1 files changed, 180 insertions, 0 deletions

diff --git a/shared/extra-utils/ffprobe.ts b/shared/extra-utils/ffprobe.ts
new file mode 100644
index 000000000..9257bbd5f
--- /dev/null
+++ b/shared/extra-utils/ffprobe.ts
@@ -0,0 +1,180 @@
+import { ffprobe, FfprobeData } from 'fluent-ffmpeg'
+import { VideoFileMetadata } from '@shared/models/videos'
+
+/**
+ *
+ * Helpers to run ffprobe and extract data from the JSON output
+ *
+ */
+
+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 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
+}
+
+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
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  getVideoStreamSize,
+  getVideoFileResolution,
+  getMetadataFromFile,
+  getMaxAudioBitrate,
+  getVideoStreamFromFile,
+  getDurationFromVideoFile,
+  getAudioStream,
+  getVideoFileFPS,
+  ffprobePromise,
+  getVideoFileBitrate,
+  canDoQuickAudioTranscode
+}