JP2011199473A - Device for setting bit rate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a bit rate so as to record all codes of a moving image in a recording medium with respect to an encoder of a variable bit rate system.SOLUTION: A cumulative code amount calculation unit 14 outputs a cumulative code amount D. A remaining capacity calculation unit 15 subtracts the cumulative code amount D from recording medium capacity C to obtain the remaining capacity (C-D). An encoded recording time length acquisition unit 16 acquires encoded recording time length N. A remaining recording time length calculation unit 17 subtracts the encoded recording time length N from moving image recording time length M to obtain the remaining recording time length (M-N). A bit rate calculation unit 18 divides the remaining capacity (C-D) by the remaining recording time length (M-N) to obtain the bit rate K. A bit rate setting unit 19 sets bit rate BR equal to the bit rate K in a bit rate calculation unit 22 of an encoder 2.

Description

  The present invention relates to a bit rate setting device that can set a bit rate that allows a variable bit rate encoding device to record all the codes of a moving image on a recording medium.

  2. Description of the Related Art Conventionally, for example, a variable bit rate encoding apparatus is known as one of encoding apparatuses that encode a moving image such as a movie.

  In FIG. 6, the encoding device 2 corresponds to the data amount of the encoding target portion of the moving image V so as to encode the moving image V so as to obtain the total code amount corresponding to the bit rate BR set from the outside. This is a variable bit rate type encoding apparatus that encodes the encoding target portion at a bit rate larger or smaller than the bit rate BR.

  For example, the encoding device 2 encodes the moving image V transmitted from the moving image storage device 3 by the variable bit rate method, and transmits the code to the code storage device 4 for storage.

  The encoding device 2 acquires an encoding unit 21 that encodes the moving image V and the data amount of the encoding target portion from the encoding unit 21. If the data amount is large, for example, intense motion continues. In the case of the encoding target part, a bit rate larger than the bit rate BR is calculated. On the other hand, when the data amount is small, for example, in the case of the encoding target part which is a still image, the bit rate smaller than the bit rate BR And a bit rate calculation unit 22 that gives the bit rate to the encoding unit 21. The encoding unit 21 encodes the encoding target portion at the given bit rate.

  Thereby, the encoding apparatus 2 can encode the moving image V so that the total code amount according to the bit rate BR can be obtained.

  All the codes corresponding to the total code amount are read from the code storage device 4 and recorded on, for example, a recording medium (DVD disc or the like).

JP 2000-156857 A

  FIG. 7 is a diagram showing how the total code amount changes during the encoding process. The horizontal axis shows the transition of time on the recording time of the moving image V, and the vertical axis shows the code amount.

  If the data amount of each encoding target portion of the moving image V is constant and a bit rate equal to the bit rate BR is always given to the encoding unit 21, the period from the beginning of encoding to an arbitrary timing The total code amount is equal to the target code amount P0, that is, the constant integral of the bit rate during the period, and increases with a constant slope equal to the bit rate BR.

  However, the data amount of each encoding target portion of the moving image V is not usually constant, and the actual total code amount D2 may be larger than the target code amount P0 when the data amount increases, for example.

  Therefore, the total code amount eventually becomes larger than the capacity of the recording medium, and all codes may not be recorded on the recording medium.

  Therefore, it is conceivable to add a function to the encoding device 2 so that all codes can be recorded on the recording medium.

  However, for example, the encoding device 2 may be made by another company and the inside thereof may not be disclosed, or may be already integrated, so that it is actually difficult to add functions.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bit rate that allows a variable bit rate encoding apparatus to record all the codes of a moving image on a recording medium. An object of the present invention is to provide a bit rate setting device that can be set.

  In order to solve the above-described problem, the bit rate setting device according to the first aspect of the present invention is configured to encode a moving image so as to obtain a total code amount corresponding to a bit rate set from the outside. Until the encoding of the moving image is completed with respect to the variable bit rate encoding apparatus that encodes the encoding target portion at a bit rate larger or smaller than the bit rate according to the data amount of the encoding target portion. A bit rate setting device for setting a bit rate at a plurality of timings, and a recording medium capacity storage in which a recording medium capacity that is a maximum code amount that can be recorded on a recording medium on which an encoded moving image is recorded is stored in advance A moving image recording time length storage unit that stores in advance a moving image recording time length that is a recording time length of the moving image, and a plurality of times until the encoding of the moving image ends. A cumulative code amount calculation unit that calculates a cumulative code amount that is a cumulative code amount that has been encoded in encoding, and if the cumulative code amount is calculated, reads the recording medium capacity from the recording medium capacity storage unit, A remaining capacity calculation unit that calculates a remaining capacity obtained by subtracting the accumulated code amount from the medium capacity, and a moving image portion corresponding to the accumulated code amount that has been encoded at a plurality of timings until the encoding of the moving image ends. An encoded recording time length acquisition unit that acquires an encoded recording time length that is a recording time length of the video, and if the encoded recording time length is acquired, a moving image recording from the moving image recording time length storage unit A remaining recording time length calculation unit that reads a time length and calculates a remaining recording time length obtained by subtracting the encoded recording time length from the moving image recording time length, and the remaining capacity and the remaining recording time length are calculated. Na A bit rate calculation unit that calculates a bit rate obtained by dividing the remaining capacity by the remaining recording time length; and a bit rate that sets a bit rate equal to the bit rate in the encoding device if the bit rate is calculated And a setting unit.

