SE453229B - Logging appts. for off-line edited video recordings - Google Patents

Abstract

A video player (1) outputs to a monitor (6) and digitising memory unit (2). When a scene transition point of interest is encountered, the videotape is stopped by the operator via a keyboard (5) and control unit (4). The keyboard is then used to control viewing of the preceding is images (30,video fields) on another monitor (3) for the burnt-in codes at either side of the transition. Meanwhile the videotape is rewound a few frames to prevent loss of viewing at the next start up. The codes are entered via the keyboard into a register (7) which may be a computer controlled file. At the same time, other details of scene transition type, intended position of scene in the finished programme and any titles are entered.

Description

453 229 10 15 20 25 30 35 4. per hour for the use of these equipment are therefore also very different. We therefore strive to use simple equipment for as large a part as possible of the time-consuming decision-making and thought work that editing entails (called in the industry off-line editing). Only after such off-line editing has determined in detail what the final program should look like, ie. which scenes and which sequence of scenes it should contain, a more expensive high-quality equipment is used for the production of a final edited video tape with high technical quality (called in the industry on-line editing). This is done by using the more expensive high-quality editing equipment from the originally recorded videotape, or from a recent videotape copy of an originally recorded film, to copy over the scenes selected in the off-line editing in the desired order. on a new videotape. If the original recording is on film and the end result is also to be on film, the negative editing of the film takes place on the basis of the edited videotape obtained through the offline editing.

The more of the editing work that is done off-line, the faster and thus cheaper the on-line work can be done.

The cost savings can be very significant. It is t.o.m. It is conceivable that the on-line editing can be carried out completely automatically, if all the necessary decisions have already been made during the off-line editing.

In order for the on-line editing to be carried out quickly and easily and thus cheaply, and possibly even fully automatic, however, a number of requirements must be met, as high-quality, high-precision professional video editing equipment uses a standardized time code, by which exactly the desired scenes of the exact desired length are retrieved from the originally recorded video tape and copied onto a new videotape in exactly the desired order. In the case of negative cutting of a film, the film is correspondingly provided with so-called foot or edge number, by means of which the desired scenes can be selected and which correspond to the time code of the videotape copy used for the off-line editing produced from the film. The foot numbers of the film and the time code of the videotape can thus be translated into each other without difficulty.

Consequently, in order for any significant increase in efficiency and cost savings to be achieved, the off-line editing must result in a so-called EDL, Edit Decision List, also called time code list. This time code list contains the time code for the first image in each scene, the length of the scene or the time code for the last image of the scene, type of scene transition (eg cut, wipe or gradient), where the scene should be in the finished program, any texts or tricks to use. etc.

The most important and most common information is the time code for the first image and the last image in each scene, as well as the order of the scenes.

A commonly used and inexpensive method of enabling such a time code list to be easily established is that during the over-copying of the originally recorded professional videotape on the videocassette tape used in the off-line editing, at least the time code already either superimposed is present or is placed on the originally recorded professional videotape at the same time as the copy, in a part of the image on the videotape intended for subsequent off-line editing. This is generally done by copying the time code into the upper part of the image. To improve readability, a black or white back or lower part in plain text comprising eight digits is often used. basic windows or various contour effects. Such a time code incorporated in the image in plain text is called a "burn-in" code, ie. "burned code". This gives a visible reference number for each video frame on the videotape used for the off-line editing. Since an off-line editing has produced an edited videotape containing the desired scenes in the desired order, one can thus establish a time code list for this edited videotape, by an operator running the same in a videotape player and thereby detecting all scene transitions and recording the "burned-in" time code for the images on either side of each scene transition. This work is called "logging".

For this depreciation work, it would of course in principle be even better to be able to use an automatic reading 10 l5 20 25 30 35 453 229 q _ r of any machine-readable time code recorded on the videotape, for example the LTC (Longitudinal Time Code) standardized by EBU / SMPTE and VITC (Vertical Interval Time Code). However, since in the off-line editing you use a low-cost equipment and the editing further often involves several so-called generations, ie. copies, the automatically readable time codes deteriorate to a corresponding degree during the off-line editing and are therefore often not readable from the edited video tape with satisfactory accuracy and using commonly used equipment, unless the time code signal is regenerated without logical errors on virtually all editing and copying occasions during off-line editing. However, this requires more expensive and currently uncommon additional equipment for off-line editing, which seriously makes it more expensive, so that the desired cost savings and freedom in equipment selection are not achieved.

