JPH0540938A - Recording and reproducing method for digital sound track on movie film - Google Patents

Abstract

PURPOSE:To secure the number of bit required for each channel of a digital audio recording while leaving a conventional analog audio recording track and to record the digital audio of multiple channels while securing interchangeability with a conventional method. CONSTITUTION:The analog audio recording track 7 and the digital audio recording track 8 are provided on the movie film 4, and analog audio signals are recorded and reproduced for the analog audio recording track 7 by the ordinary analog recording and reproducing method. For the digital audio recording track 8, a high quality digital audio data is generated from the audio information of a specific channel, and simultaneously the digital audio data that is compressed from the audio information of other channels is generated, and each of these digital audio data is recorded and reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital sound track recording / reproducing system on a motion picture film used for recording and reproducing digital sound information on the motion picture film.

[0002]

2. Description of the Related Art Conventionally, cinema digital sound (CD
S) has been proposed (Movie Television Technology, 1991/1)
(461), P65-79). This cinema digital
Sound records digital audio information in the part used as analog audio recording part on movie film,
When this motion picture film is displayed, the pickup head optically reads out the digital audio information to reproduce an audio signal.

[0003]

However, in such a conventional digital sound track recording / reproducing system, since the digital audio information is written instead of the analog audio information, the compatibility with the conventional art is completely lost. The problem is that it is not widely used. Therefore, as a method for solving such a problem, a new track is provided on the motion picture film while leaving the conventional analog audio recording track on the motion picture film,
A method of recording digital audio information on this track is conceivable. However, in such a method, a place that is easily scratched, such as a region 103 between the perforations 102 on the motion picture film 101 is excluded as shown in FIG. Then, the gap area 106 between the picture section 104 and the conventional analog audio recording track 105, or the analog audio recording track 105 and the perforation 1
There is a space that is vacant only in the gap area 107 between the two. Further, in the present technology, considering that the size of a recording dot capable of recording and reproducing without using the focus servo is about “10” μm, it is determined based on the frame feed speed of the motion picture film 101. In order to record "16" bit, "6" channel audio at a sampling frequency of "44" KHz, "44 x
It is necessary to secure a recording capacity of about 16 × 6 ”bits / second, that is, about“ 4.22 ”Mbits / second. Considering error correction, at least a recording capacity of about“ 5 ”Mbits / second. Must be secured.

However, an area (area having a width of "660" μm) 106 between the picture section 104 and the conventional analog audio recording track 105 and an area (between the analog audio recording track 105 and the perforation 102) ( Even if the “1” bit is recorded as a “1” dot, the width of the recording area can be secured only at “1,070” μm even if the width is added to the area “width” “410” μm) 105. "45" cm / sec ("2
When the motion picture film 101 is sent at 4 "frames / second)", "45 x 10 cubed x (1,070)" bits /
There is a problem that only a transmission rate of seconds, that is, "4.8" M bits / second can be obtained, and digital audio of "6" channels or more cannot be recorded with "16" bits or more.

In view of the above circumstances, the present invention can secure the number of bits required for each channel of digital audio recording while leaving the conventional analog audio recording track, thereby ensuring compatibility with the prior art. However, it is an object of the present invention to provide a digital sound track recording / reproducing system on a movie film capable of recording digital audio information of a plurality of channels.

[0006]

To achieve the above object, a digital sound track recording / reproducing system on a motion picture film according to the present invention comprises an analog sound recording track and a digital sound recording track on the motion picture film.
An analog audio signal is recorded / reproduced to / from the analog audio recording track by a normal analog recording / reproducing system, and high-quality digital audio data is generated from digital audio information of a specific channel to the digital audio recording track. It is characterized in that compressed digital audio data is generated from the audio information of other channels and each of these digital audio data is recorded and reproduced.

[0007]

In the above structure, an analog audio recording track and a digital audio recording track are provided on the motion picture film, and an analog audio signal is recorded / reproduced on / from the analog audio recording track by a normal analog recording / reproducing system. For the digital audio recording track, high-quality digital audio data is generated from audio information of a specific channel, and compressed digital audio data is generated from audio information of other channels to generate each of these digital audio data. By recording and playing back, the number of bits required for each channel of digital audio recording is ensured while leaving the conventional analog audio recording track, thereby recording the digital audio of multiple channels while ensuring compatibility with the conventional ,Reproduce.