  The bit rate setting device according to the second aspect of the present invention is based on the data amount of the encoding target portion of the moving image so as to encode the moving image so as to obtain a total code amount corresponding to the bit rate set from the outside. A bit rate that sets a bit rate at a plurality of timings until the encoding of the moving image is completed with respect to a variable bit rate encoding apparatus that encodes the moving image at a bit rate larger or smaller than the bit rate. A setting device, a recording medium capacity storage unit in which a recording medium capacity, which is a maximum code amount that can be recorded on a recording medium on which an encoded moving image is recorded, and a recording time length of the moving image; A moving image recording time length storage unit in which a certain moving image recording time length is stored in advance, and a cumulative code that has been encoded at a plurality of timings until the encoding of the moving image is completed A cumulative code amount calculation unit that calculates the cumulative code amount, and if the cumulative code amount is calculated, the recording medium capacity is read from the recording medium capacity storage unit, and the cumulative code amount is subtracted from the recording medium capacity A remaining capacity calculation unit for calculating a remaining capacity, and an encoded recording that is a recording time length of a moving image portion corresponding to a cumulative code amount that has been encoded at a plurality of timings until the encoding of the moving image is completed; When the encoded recording time length acquisition unit acquires the time length, and the encoded recording time length is acquired, the moving image recording time length is read from the moving image recording time length storage unit, and the moving image recording time A remaining recording time length calculation unit for calculating a remaining recording time length obtained by subtracting the encoded recording time length from a length, and if the remaining capacity and the remaining recording time length are calculated, the remaining capacity is determined as the remaining recording time. Long A bit rate calculation unit for calculating the divided bit rate, an initial bit rate storage unit for storing an initial bit rate which is a bit rate calculated for the first time, and a newly calculated bit rate for the second and subsequent times. The latest bit rate storage unit for storing the latest bit rate, and if the latest bit rate is calculated, the initial bit rate is read from the initial bit rate storage unit, and whether the latest bit rate is smaller than the initial bit rate. A bit rate determination unit that determines whether or not, and the latest cumulative code amount that is an encoded code amount only for a period that goes back a predetermined time length at each timing for setting the bit rate for the encoding device If the latest accumulated code amount calculation unit and the latest bit rate are calculated, the latest bit rate and the predicted bit rate are calculated. If the latest cumulative code amount threshold value calculation unit that calculates the latest cumulative code amount threshold value obtained by multiplying the predetermined time length and a predetermined coefficient with each other, and the latest cumulative code amount threshold value and the latest cumulative code amount threshold value are calculated, The latest cumulative code amount determination unit that determines whether or not the latest cumulative code amount is smaller than the latest cumulative code amount threshold; the determination result by the bit rate determination unit is affirmative; and the latest cumulative code amount determination If the determination result by the unit is affirmative, the initial bit rate is read from the initial bit rate storage unit, and a bit rate equal to the initial bit rate is set in the encoding device, while the determination result by the bit rate determination unit Or, if the determination result by the latest cumulative code amount determination unit is negative, the latest bit rate is read from the latest bit rate storage unit, Characterized in that it comprises a bit rate setting unit for setting a bit rate equal to the new bit rate to the encoding device.

  According to the bit rate setting device of the present invention, it is possible to set a bit rate at which all the codes of a moving image can be recorded on a recording medium for a variable bit rate encoding device.

It is a figure which shows the structure and utilization form of the bit rate setting apparatus which concern on 1st Embodiment. It is a figure for demonstrating the mechanism in which the accumulation code amount in 1st Embodiment becomes ideally equal to a recording medium capacity | capacitance. It is a figure which shows the mode of the change of the actual accumulation code amount in 1st Embodiment. It is a figure which shows the structure and utilization form of the bit rate setting apparatus which concern on 2nd Embodiment. It is a figure for demonstrating the mechanism in which the accumulated code amount in 2nd Embodiment becomes ideally equal to a recording medium capacity | capacitance. It is a figure which shows the structure and utilization form of the encoding apparatus in the past. It is a figure which shows the mode of the change of the total code amount in the process of the encoding in the past.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram illustrating the configuration and usage of the bit rate setting device according to the first embodiment.

  The bit rate setting device 1 is a device that sets the bit rate BR for the encoding device 2.

  The encoding device 2 depends on the data amount of the encoding target portion of the moving image V so as to encode the moving image V so that the total code amount corresponding to the bit rate BR set from the bit rate setting device 1 is obtained. This is a variable bit rate type encoding apparatus that encodes a part to be encoded at a bit rate larger or smaller than the bit rate BR.

  For example, the encoding device 2 encodes the moving image V transmitted from the moving image storage device 3 by the variable bit rate method, and transmits the code to the code storage device 4 for storage.

  The encoding device 2 acquires an encoding unit 21 that encodes the moving image V and the data amount of the encoding target portion from the encoding unit 21. If the data amount is large, for example, intense motion continues. In the case of the encoding target part, a bit rate larger than the bit rate BR is calculated. On the other hand, when the data amount is small, for example, in the case of the encoding target part which is a still image, the bit rate smaller than the bit rate BR And a bit rate calculation unit 22 that gives the bit rate to the encoding unit 21, and the encoding unit 21 encodes the part to be encoded at the bit rate supplied from the bit rate calculation unit 22.

  Thereby, the encoding apparatus 2 can encode the moving image V so that the total code amount corresponding to the bit rate BR set from the bit rate setting apparatus 1 can be obtained.

  The bit rate setting device 1 is a device that sets the bit rate BR, for example, every 10 seconds at a plurality of timings until the encoding of the moving image V is completed with respect to such an encoding device 2.

