Movie film having two digital audio data recording areas along its longitudinal direction

The movie film has two tracks of left and right digital audio data recording areas in addition to a frame image information recording area in the form of frames, an analog audio data recording area, and left and right perforations. In these audio data recording areas, the same encoded audio data is recorded. Preferably, the audio data is constituted, using the encoding system called the ATRAC system, by the encoding parameter data, the encoded audio data, and the same parameter as the encoding parameter doubly written. This doubly written parameter is recorded in a manner so that when for example the encoding parameter and the encoded audio data are recorded on the left side audio data recording area for a certain channel, the tracks are switched so that the recording is carried out on the opposite right side audio data recording area.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a movie film (or a projection film or a 
motion picture), more particularly relates to a movie film recording 
digital audio data. 
2. Description of the Related Art 
In a movie film, a plurality of video recording portions are arranged in a 
longitudinal direction in the form of frames. Audio data related to the 
video images recorded in the corresponding video recording portions is 
recorded in an analog format along these video recording portions. 
To achieve an improvement of the audio reproduction, contrary to this, a 
method of recording the audio data in a digital format has been proposed. 
The conventional method of recording audio data in a digital format suffers 
from the disadvantage of a pour encoding and recording efficiency and data 
loss due to scratches on the movie film or the like. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a movie film in which the 
reproduction ability of audio data is not lost in practice even in the 
event of scratches on the movie film, the efficiency of encoding is high, 
and the audio reproduction data is recorded in a digital format. 
Another object of the present is to enable the reproduction of an audio 
having a high quality with a small number of bits (or bytes) effective for 
a movie film restricted in space. 
Still another object of the present invention is to provide an audio signal 
having a high reliability and good reproduction quality without requiring 
a great modification in the already existing apparatus. 
To achieve the above-mentioned objects, the movie film of the present 
invention is characterized in that it includes a frame image information 
recording area (portion) arranged along a longitudinal direction in the 
form of frames and at least two digital audio data recording areas 
arranged at different positions in a direction orthogonal to the 
longitudinal direction and in that the audio reproduction data is recorded 
in a digital format with a predetermined relationship in at least two 
digital audio data recording areas. 
In the movie film of the present invention, the same audio reproduction 
data is preferably doubly recorded on at least two digital audio data 
recording areas with a predetermined relationship, and therefore even in a 
case where a scratch or the like is formed on one digital audio data 
recording area and reproduction cannot be performed there, the 
reproduction can be carried out using the other audio reproduction data, 
so the reliability of the reproduction of the audio data is high. 
Specifically, the audio reproduction data recorded in the digital audio 
data recording areas is constituted by a plurality of channels. Each 
channel has a parameter by which the audio reproduction data is encoded, 
the encoded data, and a doubly written parameter the same as the parameter 
or the same as a part of the parameter. 
Preferably, the doubly written encoding parameter is recorded in a digital 
audio data recording area which is different from the digital audio data 
recording area in which the encoding parameter and the encoded data are 
recorded. 
In the method for recording the doubly written encoding parameter, a 
preferable relationship exists depending on the number of channels. 
When the number of the channels is an even number, the doubly written 
encoding parameter is recorded at the recording position of another 
digital audio data recording area corresponding to the recording position 
of the digital audio data recording area in which the encoding parameter 
and the encoded data are recorded. 
Also, when the number of the channels is an odd number, the doubly written 
encoding parameter is recorded in another digital audio data recording 
area in units of two cycles. 
Preferably, the encoding of the audio reproduction data is carried out 
based on an encoding system called the ATRAC system (adaptive transform 
acoustic coding encoding system developed by Sony Corporation) wherein 
that data is broken down on a two-dimensional region of time and 
frequency, what types of components that audio data is constituted by is 
analyzed; with what degree of precision these components should be encoded 
is determined to determine the encoding parameter; and the components of 
the respective audio data are normalized and requantized for each 
two-dimensional sub-region of time and frequency on the basis of the 
encoding parameter to produce the encoded data. 
If the doubly written encoding parameter is recorded in a digital audio 
data recording area which is different from another digital audio data 
recording area in which the encoding parameter and the encoded data are 
recorded, in particular, it becomes possible to prevent decoding 
(reproduction) error of the compressed data due to encoding in the event 
of scratches peculiar to the movie film. 
