JP3901803B2 - Image information conversion method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image information conversion method for optically reading image information photographed on a motion picture film and converting the image information into PAL and NTSC standard video signals.
[0002]
[Prior art]
Conventionally, in order to convert image information photographed on a motion picture film into a standard video signal of NTSC (National Television System Commitee) system and PAL (Phase Alternating by Line) system, Telecine, an image reading device, is used. The system shown in FIG. 11 using an apparatus has been considered.
[0003]
The number of scanning lines (lines) / field frequency (Hz) of a PAL video signal used mainly in Europe is 625/50. On the other hand, NTSC video signals used mainly in the United States and Japan are 525 / 59.94 (more accurately, the field frequency is 60 / 1.001 = 59.94005994. Hereinafter, it is expressed as 525 / 59.94.)
[0004]
Normally, a movie film 141 is shot at 24 frames per second. However, in the system shown in FIG. 11, a PAL 625/50 video signal is set at a playback speed of the telecine device 142 of 25 frames per second. I was getting.
[0005]
On the other hand, the NTSC video signal of 525 / 59.94 has a playback speed of 24 frames per second (accurately, 24 / 1.001 = 23.99762398... .) And then the field frequency was converted to 59.94 Hz by the field frequency converter 143.
[0006]
[Problems to be solved by the invention]
By the way, when the image information on the motion picture film is converted into the PAL and NTSC video signals by the system shown in FIG. 11, the following problems occur.
[0007]
First, in the above system, the telecine device 142 is used twice when obtaining a PAL 625/50 video signal and when obtaining an NTSC 525 / 59.94 video signal. The telecine device 2 is expensive and it is rare that one user owns a plurality of devices. For this reason, occupying the telecine device 142 deteriorates its use efficiency.
[0008]
Further, in the telecine device 142, the movie film 141 is run at a constant speed or is intermittently fed by a sprocket formed in the width direction of the movie film 141, for example, meshing with both side perforations. By applying the film 141 to the telecine device 142, the frequency of damaging the movie film 141 is increased.
[0009]
In addition, before the PAL 625/50 video signal and NTSC 525 / 59.94 video signal obtained by the above system are broadcast, it is common to add editing processing. In this case, two master tapes for a 625/50 video signal and a 525 / 59.94 video signal are required.
[0010]
The NTSC 525 / 59.94 video signal only has a performance time of 0.1% longer than that of the original movie film 141, but the PAL 625/50 video signal has a conversion process. Since the movie information shot at 24 frames per second is reproduced at 25 frames per second, the performance time is shortened by about 4%.
[0011]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image information conversion method in which the telecine device is used only once to increase the use efficiency and reduce the frequency of damaging movie films.
[0012]
It is another object of the present invention to provide an image information conversion method that allows only one master tape.
[0013]
Another object of the present invention is to provide an image information conversion method in which the performance time of the video signals of the above two methods is practically the same as the performance time of a movie film.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problem, the image information conversion method according to the present invention converts image information on a motion picture film taken at a predetermined number of frames per second into a number of scanning lines of 625 (lines) / The video signal is converted into a video signal having a field frequency of 50 (Hz), the 625/50 video signal is recorded on the recording medium, and the video signal from the recording medium is reproduced in the first conversion process. After reproduction at a field frequency different from the used field frequency of 50 Hz, the second conversion step converts the video signal into an NTSC 525 / 59.94 video signal.
[0015]
Here, this image information conversion method includes another reproduction process for reproducing the recording medium on which the 625/50 video signal is recorded by the recording process at a field frequency of 50 Hz, and may be used by switching to the reproduction process. Good.
[0016]
Further, when the first conversion process reproduces image information on a motion picture film shot at 24 frames per second at a speed of 25 frames per second, the second conversion process is obtained in the reproduction process. The field frequency of the recorded video signal is increased to 5/4 times.
[0017]
Further, when image information on a motion picture film shot at 25 frames per second is reproduced at the same speed in the first conversion step, the second conversion step is a field of the video signal obtained in the reproduction step. Increase the frequency 6/5 times.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Several embodiments of the image information conversion method according to the present invention will be described below.
First, a first embodiment will be described with reference to FIGS.
In the first embodiment, image information on a motion picture film 10 taken at 24 frames per second, that is, 24 frames per second (Fps) is converted into PAL scanning lines 625 (lines) / field frequency 50 (Hz). ) And an image information conversion system to which an image information conversion method for converting to an NTSC 525 / 59.94 video signal is applied.
