Method and apparatus for converting video field sequences

[0001] The present invention relates to a video editing method and a video editing system in post-production, and particularly, a video editing used for editing a moving image material converted from a standard 24-frame / sec movie film. Regarding methods and video editing systems.

PROBLEM TO BE SOLVED: To generate a moving image by reproducing a continuous still image called a frame at high speed in a movie film or a video tape. For example, commercial movies are set to play 24 frames per second. On the other hand, for videotapes that comply with the television standard NTSC adopted in the United States, it is stipulated that 29.97 frames are played per second. In addition, for high-resolution video tapes that comply with the high-definition video standard SMPTE-240M, it is stipulated that 30 frames are played per second. The PAL and SECAM standards in Europe stipulate that videotapes play 25 frames per second.

[0003] In addition to the difference in frame rate, there are important differences between video playback and movie playback. That is, in the video tape, the image displayed on the screen is divided into a large number of horizontal scanning lines. The US NTSC standard has 525 scanlines, although not all are visible on the screen, while the European PAL standard has 625 scanlines. In the videotape, the scanning lines corresponding to each frame are divided into those corresponding to even-numbered fields and those corresponding to odd-numbered fields. On videotapes, one field is first recorded and then the other field is recorded in order to record a frame. Therefore, one frame in a videotape is composed of two fields. For example, in a videotape compliant with SMPTE-240M, 30 frames per second, that is, 60 fields per second are played.

[0004] Converting moving image material from cinema film to videotape is a frequent practice. A device called a telecine having such a function is known. Details of telecine are disclosed in US Pat. No. 5,428,387 by the inventor of the present application. In recent years, on the contrary, the material of the moving image recorded on the video tape is frequently converted into a movie film. In particular, by using a high-definition video editing device, such conversion can be performed without deteriorating the image quality. In either case, an interpolation between 24 frames / sec for movie film and 25, 29.97 or 30 frames / sec for videotape is required.

[0005] The standard process of interpolating the frame rate differences required when converting a 24 frame / sec movie film to a 29.97 or 30 frame / sec videotape is called 3-2 pulldown. ing. In this process, the even-numbered frames of the movie film are recorded in two consecutive fields on the videotape. The two fields are identical, except that the corresponding scanline pairs are different. On the other hand, odd-numbered frames of movie film are recorded in three consecutive fields of videotape. These three fields are also the same, except that the corresponding scan line pairs are different. In this way, a set of two frames of a movie film recorded at a frame rate of 24 frames / second, which corresponds to a playback time of 1/12 second, is converted into five fields on a videotape. The playback time of the five fields is 1/12 second for videotapes played at a frame rate of 60 fields / second, similar to movie film.

[0006] As shown in FIG. 8, field groups 125, 130, 135, 140, etc. are recorded on the videotape obtained by converting the movie film 100 by 3-2 pull-down, and each field group is, for example, a frame of the movie film 100. For example, it corresponds to frames 105, 110, 115, 120 and the like. Field groups are substantially classified into four types, and in the following, each field group will be referred to as A, B, C, and D. The A field group consists of two fields corresponding to one frame of videotape and one frame of movie film. The B field group consists of three fields, the first and second fields correspond to one frame of the videotape, the third field belongs to the next frame of the videotape, and this The three fields correspond to one frame of movie film. The C-field group consists of two fields, which belong to two different frames of videotape and also correspond to one frame of movie film. The D-field group consists of three fields, the first field belongs to one frame of the videotape, the second and third fields belong to the next frame of the videotape, and all fields. Corresponds to one frame of movie film.

[0007] In the example shown here, the following differences are observed between the A field group and the C field group. That is, the A field group and the C field group both correspond to one frame of the movie film, but the first field of the A field group is the scanning line of the first field of the videotape, that is, the even field. The first field of the C field group corresponds to the second field of the videotape, that is, the scan line of the odd field. Similar differences are found between the B field group and the D field group. That is, the first field of the B field group corresponds to the scan line of the first field of the videotape, that is, the even field, while the first field of the D field group corresponds to the second field of the videotape. Corresponds to the scanning lines of the field, that is, the odd field.

