JPS6048948B2 - Video signal recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, when a video signal is recorded on a magnetic tape by forming diagonal tracks Tv, an absolute address is given to each frame of the video signal, and this absolute address is code and extend the code signal in the longitudinal direction of the tape.
That is, recording is performed on an auxiliary track TQ parallel to the audio track TA and the control track Tc.

Note that the figure shows a case where one track Tv is formed for one field of the video signal. A specific example of this is SMPTE time code.

As shown in Figure 2, one frame has 80 bits, so the bit frequency is 2.4kHz, and of these 80 bits, 32 bits are used as a time code, and 32 bits are used for the user. The 16 bits are used as empty bits, and the 16 bits are used as a zinc word.

The 32-bit time code is composed of a frame code, a second code, a minute code, and an hour code, and is designed to indicate what hour, minute, second, and number frame.
Each is divided into two parts of 4 bits, and 4 user bits are inserted between each part.

The 16-bit zinc word indicates that the tape is running in the forward direction and therefore this SIVIPTE time code signal is
The SMPTE time code signal is read out in the direction shown by arrow R, or the tape is running in the opposite direction, and therefore this SMPTE time code signal is read out in the direction shown by arrow R. The time code can be read without error even when driving in any direction.

Note that this code signal is a so-called bi-phase signal in which information of "1" and "O" is expressed by a difference in inverted phase as shown in the figure.

In this way, the track TQ extending in the longitudinal direction of the tape
In addition, it is convenient when editing a tape to record a signal indicating the absolute address of each frame of the video signal.

However, in the case of slow or stealth motion playback, the speed of the tape is slow or the tape stops, so there is an inconvenience that the code signal recorded on the track TQ cannot be read out.

Therefore, even in the case of slow or still motion playback, the track Tv of the video signal is determined as shown with diagonal lines in FIG. 3, so that the code signal indicating the absolute address can be reliably read. It is conceivable to record a code signal Sc indicating the absolute address of this track Tv at the position shown in FIG.

In this case, as shown in the figure, this signal Sc is inserted and recorded in both the first (odd) field and the second (even) field of each frame.

The code signal inserted into the video signal and recorded on the track Tv can be in exactly the same manner as the SMPTE time code signal shown in FIG.

In this case, the code signals of the two tracks in which the first and second fields in the same frame are recorded have the same content. However, in the case of slow or stealth motion playback, the head scans across two adjacent recording tracks. In that case,
Sometimes the head straddles track 029 where the first field of a certain frame is recorded and track E29 where the second field of the same frame is recorded, as shown in FIG. , track E on which the second field of a certain frame is recorded. 9 and the track 030 where the first field of the next frame is recorded.

However, since the above-mentioned code signal Sc is inserted and recorded, for example, in a predetermined horizontal interval within the vertical retrace period of each field, the code signal Sc is As signals Sc, signals indicating the same frame are read out, and therefore, the same frame is displayed as shown in FIG. 6, which is extremely inconvenient. In view of this point, the present invention has been devised so that it is possible to determine and display which of the above-mentioned modes is being played back, so that editing and the like can be performed more efficiently.

In the present invention, not only a code signal indicating the absolute address of a frame but also a code signal indicating whether the field belongs to the first field or the second field of the same frame is recorded on the video signal track.

Specifically, for example, it is as shown in FIG.

That is, as shown with diagonal lines in the figure, in both the first and second fields, for example, the vertical synchronizing pulse period Tvp and the equalization pulse period TEp within the vertical retrace period are excluded. A code signal is inserted into a video section after the burst signal SB in a predetermined horizontal section. This code signal has, for example, 80 bits like the SMPTE time code signal shown in FIG. 2, and its bit frequency FB is, for example, an integer fraction of the color subcarrier transmission frequency Fsc (=3.58 MHz), for example, one. If the horizontal frequency is FH) and the vertical frequency is Fv, then there is a relationship of 455455 x 525 f, c = -FH = -Fv...Mountain 24, therefore, FB = -Fsc... (2) When 7455f B=-FH (3), 80 bits easily fit within the video section of the horizontal section.

