Further Possibilities and Optimizations
1. Variable Start Jumping Distance and Initial Position
The seek system can be further optimized in differentiating if at the beginning of the search (thus, during first press of a jump key) the recording has been selected only but is still not in replay mode, or if the search is started out of replay mode.
If the user presses a jump key during playing a recording, he perhaps wants to skip only a small part, e.g. to watch a short sequence again, if he jumps reverse. If he jumps forward, he probably wants to skip only a commercial or a longer applause. The initial jumping distance of ten minutes would not be optimal here, because this would mean to drift away too far. Therefore, in this case the searchsystem can start with a substantially smaller start jumping distance of one minute or less. In order to reach, nevertheless, farer destinations also fastly, the system can use a higher factor of e.g. 1.6 or 1.7 instead of 1.4 for increasing the jumping distance. (The factor, however, should be considerably under two, because otherwise the search characteristics deteriorate.)
If, by contrast, the user has only selected a recording but has still not started play, he can assume that the searched destination is rather not at the beginning of the recording. In such a case, the searchsystem can work more effective if started with a higher jumping distance (maybe even with the maximum jumping distance).
This possibility allows the user to test the content of several longer recordings very fastly by simply selecting them one after the other and respectively pressing the forward jumping key some times. Thus, only a few seconds per recording are required to find out which films are contained on it. This is how e.g. the hard disk can easily be cleared by shortly searching all recordings and deleting all those which are not required any more. The possibilities with currently available devices require approx. 20 to 30 times more!
Furthermore, the system in this case (if play has still not been started) can decide, which of both jump keys is pressed at first. If the forward jump key is pressed at first, search starts at the beginning of recording. If, however, the reverse jump key is pressed at first, the system can start to search at the end of recording and jump back from there. This option is above all interesting if the user knows that the searched position is rather to find in the second half, thus in the back part of recording. But the system should immediately execute the first reverse jump here, because a jump at the end of recording does not make sense, as it is impossible to further replay there. If, however, the user starts to search at the beginning of recording, it would be eventually better to start search at the very beginning (time zero) of recording, and the first jump is initiated only during repeated press of the forward jump key.
As it is easier to orient by moving pictures than by a still one, the system should automatically switch into replay mode after each jump, even if the replay mode has still not been started in advance.
2. Automatic Reset
If a certain position (e.g. the beginning of a film) is searched by using the searchsystem, the user can see at first sight after each jump if the searched film has already started or not yet. Thus, he knows at once if he needs to jump further forward or reverse. Therefore, this two-key searchsystem is very fastly to operate. If none of the two jump keys is pressed any more for some seconds, this is the sign that the user has found the searched position. The search logic can now execute an automatic reset, i.e. all variables (jumping distance, seek area limitation etc.) are reset again to the initial values. Pressing the jump keys again means that a new search is started.
3. On Screen Display
For a better usability the searchsystem can fade in a horizontal bar in the picture after pressing, which symbolizes the current position. (The left margin of the picture corresponds to the beginning of recording and the right margin to the end. And the position display which is somewhere in between shows the user the current position.). In addition, the current seek area can also be shown by a bar, with e.g. the current position only being displayed by a small vertical line. This display appears as soon as the user presses a jump key, disappears if reset of the variables is executed (thus, a few seconds after the last keystroke). This kills two birds with one stone. On the one hand, this position display does not interfere for a long time because it disappears after a short time, and on the other hand the user can see when the searchsystem is reset to initial conditions again.
4. Reading Data in Advance
The access time to a new position is very short when it comes to DVDs and hard disks. Nevertheless, it can take half a second after pressing until the audio and video data of the new position is available, and the replay is continued at the new position. This time can be shortened, if the system calculates both possible destination positions for the next jump in advance and reads the corresponding audio and video data in the random access memory. For this purpose, a very short sequence of one or two seconds from the possible destination position on is sufficient. If the jump calculated in advance is actually executed, the corresponding audio and video data is immediately available (without any remarkable delay), and until the intermediately stored sequence of one or two seconds will be replayed, the system has enough time to read the further AV data. As there are always two possible jumping destinations at any time (depending on which of both jump keys is pressed next time), only two very short sequences need to be stored intermediately for this optimization.
5. Adaption for PC Applications
Audio and videotape recorder programs for the personal computer ususally have a smaller horizontal scroll bar, which displays the current replay position and which can be moved to any position by using the mouse. When it comes to files of a very long playing time (e.g. one hour or longer), this bar, however, does not enable any exact positioning, because the smallest move makes up several minutes. For this purpose, the system can be modified on the simpliest way, namly so that the user must simply klick right or left beside the bar, in order to jump forward or reverse. As start jumping distance (thus the very first jumping distance), no fixed time value must be used here. It would me more favourable to use a percentage value (e.g. five per cent of total playing time) as start jumping distance. This allows a rough setting by moving the bar as usually, and for exact setting it must be klicked right or left beside the bar to exactly head for the requested position.