From 06bcfbd9f715055f2f00bb66149b1dba926d007a Mon Sep 17 00:00:00 2001
From: Rigel Kent <sendmemail@rigelk.eu>
Date: Tue, 14 Jan 2020 23:34:03 +0100
Subject: Downsample to the closest divisor standard framerate

---
 server/controllers/api/videos/index.ts         |  3 ++-
 server/helpers/ffmpeg-utils.ts                 | 11 +++++++----
 server/initializers/constants.ts               |  2 ++
 server/middlewares/validators/videos/videos.ts |  2 +-
 4 files changed, 12 insertions(+), 6 deletions(-)

(limited to 'server')

diff --git a/server/controllers/api/videos/index.ts b/server/controllers/api/videos/index.ts
index 8d4ff07eb..a593f7076 100644
--- a/server/controllers/api/videos/index.ts
+++ b/server/controllers/api/videos/index.ts
@@ -12,7 +12,8 @@ import {
   VIDEO_CATEGORIES,
   VIDEO_LANGUAGES,
   VIDEO_LICENCES,
-  VIDEO_PRIVACIES
+  VIDEO_PRIVACIES,
+  VIDEO_TRANSCODING_FPS
 } from '../../../initializers/constants'
 import {
   changeVideoChannelShare,
diff --git a/server/helpers/ffmpeg-utils.ts b/server/helpers/ffmpeg-utils.ts
index 00c32e99a..78f9ba07c 100644
--- a/server/helpers/ffmpeg-utils.ts
+++ b/server/helpers/ffmpeg-utils.ts
@@ -286,13 +286,16 @@ export {
 
 async function buildx264Command (command: ffmpeg.FfmpegCommand, options: TranscodeOptions) {
   let fps = await getVideoFileFPS(options.inputPath)
-  // On small/medium resolutions, limit FPS
   if (
+    // On small/medium resolutions, limit FPS
     options.resolution !== undefined &&
     options.resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
-    fps > VIDEO_TRANSCODING_FPS.AVERAGE
+    fps > VIDEO_TRANSCODING_FPS.AVERAGE ||
+    // If the video is doesn't match had standard
+    !VIDEO_TRANSCODING_FPS.HD_STANDARD.map(value => fps % value).includes(0)
   ) {
-    fps = VIDEO_TRANSCODING_FPS.AVERAGE
+    // Get closest standard framerate by modulo: downsampling has to be done to a divisor of the nominal fps value
+    fps = VIDEO_TRANSCODING_FPS.STANDARD.sort((a, b) => fps % a - fps % b)[0]
   }
 
   command = await presetH264(command, options.inputPath, options.resolution, fps)
@@ -305,7 +308,7 @@ async function buildx264Command (command: ffmpeg.FfmpegCommand, options: Transco
 
   if (fps) {
     // Hard FPS limits
-    if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = VIDEO_TRANSCODING_FPS.MAX
+    if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = VIDEO_TRANSCODING_FPS.HD_STANDARD.sort((a, b) => fps % a - fps % b)[0]
     else if (fps < VIDEO_TRANSCODING_FPS.MIN) fps = VIDEO_TRANSCODING_FPS.MIN
 
     command = command.withFPS(fps)
diff --git a/server/initializers/constants.ts b/server/initializers/constants.ts
index e01ab8943..64803b1db 100644
--- a/server/initializers/constants.ts
+++ b/server/initializers/constants.ts
@@ -310,6 +310,8 @@ let CONTACT_FORM_LIFETIME = 60000 * 60 // 1 hour
 
 const VIDEO_TRANSCODING_FPS: VideoTranscodingFPS = {
   MIN: 10,
+  STANDARD: [24, 25, 30],
+  HD_STANDARD: [50, 60],
   AVERAGE: 30,
   MAX: 60,
   KEEP_ORIGIN_FPS_RESOLUTION_MIN: 720 // We keep the original FPS on high resolutions (720 minimum)
diff --git a/server/middlewares/validators/videos/videos.ts b/server/middlewares/validators/videos/videos.ts
index 6733d9dec..00ee375cb 100644
--- a/server/middlewares/validators/videos/videos.ts
+++ b/server/middlewares/validators/videos/videos.ts
@@ -81,7 +81,7 @@ const videosAddValidator = getCommonVideoEditAttributes().concat([
       duration = await getDurationFromVideoFile(videoFile.path)
     } catch (err) {
       logger.error('Invalid input file in videosAddValidator.', { err })
-      res.status(400)
+      res.status(422)
          .json({ error: 'Invalid input file.' })
 
       return cleanUpReqFiles(req)
-- 
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