JP5179306B2 - Moving picture coding method, moving picture coding apparatus, and moving picture coding program - Google Patents

Description

  The present invention relates to a technique for improving subjective video quality by appropriately controlling a quantization parameter and a frame rate with a limited code amount.

Conventionally, various image encoding techniques have been proposed. For example, Patent Document 1 discloses a technique for preparing a correspondence between a bit rate and a frame rate at which the image quality is considered optimal by a subjective quality evaluation experiment, and determining a frame rate at which the image quality is optimal based on this. It is disclosed. The technique disclosed in Patent Document 2 determines the code amount and the number of frames to be encoded within a range that does not exceed the delay amount when the encoded data is output, and determines the frame rate in accordance with the image quality. Furthermore, Patent Document 3 discloses an image quality parameter indicating a degree of change of an image in order to avoid a loss of image smoothness due to frame dropping or a rapid change in the number of frames when the property of the image changes depending on the reproduction time. A technique is disclosed in which a value is defined in advance and controlled to fall within a target frame drop range.
Japanese Patent Laid-Open No. 06-090441 Japanese Patent No. 3651706 JP 09-261638 A

  However, since the nature of the image sequence to be encoded, such as the complexity within the screen and the speed of movement, varies, the technique disclosed in Patent Document 1 does not uniquely associate the bit rate with the optimum frame rate. Have difficulty. Further, in Patent Document 2, it is considered that a sufficient code amount cannot be allocated and image quality is not sufficient in order to keep the restriction on the delay amount when outputting encoded data. Further, in Patent Document 3, there are cases where control of an image quality parameter within a target range may not be possible due to limitations of a virtual buffer represented by VBV (Video Buffer Verifier) and a bit rate.

Moreover, in a general moving image encoding device, control is performed in the following order in order to satisfy the restrictions of the virtual buffer and the bit rate.
(1) Increase the quantization parameter (QP).
(2) Perform frame skipping.

  However, when the frame skip of (2) is performed, the quantization parameter takes a maximum value. This results in the lowest image frame quality.

  Further, H.C. In the high compression encoding system represented by H.264, it is possible to satisfy the restrictions of the virtual buffer and the bit rate within the control range of the quantization parameter in many cases. However, a high quantization parameter value is sufficient. Image quality may not be achieved. On the other hand, when the bit rate is high and the image quality of each frame is more than necessary, it is better to improve the temporal resolution (smoothness of motion) by encoding at a frame rate higher than the specified frame rate. Subjective image quality can be improved.

  The present invention has been made in view of such circumstances, and a moving image code capable of improving subjective moving image quality by appropriately controlling a quantization parameter and a frame rate with a limited code amount. An object of the present invention is to provide an encoding method, a moving image encoding device, and a moving image encoding program.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the moving picture coding method of the present invention is a moving picture coding method for changing a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required picture quality, Performing first encoding on the image material constituting the image, estimating a generated code amount of each frame in all quantization parameters based on the first encoded image data, and estimating A step of determining an allocation code amount in units of frames according to encoding conditions using a generated code amount of each frame; and a step of determining whether or not the determined allocation code amount in units of frames satisfies a required image quality , A step of changing a frame rate according to the result of the determination, and the determined code amount determined by changing the frame rate If it meets the requested image quality, it is characterized by comprising the steps of performing a second encoding, the.

  In this way, it is determined whether the allocated code amount per frame satisfies the required image quality, and the frame rate is changed according to the determination result. Therefore, the quantization parameter and the frame rate are appropriately set with the limited code amount. Can be controlled. As a result, the subjective moving image quality can be improved. For example, in a low bit rate environment, subjective image quality can be improved by lowering the image quality of a certain level or more in each image frame, that is, by reducing the quantization parameter and reducing the encoding degradation. Also, in a high bit rate environment, the subjective image quality can be improved by reducing the image quality, which is more than necessary, by increasing the quantization parameter and increasing the time resolution.

  (2) In the moving image encoding method of the present invention, the image quality of the entire image sequence is calculated based on the determined allocated code amount for each frame, and the image quality indicates a first required image quality. If it is less than the threshold value, the frame rate is uniformly reduced in the entire image sequence.