[0008] The videotape converted from the movie film by 3-2 pull-down repeats the sequence of field groups such as ABCD, ABCD, ABCD, etc. as shown in FIG. Since the first two fields of the videotape belong to the A field group, by knowing the position of the field in the videotape, you can know which field group A, B, C, or D the field belongs to. be able to. In recent videotape editing, a time code is attached to each frame. This timecode is expressed in the format of hh: mm: ss: ff, where hours are hh, minutes are mm, seconds are ss, and frames (not fields) are ff. Six sets of A, B, C and D field groups are recorded on the videotape per second, and one set of field groups corresponds to five frames, so only the video frame number ff of the time code is used. It is possible to know which field group A, B, C or D the fields constituting the frame belong to. In particular, the first frame of each second consists of two fields that make up the A field group, and the fields that make up the second frame of each second are the two fields that make up part of the B field group. , The third frame of each second consists of one field that is part of the B field group and one field that is part of the C field group. In this way, it is possible to know which field group each field belongs to.

[0009] In video editing, processing such as cut, wipe, or dissolve using two or more video sources is known. Video editing systems known in the post-production industry can perform this cut, wipe and dissolve at any frame boundary.

[0010] Below, we consider a typical video editing procedure as shown in Figure 9. In this example, the user of the video editing system is using videotape X and videotape Y converted from movie film by 3-2 pulldown. For example, a process in which a user outputs 6 frames of numbers 0 to 5 shown in FIG. 9 for copying from videotape X, and then outputs 5 frames of videotapes Y of numbers 0 to 4. Suppose you are trying to do. Since videotapes X and Y are each converted by 3-2 pull-down, frames 0 to 5 of videotape X are based on 5 frames of movie film (hereinafter referred to as 5 film frames). And consists of a sequence of field groups such as ABCDA, while frames 0-4 of videotape Y are based on four film frames and consist of a sequence of field groups such as ABCD. If this process is done by a conventional video editing system, the first six videoframes 0-5 of videotape X are copied to output videotape Z to form the first sequence, such as ABCDA. Subsequently, video frames 0 to 4 of videotape Y are copied to output videotape Z. This additional copy forms an unwanted irregular sequence, such as ABCDAABCD, on the output videotape Z, as shown in FIG.

[0011] It is assumed that the process shown in FIG. 9 is not a cut but a dissolve. That is, it is assumed that the image of the videotape X is mixed with the image of the videotape Y, and the process is performed so as to gradually change to the image of the videotape Y over time. As is clear from FIG. 9, frame 7 of the output videotape Z is composed of two fields. The first field of frame 7 on output videotape Z is the image based on the B film frame between the numbers 7 and 8 on videotape X and the B film frame between the numbers 1 and 2 on videotape Y. It is a mixture of the original image. On the other hand, in the second field of frame 7 of output videotape Z, there is an image based on the C film frame sandwiched between the numbers 7 and 8 of videotape X and B sandwiched between the numbers 1 and 2 of videotape Y. There is an inconvenience that the image based on the film frame is mixed.

[0012] As shown in the above example, even if the source videotapes X and Y are converted from the film by 3-2 pull-down and the field group consists of a complete sequence of consecutive ABCDs, video editing. In the tape output by the processing, the ABCD sequence may be disturbed and the tape may have an irregular sequence. This irregularity causes a visually perceptible adverse effect on the image when the output videotape Z is converted back to film. Even if the cut process is performed only once, the ABCD sequence shifts in the entire videotape after the cut, and it is possible to determine from the time code which field group A, B, C, or D the current field belongs to. become unable.

[0013] As a technique for avoiding such a problem, there is a method of limiting ABCD sequences to one set and performing processing such as cut, wipe, or dissolve only at the boundary of the set. A set of ABCDs has a length of 5 frames, which is equivalent to 1/6 second, and this technique severely limits the editor's intended technique, such as synchronizing video and sound effects. .. Such creativity restrictions are actually unacceptable.