As the method of recording of the doubly written encoding parameter, a 
preferable method is adopted in accordance with whether the number of the 
channels is even or odd as mentioned above.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a partial plan view of a movie film of a first embodiment of the 
present invention. 
This movie film 1 has a plurality of video recording portions 10 provided 
in the form of frames along a longitudinal (advancing) direction of the 
movie film 1; an analog and audio data recording portion 16 provided 
beside these video recording portions 10; a left side perforation 12 which 
is provided on the outside of the video recording portions 10 and the 
analog and audio data recording portion 16 and feeds the movie film 1; and 
a right side perforation 14. The structure of the above-mentioned movie 
film 1 is that of a movie film transmitting a usual analog audio signal. 
The movie film 1 is further provided with a digital audio data recording 
portion 18 beside the left side perforation 12. 
In this way, the movie film 1 in which the analog and audio data recording 
portion 16 and the digital audio data recording portion 18 are provided 
can be used in both a projector having an analog type audio reproduction 
device and a projector having a digital type audio reproduction device. 
Note that, in the present invention, the audio (sound) reproduction data 
means a broad range of sound information recognized by the auditory sense 
and including voice and other sounds. 
FIG. 2 is an enlarged partial view of the digital audio data recording 
portion 18. 
The digital audio data recording portion 18 is provided with a digital 
audio data recording portion 184 at the center. A left side tracking bar 
180 and a right side tracking bar 182 are provided on the two sides of 
this digital audio data recording portion 184 so that correct positioning 
or position detection for reproducing (decoding) the audio data recorded 
on the digital audio data recording portion 184 is carried out. 
The left side tracking bar 180 and the right side tracking bar 182 are not 
directly related with the gist of the present invention, and therefore a 
detailed explanation thereof will be omitted. 
FIG. 3 is a view of the format of the audio reproduction data recorded on 
the digital audio data recording portion 184 shown in FIG. 2. 
On the digital audio data recording portion 184, based on the SDDS (Sony 
Dynamic Digital Sound) recording system, 8 channels of the digital audio 
data are provided for one unit of the audio data. Each channel comprises 
an encoding parameter recording portion, an encoded and compressed audio 
data recording portion, and an encoding parameter double writing recording 
portion which doubly writes the encoding parameter the same as the 
above-described encoding parameter or a part thereof. The encoding 
parameter double writing recording portion is a part for doubly writing 
the same encoding parameter or a part thereof, for enabling recovery when 
trouble occurs with the encoding parameter recorded on the encoding 
parameter recording portion. In this way, the reliability is improved with 
respect to the loss of the storage of the encoding parameter. 
Details of these will be given later. 
As mentioned above, in the SDDS recording system, the digital audio data is 
standardized to 8 channel data. However, it is difficult to ensure a 
region for recording 8 channels of audio data consisting of 16 bits at 
44.1 kHz on the movie film 1 as they are. Also, the medium of a movie film 
1 is often repeatedly used for reproduction in contact with other 
elements, and therefore it is difficult to avoid the occurrence of 
scratches etc. on the surface thereof. That is, if the digital audio data 
is recorded as the original data as is, there is a tremendous loss of the 
data, and thus the film is not suitable for practical use. Accordingly, 
the error correction code ability becomes very important, and compression 
of the audio reproduction data to an extent to which the recording region 
of that correction code can be sufficiently ensured becomes necessary. 
Therefore, the digital audio data compression technique called the ATRAC 
(adaptive transform acoustic coding) system used in the Minidisk device is 
used for the compression of the digital audio data recorded on the digital 
audio data recording portion 184 in the SDDS recording system. 
FIG. 4 is a view illustrating the principle of the ATRAC system. 
The A/D-converted digital audio data is picked out with time windows of 
11.6 ms at the maximum and broken down into frequency components by an 
MDCT (modified discrete cosine transform) computation. In this example, 
the frequency band is divided into three bands. The reasons why the 
frequency band is divided are for an improvement of the performance and 
for reduction of the price. 
