diff --git a/server/helpers/ffmpeg-utils.ts b/server/helpers/ffmpeg-utils.ts
index a4d02908d..f85b9f316 100644
--- a/server/helpers/ffmpeg-utils.ts
+++ b/server/helpers/ffmpeg-utils.ts
@@ -56,7 +56,7 @@ export type AvailableEncoders = {
 // ---------------------------------------------------------------------------
 
 function convertWebPToJPG (path: string, destination: string): Promise<void> {
-  const command = ffmpeg(path)
+  const command = ffmpeg(path, { niceness: FFMPEG_NICE.THUMBNAIL })
     .output(destination)
 
   return runCommand(command)
@@ -67,7 +67,7 @@ function processGIF (
   destination: string,
   newSize: { width: number, height: number }
 ): Promise<void> {
-  const command = ffmpeg(path)
+  const command = ffmpeg(path, { niceness: FFMPEG_NICE.THUMBNAIL })
     .fps(20)
     .size(`${newSize.width}x${newSize.height}`)
     .output(destination)
diff --git a/server/initializers/constants.ts b/server/initializers/constants.ts
index 0b4b41273..a78a66d78 100644
--- a/server/initializers/constants.ts
+++ b/server/initializers/constants.ts
@@ -362,8 +362,8 @@ const VIDEO_RATE_TYPES: { [ id: string ]: VideoRateType } = {
 const FFMPEG_NICE: { [ id: string ]: number } = {
   // parent process defaults to niceness = 0
   // reminder: lower = higher priority, max value is 19, lowest is -20
-  THUMBNAIL: 2, // low value in order to avoid blocking server
-  LIVE: 9, // prioritize over VOD
+  LIVE: 5, // prioritize over VOD and THUMBNAIL
+  THUMBNAIL: 10,
   VOD: 15
 }