Encoding Discussion Megathread (ffmpeg, Handbrake, AV1, etc...)

[TheDreadPirate]

Actually "-bf 39" is a valid value. The forum post I read stated it has to be lower than the look_ahead_depth and recommended a bf value of 39. It was also the thread that recommended extra_hw_frames and look_ahead_depth be 40. I set it to 16, based on what the ffmpeg documentation said was the highest valid value, and the file size difference is pretty significant.

Code:

-rw-rw-r--  1 chris chris    24054028429 Dec  3 12:41 'The Lord of the Rings - The Return of the King (2003)-bf16.mkv'
-rw-rw-r--  1 chris chris    20396465931 Dec  3 13:59 'The Lord of the Rings - The Return of the King (2003)-bf39.mkv'
-rw-r--r--  1 chris chris    52982399272 Dec  2 17:25 'The Lord of the Rings - The Return of the King (2003).mkv'

When I get home, I will see if there is a perceivable difference in quality. I'm not sure why a higher bf would result in a lower bit rate. The description implies that a lower number reduces the number of frames between b-frames. B-frames are supposed to be more efficient.