At present, therefore, the edited video tape obtained by the off-line editing is usually depreciated or listed, so that the time code list required for the subsequent online editing is obtained, by an operator running the edited video tape in a video cassette recorder. with still image function, the operator stopping the tape recorder at each observed scene transition to then reverse the tape and then advance the same image by image to the last frame before the scene transition and the first frame after the scene transition, so that he can record the "burned in" time codes for these two frames, which time codes are displayed in the image displayed by the monitor connected to the VCR.

This depreciation work is time consuming and carries a significant risk of error due to the human factor, in particular because the VCRs used so far for this depreciation work are subject to one or more of the disadvantages listed below, which are significant for - complicates the operator's work during depreciation: l. The tape recorder displays an unstable image when stopped, which makes reading difficult and very tiring and annoying for the operator. 10 15 20 25 30 35 453 22§ 5 _ 2. The tape recorder shows one or more noise tapes when stopped, whereby video fields belonging to different images can be displayed on either side of the noise tape, which means that the visible time code does not belong to the image you otherwise see. As is known, a video signal consists of two consecutive video fields for each image, both consecutive video fields each containing half of the complete image. 3. When stopped, the tape recorder shows only a certain field in the two-field sequence of the video signal, the other field may contain another subject, without the operator being able to detect this.

H. When playing back, the tape recorder shows two alternating video fields, whereby two different subjects and two different time codes may be displayed "double-copied" time division multiplex, which makes the image very flickering and very difficult to read. 5. When stopped, the tape recorder displays two adjacent video fields only in a certain predetermined combination (either fields 1 and 2 with the same time code, or field 2 with a time code and field 1 with the next time code). This gives rise to problems, especially if the on-line editing equipment used does not have the same standard. 6. The tape recorder cannot back up frame by frame in stop mode. 7. The tape recorder has a certain changeover time between driving picture by picture forwards and driving picture by picture backwards, which delays the depreciation work.

Furthermore, the depreciation work using a conventional video recorder with still image function is always, regardless of whether the tape recorder suffers from any or some of the disadvantages listed above, suffers from the following disadvantages: l. The handling is sequential, which means that each movement from an image to another image (for example from image 10 to image 25) requires a corresponding mechanical movement of the tape (in the given example with a tape length corresponding to fifteen images), which always requires a corresponding time. 2. The same image cannot be displayed for any length of time using the tape recorder's still image function without the tape recorder's video head being worn and the tape being damaged or the tape recorder automatically turning off and thus moving the tape.

In the foregoing, it has been assumed that the off-line editing is performed on videotape, so that an edited video tape is obtained, which must be depreciated to obtain the required time code list. The use of videotapes in this context is the most common today. However, it may also happen, already today and to an even greater extent in the future, that a video recording on a disc or so-called disk, the edited video recording will also be on a disc, which will thus be transcribed to obtain the required time code list. This depreciation is conventionally done in the same way as described above but of course using a video disc player instead of a video tape recorder. The video disc players available for this purpose are also, at least if they are of a cheaper price range, suffer from several of the disadvantages listed above for VCRs. The object of the present invention is therefore to provide a device for recording or listing an edited video recording, for example obtained by off-line editing and present either on tape or disc, which device for the depreciation work is much faster, safer, less tiring for the operator. and easier.

According to the invention, this is achieved with a depreciation device designed in accordance with the appended claims.

In the following, the invention will be described in more detail in connection with the accompanying drawing, which shows a basic block diagram for a depreciation device according to the invention.

The exemplary device according to the invention comprises a video tape recorder 1, for example a video cassette recorder if the edited video recording is present on a video cassette tape, with pause or still image function, to which a digitization and memory unit 2 is connected. This digitizing and memory unit 2 receives the video signal from the player 1 and digitizes it and continuously stores the digitized video signal frame by frame in a memory. This memory is of a "circulating" type with a memory 10 10 20 20 25 30 35 453 229 7. F capacity corresponding to a predetermined number of images, so that the most recently digitized image replaces the oldest of the images previously stored in memory. A monitor or display unit 3 is connected to the digitization and memory unit 2.

Furthermore, there is a control unit H with associated keyboard or the like 5, which is connected to the player 1 and the digitization and memory unit 2 and by means of which it is possible for an operator to stop and start the player 1 and further to arbitrarily select in the unit 2's memory which of the images stored in the memory is to be displayed on the monitor 3 screen. The operator can thus, with the aid of the keypad 5 and the control unit U, "scroll" back and forth in the memory of the unit 2, so that the images stored in the memory are displayed on the monitor 3.