  The bit rate setting device 1 stores in advance a recording medium capacity C (for example, 4.7 gigabytes) that is the maximum code amount that can be recorded on a recording medium (DVD disc or the like) on which an encoded moving image is recorded. A recording medium capacity storage unit 11 and a moving image recording time length M that is a recording time length (also referred to as a reproduction time length) of the moving image V (for example, a time length of 2 hours when the moving image V is a movie) are stored in advance. A moving image recording time length storage unit 12, a timer 13 that outputs a timing signal t at each timing, for example, a code is monitored and a cumulative code amount is continuously calculated, and a timing signal t is received. When the accumulated code amount calculation unit 14 for outputting the accumulated code amount D, which is the latest calculated value, is output at the timing, and the accumulated code amount D is output, the recording medium capacity C is read from the recording medium capacity storage unit 11 and recorded. The remaining capacity calculation unit 15 that calculates the remaining capacity (C−D) obtained by subtracting the accumulated code amount D from the medium capacity C and the timing at which the timing signal t is received, for example, the encoded accumulated from the encoding device 2. If the encoded recording time length acquisition unit 16 that acquires the encoded recording time length N, which is the recording time length of the moving image portion corresponding to the code amount, is acquired, The remaining recording time length is calculated by reading the moving image recording time length M from the image recording time length storage unit 12 and calculating the remaining recording time length (MN) obtained by subtracting the encoded recording time length N from the moving image recording time length M. If the calculation unit 17 calculates the remaining capacity (CD) and the remaining recording time length (MN), the bit rate obtained by dividing the remaining capacity (CD) by the remaining recording time length (MN). Bit rate calculation to calculate K (= (C−D) ÷ (MN)) When the bit rate K is calculated, the unit 18 includes a bit rate setting unit 19 that sets a bit rate BR equal to the bit rate K in the bit rate calculation unit 22 of the encoding device 2, and an input unit (not shown).

(Operation of the first embodiment)
In the first embodiment, the recording medium capacity C and the moving image recording time length M are input from the input unit, the recording medium capacity C is input to the recording medium capacity storage unit 11, and the moving image recording time length M is the moving image recording time. It is stored in the time length storage unit 12.

  For example, the timer 13 outputs a timing signal t at each timing of 10 seconds including the timing before the transmission of the moving image V to the encoding device 2 is started.

  The accumulated code amount calculation unit 14 first outputs zero as the accumulated code amount D at the timing of receiving the first timing signal t.

  The remaining capacity calculation unit 15 reads out, for example, 4.7 gigabytes, which is the recording medium capacity C, from the recording medium capacity storage unit 11 and outputs zero from the recording medium capacity C when zero which is the accumulated code amount D is output. Subtract and obtain 4.7 GB, the remaining capacity (C-D).

  The encoded recording time length acquisition unit 16 first acquires, for example, zero that is the encoded recording time length N from the encoding device 2 at the timing of receiving the first timing signal t.

  If the encoded recording time length N is acquired, the remaining recording time length calculation unit 17 reads out, for example, 2 hours, which is the moving image recording time length M, from the moving image recording time length storage unit 12, and the moving image recording time The encoded recording time length N (zero) is subtracted from the length M to obtain, for example, 2 hours, which is the remaining recording time length (MN).

  For example, if the remaining capacity (C−D) of 4.7 gigabytes and the remaining recording time length (M−N) of 2 hours are calculated, the bit rate calculation unit 18 calculates the remaining capacity (C−D). Dividing by the remaining recording time length (M−N), the bit rate K (= (C−D) ÷ (M−N)), that is, the initial bit rate K0 is obtained.

  When the initial bit rate K0 is calculated, the bit rate setting unit 19 sets a bit rate BR equal to the initial bit rate K0 in the bit rate calculation unit 22 of the encoding device 2.

  The bit rate calculation unit 22 acquires the data amount of the encoding target portion from the encoding unit 21. When the data amount is large, for example, in the case of the encoding target portion where intense motion continues, the initial bit rate K0. When a larger bit rate is calculated, on the other hand, when the amount of data is small, for example, in the case of an encoding target portion that is a still image, a bit rate smaller than the initial bit rate K0 is calculated and the bit rate is encoded. Part 21 is given.

  The encoding unit 21 encodes the encoding target portion at the bit rate given from the bit rate calculation unit 22, transmits the code to the code storage device 4, and stores it.

  Next, the bit rate calculation unit 22 acquires the data amount of the next encoding target portion from the encoding unit 21, similarly calculates the bit rate, and gives the bit rate to the encoding unit 21.

  The encoding unit 21 encodes the encoding target portion at the bit rate given from the bit rate calculation unit 22, transmits the code to the code storage device 4, and stores it.

  While the same processing continues, the accumulated code amount calculation unit 14 monitors the code, and continuously calculates and stores the accumulated code amount D.

  For example, the timer 13 outputs the second timing signal t 10 seconds after the first timing.

  The accumulated code amount calculation unit 14 outputs the accumulated code amount D at the timing when the second timing signal t is received. Of course, the accumulated code amount D is larger than the previous accumulated code amount D.

  When the second cumulative code amount D is output, the remaining capacity calculation unit 15 reads the recording medium capacity C from the recording medium capacity storage unit 11, subtracts the second cumulative code amount D from the recording medium capacity C, and Capacitance (C-D) is obtained.

  The encoded recording time length acquisition unit 16 acquires, for example, the encoded recording time length N from the encoding device 2 at the timing of receiving the second timing signal t. The encoded recording time length N is, of course, longer than the previous encoded recording time length N.