[0019]
This image information conversion system includes a telecine device 11 that reproduces image information on a movie film 10 taken at 24 Fps at 25 Fps and converts it to a 625/50 video signal, and 625/50 converted by the telecine device 11. Are recorded on the video tape cassette 13 with the same number of scanning lines / field frequency, and the video tape cassette 13 on which 625/50 video signals are recorded by the digital video tape recording apparatus 12. Is recorded at a field frequency of 47.952 Hz (more precisely 60/1. 001 × 4/5 = 47. 5204795..., But hereinafter referred to as 47.952), the modified digital video tape reproducing device 15 that reproduces the video signal of 625 / 47.952 obtained by the modified digital video tape reproducing device 15 and 525. NTSC converter 16 for converting the video signal to /59.94.
[0020]
This NTSC converter 16 includes a scanning line number conversion device 17 for converting the number of scanning lines of the 625 / 47.952 video signal obtained by the modified digital video tape reproducing device 15 to 525, and a field frequency of 59.94 Hz. And a field frequency conversion device 18 for conversion into
[0021]
The motion picture film 10 includes film feeding perforations 10a on both sides in the width direction.
The telecine device 11 converts the image information of each frame into a 625/50 video signal by causing the movie film 10 to travel at a constant speed by a sprocket meshing with the perforation 10a.
[0022]
The configuration of the telecine device 11 is shown in FIG.
The telecine device 11 is mounted so that the movie film 10 is pulled out from the supply reel 21 and taken up on a take-up reel 27 via a guide roller 22, a tension roller 23, a guide roller 24, a drive roller 25 and a guide roller 26. A film traveling system is provided, and image information and audio information are optically read from the movie film 10 by the information reading unit 30 provided between the guide roller 24 and the driving roller 25 of the film traveling system. A video signal and an audio signal are generated from the read signal by the signal processing unit 40 and are output from the signal output terminals 51 and 52 to the digital video tape recording apparatus 12.
[0023]
The supply reel 21, the drive roller 25, and the take-up reel 27 of the film running system function as a transport means for transporting the movie film 10 at a constant speed. The movie film 10 is rotated at a constant speed.
[0024]
The tension roller 23 is provided at one end of a tension arm 23B elastically biased by a tension coil spring 23A, and keeps the tension constant by rolling to the movie film 10 with an elastic biasing force of the tension coil spring 23A. To do. The movie film 10 is run at a constant speed by the drive roller 25 while being kept constant in tension by the tension controller 23 and is taken up on the take-up reel 27. The drive roller 25 rotates the movie film 10 with the movie film 10 sandwiched therebetween, thereby causing the movie film 10 to travel at a constant speed.
[0025]
The information reading unit 30 optically reads various information imprinted on the motion picture film 10 between the guide roller 24 and the driving roller 25 of the film running system. It comprises a CCD linear sensor 32 that receives information reading light emitted from the light source 31 via the movie film 10. The CCD linear sensor 32 is arranged corresponding to the entire width of the movie film 10. The information reading unit 30 reads information for the entire width of the movie film 10 traveling at a constant speed in the film traveling system by the CCD linear sensor 32 every unit time, and supplies the read signal to the signal processing unit 40. .
[0026]
Further, the signal processing unit 40 is supplied with an A / D converter 41 to which a reading signal is supplied from the CCD linear sensor 32 of the information reading unit 30, and reading data obtained by digitizing the reading signal by the A / D converter 41 is supplied. Buffer memory 42, the screen position control block 43, the image processing block 44 and the audio processing block 45 to which the read data is read and supplied from the buffer memory 42, and frame timing information of the screen from the screen position control block 43. Is supplied to the video timing block 46, the D / A converter 47 is supplied with video data from the image processing block 44, and the D / A converter 47 is supplied with an analog video signal supplied from the video data. 48, the audio processing block 45 Comprising and the like D / A converter 49 to the audio data is supplied.
[0027]
The buffer memory 42 temporarily stores read data obtained by digitizing the read signal from the CCD linear sensor 32 of the information reading unit 30 by the A / D converter 41. The read data temporarily stored in the buffer memory 42 includes image information obtained by digitizing a read signal for the screen area of the movie film 10, frame position information, control information for each frame, digital audio information, and the like. .