  As described above, when the image quality of the entire image sequence is lower than the first threshold value indicating the required image quality, the frame rate is uniformly reduced for the entire image sequence, so that the image quality of a certain level or more is increased in each image frame Thus, the subjective image can be improved.

  (3) Further, in the moving image encoding method of the present invention, the image quality calculated from the assigned code amount of any frame unit among the determined assigned code amounts of each frame indicates the required image quality. If it is less than the first threshold, the frame rate is lowered by excluding frames that are less than the first threshold.

  In this way, when the image quality calculated from the assigned code amount of any frame unit among the determined assigned code amounts of each frame unit is less than the first threshold value indicating the required image quality, the first Since the frame rate is lowered by excluding frames that are less than the threshold value, the subjective image can be improved by raising the image quality above a certain level in each image frame.

  (4) Also, the moving picture coding method of the present invention is characterized in that the image quality calculated from the allocated code amount of any frame unit among the determined allocated code amount of each frame unit or a frame having a predetermined ratio or more. When the image quality calculated from the unit assigned code amount is less than the first threshold value indicating the required image quality, the frame rate is uniformly reduced in the entire image sequence.

  In this way, among the determined assigned code amounts for each frame, the image quality calculated from the assigned code amount for any frame unit or the image quality calculated from the assigned code amount for a frame unit equal to or greater than a predetermined ratio When the image quality is less than the first threshold value indicating the required image quality, the frame rate is uniformly reduced for the entire image sequence, so that the subjective image can be improved by increasing the image quality above a certain level in each image frame.

  (5) Further, the moving image encoding method of the present invention calculates the image quality of the entire image sequence based on the determined allocated code amount in units of frames, and the image quality indicates a second required image quality. If the threshold value is exceeded, the frame rate is uniformly increased in the entire image sequence.

  In this way, when the image quality of the entire image sequence exceeds the second threshold value indicating the required image quality, the frame rate is uniformly increased throughout the entire image sequence. The time resolution can be increased. Thereby, subjective image quality can be improved.

  (6) Further, the moving image encoding method of the present invention is characterized in that the image quality calculated from the assigned code amount of any frame unit among the determined assigned code amount of each frame unit or a frame having a predetermined ratio or more. When the image quality calculated from the unit assigned code amount exceeds the second threshold value indicating the required image quality, the frame rate is increased uniformly in the entire image sequence.

  In this way, among the determined assigned code amounts for each frame, the image quality calculated from the assigned code amount for any frame unit or the image quality calculated from the assigned code amount for a frame unit equal to or greater than a predetermined ratio When the second threshold value indicating the required image quality is exceeded, the frame rate is uniformly increased for the entire image sequence, so that the image quality that is more than necessary can be lowered and the temporal resolution can be increased. Thereby, subjective image quality can be improved.

  (7) Moreover, the moving image encoding method of the present invention further includes a step of re-determining whether the allocated code amount for each frame satisfies the required image quality based on the changed frame rate. It is characterized by.

  Thus, since it is determined again whether the allocated code amount for each frame satisfies the required image quality based on the changed frame rate, the process can be repeated recursively. Thereby, it is possible to appropriately control the quantization parameter and the frame rate with a limited code amount. As a result, the subjective moving image quality can be improved.

  (8) The moving picture encoding apparatus of the present invention is a moving picture encoding apparatus that changes a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required image quality. A first encoding unit that performs first encoding on an image material constituting a moving image, and a generated code amount of each frame in all quantization parameters based on the first encoded image data A code amount estimator, an allocation code amount determination unit that determines an allocation code amount in units of frames according to encoding conditions using the estimated generated code amount of each frame, and the determined allocation code in units of frames A determination unit that determines whether or not the amount satisfies the required image quality, a frame rate change unit that changes a frame rate according to a result of the determination, and a change in the frame rate Ri, assignment code amount said determining if they meet the requested image quality, it is characterized in that it comprises a second coding section that performs second encoding, the.

  In this way, it is determined whether the allocated code amount per frame satisfies the required image quality, and the frame rate is changed according to the determination result. Therefore, the quantization parameter and the frame rate are appropriately set with the limited code amount. Can be controlled. As a result, the subjective moving image quality can be improved. For example, in a low bit rate environment, subjective image quality can be improved by lowering the image quality of a certain level or more in each image frame, that is, by reducing the quantization parameter and reducing the encoding degradation. Also, in a high bit rate environment, the subjective image quality can be improved by reducing the image quality, which is more than necessary, by increasing the quantization parameter and increasing the time resolution.