  When the encoded recording time length N is acquired, the remaining recording time length calculation unit 17 reads the moving image recording time length M from the moving image recording time length storage unit 12 and encodes it from the moving image recording time length M. The recording time length N is reduced to obtain the remaining recording time length (MN).

  When the remaining capacity (CD) and the remaining recording time length (MN) are calculated, the bit rate calculation unit 18 divides the remaining capacity (CD) by the remaining recording time length (MN). The bit rate K, that is, the second bit rate K is obtained.

  When the second bit rate K is calculated, the bit rate setting unit 19 sets a bit rate BR equal to the bit rate K in the bit rate calculation unit 22 of the encoding device 2.

  The bit rate calculation unit 22 acquires the data amount of the encoding target portion from the encoding unit 21, and when the data amount is large, for example, in the case of the encoding target portion where intense motion continues, the second bit When the bit rate is larger than the rate K, and the amount of data is small, for example, in the case of the encoding target portion that is a still image, the bit rate smaller than the second bit rate K is calculated and the bit The rate is given to the encoding unit 21.

  The encoding unit 21 encodes the encoding target portion at the bit rate given from the bit rate calculation unit 22, transmits the code to the code storage device 4, and stores it.

  Next, the bit rate calculation unit 22 acquires the data amount of the next encoding target portion from the encoding unit 21, similarly calculates the bit rate, and gives the bit rate to the encoding unit 21.

  The encoding unit 21 encodes the encoding target portion at the bit rate given from the bit rate calculation unit 22, transmits the code to the code storage device 4, and stores it.

  While the same processing continues, the accumulated code amount calculation unit 14 monitors the code, and continuously calculates and stores the accumulated code amount D.

  Thereafter, the same processing as when the second timing signal t is output is performed, and the code is stored in the code storage device 4.

  FIG. 2 is a diagram for explaining a mechanism in which the accumulated code amount D is ideally equal to the recording medium capacity C in the first embodiment. The horizontal axis indicates the transition of time on the recording time of the moving image V, and the vertical axis indicates the code amount.

  At the first timing T0, the encoding device 2 is set with a bit rate BR equal to the initial bit rate K0.

  If the data amount of each encoding target portion of the moving image V is constant and a bit rate equal to the bit rate BR is always given to the encoding unit 21, the target code amount P0 in that case, that is, the encoding unit The constant integral in the period from the timing T0 to an arbitrary timing for the bit rate given to 21 increases with a constant slope equal to the bit rate BR and finally becomes equal to the recording medium capacity C. In this case, the target code amount P0 is always equal to the cumulative code amount D, and all codes can be recorded on a recording medium (DVD disc or the like), for example.

  In the first embodiment, all codes can be recorded on a recording medium (DVD disc or the like) even if the data amount of each encoding target portion of the moving image V is not constant. The mechanism is as follows.

  During the period from timing T0 to timing T1 when the second bit rate BR is set, for example, when the data amount of the encoding target portion of the moving image V increases, the cumulative code amount D becomes larger than the target code amount P0. .

  As a result, at the timing T1, the remaining capacity (C-D) is greatly reduced, so that the bit rate BR is reduced. Thereafter, if the data amount of each encoding target portion of the moving image V is constant, the definite integral in the period from the timing T1 regarding the target code amount P1 in that case, that is, the bit rate given to the encoding unit 21, to an arbitrary timing is It increases at a constant slope equal to the bit rate BR and finally becomes equal to the recording medium capacity C.

  The bit rate BR after the reduction is equal to the gradient of the target code amount P1, and is smaller than the gradient of the target code amount P0.

  On the contrary, during the period from the timing T1 to the timing T2 when the third bit rate BR is set, for example, when the data amount of the encoding target portion of the moving image V decreases, the cumulative code amount D becomes the target code amount P1. It may become smaller and may be smaller than the target code amount P0.

  Thereby, at the timing T2, the decrease in the remaining capacity (C-D) is reduced, so that the bit rate BR is increased. Thereafter, if the data amount of each encoding target portion of the moving image V is constant, the definite integration from the timing T2 regarding the target code amount P2 in that case, that is, the bit rate given to the encoding unit 21 to an arbitrary timing, It increases with a constant slope equal to the rate BR and finally becomes equal to the recording medium capacity C.

  The increased bit rate BR is equal to the gradient of the target code amount P2, and is larger than the gradient of the target code amount P1.

  As a result, after timing T2, the accumulated code amount D approaches the target code amount P2, and ideally becomes equal to the recording medium capacity C. That is, all the codes can be ideally recorded on a recording medium (DVD disc or the like).

  FIG. 3 is a diagram illustrating how the actual accumulated code amount D changes in the first embodiment. The horizontal axis shows the transition of time on the recording time of the moving image V, and the vertical axis shows the code amount. As a comparative example, changes in the total code amount D2 and the target code amount P0 in the past are shown.

  For example, when the data amount of the encoding target portion of the moving image V increases, the total code amount D2 becomes larger than the target code amount P0 and may eventually exceed 4.7 gigabytes.

  However, in the first embodiment, when the data amount of the encoding target portion of the moving image V increases and the accumulated code amount D becomes larger than the target code amount P0, the remaining capacity (C−D) decreases more greatly. In addition, the bit rate BR is reduced. As a result, the accumulated code amount D approaches the target code amount P0, and can finally be within the recording medium capacity C and within a small error.