[0014] [Problems to be Solved by the Invention] In view of the above problems, the present invention maintains the regularity of the ABCD sequence of the field group and enables editing processing such as cutting and dissolving without deteriorating the resolution of the image. It is an object of the present invention to provide a video editing method and a video editing system. Another object of the present invention is to solve the above-mentioned problems with the minimum necessary changes without making major changes to the conventional video editing system.

[Means for Solving Problems] In order to solve the above-mentioned problems, the video editing method according to the present invention is performed from two fields corresponding to one frame of a videotape and one frame of a movie film in a video signal obtained by 3-2 pull-down from a movie film. Consists of a first field group and three fields, the first and second fields correspond to one frame of the videotape, the third field belongs to the next frame of the videotape, these The three fields consist of a second field group that corresponds to one frame of the movie film and two fields, these two fields belong to two different frames of the videotape, and these two fields are the movie film. Consists of a third field group corresponding to one frame of, one field belongs to one frame of the videotape, the second and third fields belong to the next frame of the videotape. These three fields belong to the input sequence in which the fourth field group corresponding to one frame of the movie film and the first, second, third, and fourth field groups are arranged in a cyclic order. , In a video editing method that converts to an output sequence different from this input sequence and wipes or dissolves it from a movie film to another video signal obtained by 3-2 pull-down, each field that is sequentially input according to the input sequence is sequentially pluralized. It has a write step of cyclically writing to the field memory of the above, and a read step of cyclically reading each field from a plurality of field memories according to an output sequence. In the read step, the output sequence is a sequence of other video signals. Read each field to maintain.

[0016] Further, the video editing system according to the present invention has a first field composed of two fields corresponding to one frame of a video tape and one frame of a movie film in a video signal obtained from a movie film by 3-2 pull-down. It consists of a group and three fields, the first and second fields correspond to one frame of the videotape, the third field belongs to the next frame of the videotape, and these three fields are of the movie film. It consists of a second field group corresponding to one frame and two fields, these two fields belong to two different frames of the videotape, and these two fields correspond to one frame of the movie film. It consists of a third field group and three fields, the first field belongs to one frame of the videotape, the second and third fields belong to the next frame of the videotape, these three fields Is an output sequence different from this input sequence, in which the fourth field group corresponding to one frame of the movie film and the first, second, third, and fourth field groups are arranged in a cyclical order. In a video editing system that converts to a sequence and wipes or dissolves it from a movie film to another video signal obtained by 3-2 pulldown, a plurality of field memories and each field sequentially input according to an input sequence are sequentially input. A writing means that cyclically writes to the field memory, a reading means that cyclically reads each field from a plurality of field memories according to an output sequence, and an output sequence that maintains the sequence of other video signals to read each field. It is provided with a writing means and a control means for controlling the reading means so as to read.

[0017] Further, the video editing system for video post-production according to the present invention is composed of two fields corresponding to one frame of a video tape and one frame of a movie film in a video signal obtained from a movie film by 3-2 pull-down. The first field group consists of three fields, the first and second fields correspond to one frame of the videotape, and the third field belongs to the next frame of the videotape. The field consists of a second field group corresponding to one frame of the movie film and two fields, these two fields belong to two different frames of the videotape, and these two fields are one of the movie film. It consists of a third field group corresponding to one frame and three fields, the first field belongs to one frame of the videotape, the second and third fields belong to the next frame of the videotape, These three fields are the video signals of the input sequence in which the fourth field group corresponding to one frame of the movie film and the first, second, third, and fourth field groups are arranged in a cyclic manner. Connected to the output of the first video player, the second video player that plays the other video signal obtained from the movie film by 3-2 pull-down according to the output sequence, and the output of the first video player. A switching device connected to the output of the resequencer, the resequencer, and a second video playback device, and switching and outputting a plurality of video signals including the output of the resequencer, and a switching device connected to the output of the switching device. It includes a video recording device that records a video signal from the movie, and an editing control device that controls a first video playback device, a resequencer, a switching device, and a video recording device. Further, the resequencer is connected to the output of the video playback device and cyclics a plurality of field memories for storing the video signal for each field and each field sequentially input according to the input sequence to the plurality of field memories.

