はじまりの大地

packages/ffmpeg/src/ffprobe.ts

@@ -0,0 +1,213 @@
+import ffmpeg, { FfprobeData } from 'fluent-ffmpeg'
+import { buildAspectRatio, forceNumber } from '@peertube/peertube-core-utils'
+import { VideoResolution } from '@peertube/peertube-models'
+
+/**
+ *
+ * Helpers to run ffprobe and extract data from the JSON output
+ *
+ */
+
+function ffprobePromise (path: string) {
+  return new Promise<FfprobeData>((res, rej) => {
+    ffmpeg.ffprobe(path, [ '-show_chapters' ], (err, data) => {
+      if (err) return rej(err)
+
+      return res(data)
+    })
+  })
+}
+
+// ---------------------------------------------------------------------------
+// Audio
+// ---------------------------------------------------------------------------
+
+const imageCodecs = new Set([
+  'ansi', 'apng', 'bintext', 'bmp', 'brender_pix', 'dpx', 'exr', 'fits', 'gem', 'gif', 'jpeg2000', 'jpgls', 'mjpeg', 'mjpegb', 'msp2',
+  'pam', 'pbm', 'pcx', 'pfm', 'pgm', 'pgmyuv', 'pgx', 'photocd', 'pictor', 'png', 'ppm', 'psd', 'sgi', 'sunrast', 'svg', 'targa', 'tiff',
+  'txd', 'webp', 'xbin', 'xbm', 'xface', 'xpm', 'xwd'
+])
+
+async function isAudioFile (path: string, existingProbe?: FfprobeData) {
+  const videoStream = await getVideoStream(path, existingProbe)
+  if (!videoStream) return true
+
+  if (imageCodecs.has(videoStream.codec_name)) return true
+
+  return false
+}
+
+async function hasAudioStream (path: string, existingProbe?: FfprobeData) {
+  const { audioStream } = await getAudioStream(path, existingProbe)
+
+  return !!audioStream
+}
+
+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: forceNumber(audioStream['bit_rate'])
+      }
+    }
+  }
+
+  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
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Video
+// ---------------------------------------------------------------------------
+
+async function getVideoStreamDimensionsInfo (path: string, existingProbe?: FfprobeData) {
+  const videoStream = await getVideoStream(path, existingProbe)
+  if (!videoStream) {
+    return {
+      width: 0,
+      height: 0,
+      ratio: 0,
+      resolution: VideoResolution.H_NOVIDEO,
+      isPortraitMode: false
+    }
+  }
+
+  if (videoStream.rotation === '90' || videoStream.rotation === '-90') {
+    const width = videoStream.width
+    videoStream.width = videoStream.height
+    videoStream.height = width
+  }
+
+  return {
+    width: videoStream.width,
+    height: videoStream.height,
+    ratio: buildAspectRatio({ width: videoStream.width, height: videoStream.height }),
+    resolution: Math.min(videoStream.height, videoStream.width),
+    isPortraitMode: videoStream.height > videoStream.width
+  }
+}
+
+async function getVideoStreamFPS (path: string, existingProbe?: FfprobeData) {
+  const videoStream = await getVideoStream(path, existingProbe)
+  if (!videoStream) 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 getVideoStreamBitrate (path: string, existingProbe?: FfprobeData): Promise<number> {
+  const metadata = existingProbe || await ffprobePromise(path)
+
+  let bitrate = metadata.format.bit_rate
+  if (bitrate && !isNaN(bitrate)) return bitrate
+
+  const videoStream = await getVideoStream(path, existingProbe)
+  if (!videoStream) return undefined
+
+  bitrate = forceNumber(videoStream?.bit_rate)
+  if (bitrate && !isNaN(bitrate)) return bitrate
+
+  return undefined
+}
+
+async function getVideoStreamDuration (path: string, existingProbe?: FfprobeData) {
+  const metadata = existingProbe || await ffprobePromise(path)
+
+  return Math.round(metadata.format.duration)
+}
+
+async function getVideoStream (path: string, existingProbe?: FfprobeData) {
+  const metadata = existingProbe || await ffprobePromise(path)
+
+  return metadata.streams.find(s => s.codec_type === 'video')
+}
+
+// ---------------------------------------------------------------------------
+// Chapters
+// ---------------------------------------------------------------------------
+
+async function getChaptersFromContainer (options: {
+  path: string
+  maxTitleLength: number
+  ffprobe?: FfprobeData
+}) {
+  const { path, maxTitleLength, ffprobe } = options
+
+  const metadata = ffprobe || await ffprobePromise(path)
+
+  if (!Array.isArray(metadata?.chapters)) return []
+
+  return metadata.chapters
+    .map(c => ({
+      timecode: Math.round(c.start_time),
+      title: (c['TAG:title'] || '').slice(0, maxTitleLength)
+    }))
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  getVideoStreamDimensionsInfo,
+  getChaptersFromContainer,
+  getMaxAudioBitrate,
+  getVideoStream,
+  getVideoStreamDuration,
+  getAudioStream,
+  getVideoStreamFPS,
+  isAudioFile,
+  ffprobePromise,
+  getVideoStreamBitrate,
+  hasAudioStream
+}