Merge branch 'release/2.1.0' into develop

[github/Chocobozzz/PeerTube.git] / shared / models / videos / video-resolution.enum.ts

diff --git a/shared/models/videos/video-resolution.enum.ts b/shared/models/videos/video-resolution.enum.ts
index 100fc0e6ebd2ded2d2234f1ef8bebc98094d2e88..06e0779617f908386d839c6c8b9e7ed2246fc651 100644 (file)
--- a/shared/models/videos/video-resolution.enum.ts
+++ b/shared/models/videos/video-resolution.enum.ts
@@ -1,7 +1,89 @@
+import { VideoTranscodingFPS } from './video-transcoding-fps.model'
+
 export enum VideoResolution {
+  H_NOVIDEO = 0,
   H_240P = 240,
   H_360P = 360,
   H_480P = 480,
   H_720P = 720,
-  H_1080P = 1080
+  H_1080P = 1080,
+  H_4K = 2160
+}
+
+/**
+ * Bitrate targets for different resolutions, at VideoTranscodingFPS.AVERAGE.
+ *
+ * Sources for individual quality levels:
+ * Google Live Encoder: https://support.google.com/youtube/answer/2853702?hl=en
+ * YouTube Video Info: youtube-dl --list-formats, with sample videos
+ */
+function getBaseBitrate (resolution: VideoResolution) {
+  switch (resolution) {
+    case VideoResolution.H_NOVIDEO:
+      // audio-only
+      return 64 * 1000
+
+    case VideoResolution.H_240P:
+      // quality according to Google Live Encoder: 300 - 700 Kbps
+      // Quality according to YouTube Video Info: 285 Kbps
+      return 320 * 1000
+
+    case VideoResolution.H_360P:
+      // quality according to Google Live Encoder: 400 - 1,000 Kbps
+      // Quality according to YouTube Video Info: 700 Kbps
+      return 780 * 1000
+
+    case VideoResolution.H_480P:
+      // quality according to Google Live Encoder: 500 - 2,000 Kbps
+      // Quality according to YouTube Video Info: 1300 Kbps
+      return 1500 * 1000
+
+    case VideoResolution.H_720P:
+      // quality according to Google Live Encoder: 1,500 - 4,000 Kbps
+      // Quality according to YouTube Video Info: 2680 Kbps
+      return 2800 * 1000
+
+    case VideoResolution.H_1080P:
+      // quality according to Google Live Encoder: 3000 - 6000 Kbps
+      // Quality according to YouTube Video Info: 5081 Kbps
+      return 5200 * 1000
+
+    case VideoResolution.H_4K: // fallthrough
+    default:
+      // quality according to Google Live Encoder: 13000 - 34000 Kbps
+      return 22000 * 1000
+  }
+}
+
+/**
+ * Calculate the target bitrate based on video resolution and FPS.
+ *
+ * The calculation is based on two values:
+ * Bitrate at VideoTranscodingFPS.AVERAGE is always the same as
+ * getBaseBitrate(). Bitrate at VideoTranscodingFPS.MAX is always
+ * getBaseBitrate() * 1.4. All other values are calculated linearly
+ * between these two points.
+ */
+export function getTargetBitrate (resolution: VideoResolution, fps: number, fpsTranscodingConstants: VideoTranscodingFPS) {
+  const baseBitrate = getBaseBitrate(resolution)
+  // The maximum bitrate, used when fps === VideoTranscodingFPS.MAX
+  // Based on numbers from Youtube, 60 fps bitrate divided by 30 fps bitrate:
+  //  720p: 2600 / 1750 = 1.49
+  // 1080p: 4400 / 3300 = 1.33
+  const maxBitrate = baseBitrate * 1.4
+  const maxBitrateDifference = maxBitrate - baseBitrate
+  const maxFpsDifference = fpsTranscodingConstants.MAX - fpsTranscodingConstants.AVERAGE
+  // For 1080p video with default settings, this results in the following formula:
+  // 3300 + (x - 30) * (1320/30)
+  // Example outputs:
+  // 1080p10: 2420 kbps, 1080p30: 3300 kbps, 1080p60: 4620 kbps
+  //  720p10: 1283 kbps,  720p30: 1750 kbps,  720p60: 2450 kbps
+  return baseBitrate + (fps - fpsTranscodingConstants.AVERAGE) * (maxBitrateDifference / maxFpsDifference)
+}
+
+/**
+ * The maximum bitrate we expect to see on a transcoded video in bytes per second.
+ */
+export function getMaxBitrate (resolution: VideoResolution, fps: number, fpsTranscodingConstants: VideoTranscodingFPS) {
+  return getTargetBitrate(resolution, fps, fpsTranscodingConstants) * 2
 }