That is, in order to solve the above-mentioned problems, the present invention uses a novel device called a resequencer. The resequencer is provided with eight field storage means for storing images for one video field according to the number of frames per second based on standards such as NTSC and SMPTE-240M used in video equipment. A video playback means is connected to the input terminal of the resequencer, and the resequencer outputs a video signal from the output terminal. The resequencer has a one-to-one correspondence with the video playback means in the video editing system. For example, if the video editing system performs editing work from the three video playback means to produce the output videotape Z, three resequencers are used. A sequencer is required.

[0019] Further, the video editing system according to the present invention includes an editing controller that controls and controls the interfaces of the resequencer. The editing controller controls the resequencer to convert the signal input to the resequencer into an appropriate format, outputs a video signal in which the ABCD sequence of the field group is regularly repeated, and ABCD on the output videotape Z. A desirable video signal with a regularly repeated sequence is recorded.

[0020] By the cooperation of the editing controller and the resequencer, it is possible to edit the two video signals such as cut, wipe, and dissolve while maintaining the regularity of the ABCD sequence of the field group of the output videotape Z. Processing such as cut, wipe and dissolve can be performed in the minimum frame unit, and even if cut, wipe or dissolve is performed from any of the A, B, C and D field groups of the video signal as the material, A, B , C and D field groups, any field group can be output.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a video editing method and a video editing system according to the present invention will be described with reference to the drawings.

[0022] Hereinafter, embodiments of the invention will be described using specific names for the components of the invention for the sake of description. It will be apparent to those skilled in the art that the detailed description given below is merely an example and is not necessarily necessary for the practice of the invention. Further, in the drawings for explaining the invention, in order to clarify the invention, well-known circuits and devices are shown as block diagrams.

[0023] A video editing system to which the present invention is applied is used for video editing and the like in post production. As shown in FIG. 1, this video editing system includes an editing controller 330, and a user operates the editing controller 330 to perform editing work. In addition, this video editing system includes two or more video tape recorders (hereinafter referred to as VTRs) 300 and 320 that reproduce the video signal as the material, two or more resequencers 305 and 325, and a switching device 310. , Equipped with VTR315 for recording on output videotape Z. The VTR300 and 320 are connected to the resequencers 305 and 325, respectively, and the resequencers 305 and 325 are connected to the switching device 310, respectively. Although not shown, the video editing system typically includes a console, a video monitor device, an audio mixer, and other equipment such as speakers.

[0024] FIG. 2 shows the operation of this video editing system in an actual editing process. First, the first six videoframes of videotape X on VTR320 are as video signals of five fieldgroups (hereinafter simply referred to as fieldgroups) having a sequence of ABCDA in the first part of output videotape Z on VTR315. Recorded. On the other hand, the sequence of the first frame of the videotape Y on the VTR300 is converted from the ABCD sequence to the BCDA sequence by the resequencer 305 before being recorded on the output videotape Z. By this conversion (hereinafter, also referred to as phase conversion), the ABCD sequence is repeated on the output videotape Z.

[0025] In this way, for example, in order to convert an ABCD sequence into a BCDA sequence, the resequencer 305 performs an operation such as copying some video fields and deleting the remaining fields. For example, the first A-field group of videotape Y shown in FIG. 2 consists of two fields, which the resequencer 305 converts to a B-field group of three fields for output videotape Z. Record in. For this operation, the resequencer 305 records the first field of the A field group of videotape Y as the first and third fields of the B field group of output videotape Z and videotapes. Record the second field in the A field group for Y as the second field in the B field group for output videotape Z. Subsequently, in order to convert the B field group of the videotape Y shown in FIG. 2 into the C field group, the resequencer 305 converts three fields into two fields. This is done by removing the third field at the end of the B field group on videotape Y and reversing the order of the first two fields. The reason for changing the order of the fields in this way is that the first field in the B field group corresponds to the scan line of the even field, while the first field in the C field group is the odd field. This is because it corresponds to the scanning line of. Subsequently, the resequencer 305 similarly converts the C field group of the videotape Y into the D field group. Record the first field of the C field group of videotape Y in the first and third fields of the D field group of output videotape Z, similar to the conversion from A field group to B field group. Record the second field in the C field group on videotape Y in the second field in the D field group on output videotape Z. Finally