Of the 80 bits, 32 bits are the time code,
32 bits are used as user bits, and 16 bits are used as a sync word.

The arrangement relationship between time code and user bits is S in Figure 2.
It may be the same as that of the MPTE time code signal. The sync word also comes at the beginning, that is, immediately after the burst signal SB. The position of the head of this sync word, ie, the start position of the code signal, is always a constant time T from the horizontal synchronizing pulse PH. I'll try to get to where I am. In addition, in this code signal, the information of "1" and "O" may be expressed by different levels as shown in the figure, for example,
"O" is the pedestal level, "1" is 50 IREun
ITS or higher levels, respectively, can be as shown. By the way, the frame code in the figure is divided into two by the user bits in between, that is, the 4 bits on the right side of the figure are the "1" bits of the frame.
This indicates the digit "0", but since the frame is up to "30", the upper two bits of these four bits, that is, the two bits on the right side of the figure, are always "O", and are essentially the frame code. It has no role as a

For this reason, for example, as shown in the figure, these two bits are used to indicate whether the field is the first field or the second field, and a field code is inserted into these two bits. For example, the code format is "00" in the first field,
The second field is set to "0I" as shown by the broken line.
In this way, when this code signal is read out by the reading circuit, this field code is also read out at the same time.

Therefore, the frame. It is possible to detect the absolute address, that is, what hour, minute, and second frame it is, and it is also possible to determine whether it is the first field or the second field of the frame. Therefore, in the case of slow or stealth motion playback, when the head plays across two tracks in the manner shown in FIG. 4 or FIG. 5, it is necessary to identify and display which of the two tracks it is playing. Can be done.

For this purpose, for example, as shown in FIGS. 8 and 9,
Corresponding to the upper half IA and lower half IB of the screen 1, the display device 2 is provided with two display sections 2A and 2B arranged vertically.

As shown in FIG. 4, tracks 029 and E record the first and second fields of the same frame. When scanning across 9, the code signal Sc is read from track 03 of the first field and the above field code is "00".
For example, as shown in FIG. 8, the absolute address of the frame is displayed only on the display section 2A.

On the other hand, as shown in FIG. 5, the track E29 in which the second field of a certain frame is recorded and the
Track 03 where the field was recorded. When scanning across frames, the absolute addresses of the frames will be the same, and the 9th
As shown in the figure, this is displayed on the display section 2A, and the code signal Sc from track E29 of the second field is displayed.
is read out and the field code becomes "0I", the absolute address of the next frame is calculated and displayed on the display section 2B. In this way, in the case of Figure 8, it can be seen that the upper and lower halves of the screen are from the same frame, and in the case of Figure 9, the upper and lower halves of the screen are adjacent frames. It can be seen that the upper half is the previous frame and the lower half is the later frame.

Therefore, it is extremely convenient when editing or the like.

Brief Description of the Drawings Fig. 1 is a diagram showing an example of a recording pattern of a tape on which a SIVIPTE time code signal is recorded.
Figure 2 is a diagram showing the state of the SMPTE time code signal,
Figure 3 shows a tape recorded by the recording method according to the present invention.
Figures 4 and 5 are diagrams showing an example of a recording pattern, Figures 4 and 5 are diagrams for explaining the state in slow or stealth motion reproduction, Figure 6 is a diagram showing absolute address display, and Figure 7 is a diagram showing an example of a recording pattern.
The figure is a diagram showing an example of the form of a code signal in a video signal recorded by the method of the present invention, and Figures 8 and 9 are diagrams for explaining the method of displaying an absolute address by the method of the present invention. be.

Claims (1)

[Claims] 1 A video signal is recorded on a magnetic tape by forming one magnetic track for each field, and the first and second fields in the same frame as the digital signal indicating the absolute address of the frame of the video signal are recorded. A method for recording a video signal, in which a digital signal indicating which field is selected is recorded within a predetermined horizontal interval of each field.