio: Math.max(size.height, size.width) / Math.min(size.height, size.width),
-    resolution: Math.min(size.height, size.width),
-    isPortraitMode: size.height > size.width
-  }
-}
-
-async function getVideoFileFPS (path: string, existingProbe?: FfprobeData) {
-  const videoStream = await getVideoStreamFromFile(path, existingProbe)
-  if (videoStream === null) return 0
-
-  for (const key of [ 'avg_frame_rate', 'r_frame_rate' ]) {
-    const valuesText: string = videoStream[key]
-    if (!valuesText) continue
-
-    const [ frames, seconds ] = valuesText.split('/')
-    if (!frames || !seconds) continue
-
-    const result = parseInt(frames, 10) / parseInt(seconds, 10)
-    if (result > 0) return Math.round(result)
-  }
-
-  return 0
-}
-
-async function getMetadataFromFile (path: string, existingProbe?: FfprobeData) {
-  const metadata = existingProbe || await ffprobePromise(path)
-
-  return new VideoFileMetadata(metadata)
-}
-
-async function getVideoFileBitrate (path: string, existingProbe?: FfprobeData): Promise<number> {
-  const metadata = await getMetadataFromFile(path, existingProbe)
-
-  let bitrate = metadata.format.bit_rate as number
-  if (bitrate && !isNaN(bitrate)) return bitrate
-
-  const videoStream = await getVideoStreamFromFile(path, existingProbe)
-  if (!videoStream) return undefined
-
-  bitrate = videoStream?.bit_rate
-  if (bitrate && !isNaN(bitrate)) return bitrate
-
-  return undefined
-}
-
-async function getDurationFromVideoFile (path: string, existingProbe?: FfprobeData) {
-  const metadata = await getMetadataFromFile(path, existingProbe)
-
-  return Math.round(metadata.format.duration)
-}
-
-async function getVideoStreamFromFile (path: string, existingProbe?: FfprobeData) {
-  const metadata = await getMetadataFromFile(path, existingProbe)
-
-  return metadata.streams.find(s => s.codec_type === 'video') || null
-}
-
 function computeLowerResolutionsToTranscode (videoFileResolution: number, type: 'vod' | 'live') {
   const configResolutions = type === 'vod'
     ? CONFIG.TRANSCODING.RESOLUTIONS
@@ -263,26 +140,6 @@ async function canDoQuickVideoTranscode (path: string, probe?: FfprobeData): Pro
   return true
 }
 
-async function canDoQuickAudioTranscode (path: string, probe?: FfprobeData): Promise<boolean> {
-  const parsedAudio = await getAudioStream(path, probe)
-
-  if (!parsedAudio.audioStream) return true
-
-  if (parsedAudio.audioStream['codec_name'] !== 'aac') return false
-
-  const audioBitrate = parsedAudio.bitrate
-  if (!audioBitrate) return false
-
-  const maxAudioBitrate = getMaxAudioBitrate('aac', audioBitrate)
-  if (maxAudioBitrate !== -1 && audioBitrate > maxAudioBitrate) return false
-
-  const channelLayout = parsedAudio.audioStream['channel_layout']
-  // Causes playback issues with Chrome
-  if (!channelLayout || channelLayout === 'unknown') return false
-
-  return true
-}
-
 function getClosestFramerateStandard <K extends keyof Pick<VideoTranscodingFPS, 'HD_STANDARD' | 'STANDARD'>> (fps: number, type: K) {
   return VIDEO_TRANSCODING_FPS[type].slice(0)
                                     .sort((a, b) => fps % a - fps % b)[0]