KR100224805B1 - Video tape format for providing special effects capabilities - Google Patents

Abstract

The digital video information recorded on the recording medium scans a part of the video signal field stored in the recording medium during the scanning period of the recording medium, reads data including the video signal information and the video signal identification information during the scanning period, and the video signal. Read from the medium by storing at least a portion of the video signal information in the field memory at the location identified by the identification information.

Description

[Name of invention]

Video tape format with special effects

[Brief Description of Drawings]

Other features of the present invention will become apparent from the following detailed description of the preferred embodiments described in connection with the accompanying drawings.

1 shows a high-speed scan trace of a playhead in a conventional video recording system as described above,

2 shows a sinusoidal trace for recording and reading video information,

3 shows a trace of recorded tracks of video information generating an exemplary fast forward special effect mode,

4 (a) through 4 (c) illustrate the use of field memory to implement the special effects mode of operation.

Detailed description of the invention

[Technical Field]

The present invention relates generally to video recording systems, and more particularly to a system for providing video special effects while playing back recorded video information.

[Background]

In general, a television image is composed of snapshot-like frames that accept only video signal information in a horizontal scanning line composed of synchronization signals. For example, according to the National Television Systems Committee (NTSC) standard method, each frame of video information consists of 525 horizontal scanning lines. Moreover, according to this NTSC standard, the frame repetition rate is 30 frames per second or 15,750 horizontal scan lines per second.

In practice, not all video information in a complete television frame is played back at the receiver simultaneously, but instead a technique known as interlaced scanning is used to reduce flicker. In interlaced scanning, each frame of video information is divided into two interlaced fields, each field consisting of a raster array of odd or even horizontal scan lines. Thus, if the horizontal scan lines of a 525-line NTSC frame are numbered consecutively from the top of the raster array, the odd-numbered fields will consist of horizontal scan lines with 1, 3, 5, ..., 525 frame line numbers. Similarly, the even field will contain horizontal scan lines with frame numbers 2, 4, ..., 524. According to the NTSC format, the field repetition rate is 60 fields per second.

In a video recording system using a magnetic video tape as a recording medium, recording of each television field using only one track on a recording medium tracked by a helical format recording head is common. It is widely used for relatively slow moving tapes, since it provides a high head-to-tape relative speed, usually greater than 1 meter per second). 1 shows an example of four fields of video information recorded on parallel tracks 2, 4, 6 and 8, respectively, extending at a small angle with respect to the longitudinal edge of the magnetic videotape 10. FIG.

Of course, it is well known that video tape recorders can provide special effects. One common special effect is the still property of freezing recorded television frames for viewing during playback. Other common special effects have low and high speed scanning characteristics.

The slow scan feature, which allows the viewer to find recorded video information at a slower speed than normal playback speed, is achieved by reducing the relative speed between the playhead and the magnetic videotape.

The high-speed scanning feature in which the viewer can find recorded video information at a speed faster than normal playback speed is obtained by increasing the relative speed between the playhead and the magnetic videotape. For example, FIG. 1 shows a case of high-speed scanning of a magnetic videotape by a helical playhead along the acceleration path 12. In practice, high-speed scanning often distorts moving images and changing scenes, as the playhead reads information from different tracks (ie, fields) during high-speed scanning, as shown in FIG.

[Initiation of invention]

In general, the present invention relates to a system for performing special effects such as still, slow scan, and fast scan of recorded video information. In one preferred embodiment, the present invention scans a portion of a video signal screen stored on a recording medium during one scanning period on the recording medium to read digital video information from the recording medium, and the data (video signal information and Video signal identification information) and store at least a portion of the video signal information in a field memory at a location identified by the video signal identification.

Best Mode for Carrying Out the Invention

2 shows an example of a trace 13 of a typical sinusoidal waveform formed by a laser beam moving across an optical recording tape 14 moving slowly in the direction of an arrow 18 manipulated by a torsion resonance-mirror galvanometer. It should be noted that video signal information can be recorded in both directions across the tape. That is, recording can be done from left to right and right to left across the tape.

Referring to FIG. 2, it should be noted that a torsional galvanometer provides an essentially discrete record. That is, recording occurs when the laser beam traces over the recording medium and does not occur during the period at the end of each trace instead of stopping and redirecting the scanning motion of the laser beam. Therefore, in the active portion 17 of the sinusoidal trace 13, the trace speed can be defined as the portion of the trace that is at least half of the value at the center of the trace.

