Issue: After Effects CC, Premiere Pro CC, and Adobe Media Encoder CC do not include exporters for creating FLV and F4V files.
After Effects CC 2014 (13.0) and later, Premiere Pro CC 2014 (8.0) and later, and Adobe Media Encoder CC 2014 (8.0) and later no longer include the exporters.
To create FLV or F4V files for some legacy workflows, keep the previous versions—Adobe Media Encoder CC (7.2) and After Effects CC (12.2.1)—installed alongside the current versions. Then, you can start the previous version of the application whenever you need to transcode or export a file in one of these legacy formats.
We removed the exporters for FLV and F4V files from the Adobe video applications (Adobe Media Encoder, After Effects, and Premiere Pro) because maintaining these obsolete exporters was a large amount of work, and we could better spend that effort on developing new features and fixing bugs in areas that are used by more people.
We are still committed to creating video files that play well in Flash Player, and that is why we are focusing our efforts on the H.264 (.mp4) exporter, which is currently recommended by the Adobe Flash team.
You can still import videos in FLV and F4V formats into After Effects and Adobe Media Encoder. You can still import videos in the F4V format into Premiere Pro. If you want to create a video to play in Flash Player, use H.264 (.mp4), not the obsolete FLV or F4V formats.
This has been the recommendation from the Adobe Flash team dating back to Flash Player 9.