  (9) The moving picture encoding program of the present invention is a moving picture encoding program for changing a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required picture quality. A process of performing a first encoding on an image material constituting a moving image, a process of estimating a generated code amount of each frame in all quantization parameters based on the first encoded image data, Using the estimated generated code amount of each frame, a process for determining an allocated code amount in frame units according to encoding conditions, and determining whether the determined allocated code amount in frame units satisfies a required image quality Processing, changing the frame rate according to the result of the determination, and changing the frame rate, the determined allocated code amount is requested. If they meet the image quality, a process of performing a second encoding, a series of processes including, is characterized in that a read by a computer, and can execute the command of.

  In this way, it is determined whether the allocated code amount per frame satisfies the required image quality, and the frame rate is changed according to the determination result. Therefore, the quantization parameter and the frame rate are appropriately set with the limited code amount. Can be controlled. As a result, the subjective moving image quality can be improved. For example, in a low bit rate environment, subjective image quality can be improved by lowering the image quality of a certain level or more in each image frame, that is, by reducing the quantization parameter and reducing the encoding degradation. Also, in a high bit rate environment, the subjective image quality can be improved by reducing the image quality, which is more than necessary, by increasing the quantization parameter and increasing the time resolution.

  According to the present invention, since it is determined whether the allocated code amount per frame satisfies the required image quality and the frame rate is changed according to the determination result, the quantization parameter and the frame rate are limited with a limited code amount. Can be controlled appropriately. As a result, the subjective moving image quality can be improved.

  The present invention appropriately controls the quantization parameter and the frame rate with a limited code amount, and improves the subjective moving image quality of the generated video stream. For this reason, the first-stage encoding analyzes the characteristics of the encoding difficulty of the image frame, changes the frame rate as appropriate based on the analysis result, and performs the second-stage encoding. A moving image encoding method is adopted. Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a video encoding apparatus according to the present embodiment. The moving image encoding apparatus 10 inputs an image material from the database 11 via the input / output interface 12. The 1st encoding part 13 performs 1st encoding with respect to the image material which comprises a moving image. The code amount estimation unit 14 analyzes the encoding difficulty level based on the first encoded image data, and estimates the generated code amount of each frame in all quantization parameters. The assigned code amount determination unit 15 uses the generated code amount of each frame estimated by the code amount estimation unit 14 to determine an assigned code amount (bit allocation) for each frame according to the encoding condition.

  The determination unit 16 determines whether the allocation code amount in units of frames determined by the allocation code amount determination unit 15 satisfies the required image quality. The frame rate changing unit 17 changes the frame rate according to the determination result of the determining unit 16. Further, the VBV check unit 18 models the state of the reception buffer and determines whether or not a moving image can be normally reproduced (VBV check). As a result of this determination (VBV check), when it is determined that reassignment of the code amount in units of frames is necessary, the assigned code amount correction unit 19 sets the assigned code amount in units of frames satisfying the condition of VBV. decide. The second encoding unit 20 performs the second encoding when the determined allocated code amount satisfies the required image quality due to the change in the frame rate, and finally the video stream is output. These components are connected to the control bus 30 and configured to be able to transmit / receive data to / from each other.

  FIG. 2 is a flowchart showing the operation of the video encoding apparatus according to the present embodiment. In the two-pass moving image encoding method shown in the present embodiment, first, an image material to be encoded is acquired from the database 11, and first encoding is performed on the acquired image material (step S1). Next, the encoding difficulty level is analyzed from the data acquired as a result of the first encoding, and the generated code amount of each frame in all quantization parameters is estimated (step S2). Next, using the generated code amount of each frame estimated in step S2, bit allocation is performed to determine the allocated code amount in units of frames according to the encoding condition (step S3).

  Next, it is determined whether or not the allocated code amount for each frame determined in step S3 satisfies the required image quality (step S4). That is, it is determined whether the image quality is appropriate. The determination method in step S4 includes the following.