In the example shown in FIG. 2, the ABCD sequence recorded on the tape is converted into the BCDA sequence, but in other editing processes, the field group sequence is changed from ABCD to CDAB, or the ABCD sequence is changed to DABC. It may need to be converted to a sequence, or the ABCD sequence may be recorded on output videotape Z as is. In this way, there are four operation modes for the resequencers 305 and 325. For convenience, the mode that outputs the input ABCD sequence as it is is the ABCD mode, and the input ABCD sequence is the BCDA sequence. The output mode is called BCDA mode, the mode to output the input ABCD sequence as CDAB sequence is called CDAB mode, and the mode to output the input ABCD sequence as DABC sequence is called DABC mode.

[0027] As shown in FIG. 3, the resequencers 305 and 325 have a field memory 500 that stores video signals of eight fields (hereinafter, simply referred to as fields).₁、500₂、・・・、500₈And field memory 500₁~500₈It includes a read / write controller 505 that controls the operation of the resequencers 305 and 325, and a controller 515 that controls the operations of the resequencers 305 and 325 by input from the edit controller 330. The fields input to or output from the resequencers 305 and 325 are, for example, in digital format and conform to any of the many video formats well known in the art. You may. The playback time of each field, that is, the field input every 1/60 second, is 8 field memory 500₁~500₈Written to one of, and at the same time another field memory 500₁~500₈The field stored in is read out and output from the output terminals of the resequencers 305 and 325. Further, the resequencers 305 and 325 include a field counter 510 that counts the number of fields to be output each time a field is output, that is, every 1/60 second. The number counted by the field counter 510 is called a field count. The field count takes a value from 0 to 9 modulo 10. This can be conveniently achieved by resetting to 0 each time the field count exceeds 9. The controller 515 has one of the field memories 500 according to each operation mode.₁~500₈Write to any field memory 500₁~500₈While deciding whether to read from, the number of fields is counted. This procedure will be described in detail below.

[0028] FIGS. 4 to 7 correspond to four modes, respectively, and which field memory 500 corresponds to the time corresponding to each field count of each mode.₁~500₈Indicates whether writing is performed and reading is performed. Figure 4 shows which field memory 500 at the time corresponding to each field count when the resequencer 305 is operating in ABCD mode.₁~500₈Indicates whether writing is performed and reading is performed. Figure 4 shows, for example, a field memory of 500 when the field count is 0.₁Is written to, and field memory 500₇Indicates that reading is performed from. When the field count is 1, field memory 500, as shown in the second column₂Is written to, and field memory 500₈Is read from. When the field count is 2, the field memory is 500.₃Is written to, and field memory 500₁Is read from. When the field count is 3, the field memory is 500.₄Is written to, and field memory 500₂Is read from. When the field count is 4, no writing is performed and the field memory is 500.₃Is read from. When the field count is 5. Field memory 500₆Is written to, and field memory 500₄Is read from. When the field count is 6, the field memory is 500.₅Is written to, and field memory 500₃Is read from. When the field count is 7, the field memory is 500.₈Is written to, and field memory 500₆Is read from. When the field count is 8, the field memory is 500.₇Is written to, and field memory 500₅Is read from. And when the field count is 9, no writing is done and the field memory 500₈Is read from.

As shown in FIG. 4, in the processing by the resequencer 305, there is a delay between the input and the output. For example, in ABCD mode, the input field is written when the field count is 0 and read and output when the field count is 2. That is, there is a delay of 2 fields, that is, 1/30 second. The editing controller 330 has a function of adjusting the synchronization of the entire system based on this time delay.