[0028]
Reading of the read data from the buffer memory 42 is controlled by the video timing block 46 based on the frame timing information of the screen supplied from the screen position control block 43, and the image information is read from the buffer memory 42. The frame position information, the control information of each frame, the digital audio information, etc. are read out separately. Then, the frame position information and control information of each frame are supplied to the screen position control block 43, the image information is supplied to the image processing block 44, and the digital audio information is supplied to the audio processing block 45. To be supplied.
[0029]
The screen position control block 43 generates film feed control information and screen frame timing information from the frame position information and the control information of each frame, supplies this information to the motor control circuit 28, and also supplies the frame timing information. The video timing block 46 is supplied.
[0030]
The motor control circuit 28 drives each drive motor in accordance with the control information and controls the rotation of the supply reel 21, the drive roller 25, and the take-up reel 27 of the film running system. Drive at speed.
[0031]
In the telecine device 11, the motor control circuit 28 drives each drive motor in accordance with the control information so as to reproduce the movie film 10 shot at 24Fps at 25Fps, and supplies the film running system supply reel 21, drive roller. 25 and the take-up reel 27 are controlled to rotate.
[0032]
The image processing block 44 includes a frame memory that temporarily stores image data for one frame, and performs image processing such as color correction and screen size correction on the image information. The image processing block 44 supplies the video data subjected to the image processing to the D / A converter 47. Then, the D / A converter 47 converts the image information subjected to the image processing by the image processing block 44 into an analog form and supplies the analog information to the encoder 44. The encoder 48 converts the video signal analogized by the D / A converter 47 into a video signal conforming to a predetermined television system such as a high-definition television, and the video signal is output from the output terminal 51 to the digital video tape recording device 12. Output.
[0033]
The audio processing block 45 performs audio processing such as error correction processing on the digital audio information read from the buffer memory 42. The audio processing block 45 supplies digital audio data subjected to audio processing to the D / A converter 49. Then, the D / A converter 49 converts the digital audio data subjected to the audio processing by the audio processing block 45 into an analog form. The audio signal analogized by the D / A converter 49 is output from the signal output terminal 52 to the digital video tape recording apparatus 12.
[0034]
Thus, the telecine device 11 is supplied to the digital video tape recording device 12 with a 625/50 video signal and an audio signal obtained by reproducing the movie film 10 originally shot at 24 Fps at 25 Fps.
[0035]
As the digital video tape recording device 12, for example, a D-1 format video tape recording device (hereinafter referred to as a D-1 video tape recording device) can be used. The D-1 video tape recording apparatus is CCIR. Rec. This is a standard videotape recording apparatus based on the so-called 4: 2: 2 component encoding system corresponding to 601. Therefore, when the D-1 video tape recording apparatus is used as the digital video tape recording apparatus 12, the video signal supplied from the telecine apparatus 11 is a video signal of 4: 2: 2 component encoding system. Yes.
[0036]
FIG. 3 shows a schematic configuration of a video and audio processing system of the D-1 video tape recording apparatus.
The component video signals Y, BY, RY output from the telecine device 11 via the output terminal 51 are converted into digital video signals Y, Cb, Cr by the A / D converter 61, respectively. These digital video signals Y, Cb, and Cr are supplied to the source coding circuit 62.
[0037]
The source coding circuit 62 encodes the digital video signals Y, Cb, and Cr using a weight order code. This is a coding process in which, for example, an 8-bit code arranged in decimal order is converted in correspondence with codes arranged in weight order. This reduces the influence of errors that cannot be detected by the error correction code and remain on the screen. The digital video signals Y, Cb and Cr encoded by the source coding circuit 62 are supplied to the inter-sector shuffling circuit 63.
[0038]
The inter-sector shuffling circuit 63 performs inter-sector shuffling on the digital video signals Y, Cb, and Cr. The presence of an error can be detected but cannot be corrected by an error correction code (ECC) performed by the outer encoder 64 in the subsequent stage. In this case, processing is performed so as not to be noticeable by the modification, but even when the modified pixels are concentrated in the screen, the image quality deterioration cannot be ignored. For this purpose, in the inter-sector shuffling circuit 63, the generation order of image codes and the order of recording codes are interchanged by inter-sectors. The shuffling output of the inter-sector shuffling circuit 63 is supplied to the outer encoder 64.