Describing first about the performance, this is done for enhancing the time 
response characteristic in the respective frequency bands. When the audio 
signal is in a steady state, to ensure a high precision frequency 
resolution, a long block (11.6 ms) is used, and the effective transmission 
of the signal components and the quantization noise are controlled. While 
the audio signal abruptly changes, the time resolution is raised up to 2.9 
ms at 11 kHz or less and up to 1.45 ms at more than 11 kHz in parts. 
In regard to the price, the size of the hardware is reduced since the 
memory capacity necessary for the MDCT computation can be reduced and by 
selectively emphasizing the bands up to the intermediate band where the 
human auditory sense is high. 
That is, the ATRACT system performs compression of the audio data by 
encoding the digital audio data utilizing the nature of the human auditory 
sense. More concretely, first, the audio data to be compressed is broken 
down into signal components on a two-dimensional region of time and 
frequency, then what types of components that audio signal is constituted 
by is analyzed to find with what degree of precision the respective 
components are to be encoded, and then the parameters are formed. Finally, 
based on these encoding parameters, the audio signal components are 
normalized and requantized (block floated) for every two-dimensional 
sub-region of time and frequency to obtain an encoded audio data. 
As a result, the audio data of the ATRAC system is recorded in units called 
sound frames. 
FIG. 5 is a view showing the state of recording of the data inside a sound 
frame. 
One sound frame consists of 212 bytes. Here, audio reproduction data 
corresponding to 512 samples, i.e., one channel with a sampling rate of 
44.1 kHz is recorded. 
The 212 bytes of sound frame data are comprised of a block size mode, a 
sub-information amount, a word length data, scale factor data, spectrum 
data, a redundant scale factor byte, a redundant word length byte, a lower 
sub-information amount, and a lower block size mode. That is, the 212 
bytes of data include a doubly written part for the error correction, the 
redundant scale factor byte, redundant word length byte, and the lower 
block size mode. Further, information defining the amount of this double 
writing and the lower sub-information amount are included in the 212 
bytes. The amount occupied by the double writing can be changed for each 
sound frame. In this example, among the 212 bytes, 186 bytes are used for 
parts other than the double writing. 
The digital audio data recorded in the digital audio data recording portion 
184 inside the digital audio data recording portion 18 of the movie film 1 
is constituted based on this ATRAC system. 
FIG. 6 is a view showing the format thereof. 
This format data is composed of a sector ID of 20 bytes, DATA0 to DATA7 
each consisting of 212 bytes, and 4 bytes of CRC. More precisely, an error 
correction code (ECC) is added to the data of this format. 
A "sector" means a unit of data to which the CRC and sector ID are added 
for each 8 sound frames. 
The above related to the recording image of the digital audio data 
recording portion 184 shown in FIG. 3. 
In this way, the encoded and compressed digital audio data is divided into 
an encoding parameter region and encoded data region. The information used 
for compression is recorded in the encoding parameter region, and 
therefore when this region is destroyed, the encoded data in that region 
becomes completely meaningless. Therefore, in the ATRAC system, the most 
important encoding parameters are doubly written. 
In this way, in the movie film 1, according to the recording system of the 
MD, audio data having a high reliability even with respect to scratches 
etc. is recorded in a digital format with a high encoding efficiency. 
Accordingly, when this digital audio data is reproduced, sound having a 
high quality corresponding to that of the MD can be reproduced. 
In the movie film 1 of the above-described first embodiment, there are 
points which should be improved on from the viewpoint of the reliability. 
Even though the parameters are doubly written in the same region as in the 
movie film 1, this is not sufficient in terms of the reliability. The 
reason for this is that the direction of advance of the movie film 1 is 
the longitudinal (vertical) direction and the contact surface (sprocket), 
which is not an object of reading, passes from the top toward the bottom 
in FIG. 3 at the time of reading of the audio data from the relationship 
of the position for recording the audio data in the movie film 1. At this 
time, there is a high probability of occurrence of a linear scratch as 
indicated by the scratch 186. As a result, the encoding parameter double 
writing portion written on the same region is destroyed, and there 
sometimes occurs a case where the meaning of the double writing is lost. 