<Determination method using PSNR value>
FIG. 3 is a diagram illustrating a determination method using a PSNR (Peak Signal-to-Noise Ratio) value. In FIG. 3, a circle 1 indicates a method using the average PSNR value of the entire image sequence to be encoded. In this method, two threshold values are used for the average PSNR value of the entire image sequence: a threshold value 1 for determining that the image quality is not sufficient, and a threshold value 2 for determining that the image quality is more than necessary. . By using these two thresholds, it is determined whether the average PSNR value satisfies the required image quality. Accordingly, whether or not the required image quality is satisfied is determined for the entire image sequence. For example, in the example shown in FIG. 3, the average PSNR value is 27.5 [dB].

[When threshold 1 is set to 30 [dB] and threshold 2 is set to 35 [dB]]
In this case, since the average PSNR value is below the threshold value 1, it is determined that the required image quality is not satisfied.

[When threshold 1 is set to 25 [dB] and threshold 2 is set to 30 [dB]]
In this case, since the average PSNR value exceeds the threshold value 1 and falls below the threshold value 2, it is determined that the required image quality is satisfied, that is, the image quality is appropriate.

[When threshold 1 is set to 20 [dB] and threshold 2 is set to 25 [dB]]
In this case, since the average PSNR value exceeds the threshold value 2, it is determined that the required image quality is more than necessary.

  In FIG. 3, circle 2 indicates a method using the PSNR value of each frame. In this method, two threshold values, ie, a threshold value 1 for determining that the image quality is not sufficient and a threshold value 2 for determining that the image quality is more than necessary are used for the PSNR value of each frame. By using these two thresholds, it is determined whether the PSNR value of each frame satisfies the required image quality. Accordingly, whether or not the required image quality is satisfied is determined for each frame.

[When threshold 1 is set to 25 [dB] and threshold 2 is set to 30 [dB]]
In this case, frames 1 and 2 are determined to satisfy the required image quality more than necessary, frames 3 and 4 are determined to satisfy the required image quality, that is, the image quality is determined to be appropriate, and frames 5 and 6 are required. It is determined that the image quality is not satisfied.

<Determination method using QP value>
FIG. 4 is a diagram illustrating a determination method using a QP (Quantization Parameter) value. In FIG. 4, circle 1 indicates a method using the average QP value of the entire image sequence to be encoded. In this method, two threshold values are used for the average QP value of the entire image sequence: a threshold value 1 for determining that the image quality is not sufficient, and a threshold value 2 for determining that the image quality is more than necessary. . By using these two threshold values, it is determined whether the average QP value satisfies the required image quality. Accordingly, whether or not the required image quality is satisfied is determined for the entire image sequence. Here, the QP value is a parameter that defines the roughness of quantization. The smaller the value, the finer the quantization and the higher the quality. Conversely, the larger the value, the rougher the quantization and the quality deteriorates. In the example shown in FIG. 3, the average QP value is 35.

[When threshold 1 is set to 30 and threshold 2 is set to 20]
In this case, since the average QP value exceeds the threshold value 1, it is determined that the required image quality is not satisfied.

[When threshold 1 is set to 40 and threshold 2 is set to 30]
In this case, since the average QP value is lower than the threshold value 1 and higher than the threshold value 2, it is determined that the required image quality is satisfied, that is, the image quality is appropriate.

[When threshold 1 is set to 50 and threshold 2 is set to 40]
In this case, since the average QP value is lower than the threshold value 2, it is determined that the required image quality is sufficiently satisfied more than necessary.

  In FIG. 4, circle 2 indicates a method using the QP value of each frame. In this method, two threshold values are used for the QP value of each frame: a threshold value 1 for determining that the image quality is not sufficient and a threshold value 2 for determining that the image quality is more than necessary. By using these two threshold values, it is determined whether or not the QP value of each frame satisfies the required image quality. Accordingly, whether or not the required image quality is satisfied is determined for each frame.

[When threshold 1 is set to 40 and threshold 2 is set to 30]
In this case, frames 1 and 2 are determined to satisfy the required image quality more than necessary, frames 3 and 4 are determined to satisfy the required image quality, that is, the image quality is determined to be appropriate, and frames 5 and 6 are required. It is determined that the image quality is not satisfied.

  Next, when the image quality is not appropriate in step S4 shown in FIG. 2, it is determined whether the image quality is low (step S5). If the image quality is low, the frame rate is lowered (step S6), and the process proceeds to step S4. In step S6, there are the following methods for reducing the frame rate.