[0030] FIG. 5 shows which field memory 500 at the time corresponding to each field count when the resequencer 305 is operating in BCDA mode.₁~500₈Is written to which field memory 500₁~500₈Indicates whether reading is performed from. In this case, for example, when the field count is 0, the field memory is 500.₁Is written to, and field memory 500₇Is read from. When the field count is 1, field memory 500₂Is written to, and field memory 500₈Is read from. When the field count is 2, field memory 500₃Is written to, and field memory 500₁Is read from. Which field memory 500, even if the field count shows a value of 3 or more₁~500₈Is written to which field memory 500₁~500₈It is clear from the remaining columns in FIG. 5 as well as the explanation using FIG. 6 and 7 show the field memory 500 according to each field count when the resequencer 305 is operating in CDAB mode and DABC mode, respectively.₁~500₈It is a figure which shows the reading and writing with respect to. In these CDAB mode and DABC mode, there is a delay of 3 fields of playback time, that is, 1/20 second between input and output.

[0031] In the above, the operation of the resequencer 305 has been described assuming that all the sequences input from the videotape as the source start from A. However, the resequencer 305 can operate in the same manner even if a sequence starting from the B, C or D field group is input. To accommodate sequences starting with a B, C or D field group, the operation may start with a non-zero field count. For example, suppose the resequencer 305 is operating in BCDA mode as shown in FIG. 5, and the sequence input from the source videotape starts at C. In this case, as is clear from FIG. 5, the operation should be started at the time when the field count is not 0 but 5. In this example, the editing controller 330 supplies the resequencer 305 with information indicating which field group the source videotape first sends out belongs to. Based on this information, the resequencer 305 determines from which field count the operation starts.

[0032] Field memory 500 used for writing and reading shown in FIG.₁~500₈The choice of is just an example. One of ordinary skill in the art can change the field memory used in various ways to convert the sequence input in the specified mode into the required ABCD sequence.

Further, in FIG. 1, the resequencers 305 and 325 are shown as having separate housings, but a plurality of resequencers are housed in one housing and connected to a power supply or, for example, an editing controller 330. It is self-evident to those skilled in the art that other components, such as RS-422 terminals, may be shared. Further, although videotape editing has been described as a preferred embodiment, it will be apparent to those skilled in the art that the present invention can be similarly applied to other media such as laser discs on which video is recorded.

[Effect of the Invention] The video editing method and the video editing system according to the present invention select a first field memory for storing an input field from a plurality of field memories, and write an input field to the first field memory. , Select a second field memory from a plurality of field memories, read the output field from the above second field memory, and output the output field. Each field group in the output sequence is made to belong to any of the field groups in the input sequence, and the input sequence is converted into an output sequence having a different sequence and output.

[0035] According to the present invention, when editing a plurality of video tapes converted from a movie film by 3-2 pull-down, it is possible to perform editing processing such as cutting, wiping, and dissolving without limiting the editing points. It is possible to maintain the regularity of the sequence of the field group recorded on the output tape, and it is possible to prevent the image from being deteriorated.

BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a diagram showing a configuration of a video editing system to which the present invention is applied.

FIG. 2 is a diagram showing an editing example of the video tape of the present invention.

FIG. 3 is a diagram illustrating the inside of a resequencer.

FIG. 4 is a diagram showing the operation of the ABCD mode of the resequencer.

FIG. 5 is a diagram showing the operation of the resequencer in BCDA mode.

FIG. 6 is a diagram showing the operation of the CDAB mode of the resequencer.

FIG. 7 is a diagram showing the operation of the resequencer in the DABC mode.

FIG. 8 is a diagram illustrating a 3-2 pull-down.

FIG. 9 is a diagram showing an editing example of a conventional video tape.

[Code description] 300 VTR, 305 resequencer, 310 switching device, 315 VTR, 320 VTR, 325 resequencer, 330 editing controller