How to jump to the exact time interval? (What is Keyframe Search?)

[Leif]

I've tried setting the jump intervals (rewind using left arrow key) to 1 and to 2 seconds. But it almost always rewinds at least four seconds. I'd really appreciate a fix for this - very essential for my students, actually. GOM player does this perfectly but I'd like to stick to KMPlayer, which in so many respects is much superior to the rest of the media players. :)

[formuller]

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[Leif]

Thanks a lot! Seems to work OK! Could you please expand a little on the meaning of those two items? I'm translating KMP into Swedish and need all the help I can get. And this I'm afraid I don't fully understand. :(

[z]

Keyframe
In video compression, a key frame is a frame encoded without reference to any images in another frame, meaning it contains the entire image as it appears on that frame. In this context, it is also often referred to as an intra frame or I-frame. It is often followed by one or more inter frames which are calculated from the preceding key frame.

In non-linear digital video editing as well as in video compositing software, a key frame is a frame used to indicate the beginning or end of a change made to the signal. For instance, a key frame could be set to indicate the point at which audio will have faded up or down to a certain level.
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Simply speaking, Keyframe is a complete frame but heavily compressed. Keyframe search changes a position of playing very fast but it is not possible to seek to the exact time interval. The reason of fast seeking with keyframe search is that additional decoding procedure is not required to access the keyframes. When enabled, the keyframe search will find the adjacent keyframe from the current position.


Frame:

The basic source of a movie. One frame represents one image. A movie usually runs at 24 frames per seconds, so it has 24 different images per second. Imagine 24 images with a bird on it, in the first image it's on the left, then it gradually movies somewhat to the right. On the 24th frame the bird is on the right end of the image. Imagine these 24 images being played in sequence fast enough and it looks like a bird would fly from left to right to the human eye.
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Delta frame
In interframe coding, a frame that provides an incremental change from the key frame.

Interframe coding
In video compression, the coding of the differences between frames. Interframe coding often provides substantial compression because in many motion sequences, only a small percentage of the pixels are actually different from one frame to another. However, it depends entirely on the content. A room full of people dancing will not compress as well as a person sitting in a chair talking.

With interframe coding, a video sequence is made up of keyframes that contain the entire image. In between the keyframes are delta frames, which are encoded with only the incremental differences. Depending on the compression method, a new keyframe is generated based on a set number of frames or when a certain percentage of pixels in the material has changed. See intraframe coding.
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[Leif]

Many thanks, both of you! I'm very impressed with this forum. And, of course, with KMPlayer!