Big Market Research, Digital Pre-Roll and In-Stream Video Avails Market Size, Share, Forecast, Trends, Analysis, Growth, Segment, Global 2005-2016. Read full report @ br Digital pre-roll and in-stream video inventory is expanding at a 20.3 rate in 2013, while corresponding media spend is expected to increase 37.8 over the calendar year. This reportÕs analytics attributes increased video spend to higher sellout rates sector-wide--even as insertion frequencies rise--to marketers who are buying scale, including campaigns against YouTubeÕs expansive library and inside social networking environments strengthened by greater inventory transparency.