A second embodiment of the movie film of the present invention solves the 
problem in the first embodiment mentioned above. 
FIG. 7 is a partial plan view of the movie film 1A of a second embodiment 
of the movie film of the present invention. 
This movie film 1A has, in the same way as the movie film 1 shown in FIG. 
3, a right side digital audio data recording portion 20 at the position 
opposite to the left side digital audio data recording portion 18 in 
addition to the video recording portions 10, a left side perforation 12, a 
right side perforation 14, an analog audio data recording portion 16, and 
a digital audio data recording portion 18 (left side digital audio data 
recording portion 18). 
This example indicates a case wherein the left side digital audio data 
recording portion 18 and the right side digital audio data recording 
portion 20 are arranged on the outside of the left side perforation 12 and 
the right side perforation 14. 
It is sufficient if the left side digital audio data recording portion 18 
and the right side digital audio data recording portion 20 are arranged at 
positions at which they are resistant to the effects of a scratch, but by 
arranging the left side digital audio data recording portion 18 and right 
side digital audio data recording portion 20 as shown in FIG. 7, since the 
positional relationship among the left side perforation 12, video 
recording portions 10, analog audio data recording portion 16, and the 
right side perforation 14 is not changed, in a projector using the analog 
audio data recording portion 16, the analog audio data recording portion 
16 can be used as it is. 
On the left side digital audio data recording portion 18 and the right side 
digital audio data recording portion 20, the digital audio data mentioned 
referring to FIG. 3 to FIG. 6 is recorded. Substantially the same Code 
data is recorded as the digital audio data recorded on the left side 
digital audio data recording portion 18 and the digital audio data 
recorded on the right side digital audio data recording portion 20. 
In this way, the digital audio data is recorded divided at different 
positions which face each other in the longitudinal direction of the movie 
film 1A with redundancy, whereby even if a scratch such as the scratch 186 
shown in FIG. 3 is caused on for example the left side digital audio data 
recording portion 18 side, the digital audio data recorded on the right 
side digital audio data recording portion 20 can be used without problem. 
A preferable example of the recording method of the digital audio data 
having redundancy will be explained below. 
FIG. 8 shows a method of recording where the number of channels is even, 
and FIG. 9 shows a method of recording where the number of the channels is 
odd. 
FIG. 8 and FIG. 9 show the configuration of the digital audio data recorded 
on the digital audio data recording portion 184 inside the left side 
digital audio data recording portion 18 and the digital audio data 
recorded on the digital audio data recording portion 204 corresponding to 
the digital audio data recording portion 184 inside the right side digital 
audio data recording portion 20. 
The audio data compressed by the above-mentioned ATRAC system is written in 
three regions of the encoding parameter region, the encoded data region, 
and the encoding parameter double writing region. 
The size of the encoding parameter region and encoded data region differs 
depending upon the value of the encoding parameter, but the total size of 
these two regions and the size of the encoding parameter double writing 
region are constant. 
Accordingly, if the encoding parameter double writing region is ensured in 
regions which are not simultaneously destroyed, it becomes possible to 
suppress the occurrence of decoding (reproduction) error, and since the 
size is constant, the ensuring of that region is easy. 
Therefore, as shown in FIG. 8, the contents written in the encoding 
parameter double writing regions existing at the same positions at two 
tracks are switched with each other. 
By this, the following is performed so as to avoid problems. 
(1) In the encoding stage, immediately before the encoding, the tracks are 
switched only in the encoding parameter double writing regions. 
(2) At the decoding (reproduction) stage, immediately before the decoding, 
switching is performed only in the encoding parameter double writing 
regions. 
By this, the occurrence of decoding error of data can be easily suppressed. 
This divisional recording system is not restricted to a movie film and not 
restricted to the compression technique according to the ATRAC system, 
which is preferable when applied to a recording medium which vigorously 
deteriorates. It is a recording system effective when data compressed by 
using various types of audio signal compression techniques is recorded. 
Particularly, where the ATRAC system is used, it is defined by the format 
that the encoding parameter double writing region have a size of 26 bytes 
at the present and a size of more than 2 bytes and less than 67 bytes in 
the future. Therefore, to suppress the occurrence of decoding error due to 
the compression of the data, the above-mentioned divisional recording 
system is necessary and effective. 