[0008]

1 is a block diagram showing an example of an audio information writing apparatus to which an embodiment of a digital sound track recording / reproducing system on a motion picture film according to the present invention is applied. The audio information writing device shown in this figure is a digital audio recording unit 1.
And an analog audio recording section 2 are provided, and analog audio information is taken from the audio master tape 3 and recorded on an analog audio recording track 7 provided between the picture section 5 on the motion picture film 4 and the perforation 6. On the other hand, the main audio information of 2 channels (main audio information) and the surround audio information of 4 channels (sub audio information) are taken in from the audio master tape 3 and a part of them is compressed to be recorded on the movie film 4. Recording is performed on a digital audio recording track 8 provided between the picture section 5 and the analog audio recording track 7.

The digital audio recording section 1 comprises a digital audio information processing circuit 10 and a digital audio information writing mechanism 11, which takes in two channels of main audio information from the audio master tape 3 and stores it as "16" bits. Of the digital audio data, the 4-channel surround audio information is fetched from the audio master tape 3 and converted into "4" -bit digital audio data, and these are time-multiplexed to record the digital audio data. Record on track 8. As shown in FIG. 2, the digital audio information processing circuit 10 includes two A / D conversion circuits 12 and 13, an audio compression encoder circuit 14, a clock generation circuit 15, a time base multiplexing circuit 16, and an error correction code addition circuit. 17 and the interleave circuit 18
And a modulation circuit 19, which takes in two-channel main audio information from the audio master tape 3 and converts it into "16" -bit digital audio data.
Digital surround sound information of the channel is taken in, converted into digital sound data of predetermined bits, then compressed into digital sound data of "4" bits, and these digital sound data are time-multiplexed to form write information. Voice data is generated and supplied to the digital voice information writing mechanism 11.

On the other hand, the A / D conversion circuit 12 takes in two channels of main audio information from the audio master tape 3 and A / D converts this to generate "16" bit digital audio data for each channel. Then, this is supplied to the time base multiplexing circuit 16. Also, the other A /
The D conversion circuit 13 takes in 4-channel surround sound information from the audio master tape 3 and
This is A / D converted to generate digital audio data of a predetermined bit for each channel, and this is supplied to the audio compression encoder circuit 14. The audio compression encoder circuit 14 takes in the 4-channel digital audio data output from the other A / D conversion circuit 13, compresses it for each channel, and generates "4" bit data for 4 channels. Is used as digital sub-audio data and the time axis multiplexing circuit 16
Supply to.

Further, the clock generation circuit 15 generates a clock signal at predetermined time intervals and outputs it to the time base multiplexing circuit 16
And a film feed signal is generated at a timing corresponding to the clock signal and is supplied to a film feed device (not shown) for the motion picture film 4 to feed the motion picture film 4. Time axis multiplexing circuit 1
Reference numeral 6 denotes 2-channel digital audio data output from the A / D conversion circuit 12 and 4-channel digital audio output from the audio compression encoder circuit 14 based on the clock signal output from the clock generation circuit 15. The data and the data are fetched, and these are time-axis-multiplexed to generate digital audio data for one track shown in FIG. 3, and the digital audio data is supplied to the error correction code adding circuit 17.

The error correction code adding circuit 17 takes in the digital audio data output from the time base multiplexing circuit 16, creates an error correction code corresponding to this digital audio data, and then, as shown in FIG. The error correction code is added to the audio data and supplied to the interleave circuit 18. The interleave circuit 18 takes in the digital audio data for each track output from the error correction code adding circuit 17 and temporarily stores the digital audio data, and blocks the digital audio data of several tracks for interleaving to process the processed digital audio. The data is supplied to the modulation circuit 19. The modulation circuit 19 takes in the digital audio data output from the interleave circuit 18, generates spatial modulation data from this digital audio data, and supplies this to the digital audio information writing mechanism 11.