[0039]
The outer encoder 64 adds an ECC code to the shuffling output. Specifically, the shuffling output is divided into blocks of a predetermined length, and a 2-word Reed-Solomon product code (check code) for outer code is generated and added by a predetermined operation. The encoder output of the outer encoder 64 is supplied to an intra sector shuffling circuit 65.
[0040]
The intra sector shuffling circuit 65 performs a shuffling process on the intra sector of the encoded output. Specifically, the codes arranged two-dimensionally after generating the outer check code are rearranged as randomly as possible in the same two-dimensional block.
[0041]
On the other hand, the analog audio signal output from the telecine device 11 via the output terminal 52, for example, the R and L channel signals, is converted into a digital audio signal by the A / D converter 66. This digital audio signal is supplied to the preprocessing circuit 67 and preprocessed, and then supplied to the blocking circuit 68.
[0042]
The blocking circuit 68 blocks the audio signal and supplies it to the outer encoder 69. The outer encoder 69 adds an ECC code to the audio signal that has been blocked, and supplies it to the shuffling circuit 70. The shuffling circuit 70 shuffles the encoded output.
[0043]
The video shuffling output from the intra sector shuffling circuit 65 and the audio shuffling output from the shuffling circuit 70 are supplied to the multiplexing circuit 71.
[0044]
The multiplexing circuit 71 time-division multiplexes the video shuffling output and the audio shuffling output. This multiplexed output is supplied to the inner encoder 72.
[0045]
The inner encoder 72 adds a common inner code (inner code), which is a kind of ECC code, to the multiplexed output. This encoded output is supplied to the synchronization / ID adding circuit 73.
[0046]
The audio signal and the video signal are configured in a common format called a sync block, and the sync / ID adding circuit 73 adds an ID pattern indicating a sync pattern and a block number to two inner code blocks, and one sync block Is output to the scramble circuit 74.
[0047]
The scramble output from the scramble circuit 74 is supplied as a recording current to the head 76 via a recording amplifier 75 and a rotary transformer, and is digitally recorded on the magnetic tape 77 by unsaturated recording suitable for high density recording.
[0048]
A digital video tape recording apparatus such as the D-1 video tape recording apparatus can improve the image quality and sound quality of the recording signal and improve the dubbing characteristics as compared with the analog video tape recording apparatus. The reproduction image quality by digital recording mainly depends on the encoding parameters and is not easily influenced by the recording / reproduction characteristics. For example, the waveform distortion of the reproduced image is only the distortion of the analog circuit before and after A / D and D / A conversion. In addition, distortion and noise during recording / reproduction may cause errors in the reproduction code and cause image quality degradation. However, if the error rate is below a certain value, it can be corrected or corrected by using an error correction code. . For these reasons, digital recording can be expected to have higher image quality, and is particularly noticeable during dubbing.
[0049]
The video signal from the telecine device 11 is recorded on the magnetic tape 77 of the video tape cassette 13 at 625/50 by the D-1 video tape recording device which is the digital video tape recording device 12. The video tape cassette 13 on which the 625/50 standard video signal is recorded by the digital video tape recording device 12 is reproduced by the digital video tape playback of the D-1 video tape playback device in the PAL playback system and the NTSC playback system. By using the apparatus 14 and the modified digital video tape reproducing apparatus 15, a common master video tape cassette 13 can be obtained.
[0050]
Having one master video tape cassette 13 means using the telecine device 11 only once, so that the frequency of damaging the movie film 10 having a very high software value can be reduced.
[0051]
In addition, even when editing is performed on an NTSC video signal, the master video tape cassette 13 on which a 625/50 video signal is recorded is used. Therefore, editing at 625/50 is possible and vertical resolution can be improved. .
[0052]
If the digital video tape reproducing device 14 directly reproduces the magnetic tape 77 of the master video tape cassette 13 at a field frequency of 50 Hz, a PAL 625/50 video signal can be obtained. In this case, the reproduction time of the video signal is 4% shorter because it depends on the tape speed of 25 Fps reproduction in the telecine device 11. For example, when a 120 minute movie is played back as a 625/50 video signal, it ends in 115 minutes.
[0053]
As the digital playback device 14, a D-1 video tape playback device can be used.
[0054]
FIG. 4 shows a schematic configuration of a video and audio processing system of the D-1 video tape reproducing apparatus.