In practice, the active interval of each trace occupies about 87 percent of the peak-to-peak amplitude of the trace and represents approximately 67 percent duty cycle. Television video information encoded in digital form can be recorded in the active section 17. Other parts of the trace are recorded at too low a rate to record high frequency video signals, but can be used to record low frequency information.

With further reference to FIG. 2, it should be noted that the active sections 17 are nearly perpendicular to the longitudinal edge of the tape 14. The direction of this recorded video information can be compared with the recorded track of FIG. 1 which is not substantially perpendicular to the longitudinal edge of the tape. As described below, the traces in the nearly vertical direction enable improved performance of special effects such as still, slow scan, and fast scan of the recorded video information.

3 is a video of the recorded information recorded on the optical recording tape (14). The formatting arrangement is shown spatially and temporally separated between audio and control information. It should be noted that optical deflection mechanisms, such as the resonant mirror galvanometer described above, can be used to record video information in an active section 17 of traces extending substantially horizontally across the tape. Thus, in the exemplary embodiment, the video information recorded in each active section 17 consists of the entire horizontal scanning line of the integer television field. More specifically, the first horizontal active section 17 has four horizontal scan lines 2, 4, 6 and 8 from an even field of one television video frame, and the second horizontal active section 17 It has four consecutive horizontal scanning lines 10, 12, 14 and 16 from the same field.

Referring also to FIG. 3, it should be noted that the left and right ends of each active scan interval are used to record low frequency control data. The low frequency data may include, for example, information identifying the line number of the first horizontal scan line stored in the active scanning section for tracking the data. In addition, the audio information accompanying the recorded video information may be encoded in a digital form and recorded in the left and right ends 13 and 15 of the respective active scan sections.

3 also shows a fast forward scanning path 20 that the playhead 25 can track along the tape 14. In the illustrated embodiment, for example, the fast forward scanning speed is about 10 times faster than the normal speed of the recording head. During the high speed scan shown, the playhead moves on top of the horizontal scan lines 18, 26, 28, 36, and the like.

Remembering Figure 3, the relative speed between the playhead and the optical tape 14 can be selected such that all horizontal scan lines in the frame of video information recorded on the tape are read once before any horizontal scan line is read twice. Should work. For example, when the fast scan playback speed is about 10 times faster than the normal playback speed, about 20 frames of video information are tracked by the playhead to read all the horizontal scan lines at least once.

It can be seen that the low frequency information recorded at the beginning and / or end of each active scan of the optical recording tape can cause the playhead to identify the horizontal scan lines to be read. In addition, when the playhead is interlaced from the horizontal scan line to the horizontal scan line (e.g., from the scan line 18 to the scan line 36), the regeneration system intercepts the multiple horizontal scan lines based on the selected tape speed. It will be deduced. The inferred and sensed information may be used as described below in conjunction with FIGS. 4 (a) to 4 (c) for demonstrating clarity of television special effect characteristics.

In FIGS. 4 (a) to 4 (c), the system includes a field memory 30 having an addressable location for storing video information from even and odd horizontal scan lines of a complete frame of video information. It may include. As shown, the field memory can be used in three different modes of operation: normal playback mode, still special effects mode and fast vision mode.

In the normal playback mode shown in Fig. 4A, the playback head is moved along the optical tape at the same speed as the recording head, and the recorded video information is read out from each recorded line of the tape. More specifically, in the above-mentioned example, in addition to FIG. 3, the playhead first reads the horizontal scan lines 2, 4, 6, and 8 from the first recorded active section and then horizontally from the second recorded active section. Scan lines 16, 14, 12, 10) in sequence. The reading mechanism buffers the read information and the buffered information is provided to the field monitor 30 or the video monitor in the exact reverse order (ie 10, 12, 14, 16). Thus, in the normal playback mode, the field memory is continuously updated.

4 (b) shows a pause frame in which the movement of the optical tape is stopped and video information in the field memory read out by the display. Since the information is not updated continuously in the field memory, the information to be read remains the same, so that the display of any information remains unchanged.