  Therefore, the bit rate setting apparatus 1 according to the first embodiment encodes the moving image in order to encode the moving image V so that the total code amount corresponding to the bit rate BR set from outside is obtained. Depending on the data amount of the portion, the variable bit rate type encoding device 2 that encodes the portion to be encoded at a bit rate larger or smaller than the bit rate, a plurality of times until the encoding of the moving image is completed. A bit rate setting device that sets a bit rate BR at timing, and a recording medium capacity storage that stores in advance a recording medium capacity C that is a maximum code amount that can be recorded on a recording medium on which an encoded moving image is recorded Unit 11, a moving image recording time length storage unit 12 in which a moving image recording time length M, which is a moving image recording time length, is stored in advance, and a plurality of times until encoding of moving images is completed A cumulative code amount calculation unit 14 that calculates a cumulative code amount D, which is a cumulative code amount that has been encoded at the timing, and, when the cumulative code amount is calculated, reads the recording medium capacity from the recording medium capacity storage unit, A remaining capacity calculation unit 15 that calculates a remaining capacity (C−D) obtained by subtracting the accumulated code amount from the medium capacity, and a cumulative code amount that has been encoded at a plurality of timings until encoding of the moving image ends. The encoded recording time length acquisition unit 16 that acquires the encoded recording time length N that is the recording time length of the corresponding moving image portion, and the moving image recording time length storage if the encoded recording time length is acquired A remaining recording time length calculation unit 17 that reads out a moving image recording time length from the recording unit and calculates a remaining recording time length (MN) obtained by subtracting the encoded recording time length from the moving image recording time length; And remaining record If the length is calculated, the bit rate calculation unit 18 that calculates the bit rate K, K0 obtained by dividing the remaining capacity by the remaining recording time length, and if the bit rate is calculated, the bit rate BR equal to the bit rate. And a bit rate setting unit 19 for setting the coding rate to the encoding device, it is possible to set a bit rate at which all the codes of the moving image can be recorded on the recording medium for the variable bit rate coding device.

[Second Embodiment]
FIG. 4 is a diagram illustrating the configuration and usage of the bit rate setting device according to the second embodiment.

  In the second embodiment, the same reference numerals are given to the devices already described in the first embodiment and the components thereof, and repeated description will be omitted as appropriate.

  The bit rate setting device 1A has a plurality of timings until the encoding of the moving image V with respect to the encoding device 2, for example, the timing before the moving image V starts to be transmitted to the encoding device 2, and its timing. This is a device that sets the bit rate BR every 0.5 seconds, including the timing after the second.

  The bit rate setting device 1A includes a recording medium capacity storage unit 11, a moving image recording time length storage unit 12, a timer 13, a cumulative code amount calculation unit 14, a remaining capacity calculation unit 15, and an encoded recording time length. The acquisition unit 16, the remaining recording time length calculation unit 17, the bit rate calculation unit 18, and the timing every 0.5 seconds including 0.5 seconds after the timing when the second bit rate K is calculated, for example. The timer 100 that outputs the signal t1, the initial bit rate storage unit 101 that stores the initial bit rate K0, and the latest bit rate Ki that is the newest bit rate K calculated by the second and subsequent output of the timing signal t. Is stored in the latest bit rate storage unit 102 and the latest bit rate Ki is calculated, the initial bit rate K0 is obtained from the initial bit rate storage unit 101. A bit rate determination unit 103 that determines whether or not the latest bit rate Ki is smaller than the initial bit rate K0, and, for example, monitors a code and determines a predetermined time length L (for example, 0.5 seconds) The latest cumulative code amount H, which is the encoded amount of code that has been encoded only during the period retroactively, is output, and if the timing signal t1 is output, the latest cumulative code amount H at that time is output. When the calculation unit 104 calculates the latest bit rate Ki, it calculates the latest accumulated code amount threshold G obtained by multiplying the latest bit rate Ki, the time length L, and a predetermined coefficient α (for example, 0.5). If the latest cumulative code amount threshold calculation unit 105, the parameter storage unit 106 in which the time length L and the coefficient α are stored in advance, the latest cumulative code amount H are output, and the latest cumulative code amount threshold G is calculated, the latest cumulative code amount threshold value G is calculated. Mark The latest cumulative code amount determination unit 107 that determines whether the amount H is smaller than the latest cumulative code amount threshold G and the determination result by the bit rate determination unit 103 are affirmative, and the latest cumulative code amount determination unit 107 If the determination result is affirmative, the initial bit rate K0 is read from the initial bit rate storage unit 101, and the bit rate BR equal to the initial bit rate K0 is set in the bit rate calculation unit 22 of the encoding device 2, while the bit rate If the determination result by the determination unit 103 or the determination result by the latest cumulative code amount determination unit 107 is negative, the latest bit rate Ki is read from the latest bit rate storage unit 102, and the bit rate BR equal to the latest bit rate Ki is set. A bit rate setting unit 108 to be set in the bit rate calculation unit 22 of the encoding device 2; And an input unit.

(Operation of Second Embodiment)
In the second embodiment, a recording medium capacity C, a moving image recording time length M, a time length L, and a coefficient α are input from the input unit, and the recording medium capacity C is stored in the recording medium capacity storage unit 11 as a moving image recording time. The length M is stored in the moving image recording time length storage unit 12, and the time length L and the coefficient α are stored in the parameter storage unit 106.

  In the second embodiment, until the second bit rate K is calculated, the bit rate calculation unit 18 stores the initial bit rate K0 in the initial bit rate storage unit 101, and the bit rate setting unit 108 The initial bit rate K0 is the same as that of the first embodiment except that the initial bit rate K0 is immediately read out and set in the bit rate calculation unit 22, and thus the description thereof is omitted.

