Were you earning good income from YouTube’s Instream ad options ?
But now, pre-roll ads, Mid-roll ads and post-roll ads options are missing from your account ?
You can enable these ads only for videos with atleast 10 min of content.
Once you upload the video and the video is processed, goto Video Manager and click on the edit link beside your video.
Next, goto Monetization tab and then select pre-roll, Mid-roll and post-roll ads.
Another good news is, we need not enable Monetization individually for all the videos. Now you can set default setting, which will be pre-selected for all your future uploads.
To set your video’s default options goto: your youtube default settings