Depreciation of an edited video recording, for example obtained from an off-line edit, to establish the required time code list for the subsequent on-line edit is performed by means of the device shown in the following manner. The operator inserts the edited video recording into the video player 1 and starts it to play the videogram, the video signal from the player 1 being continuously digitized in the unit 2 and the digitized images being stored in the memory of the unit 2, which will always contain a predetermined number of the most recently played and digitized images. During this continuous playback of the videogram in the player 1, the memory in the unit 2 can be so controlled from the control unit 4 that the monitor 3 continuously always shows the last digitized image, so that the playback of the videogram can be continuously monitored on the monitor 3.

Alternatively, the device may comprise an additional monitor 6, which is connected in a conventional manner to the video output of the player 1, so that on the screen of this additional monitor 6 the playback of the videogram in the player 1 can be continuously monitored.

When the operator, by observing either the monitor 3 or the monitor 6, detects a scene change ("clip") on the played videogram, he stops the player 1 as quickly as possible by pressing a key in the keyboard 5 or by influencing something else. suitable operating means, for example a pedal or the like, whereby at the same time of course also the digitization of the video signal from the player in the unit 2 is interrupted. The memory capacity of the memory in the unit 2 is so selected that this memory contains such a number of images (the last played before the stop) that the detected scene change is certainly among these images. If it is assumed that the operator's reaction time from the detection of a scene change to the stop of the player 1 is a maximum of, for example, 0.4 seconds, which according to previous tests is a reasonable value, the memory in the unit 2 may have a capacity of e.g. images (equivalent to 30 video fields), which in European television systems corresponds to a playing time of 0.6 seconds. Then, with the help of the keyboard 5 and the control unit H, the operator can display the images stored in the unit 2's memory on the monitor 3 at his own desired rate, until he finds the current scene change and can register the time codes on both sides thereof. This registration can advantageously take place by means of a registration unit 7 connected to the control unit U, in which the operator can enter the current time codes and possibly also other information regarding the detected scene change using the keyboard 5. The recording unit 7 can then be designed such that the recorded data is stored on a suitable data carrier, for example hollow strip, flex disk or hard disk, in such a form that the recorded data can later be used directly for controlling an online editing equipment.

After the operator has thus managed a detected scene change, he restarts the player 1 and thus the continuous digitization in the unit 2. If the player is such that it does not give a stable image fast enough after its start, the control unit 4 can advantageously be so designed that after a stop command it automatically backs the player to a suitable piece. This reversing operation can take place while the operator is studying the images stored in the unit's 2 memory to find the image change that caused him to stop the player.

Since the monitor 3 gives a stable and easy-to-read presentation of the images stored in the memory of the unit 2 without any of the above-mentioned disturbances, and the operator can arbitrarily and at his own desired pace "browse" among 10 15 25 30 453 229 s> P the images stored in the memory, the device eliminates all the above-mentioned disadvantages of the hitherto used equipment for copying edited videograms.

Because the control unit H is designed with a computer, several different additional functions can be achieved in a device according to the invention.

Thus, it may be possible to assess the reasonableness of the time codes that the operator has registered. Namely, the computer can measure the video player's running time between two consecutive stops, for example by means of a clock which is started and stopped simultaneously with the player or by means of the control pulses from the player or on the basis of a consecutive LTC, VITC or the like, if any. exist, and compare this time with the time codes registered by the operator for the first image and the last image in a scene, respectively. For example, if the registered time code for the first image in a scene is 35 and the registered time code for the last image of the scene is 190 and the measured running time of the video player from the beginning to the end of the scene is 6.2 seconds, then it is the mutual difference between the two registered time codes is reasonable for EBU time code, since this is incremented 25 times per second. If, on the other hand, the playing time of the tape recorder in this example had been shorter than 6.2 seconds or longer than 6.2 seconds, with a certain suitable margin of error, the time codes entered by the operator would probably have been incorrect or an intermediate scene change was not detected by the operator.

By means of a computer in the control unit N, it may also be possible to achieve an automatic detection of the scene changes. As the images are digitized, a computer can, by examining a number of consecutive images, assess whether a scene change is likely to occur, thereby stopping the video player and interrupting the digitization and presenting the detected scene change for approval, adjustment or rejection by either the operator or the computer. As an automation of this kind is not always absolutely safe, e.g. Depending on how you define a scene change, the manual control and change option is very valuable. However, this type of automatic detection of scene changes has a much greater possibility of giving a correct result than just a continuous detection in real time. This also applies apart from the operator's possible manual control of the detected scene change, as the computer can stop the video player and examine the detected "suspicious" scene change using even slow algorithms and the images stored in the device's 2 memory.

With the aid of a computer included in the control unit H, it is thus entirely possible to achieve a completely automatic detection of scene changes and an exact determination of the position of each detected scene change.