4 (c) shows the use of the field memory 30 for fast forward scanning in which only video information that has been stored in the field buffer is read out for display, in which case the playhead is at a normal playback speed. Since the optical tape is tracked at a substantially greater rate, only a portion of the television horizontal scan lines are output in each recorded frame and used to update the address position in the field memory 30. However, although the traces on adjacent frames read completely newly recorded video information, this readout information can be read using the identification information recorded at the edge of the optical record carrier to provide a suitable position in the field memory 30 (ie, another horizontal position). Position corresponding to the scan lines). The previously read video information is maintained for address positions in the field memory that have not been updated for the currently read frame. Thus, while the entire field memory is read for display, the information stored therein is finely updated using video information written to and read from many frames stored on the optical tape.

The use of field memory as described above provides a clear still television picture. In addition, the recorded video information can be displayed in high quality in the fast forward scanning mode with little or no motion in the recorded image, and the recorded picture is displayed in the fast forward scanning mode in which the first recorded picture depicts the motion. It can be improved.

It will be appreciated that the present invention may be embodied in other specific forms without departing from its spirit and essential characteristics, and therefore, the embodiments presented herein are to be considered in all respects as illustrative and not restrictive. The scope of the invention is to be conveyed by the appended claims rather than the foregoing description, and all changes that come within the meaning, range and equivalents of the invention are intended to be embraced within the scope of the invention. For example, if modifications are made to apply a format in which video information is recorded on a tape, the present invention can be used in a conventional magnetic tape.

[Industrial use]

As described above, the present invention can be applied to a system for executing video special effects while playing back recorded video information. More specifically, the present invention is used in a system for reading and playing back digital video information from an optical recording medium.

Claims (16)

Scanning a portion of the video signal field stored in the recording medium during a scanning period on the recording medium, reading data including video signal information and video signal identification information during the scanning period, and reading the video signal identification information. And storing at least a portion of the video signal information in a field memory at the location identified by the digital video information recorded on the recording medium moving at a predetermined speed. 2. The recording medium of claim 1, wherein the scanning step is performed at a speed relative to the recording medium speed such that all video signal information related to the video signal field is read out for successive scanning periods. A method of reading recorded digital video information. The method of claim 1, wherein the scanning step is performed at a scanning speed relative to a recording medium speed that allows less video signal information to be read than all video signal information associated with the video signal field during successive scanning periods. A method of reading digital video information recorded on a recording medium moving at a predetermined speed. 4. The recording medium of claim 3, wherein the scanning speed is selected relative to the recording medium speed such that video signal information associated with a single field of read video signal information is obtained from a continuous video signal field. To read the digital video information recorded in the. 2. The method of claim 1, further comprising updating the video signal information stored in the field memory as a continuous field of the scanned video signal information. How to get poisoned. 6. The method of claim 5, wherein the continuous field of stored video information corresponds to a continuous field of video information recorded on a recording medium. . 6. The digital recorded on a recording medium moving at a predetermined speed according to claim 5, wherein the continuous field of stored video information includes video signal information from a plurality of consecutive fields of video information recorded on the recording medium. How to read video information. 6. The method of claim 5, wherein the entire field of video signal information stored in the field memory is updated with each successive field of stored video information. 9. The digital video information recorded on a recording medium moving at a predetermined speed according to claim 8, wherein the video signal information stored in the field memory is updated in a predetermined order by television line numbers associated with the recorded video information. How to get poisoned. 10. The method of claim 8, wherein the video signal information is updated from the lowest television line number in the field to the highest television line number. Storing a part of the video signal information of one field in the first portion of the track of the optical recording medium; and storing the television line number information in the track of the optical recording medium. How to store digital video information. Means for responding to a scan signal for reading digital video information stored on an optical record carrier, the information further comprising information identifying at least one horizontal scanning line number associated with the video information, and storing the digital video information as a field of video signal information. Means for recording digital video information on an optical recording medium. 13. The digital video recording medium as claimed in claim 12, wherein the digital information from the plurality of fields of the video signal recorded on the optical recording medium is used for updating a single field of video signal information to the storage means. System for recording information. Storing the information in the optical record carrier track to identify at least one of the video signal field scan lines stored in the optical record carrier track in a track of the optical record carrier. And recording the digital video information on the optical recording medium. 15. The method of claim 14, wherein said information identifies a first video signal field scan line stored on an optical record carrier scan line. 16. The method of claim 15, wherein the information further identifies a last video signal field scan line stored in the optical record carrier track.