If a creator files a dispute, copyright owners have 30 days to manually review the video and its supposed violation and decide whether Content ID’s flag was accurate. Creators whose disputes are turned down can appeal, asking YouTube and the copyright owner to take another look at their videos. Before today, that appeal period was another 30 days. But now, YouTube is narrowing it to seven days.
Source: YouTube cuts Content ID appeal period from 30 days to seven – Tubefilter