The digital signal recorded on the magnetic tape 77 of the master video tape cassette 13 is reproduced by the reproducing head 81 and then amplified by the reproducing amplifier 82. The reproduction output of the reproduction amplifier 82 is supplied to the synchronization / ID detection circuit 83.
[0055]
The synchronization / ID detection circuit 83 detects the synchronization signal and ID from the reproduction output, and clarifies the signal break and block number.
[0056]
The descramble circuit 84 releases the scramble of the reproduction output and supplies the scrambled reproduction signal to the inner decoder 85.
[0057]
The inner decoder 85 performs error correction using the inner code added to the reproduction signal and supplies the output to the data separation circuit 86.
[0058]
The digital video signal separated by the data separation circuit 86 is supplied to an intra-sector deshuffling circuit 87, and the digital audio signal is supplied to a deshuffling circuit 92.
[0059]
The intra sector deshuffling circuit 87 deshuffles the digital video signal in the intra sector and supplies the component digital video signals Y, Cb, and Cr to the outer decoder 88.
[0060]
The digital video signals Y, Cb, and Cr that have been subjected to error correction using the outer code by the outer decoder 88 are supplied to the D / A converter 91 via the inter-sector deshuffling circuit 89 and the source decoder 90. . The D / A converter 91 converts the digital video signals Y, Cb, and Cr into analog component video signals Y, BY, and RY and outputs them.
[0061]
On the other hand, the deshuffling circuit 92 solves the shuffling of the digital audio signal separated by the data separation circuit 86. The shuffled digital audio signal is subjected to error correction processing by the outer decoder 93 and then supplied to the D / A converter 96 via the post-processing circuit 94 and the audio concealment circuit 95.
[0062]
The D / A converter 96 converts the digital audio signal into an analog audio signal and outputs it as, for example, an R, L channel audio signal.
[0063]
On the other hand, in order to obtain a 525 / 59.94 video signal from the master video tape cassette 13, it is necessary to perform reproduction using the modified digital video tape reproducing device 15.
The modified digital video tape player 15 can also use a D-1 video tape player. In this case, the configuration of the video and audio processing system of the D-1 video tape reproducing apparatus is the same as that shown in FIG.
[0064]
This modified digital video tape reproducing device 15 has a servo system as shown in FIG. 5 and reproduces a 625/50 video signal recorded on the magnetic tape 77 of the master video tape cassette 13 at a field frequency of 47.952 Hz. To do.
[0065]
The synchronization signal separation circuit 101 extracts a horizontal synchronization signal from the inputted reference signal and supplies it to a phase lock loop (PLL) circuit 102. As will be described later, the PLL circuit 102 uses a voltage controlled oscillator (VCO) in which LC is variable, and the value of C changes according to the field frequency of the input reference signal. The frequency of the oscillation clock can be varied. The clock output from the PLL circuit 102 is supplied to the vertical (V) synchronization (SYNC) generator 103. The vertical synchronization signal generated by the VSYNC generator 103 is supplied to the drum servo system 104 and the capstan servo system 110. The VSYNC generator 103 also generates various clocks required for the video and audio processing systems, but description thereof is omitted here.
[0066]
In the drum servo system 104, the phase comparator 106 compares the phase of the drum rotation pulse (PG) from the drum motor 105 with the vertical synchronizing signal, and supplies the phase control signal to the inverting input terminal of the operational amplifier 107. . The operational amplifier 107 is also supplied with a speed control signal detected by the speed detector 109 from a frequency generation (FG) pulse from the drum motor 105. The operational output of the operational amplifier 107 is amplified by the drive amplifier 108 and then supplied to the drum motor 105, which is used to correct the rotational speed and rotational phase deviation of the drum motor 105.
[0067]
In the capstan servo system 110, the phase of the reproduction control signal divided by the frequency divider 115 and the vertical synchronizing signal are compared by the phase comparator 112, and the phase control signal is supplied to the inverting input terminal of the operational amplifier 113. is doing. The operational amplifier 113 is also supplied with a speed control signal detected by the speed detector 116 from a frequency generation (FG) pulse from the capstan motor 111. The operational output of the operational amplifier 113 is amplified by the drive amplifier 114 and then supplied to the capstan motor 111, which is used to correct the rotational speed and rotational phase deviation of the capstan motor 111.