  In the second embodiment, the timer 100 outputs the timing signal t1 when the second bit rate K (the latest bit rate Ki at this time) is calculated, and thereafter performs the timing every 0.5 seconds. The signal t1 is output.

  When the second bit rate K (the latest bit rate Ki at this time) is calculated, the bit rate calculation unit 18 stores the latest bit rate Ki in the latest bit rate storage unit 102.

  When the latest bit rate Ki is calculated, the bit rate determination unit 103 reads the initial bit rate K0 from the initial bit rate storage unit 101, and determines whether or not the latest bit rate Ki is smaller than the initial bit rate K0. If the latest bit rate Ki is smaller than the initial bit rate K0, the bit rate determination unit 103 gives a positive determination result to the bit rate setting unit 108. On the other hand, if the latest bit rate Ki is equal to or higher than the initial bit rate K0, the bit rate A negative determination result is given to the setting unit 108.

  When the timing signal t1 is output, the latest accumulated code amount calculation unit 104 outputs the latest accumulated code amount H at that time.

  When the latest bit rate Ki is calculated, the latest accumulated code amount threshold calculation unit 105 reads the time length L and the coefficient α from the parameter storage unit 106, and multiplies the latest bit rate Ki, the time length L, and the coefficient α with each other. Obtain and output the latest cumulative code amount threshold G.

  When the latest cumulative code amount H and the latest cumulative code amount threshold G are output, the latest cumulative code amount determination unit 107 determines whether or not the latest cumulative code amount H is smaller than the latest cumulative code amount threshold G. If the latest accumulated code amount H is smaller than the latest accumulated code amount threshold G, the latest accumulated code amount determination unit 107 gives a positive determination result to the bit rate setting unit 108, while the latest accumulated code amount H is the latest accumulated code amount H. If it is equal to or larger than the amount threshold G, a negative determination result is given to the bit rate setting unit 108.

  For example, the latest accumulated code amount H is a small value when the portion of the moving image V corresponding to the latest accumulated code amount H is a still image. That is, it can be said that the latest accumulated code amount determination unit 107 determines whether or not the portion of the moving image V corresponding to the latest accumulated code amount H is a still image.

  If the determination result by the bit rate determination unit 103 is affirmative and the determination result by the latest cumulative code amount determination unit 107 is affirmative, the bit rate setting unit 108 reads the initial bit rate from the initial bit rate storage unit 101. K0 is read and a bit rate BR equal to the initial bit rate K0 is set in the bit rate calculation unit 22 of the encoding device 2.

  On the other hand, if the determination result by the bit rate determination unit 103 or the determination result by the latest cumulative code amount determination unit 107 is negative, the bit rate setting unit 108 reads the latest bit rate Ki from the latest bit rate storage unit 102. The bit rate BR equal to the latest bit rate Ki is set in the bit rate calculation unit 22 of the encoding device 2.

  FIG. 5 is a diagram for explaining a mechanism in which the accumulated code amount D is ideally equal to the recording medium capacity C in the second embodiment. The horizontal axis shows the transition of time on the recording time of the moving image V, and the vertical axis shows the code amount.

  As in the first embodiment, if the data amount of each encoding target portion of the moving image V is constant and a bit rate equal to the initial bit rate K0 is always given to the encoding unit 21, the target code The quantity P0 increases with a constant slope equal to the initial bit rate K0 (= bit rate BR) and finally becomes equal to the recording medium capacity C. In this case, the target code amount P0 is always equal to the accumulated code amount, and all codes can be recorded on, for example, a recording medium (DVD disc or the like).

  Similarly to the first embodiment, for example, when the data amount of the encoding target portion of the moving image V increases between timing T0 and timing T1, the cumulative code amount D becomes larger than the target code amount P0. Become.

  As a result, as in the first embodiment, the remaining capacity (C−D) is greatly reduced at the timing T1, so that the bit rate BR is reduced. Similarly to the first embodiment, if the data amount of each encoding target portion of the moving image V is constant thereafter, the target code amount P1 increases with a constant slope equal to the bit rate BR, and finally It becomes equal to the recording medium capacity C.

  Similar to the first embodiment, the reduced bit rate BR is equal to the gradient of the target code amount P1 and smaller than the gradient of the target code amount P0. That is, the reduced bit rate BR is lower than the initial bit rate K0.

  Here, assuming that the bit rate setting unit 108 always sets the bit rate BR after this reduction, that is, the latest bit rate Ki to the bit rate calculation unit 22, the accumulated code amount D is represented by the reference code amount D1. As a result, the slope of the reference code amount D1 decreases between the timings T1 and T2, and the bit rate may decrease. In this case, all codes can be recorded on the recording medium. However, when the codes are reproduced, the image quality is lowered between the timings T1 and T2.

  However, when the latest accumulated code amount H is smaller than the latest accumulated code amount threshold G, the bit rate setting unit 108 encodes not the latest bit rate Ki but the bit rate BR equal to the larger initial bit rate K0. 2 bit rate calculation unit 22 is set.

  In other words, if the latest bit rate Ki is smaller than the initial bit rate K0 and the most recently encoded portion is a still image, the bit rate setting unit 108, for example, also uses the latest bit rate Ki in subsequent movie scenes. Is smaller than the initial bit rate K0 and a still image continues, a larger bit rate BR is set in the encoding device 2.