As shown in FIG. 4, the digital voice information writing mechanism 11 includes a laser light source 20, a collimator lens 21, and
The spatial light modulator 22 and the imaging lens 23 are provided, and the laser light source 20 generates laser light and the collimator lens 21 focuses the laser light on the spatial light modulator 22.
The laser light is spatially modulated by the spatial modulator 22 based on the spatial modulation data output from the digital audio information processing circuit 10, and the modulated laser light obtained by this spatial modulation operation is formed by the imaging lens 23 in the movie film. 4 picture section 5 and the analog audio recording track 7
An image corresponding to the modulated laser beam is recorded by condensing on a digital audio recording track 8 provided between the recording medium and the recording medium.

When the driving voltage is supplied to the laser light source 20, the laser light source 20 generates a laser beam and outputs it to the collimator lens 2
Supply to 1. The collimator lens 21 collimates (focuses) the laser light output from the laser light source 20 and supplies the laser light to the incident side of the spatial modulator 22. The spatial modulator 22 has a plurality of shutter arrays, and each shutter is selectively operated based on the spatial modulation data output from the digital audio information processing circuit 10 to spatially modulate the laser light. The modulated laser light obtained by the spatial modulation operation is supplied to the imaging lens 23.

The image forming lens 23 takes in the modulated laser light supplied from the spatial modulator 22 and supplies it to a digital section provided between the picture section 5 on the motion picture film 4 and the analog audio recording track 7. An image is formed on the audio recording track 8 and an image corresponding to the modulated laser beam is optically recorded as shown in FIG. In addition, the analog voice recording unit 2 has an analog voice information processing circuit 25 as shown in FIG.
And an analog voice information writing mechanism 26,
The analog audio information is taken from the audio master tape 3 and writing light having a width corresponding to the analog audio information is generated to generate a picture portion 5 on the motion picture film 4.
And the analog audio recording track 7 provided between the perforation 6 and the perforation 6.

As shown in FIG. 6, the analog audio information processing circuit 25 has an amplifier 27 which takes in and amplifies the analog audio signal from the audio master tape, and takes in the analog audio signal from the audio master tape 3 and amplifies it. And supplies it to the analog voice information writing mechanism 26. As shown in FIG. 4, the analog voice information writing mechanism 26 includes a lamp 28, a first slit plate 29, a galvano mirror 30, a second slit plate 31, and an image forming lens 32. An analog audio signal output from the circuit 25 is taken in to generate writing light of a width corresponding to the analog audio signal, and the writing light is provided between the picture portion 5 on the motion picture film 4 and the perforation 6 The light is focused on the audio recording track 7 and an image corresponding to the value of the analog audio signal is recorded.

When the driving voltage is supplied, the lamp 28 emits light to generate a light beam, which is supplied to the first slit plate 29. The first slit plate 29 is composed of a plate-like member 36 having a triangular slit 35 formed in the central portion thereof. The first slit plate 29 takes in the light beam supplied from the lamp 28 to make the luminous flux into a triangular shape, which is then galvano mirror 30. Supply to. The galvanometer mirror 30 is the amplifier 27.
The angle of the mirror is controlled according to the value of the analog audio signal output from the second slit plate 31 while switching the emission direction of the light beam supplied from the first slit plate 29.
Supply to. The second slit plate 31 is composed of a plate-shaped member 33 having a horizontally long slit 24 formed in the center thereof, and selectively passes a part of the light beam supplied from the galvanometer mirror 30 to correspond to the analog audio signal. The writing light having the specified width is generated and supplied to the imaging lens 32. The imaging lens 32 takes in the light beam supplied from the second slit plate 31 and forms an image on the analog audio recording track 7 provided between the picture portion 5 on the motion picture film 4 and the perforation 6. As shown in FIG. 7, an image corresponding to the analog audio signal is recorded.

As described above, in the audio information writing apparatus according to this embodiment, analog audio information is read from the audio master tape 3 and provided between the picture portion 5 on the motion picture film 4 and the perforation 6 for analog audio recording. While recording on the track 7, the main audio information of 2 channels and the surround audio information of 4 channels are taken in from the audio master tape 3, and a part of them is compressed and the picture part 5 on the motion picture film 4 and the Since the recording is performed on the digital audio recording track 8 provided between the analog audio recording track 7 and the analog audio recording track 7, the conventional analog audio recording track 7 is used.
It is possible to secure the number of bits required for each channel of digital audio recording while leaving the above, and it is possible to record digital audio of a plurality of channels while ensuring compatibility with the related art.

