Is it just my player, or do all DVD players have a fast forward that is, at best, maybe 10% faster than normal play mode? It seems like if I fast forward through a one minute scene, it takes 54 seconds. What good is that? Is there something about DVD playback that prevents them from speeding up the fast forward that is 4x or 5x normal speed?
It’s just your player. Every one I’ve owned has 3 FF settings, each time you press the button it goes faster.
I have a DVD player with 2X, 8X, 30X, and 100X speeds.
Another one has six fast forward settings, though none seem to be as fast as the 100X.
Do you still have your manual?
:smack:
Nevermind.
Fast forwarding is hard with DVDs, but skipping is easier.
DVD video is compressed so each frame is dependent on the previous one, except for I-frames which are “starting points” placed at every 15 frames or so. For full quality double speed playback, you’d like to drop every other frame, but you’d still have to decode the video stream as during normal playback. That’s OK if the DVD player has twice the processing capability as needed for normal playback, but that isn’t necessarily the case.
For skipping the player needs to find an I-frame in the encoded stream and show that one plus maybe an additional few frames after that. Then it can freeze the current frame while looking for the next I-frame and so on.
My cheap DVD-player can “fast forward” at 4x, 8x or 16x speed, but it is just skipping along from I-frame to iframe, producing a very jerky motion. A good player could fast-forward at full quality at any speed if it had enough processing power.
Mine does about the same thing. The first step for fast forward is 2x (I think) and pretty smooth. The next three steps are simply still-frame glimpses, further and further apart. I guess they’re selecting spaced I-frames.
Thanks for that explanation, Bagistan. I’ve always wondered about this, and now I understand why it works this way.