[0068]
The configuration of the PLL circuit 102 is shown in FIG. The PLL circuit 102 includes a phase comparator 121, a low-pass filter 122, a VCO 123, and a frequency divider 124.
[0069]
The phase comparator 121 compares the phases of the horizontal synchronization signal separated and extracted by the synchronization signal separation circuit 101 and a clock obtained by dividing the output clock of the VCO by a predetermined division ratio.
[0070]
The filter output of the low-pass filter 122 is supplied to the VCO 123. The LC value of the VCO 123 changes depending on the filter output, and the generated clock is supplied to the servo system 100, for example, 47.952 Hz, 49.95 Hz, or 50 Hz. Can be switched by a reference signal.
[0071]
Therefore, the modified digital video tape playback apparatus 15 inputs a 625 / 47.952 reference signal having a field frequency of 47.952 Hz, and reproduces a 625/50 video signal as a 625 / 47.952 video signal. be able to.
[0072]
The video signal of 525 / 47.952 obtained by the modified digital video tape playback device 15 is supplied to the NTSC converter 16 and converted to a video signal of 525 / 59.94.
[0073]
As described above, the NTSC conversion unit 16 includes the scanning line number conversion device 17 that converts the number of scanning lines of the 625 / 47.952 video signal to 525, and the field frequency conversion device that converts the field frequency to 59.94 Hz. 18.
[0074]
The scanning line number converter 17 performs scanning line interpolation (line interpolation) from 625 scanning lines to 525 scanning lines. This scanning line number conversion device 17 obtains 525 scanning lines by vertically filtering 625 scanning lines from 576 active lines to 486 active lines. Since the vertical resolution in the case of 625 scanning lines is higher than the vertical resolution in the case of 525, there is no loss of vertical resolution in the resampling process, and high image quality can be expected.
[0075]
The field frequency converter 18 performs a so-called 3: 2 pull-down process in order to convert the field frequency of 47.952 Hz by 5/4 to 59.94 Hz.
[0076]
This so-called 3: 2 pull-down process will be described with reference to FIGS. A video signal having a field frequency of 47.952 Hz is interlaced and converted so that the even field on the input side 18a becomes the even field on the output side 18b and the odd field on the input side 18a becomes the odd field on the output side 18b. Since the video signal on the input side 18a is based on the video output of the telecine device 11, there is no time difference within the same frame. For this reason, the video signal converted to the output side 18b does not cause inconvenience in terms of time. For every four frames on the input side, one new frame is created on the output side, but since there is no inconvenience in the order of the fields in the frame, the movement does not feel unnatural.
[0077]
Note that the playback time of the 525 / 59.94 video signal obtained by the NTSC converter 16 is longer than the normal playback time of the movie film 10 by 0.1%.
[0078]
In this way, the image information conversion system according to the first embodiment converts the movie film 10 shot at 24 Fps into a PAL 625/50 video signal and an NTSC 525 / 59.94 video signal. Can be converted.
[0079]
In this case, to use one master video tape cassette 13 means to use the telecine device 11 once, so that the frequency of damaging the movie film 10 can be reduced. Also in the NTSC system, a 625/50 master video tape cassette is used, and 525 scanning lines are created from line scanning by 625 scanning lines. Therefore, higher image quality can be expected than when the original 525 conversion is performed. In addition, the modified digital video tape playback device 15 only needs to change the PLL circuit of the existing D-1 video playback device and change the external reference signal, so that the cost can be reduced.
[0080]
Next, a second embodiment will be described with reference to FIGS.
[0081]
In this second embodiment, image information on a motion picture film 20 taken at 25 Fps is converted into a PAL scanning line 625 (line) / field frequency 50 (Hz) video signal, and NTSC 525/59. This is an image information conversion system to which an image information conversion method for converting into 94 video signals is applied.
[0082]
This image information conversion system differs from the first embodiment in that the movie film 20 shot at 25 Fps is played back at 25 Fps by the telecine device 11 and played back by the modified digital video tape playback device 131. The field frequency is converted to a field frequency of 49.95 Hz (precisely 50 / 1.001 = 49.95004995... But hereinafter referred to as 49.95). The point is that the field frequency conversion at 5 is multiplied by 6/5. Since other parts are the same as those in the first embodiment, detailed description thereof is omitted.