  For example, it is determined that the latest bit rate Ki is smaller than the initial bit rate K0 and the latest accumulated code amount H is smaller than the latest accumulated code amount threshold G in the period from the timing T1 to the timing T1 ′ before the timing T2. Then, a bit rate BR equal to the initial bit rate K0, that is, a bit rate BR that is at least equal to or higher than the latest bit rate Ki is set in the bit rate calculation unit 22, and the accumulated code amount D becomes larger than the reference code amount D1. Therefore, the image quality during this period is improved.

  Even if it is determined that the latest bit rate Ki is lower than the initial bit rate K0 and the latest accumulated code amount H is equal to or greater than the latest accumulated code amount threshold G after the timing T1 ′, the timings T1 and T1 ′. By increasing the cumulative code amount D between the two, the image quality when the code is reproduced can be improved. In addition, all codes can be recorded on the recording medium in spite of increasing the accumulated code amount D between the timings T1 and T1 '. That is, it is possible to satisfy both the recording of all codes on the recording medium and the improvement of the image quality.

  Therefore, the bit rate setting device 1A according to the second embodiment encodes a moving image in order to encode a moving image so as to obtain a total code amount corresponding to the bit rate BR set from the outside. Bits at a plurality of timings until the encoding of the moving image is completed with respect to the variable bit rate encoding apparatus 2 that encodes the moving image at a bit rate larger or smaller than the bit rate according to the data amount of A bit rate setting device for setting a rate BR, and a recording medium capacity storage unit 11 in which a recording medium capacity C, which is a maximum code amount that can be recorded on a recording medium on which an encoded moving image is recorded, is stored in advance; A moving image recording time length storage unit 12 in which a moving image recording time length M, which is a moving image recording time length, is stored in advance, and a plurality of timings until encoding of the moving image ends. A cumulative code amount calculation unit 14 for calculating a cumulative code amount D, which is a cumulative code amount that has been encoded in the recording, and, if the cumulative code amount is calculated, reads the recording medium capacity from the recording medium capacity storage unit, A remaining capacity calculation unit 15 that calculates a remaining capacity (C−D) obtained by subtracting the accumulated code amount from the medium capacity, and a cumulative code amount that has been encoded at a plurality of timings until encoding of the moving image ends. The encoded recording time length acquisition unit 16 that acquires the encoded recording time length N that is the recording time length of the corresponding moving image portion, and the moving image recording time length storage if the encoded recording time length is acquired A remaining recording time length calculation unit 17 that reads out a moving image recording time length from the recording unit and calculates a remaining recording time length (MN) obtained by subtracting the encoded recording time length from the moving image recording time length; And the remaining recording time length If so, the bit rate calculation unit 18 for calculating the bit rates K, K0 and Ki obtained by dividing the remaining capacity by the remaining recording time length and the initial bit rate K0 which is the first calculated bit rate are stored. The initial bit rate storage unit 101, the latest bit rate storage unit 102 for storing the latest bit rate Ki, which is the most recently calculated bit rate for the second and subsequent times, and the initial bit rate if the latest bit rate is calculated. The initial bit rate is read from the storage unit, the bit rate determination unit 103 that determines whether or not the latest bit rate is smaller than the initial bit rate, and predetermined timing at each timing for setting the bit rate for the encoding device Latest cumulative code that calculates the latest cumulative code quantity H, which is the encoded code quantity only for the period that goes back the time length L If the latest bit rate is calculated, the code amount calculation unit 104 calculates the latest cumulative code amount threshold G by multiplying the latest bit rate, a predetermined time length L, and a predetermined coefficient α. When the amount threshold value calculation unit 105, the latest accumulated code amount, and the latest accumulated code amount threshold value are calculated, it is determined whether or not the latest accumulated code amount is smaller than the latest accumulated code amount threshold value. If the determination result by the bit rate determination unit is affirmative and the determination result by the latest cumulative code amount determination unit is affirmative, the initial bit rate is read from the initial bit rate storage unit, and the initial bit rate is set. While the same bit rate is set in the encoding device, the determination result by the bit rate determination unit or the determination result by the latest cumulative code amount determination unit is negative. A bit rate setting unit 108 that reads the latest bit rate from the latest bit rate storage unit and sets the bit rate equal to the latest bit rate in the encoding device. The bit rate can be set so that all the codes can be recorded on the recording medium, and the image quality when the codes are reproduced can be improved.

  In each embodiment, 4.7 GB referred to as the recording medium capacity C, 2 hours referred to as the recording time length of the moving image V, 10 seconds referred to as the interval of the timing signal t, and intervals of the timing signal t1 The mentioned 0.5 seconds, 0.5 seconds mentioned as the time length L, and 0.5 mentioned as the coefficient α are examples used for convenience of explanation, and other numerical values may be used.

  Further, the encoded recording time length N is acquired from the encoding device 2. However, for example, when the encoded recording time length N is obtained by the moving image storage device 3, it is acquired from the moving image storage device 3. May be.