FIG. 8 is a block diagram showing an example of an audio information reproducing apparatus to which an embodiment of a digital sound track recording / reproducing system on a motion picture film according to the present invention is applied. The audio information reproducing apparatus shown in this figure has a digital audio reproducing unit 40.
And an analog audio reproducing section 42 and a selecting section 43. When the movie film 4 is shown, the analog audio information recorded in the analog voice recording track 7 on the movie film 4 is read out. While reproducing the digital audio information recorded on the digital audio recording track 7 of the movie film 4 and reproducing the digital audio information, the selecting section 42 selects either the analog audio signal or the digital audio signal. This is supplied to an amplifying device (not shown) and a voice is output from a speaker or the like.

The digital audio reproduction section 40 comprises a digital audio information pickup mechanism 43 and a digital audio information reproduction circuit 44, and when the motion picture film 4 is screened, it is recorded on the digital audio recording track 8. After reading the digital audio information, it is reproduced and supplied to the selection unit 42. As shown in FIG. 9, the digital audio information pickup mechanism 43 includes an LED light source 45, a slit plate 46, a condenser lens 47, an image forming lens 48, and a line sensor 49, and the movie film 4 is shown. When the LED light source 45 emits light, the LED light obtained thereby is condensed on the digital audio recording track 8 on the movie film 4, and the LED light transmitted through the digital audio recording track 8 by the line sensor 49. Is generated and supplied to the digital audio information reproducing circuit 44. LED
The light source 45 is arranged so as to face the digital audio recording track 8 of the movie film 4, and when a drive current is supplied, it emits light to generate LED light, which is supplied to the slit plate 46. The slit plate 46 is composed of a plate-shaped member 51 having a horizontally long slit 50 formed in the central portion thereof, and condenses the LED light obtained by the LED light source 45 into one track shape (horizontally long shape). Supply to the lens 47. The condenser lens 47 takes in the horizontally long LED light obtained by the slit plate 46 and condenses it on the digital audio recording track 8 of the motion picture film 4.

The image forming lens 48 takes in the LED light transmitted through the digital audio recording track 8 and magnifies the LED light by a factor of "6" to form an image on the line sensor 49. The line sensor 49 is provided with a plurality of photo-detecting elements arranged in one line, and the LED light collected by the imaging lens 48 is converted into an electric signal by each photo-detecting element to produce the digital audio recording track 8 The digital audio data recorded in (3) is reproduced and supplied to the digital audio information reproducing circuit 44. In this case, the LED light imaged on the line sensor 49 is “6” by the imaging lens 48.
Since the size of the minimum dot recorded on the digital audio recording track 8 on the motion picture film 4 is “10” μm, the line sensor 49
When the size of each photo-detecting element is “15” μm, the “1” dot on the motion picture film 4 indicates the line sensor 49.
The digital audio data is reproduced by being assigned to "4" photodetection elements above, and this is supplied to the digital audio information reproducing circuit 44.

The digital audio information reproducing circuit 44 includes a demodulation circuit 55 and an error correction decoder circuit 56 as shown in FIG.
An error check circuit 57, a main / sub separation circuit 58,
The audio expansion decoder circuit 59, the memory circuit 60, the controller 61, and the two D / A conversion circuits 62 and 63 are provided, and the digital audio information pickup mechanism 4 is provided.
After the digital audio data output from 3 is taken in and error-corrected, the error-correction result is supplied to the selection unit 42 and the main audio information included in the digital audio data error-corrected by the error-correction operation , The surround sound information is separated and expanded, and the surround sound information obtained by this expanding operation and the main sound information are D / A converted to 2
A channel main audio signal and a 4-channel surround audio signal are generated and supplied to the selection unit 42.

The demodulation circuit 55 takes in the digital audio data output from the digital audio information pickup mechanism 43 and demodulates it, and then performs an inverse interleave process on the digital audio data obtained by this demodulation operation to perform each track. Of the digital audio data is reproduced and supplied to the error correction decoder circuit 56. The error correction decoder circuit 56 takes in the digital audio data output from the reproduction circuit 55, and uses an error correction code included in the digital audio data to check whether the digital audio data contains an error. The check result is supplied to the error check circuit 57, and when the digital audio data contains an error and can be corrected, the digital audio data is error-corrected and the main / sub separation circuit 58 is provided.
Supply to.