[0083]
The digital video tape recording device 12 records the 625/50 video signal reproduced by the telecine device 11 at 25 Fps on the video tape cassette 13. The video tape cassette 13 on which the 625/50 standard video signal is recorded by the digital video tape recording device 12 is reproduced by the digital video tape playback of the D-1 video tape playback device in the PAL playback system and the NTSC playback system. By using the device 14 and the modified digital video tape reproducing device 131, a common master video tape cassette 13 can be obtained.
[0084]
Having one master video tape cassette 13 means using the telecine device 11 only once, so that the frequency of damaging the movie film 10 having a very high software value can be reduced.
[0085]
Even when editing is performed on an NTSC video signal, since the master tape 13 on which a 625/50 video signal is recorded is used, editing at 625/50 is possible and vertical resolution can be improved.
[0086]
If the digital video tape reproducing device 14 directly reproduces the magnetic tape 77 of the master video tape cassette 13 at a field frequency of 50 Hz, a PAL 625/50 video signal can be obtained. In this case, the playback time of the video signal can be made exactly the same because the telecine device 11 plays back the movie film 20 recorded at 25 Fps at the same speed of 25 Fps.
[0087]
The modified digital playback device 131 has a servo system configured as shown in FIG. 5 and a PLL circuit 102 configured as shown in FIG. 6, and a 625 / 49.95 reference signal having a field frequency of 49.95 Hz from the outside. , The 625/50 video signal recorded on the magnetic tape 77 of the master cassette 13 is reproduced so as to have a field frequency of 49.95 Hz.
[0088]
The video signal of 525 / 49.95 Hz obtained by this modified digital video tape playback device 131 is supplied to the NTSC converter 132 and converted to a video signal of 525 / 59.94.
[0089]
As described above, the NTSC conversion unit 132 includes the scanning line number conversion device 17 that converts the number of scanning lines of a 625 / 49.95 video signal to 525, and the field frequency conversion device that converts the field frequency to 59.94 Hz. 133.
[0090]
The scanning line number converter 17 performs scanning line interpolation (line interpolation) from 625 scanning lines to 525 scanning lines. This scanning line number conversion device 17 obtains 525 scanning lines by vertically filtering 625 scanning lines from 576 active lines to 486 active lines. Since the vertical resolution in the case of 625 scanning lines is higher than the vertical resolution in the case of 525, there is no loss of vertical resolution in the resampling process, and high image quality can be expected.
[0091]
The field frequency converter 133 performs a so-called 3: 2: 3: 2: 2 pull-down process in order to convert the field frequency of 49.95 Hz by 6/5 and convert it to 59.94 Hz.
[0092]
This so-called 3: 2: 3: 2: 2 pull-down process will be described with reference to FIG. A video signal having a field frequency of 49.95 Hz is interlaced and converted so that the even field on the input side 133a becomes the even field on the output side 133b and the odd field on the input side 133a becomes the odd field on the output side 133b. Since the video signal on the input side 133a is based on the video output of the telecine device 11, there is no time difference within the same frame. For this reason, the video signal converted to the output side 133b does not cause inconvenience in terms of time. For every 5 frames on the input side, one new frame is created on the output side, but there is no inconvenience in motion because no inconvenience occurs in the field order within the frame.
[0093]
Note that the 525 / 59.94 video signal obtained by the NTSC converter 132 is longer than the movie film 20 by 0.1%.
[0094]
In this manner, the image information conversion system according to the second embodiment converts a movie film 20 shot at 25 Fps into a PAL 625/50 video signal and an NTSC 525 / 59.94 video signal. Can be converted.
[0095]
In this case, since only one master video tape cassette 13 is required, the telecine device 11 is used only once, and the frequency of damaging the movie film 20 can be reduced. Also in the NTSC system, a 625/50 master video tape cassette is used, and 525 scanning lines are created from line scanning by 625 scanning lines. Therefore, higher image quality can be expected than when the original 525 conversion is performed.
[0096]
In addition, since the movie film 20 photographed at 25 Fps is used, both the 525 / 59.94 video signal and the 625/50 video signal, when converted to a video signal, are practically used in the performance time of the movie film. It will be the same performance time.
[0097]
Also, the modified digital video tape player 131 only needs to change the PLL circuit of the existing D-1 video player and change the external reference signal, so that the cost can be reduced.
[0098]
In the first and second embodiments, both the 625/50 video signal and the 525 / 59.94 video signal are obtained by the digital video tape playback device and the modified digital video tape playback device. However, any of the video signals may be obtained by selectively operating one of them.
