Revert "Also use the slow path for the last packet in each frame because it may be padded"

This reverts commit f2e7995747a5ed195926e88ee494602f6a09d9cf.
Revert "Fix waiting for IDR frames"

This reverts commit 37f0abfcd1e1490315e2f321db7d313d91e29cc6.
Disable FEC to remove padding from the video stream