Using a computer also enables automatic reading of VITC. When digitizing the images, it is ensured that the TV line or lines that contain the VITC code are included. As a result, this can be decoded without the need for any additional hardware. Since there is no strict requirement for real-time processing, even technically poor VITC can often be read correctly, if this is required using relatively slow algorithms. Because the image digitizer can distinguish between a large number of signal levels, often 16, SU or more, the decoding possibilities of a bad code further increase.

Since, as described above, with the aid of a computer in the control unit 4 it is possible to achieve both an automatic detection of the stage changes and an automatic reading of the time codes on either side of each detected stage change, it is possible with a device according to the invention achieve an almost completely automatic depreciation of an edited videogram. In this case, the computer included in the control unit H is suitably designed so that it starts and stops a counting unit, which counts the number of video fields between two successive detected scene changes. This can be done exactly by means of, for example, the control pulses from the video player or the sync pulses in the video signal, and the computer can be designed to compare the number of video fields thus obtained between two consecutive detected scene changes with the time codes the computer reads for these scene changes. This allows the computer to check whether the time codes have been read correctly or whether an intermediate scene change has remained undetected. In such a case, the computer may order the control unit to back up the video player and repeat the detection procedure, or the renewed control may be left to an operator.

The computer can also be used to verify an automatic VITC or LTC reading from another reader. When a jump is detected in the read code, the computer stops the video player and displays the detected scene change using the images stored in the unit 2, either for approval or adjustment by the operator or for automatic adjustment by the above-mentioned automatic scene change detector.

The computer can also be used to automatically read the "burned in" time code. If the images with the "burned-in" time code have already been digitized, the computer can, without any additional hardware required, compare the time codes in the image against input references and thus automatically read the "burned-in" codes around a scene change selected by the operator, or LTCIVITC reading, or scene change detection .

In this way, a further verification or detection of scene change / non-scene changes is obtained within the number of digitized images stored at any given time.

Thus, if the control unit H is provided with or designed as a computer, all the additional functions listed above can be obtained without the use of any additional hardware and mainly only with the aid of additional computer programs.

Claims (11)

453 229 12 P Patent claims Device for copying an edited videogram, characterized in that it comprises a video player (1) with stop function, a digitizing unit (2) connected to this video player arranged to continuously convert the video signal played by the video player into a corresponding digital signal. and comprising memory means for storing this digital signal for a predetermined number of the most recently played images on the videogram, a display unit (3) connected to the digitizing unit (2) for displaying the images stored in the memory means of the digitizing unit, and another the video player (1) and the digitizing unit (2) connected control unit (U) with control means (5) for stopping and starting the video player (1) and for selecting which of the images stored in the memory means of the digitalisation unit (2) is to be displayed of the display assembly (3). Device according to claim 1, characterized in that the control unit (H) is arranged to back it up with a predetermined playing length after stopping the video player (1). Device according to claim 1 or 2, characterized in that it comprises a further display unit (6) connected to the video player (1) for displaying the video signal played by the video player in step with the playback. H. Device according to any one of claims 1 - 3, characterized in that the first-mentioned display unit (3) connected to the digitizing unit (2) is arranged that during the continuous playback of the videogram in the video player (1) and the simultaneous digitization of the played video signal in the digitization unit (2) display the digitized image. Device according to any one of claims 1 - 4, characterized in that it comprises recording means (7) connected to said control unit (4) for automatically or manually controlled recording of data, for example time codes, regarding detected scene changes on the played the videogram. 453 229 13 Device according to any one of claims 1 - 5, characterized in that said control means (5) for stopping and starting the video player (1) and for selecting the image in the memory means of the digitizing unit (2) to be displayed by the display unit (3) can be operated manually. Device according to one of Claims 1 to 5, characterized in that the control unit (H) comprises means for analyzing the images played and digitized from the videogram for detecting scene changes on the videogram and for stopping the video player at each such detected scene change. Device according to claim 7, characterized in that the control unit (4) comprises means arranged to analyze, after stopping the video player (2) after a detected scene change, the digitized images stored in the memory of the digitizing unit (2) for determining the detected scene change. exact location. ' Device according to one of Claims 1 to 8, characterized in that the control unit (4) comprises means arranged to read time code indications present on the played videogram on either side of a detected scene change in the videogram. Device according to any one of claims 1 - 9, characterized in that the control unit (H) comprises means arranged to determine the length of the videogram, for example expressed in the number of video fields, between successive scene changes in the video program. 11. ll. Device according to claim 10, characterized in that the control unit (H) comprises means arranged to compare the length of the videogram between successive scene changes with the time code indications present on these scene changes on the videogram.