[0099]
Alternatively, only the modified digital video playback device may be used to play back video signals of 625/50 and 625 / 47.952, or to play back video signals of 625/50 and 625 / 49.95. In this case, the operation of the NTSC converter for obtaining 525 / 59.94 is made selective.
[0100]
【The invention's effect】
In the image information conversion method according to the present invention, image information on a motion picture film photographed at a predetermined number of frames per second is converted into an image having a first conversion step of 625 scanning lines / field frequency of 50 Hz. The 625/50 video signal is converted into a signal, and the recording process records the 625/50 video signal on the recording medium, and the reproduction process from the recording medium is different from the field frequency 50 Hz used in the first conversion process. After playback at the field frequency, the second conversion process converts the video signal into an NTSC 525 / 59.94 video signal. The frequency of damaging the film can be reduced. Also, only one master tape can be used.
[0101]
When the first conversion process reproduces image information on a motion picture film taken at 25 frames per second at the same speed, the second conversion process uses the field of the video signal obtained in the reproduction process. Since the frequency is 6/5 times, the performance time of the video signals of the above two systems can be practically the same as the performance time of the movie film.
[Brief description of the drawings]
FIG. 1 is a block diagram of a first embodiment of an image information conversion method according to the present invention.
FIG. 2 is a block diagram showing a detailed configuration of a telecine apparatus used in the first embodiment.
FIG. 3 is a block diagram of a video and audio processing system of a D-1 video tape recording apparatus applicable to the digital video tape recording apparatus used in the first embodiment.
FIG. 4 is a block diagram of a video and audio processing system of a D-1 video tape playback apparatus applicable to the digital video tape playback apparatus used in the first embodiment.
FIG. 5 is a block diagram of a servo system of a D-1 video tape reproducing apparatus applicable to the modified digital video tape reproducing apparatus used in the first embodiment.
FIG. 6 is a block diagram showing a specific example of a PLL circuit of the servo system.
FIG. 7 is a diagram showing interlaced scanning used to explain so-called 3: 2 bull-down processing of the field frequency converter used in the first embodiment.
FIG. 8 is a principle diagram of so-called 3: 2 bull-down processing performed by the field frequency conversion device used in the first embodiment.
FIG. 9 is a block diagram of a second embodiment of an image information conversion method according to the present invention.
FIG. 10 is a principle diagram of so-called 3: 2: 3: 2: 2 pull-down processing performed by the field frequency conversion device used in the second embodiment.
FIG. 11 is a block diagram showing a configuration of a conventional image information conversion system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Movie film, 11 Telecine device, 12 Digital video tape recording device, 13 Master video tape cassette, 14 Digital video tape playback device, 15 Modify digital video tape playback device, 16 NTSC conversion part, 17 Scan destination number conversion device, 18 fields Frequency converter

Claims (6)

In an image information conversion method for converting image information on a movie film into a standard video signal,
A first conversion step of converting image information on a motion picture film taken at a predetermined number of frames per second into a video signal having a scanning line number (lines) / field frequency (Hz) of 625/50;
A recording step of recording the 625/50 video signal converted in the first conversion step on a recording medium;
A reproduction step of reproducing the video signal at a field frequency different from the field frequency of the first conversion step from the recording medium on which the 625/50 video signal is recorded by the recording step;
A second conversion step of converting the video signal obtained in the reproduction step into a video signal of 525 / 59.94. 2. The recording apparatus according to claim 1, further comprising another reproducing process for reproducing the video signal from a recording medium on which a 625/50 video signal is recorded by the recording process, with a field frequency of 50 Hz. The image information conversion method described. 2. The image information converting method according to claim 1, wherein said first converting step reproduces image information on a motion picture film taken at 24 frames per second at a speed of 25 frames per second. 4. The image information conversion method according to claim 3, wherein the second conversion step comprises a field frequency conversion step of increasing the field frequency of the image information obtained in the reproduction step by 5/4. 2. The image information converting method according to claim 1, wherein said first converting step reproduces image information on a motion picture film taken at 25 frames per second at the same speed. 6. The image information conversion method according to claim 5, wherein the second conversion step comprises a field frequency conversion step of increasing the field frequency of the video signal obtained in the reproduction step to 6/5 times.

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