The error check circuit 57 checks whether or not the digital audio data processed by the error correction decoder circuit 56 cannot be corrected based on the check result output from the error correction decoder circuit 56. When it is uncorrectable, a digital voice unavailability detection signal is generated and supplied to the selection unit 42.
The main / sub separation circuit 58 takes in the digital audio data output from the error correction decoder circuit 56, and also includes the 2-channel digital audio data (main audio information) included in the digital audio data, and
Separated into channel digital audio data (surround audio information), 2-channel digital audio data is supplied to the memory circuit 60, and 4-channel digital audio data is supplied to the audio decompression decoder circuit 59.

The audio expansion decoder circuit 59 takes in the 4-channel digital audio data output from the main / sub separation circuit 58, expands each digital audio data for each channel, and outputs digital audio data of a predetermined number of bits. (Surround audio information) is generated and supplied to the memory circuit 60. Further, the controller 61 generates an audio output command signal at a timing corresponding to the feeding of the motion picture film 4 and supplies it to the memory circuit 60. The memory circuit 60 takes in and stores the 2-channel digital audio data output from the main / sub separation circuit 58 and the 4-channel digital audio data output from the audio decompression decoder circuit 59, and also stores the controller 6
Every time the audio output command signal is output from the unit 1, digital audio data for two channels corresponding to the track designated by the audio output command signal is read out and supplied to one D / A conversion circuit 62. Digital audio data for four channels is read out and supplied to the other D / A conversion circuit 63.

Each time the D / A conversion circuit 62 outputs the 2-channel digital audio data from the memory circuit 60, the D / A conversion circuit 62 takes in and D / A converts it to generate a 2-channel main audio signal. Is supplied to the selection unit 42. Further, the other D / A conversion circuit 63 takes in each time digital audio data of 4 channels is output from the memory circuit 60 and performs D / A conversion to generate a surround audio signal of 2 channels to generate it. The selection unit 4
Supply to 2. Further, the analog voice reproducing section 41 has an analog voice information pickup mechanism 65 as shown in FIG.
And an analog audio information reproducing circuit 66, which reads out analog audio information recorded in the analog audio recording track 7 on the motion picture film 4 and reproduces it when the motion picture film 4 is screened. It is supplied to the selection unit 42.

The analog voice information pickup mechanism 65 has a xenon lamp 67 and a slit plate 68 as shown in FIG.
And a condenser lens 69 and a solar cell 70,
When the motion picture film 4 is screened, a light beam obtained by causing the xenon lamp 67 to emit light is focused on the analog sound recording track 7 on the motion picture film 4, and the analog sound recording track 7 is controlled by the solar cell 70. The transmitted light beam is converted into an electric signal and is supplied to the analog audio information reproducing circuit 66 as an analog audio signal.

The xenon lamp 67 is arranged so as to face the analog audio recording track 7 of the motion picture film 4, and when a drive current is supplied, it emits light to generate light, which is used as a light beam to form a slit plate. Supply to 68. The slit plate 68 is composed of a plate-shaped member 72 having a horizontally long slit 71 formed in the central portion thereof, and supplies the light beam obtained by the xenon lamp 67 into the horizontally long shape to a condenser lens 69. The condenser lens 69 takes in the oblong light beam obtained by the slit plate 68, condenses it on the analog audio recording track 7 of the movie film 4, and supplies the transmitted light to the solar cell 70. The solar cell 70 receives the light beam transmitted through the analog recording track 7, generates an electric signal having a magnitude corresponding to the light amount of the light beam, and supplies the electric signal to the analog audio information reproducing circuit 66.

As shown in FIG. 11, the analog audio information reproducing circuit 66 includes a decoder circuit 75 for decoding an electric signal output from the analog audio information pickup mechanism 65 to generate an analog audio signal. The electric signal output from the pickup mechanism 65 is decoded to generate an analog audio signal, which is supplied to the selection unit 42. When the digital audio unusable detection signal is not output from the digital audio reproducing unit 40, the selecting unit 42 selects the 2-channel main audio signal and the 4-channel surround audio signal output from the digital audio reproducing unit 40. The analog audio reproduction unit 41 is selected and supplied to an amplifier to output audio from a speaker or the like, and when the digital audio reproduction unit 40 outputs a digital audio unusable detection signal.
The analog audio signal output from the speaker is selected and supplied to the amplification device to output audio from the speaker or the like.

