Context: In November 2008, 720p HD support was added. At the time of the 720p launch, the YouTube player was changed from a 4:3 aspect ratio to a widescreen 16:9. With this new feature, YouTube began a switchover to H.264/MPEG-4 AVC as its default video compression format. In November 2009, 1080p HD support was added. In July 2010, YouTube announced that it had launched a range of videos in 4K format, which allows a resolution of up to 4096×3072 pixels. In June 2015, support for 8K resolution was added, with the videos playing at 7680×4320 pixels.

Question: When was 720p HD support added to youtube?
Answer: In November 2008

Question: What did youtube change its screen format to from 4:3?
Answer: widescreen 16:9

Question: What video format support was added in 2009?
Answer: 1080p HD

Question: What is the highest resolution of video supported by youtube?
Answer: 8K resolution

Question: What is the name of the format that has dimensions of 4096×3072 pixels?
Answer: 4K

Question: What ratio was YouTube played changed to in July 2008?
Answer: Unanswerable

Question: When did YouTube begin a switchover to H.246/MPEG-4?
Answer: Unanswerable

Question: What was added in July 2009?
Answer: Unanswerable

Question: What was added in November 2015?
Answer: Unanswerable