In the current system, the audio data is standardized as 8 channels, but 
the above-mentioned method can be applied to any number of channels more 
than two. 
Concretely, the encoding parameter double writing regions are switched as 
follows: 
(a) Where the number of the channels is even, as mentioned referring to 
FIG. 8, the encoding parameter double writing regions are switched between 
the digital audio data recording portion 184 inside the left side digital 
audio data recording portion 18 and the digital audio data recording 
portion 204 inside the right side digital audio data recording portion 20 
at the same track positions as those in the encoding parameter region and 
the encoded data region. 
(b) Where the number of the channels is odd, as shown in FIG. 9, they are 
switched in units of 2 cycles as shown in FIG. 9. 
In this way, encoding parameter double writing regions having a constant 
size are simply switched. No change of the format is necessary at all, 
therefore it does not depend upon the assigned number of channels of each 
area, and thus the handling is easy. Accordingly, also, no change of the 
decoding circuit is necessary, and the occurrence of decoding error can be 
suppressed merely by adding processing for switching the encoding 
parameter double writing regions. That is, the interruption of the audio 
when correction is impossible due to a long burst error peculiar to the 
movie film can be reduced. 
The arrangement of the left side digital audio data recording portion 18 
and the right side digital audio data recording portion 20 is not 
restricted to the arrangement shown in FIG. 7. Various types of 
arrangements which enable the restoration of a long burst error due to a 
scratch etc., which is peculiar to movie film, are possible. 
For example, as illustrated in FIG. 10, for the movie film 1B, it is also 
possible to constitute the movie film by the left side perforation 12, the 
video recording portions 10, the analog audio data recording portion 16, 
the left side digital audio data recording portion 22, the right side 
perforation 14, and the right side digital audio data recording portion 
20. That is, in this movie film 1B, in place of the left side digital 
audio data recording portion 18 shown in FIG. 7, the left side digital 
audio data recording portion 22 is provided between the analog audio data 
recording portion 16 and the right side perforation 14. The left side 
digital audio data recording portion 22 and the right side digital audio 
data recording portion 20 are arranged astride the right side perforation 
14, and therefore are resistant to the effects of a scratch etc. 
Similarly, it is also possible to modify the movie film 1 shown in FIG. 7 
and arrange the left side digital audio data recording portion 18 between 
the left side perforation 12 and the video recording portions 10 and 
arrange the right side digital audio data recording portion 20 between the 
analog audio data recording portion 16 and the right side perforation 14. 
That is, from a part at the end portion of the movie film 1, which easily 
is scratched, the left side digital audio data recording portion 18 and 
the right side digital audio data recording portion 20 are provided inside 
the left side perforation 12 and the right side perforation 14. 
As the digital audio data recording portion, as mentioned referring to FIG. 
7 and FIG. 10, it is possible to provide not only a digital audio data 
recording portion having two tracks, but also provide a digital audio data 
recording portion having three or more tracks. 
Also, as the movie film of the present invention, the analog audio data 
recording portion 16 shown in FIG. 7 and FIG. 10 is not always necessary. 
While a preferred embodiment of the movie film of the present invention was 
explained above, as an easier method, in the movie film 1 shown in FIG. 7, 
it is also possible to record the same digital audio data at the same 
positions by the recording format the same as that shown in FIG. 3 in the 
left side digital audio data recording portion 18 and the right side 
digital audio data recording portion 20. 
According to the preferred movie film of the present invention, the 
reproduction ability of the audio is not lost even in the event of a 
scratch in the movie film, and the efficiency of encoding is good. 
Also, the ATRAC system adopted in the present invention enables the 
reproduction of an audio having a high quality with a small number of bits 
(or bytes), and therefore it can be applied effectively also to a movie 
film restricted in space. 
Further, according to the movie film of the present invention, it is 
possible to provide an audio signal having a high reliability and good 
reproduction quality without requiring a great modification in the already 
existing apparatus. 
Many widely different embodiments of the present invention may be 
constructed without departing from the spirit and scope of the present 
invention, and it should be understood that the present invention is not 
restricted to the specific embodiments described above.