As described above, in the audio information reproducing apparatus according to this embodiment, when the motion picture film 4 is screened, the analog sound information recorded in the analog sound recording track 7 of the motion picture film 4 is read out to obtain the analog sound signal. And the digital audio information recorded on the digital audio recording track 8 of the movie film 4 is read out to reproduce the 2-channel main audio signal and the 4-channel surround audio signal. The analog audio information recorded on the analog audio recording track 7 of the film 4 and the digital audio information recorded on the digital audio recording track 8 of the movie film 4 are read out at the same time, and both of these audio information are output from a speaker or the like. Can be output.

Further, the analog audio information recorded on the analog audio recording track 7 of the movie film 4 is read out to reproduce the analog audio signal, and the digital audio recorded on the digital audio recording track 8 of the movie film 4 is reproduced. Since the information is read and the main audio signal of 2 channels and the surround audio signal of 4 channels are reproduced, the digital audio information recorded in the digital audio recording track 8 is read out for 2 channels by any reason. Even when the main audio signal of 4 and the surround audio signal of 4 channels cannot be reproduced, the analog audio information recorded in the analog audio recording track 7 is read, the analog audio signal is reproduced, and this is reproduced from the speaker or the like. Can be output, which Even if the can reproduce sound of the same level as conventional. Further, in the above-described embodiment, the picture portion 5 on the motion picture film 4,
Although the digital audio recording track 8 is provided between the analog audio recording track 7 and the analog audio recording track 7, the digital audio recording track 8 is provided between the analog audio recording track 8 and the perforations 6, between the perforations 6 and between the picture portions 5. A digital voice recording track 8 may be provided.

[0032]

As described above, according to the present invention, the number of bits required for each channel of digital audio recording can be ensured while leaving the conventional analog audio recording track, which makes Multiple channels of digital audio can be recorded while ensuring compatibility.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an audio information writing device to which an embodiment of a digital sound track recording / reproducing system on a motion picture film according to the present invention is applied.

FIG. 2 is a block diagram showing a detailed circuit example of the digital audio information processing circuit shown in FIG.

3 is a schematic diagram showing a format example of digital audio data created by the digital audio recording unit shown in FIG. 1. FIG.

4 is a perspective view showing a detailed configuration example of a digital voice information writing mechanism and an analog voice information writing mechanism shown in FIG. 1. FIG.

5 is a schematic diagram showing an example of a digital audio recording track created by the recording operation of the digital audio information recording section shown in FIG.

FIG. 6 is a block diagram showing a detailed circuit example of the analog voice information processing circuit shown in FIG. 1.

7 is a schematic diagram showing an example of an analog audio recording track created by the recording operation of the analog audio information recording section shown in FIG.

FIG. 8 is a block diagram showing an example of an audio information reproducing apparatus to which an embodiment of a digital sound track recording / reproducing system on a motion picture film according to the present invention is applied.

9 is a perspective view showing a detailed configuration example of a digital voice information writing mechanism and an analog voice information writing mechanism shown in FIG.

10 is a block diagram showing a detailed circuit example of the digital audio information reproducing circuit shown in FIG.

11 is a block diagram showing a detailed circuit example of the analog audio information reproducing circuit shown in FIG.

FIG. 12 is a plan view showing an example of a general motion picture film.

[Explanation of symbols]

 1 Digital Audio Recording Section 2 Analog Audio Recording Section 3 Audio Master Tape 4 Movie Film 7 Analog Audio Recording Track 8 Digital Audio Recording Track 10 Digital Audio Information Processing Circuit 11 Digital Audio Information Writing Mechanism 25 Analog Audio Information Processing Circuit 26 Analog Audio Information Writing mechanism

Claims (1)

[Claims] 1. An analog audio recording track and a digital audio recording track are provided on a motion picture film, and an analog audio signal is recorded / reproduced on / from the analog audio recording track by a normal analog recording / reproducing system. For recording tracks, high-quality digital audio data is generated from digital audio information of a specific channel, and compressed digital audio data is generated from audio information of other channels to record and reproduce each of these digital audio data. A digital soundtrack recording / playback method on motion picture film characterized by the following.