DESCRIPTION OF SYMBOLS 1, 1A ... Bit rate setting device 2 ... Encoding device 3 ... Moving image storage device 4 ... Code storage device 11 ... Recording medium capacity storage unit 12 ... Moving image recording time length storage unit 13, 100 ... Timer 14 ... Cumulative code amount Calculation unit 15: Remaining capacity calculation unit 16 ... Encoded recording time length acquisition unit 17 ... Remaining recording time length calculation unit 18, 22 ... Bit rate calculation unit 19, 108 ... Bit rate setting unit 21 ... Encoding unit 101 ... Initial Bit rate storage unit 102 ... Latest bit rate storage unit 103 ... Bit rate determination unit 104 ... Latest accumulated code amount calculation unit 105 ... Latest accumulated code amount threshold calculation unit 106 ... Parameter storage unit 107 ... Latest accumulated code amount determination unit α ... Coefficient BR ... Bit rate C ... Recording medium capacity D ... Cumulative code amount D1 ... Reference code amount D2 ... Total code amount G ... Latest cumulative code amount threshold H ... Latest cumulative code K: Bit rate K0: Initial bit rate Ki: Latest bit rate L ... Time length M ... Moving image recording time length N ... Encoded recording time length P0, P1, P2 ... Target code amount V ... Moving image T0, T1, T1 ', T2 ... Timing t, t1 ... Timing signal

Claims (2)

In order to encode a moving image so that a total code amount corresponding to a bit rate set from the outside can be obtained, the code is encoded at a bit rate larger or smaller than the bit rate depending on the data amount of the encoding target portion of the moving image. A bit rate setting device that sets a bit rate at a plurality of timings until the encoding of the moving image is completed with respect to a variable bit rate encoding device that encodes a portion to be encoded;
A recording medium capacity storage unit that stores in advance a recording medium capacity that is the maximum code amount that can be recorded in a recording medium on which the encoded moving image is recorded;
A moving image recording time length storage unit in which a moving image recording time length that is a recording time length of the moving image is stored in advance;
A cumulative code amount calculation unit that calculates a cumulative code amount that is a cumulative code amount that has been encoded at a plurality of timings until encoding of the moving image is completed;
When the accumulated code amount is calculated, a recording medium capacity is read from the recording medium capacity storage unit, and a remaining capacity calculation unit that calculates a remaining capacity obtained by subtracting the accumulated code amount from the recording medium capacity; and
Encoded recording time length that acquires an encoded recording time length that is a recording time length of a moving image portion corresponding to a cumulative code amount that has been encoded at a plurality of timings until the encoding of the moving image ends. An acquisition unit;
If the encoded recording time length is acquired, the remaining recording time obtained by reading the moving image recording time length from the moving image recording time length storage unit and subtracting the encoded recording time length from the moving image recording time length A remaining recording time length calculator for calculating the length;
If the remaining capacity and the remaining recording time length are calculated, a bit rate calculation unit that calculates a bit rate obtained by dividing the remaining capacity by the remaining recording time length;
A bit rate setting device comprising: a bit rate setting unit that sets, in the encoding device, a bit rate equal to the bit rate when the bit rate is calculated. The moving image is encoded at a bit rate larger or smaller than the bit rate according to the data amount of the encoding target portion of the moving image so as to encode the moving image so that the total code amount corresponding to the bit rate set from the outside is obtained. A bit rate setting device that sets a bit rate at a plurality of timings until encoding of a moving image is completed with respect to a variable bit rate encoding device that encodes an image,
A recording medium capacity storage unit that stores in advance a recording medium capacity that is the maximum code amount that can be recorded in a recording medium on which the encoded moving image is recorded;
A moving image recording time length storage unit in which a moving image recording time length that is a recording time length of the moving image is stored in advance;
A cumulative code amount calculation unit that calculates a cumulative code amount that is a cumulative code amount that has been encoded at a plurality of timings until encoding of the moving image is completed;
When the accumulated code amount is calculated, a recording medium capacity is read from the recording medium capacity storage unit, and a remaining capacity calculation unit that calculates a remaining capacity obtained by subtracting the accumulated code amount from the recording medium capacity; and
Encoded recording time length that acquires an encoded recording time length that is a recording time length of a moving image portion corresponding to a cumulative code amount that has been encoded at a plurality of timings until the encoding of the moving image ends. An acquisition unit;
If the encoded recording time length is acquired, the remaining recording time obtained by reading the moving image recording time length from the moving image recording time length storage unit and subtracting the encoded recording time length from the moving image recording time length A remaining recording time length calculator for calculating the length;
If the remaining capacity and the remaining recording time length are calculated, a bit rate calculation unit that calculates a bit rate obtained by dividing the remaining capacity by the remaining recording time length;
An initial bit rate storage unit that stores an initial bit rate that is a bit rate calculated for the first time;
A latest bit rate storage unit for storing the latest bit rate which is the most recently calculated bit rate from the second time onward;
When the latest bit rate is calculated, the initial bit rate is read from the initial bit rate storage unit, and a bit rate determination unit that determines whether the latest bit rate is smaller than the initial bit rate;
A latest cumulative code amount calculation unit that calculates a latest cumulative code amount that is an encoded code amount only in a period that goes back a predetermined time length at each timing for setting a bit rate for the encoding device;
If the latest bit rate has been calculated, a latest cumulative code amount threshold value calculation unit that calculates a latest cumulative code amount threshold value obtained by multiplying the latest bit rate, the predetermined time length, and a predetermined coefficient,
If the latest accumulated code amount and the latest accumulated code amount threshold are calculated, a latest accumulated code amount determination unit that determines whether the latest accumulated code amount is smaller than the latest accumulated code amount threshold;
If the determination result by the bit rate determination unit is affirmative and the determination result by the latest cumulative code amount determination unit is affirmative, the initial bit rate is read from the initial bit rate storage unit, and the initial bit rate If the determination result by the bit rate determination unit or the determination result by the latest cumulative code amount determination unit is negative, the latest bit rate storage unit updates the latest bit rate to the encoding device. A bit rate setting device comprising: a bit rate setting unit that reads a bit rate and sets a bit rate equal to the latest bit rate in the encoding device.

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