<To reduce the frame rate>
FIG. 5 is a diagram illustrating a method for lowering the frame rate. In FIG. 5, a circle 1 indicates a method for uniformly reducing the frame rate in the image sequence to be encoded. In this method, the frame rate is uniformly reduced in the image sequence, that is, the frame rate is reduced to 1/2, 1/3, and the like. FIG. 5 shows an example in which the frame rate is lowered to 1/2. For example, 30 fps is lowered to 15 fps, and 10 fps is lowered to 5 fps. In FIG. 5, a circle 2 indicates a method of skipping only frames determined not to satisfy the required image quality. When determining the required image quality for each frame, the present method skips only the frames determined not to satisfy the required image quality. In FIG. 5, it is determined that the frames 2, 3, 5, 7, and 8 do not satisfy the required image quality, and these frames are excluded. Note that a method other than the above may be used as a method of reducing the frame rate.

  Various variations are conceivable when the frame rate is lowered in step S6 via steps S4 and S5. For example, there is a technique for determining whether or not the required image quality is satisfied in the entire image sequence, or determining whether or not the required image quality is satisfied for each frame and lowering the frame rate. In addition, there is a method of reducing the frame rate by determining whether or not the required image quality is satisfied for each frame and excluding (skipping) only frames that do not satisfy the required image quality. Furthermore, it is determined whether the required image quality is satisfied for each frame, and if the required image quality is not satisfied with a frame of a predetermined ratio or more (for example, more than half), the frame rate is lowered or the required image quality is satisfied. There is also a technique for lowering the frame rate by excluding (skipping) only frames that are not present. Other implementation method determination algorithms may be defined.

  Next, in step S5 shown in FIG. 2, when the image quality is not low, the frame rate is increased (step S7), and the process proceeds to step S4. In step S7, there are the following methods for increasing the frame rate.

<To increase the frame rate>
FIG. 6 is a diagram illustrating a method for increasing the frame rate. However, the upper limit of the frame rate is the frame rate of the image material to be encoded. In FIG. 6, circle 1 shows a method of uniformly increasing the frame rate in the image sequence to be encoded. In this method, the frame rate is uniformly increased in the image sequence, that is, the frame rate is increased to 2 times, 3 times, or the like. FIG. 6 shows an example in which the frame rate is doubled. For example, 15 fps is increased to 30 fps, and 5 fps is increased to 10 fps. A method other than the above may be used as a method for increasing the frame rate.

  Various variations are conceivable when the frame rate is increased in step S7 via steps S4 and S5. For example, there is a method of increasing the frame rate by determining whether or not the required image quality is satisfied for the entire image sequence, or determining whether or not the required image quality is satisfied for each frame. For example, it is conceivable to increase the frame rate when there is even one frame that satisfies the required image quality, or when the required image quality is satisfied with a frame of a predetermined ratio or higher (for example, more than half).

  Next, in step S4 shown in FIG. 2, when the image quality is appropriate, the state of the reception buffer is modeled, and a VBV check is performed to determine whether or not a moving image can be normally reproduced (step S8). As a result of the VBV check in step S8, when it is determined that the code amount reassignment in units of frames is necessary without being OK, the bit allocation is corrected again (step S9), and the process proceeds to step S8. On the other hand, if the result of the VBV check in step S8 is OK, the second encoding is performed according to the determined code amount for each frame (step S10), and a final output video stream is obtained.

  In the present embodiment, steps S4 to S7 are defined, and the conventional two-pass moving image encoding method can be used for the other components. The required image quality determination method and the frame rate change method defined in steps S4 to S7 can be arbitrarily selected for each step. Further, the required image quality is once determined and the frame rate is changed, so that the steps S4 to S7 are in a loop, the required image quality is determined again, and the second and subsequent frame rates are changed. Recursive processing such as implementation is also possible.

  The characteristic operations of the present invention as described above can be performed by causing a computer to execute a program. That is, the moving image encoding program of the present invention is a moving image encoding program for changing a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required image quality. Processing for performing the first encoding on the image material constituting the image, processing for estimating the generated code amount of each frame in all quantization parameters based on the first encoded image data, and the estimation A process for determining an allocated code amount in units of frames according to encoding conditions using a generated code amount of each frame, and a process for determining whether the determined allocated code amount in units of frames satisfies a required image quality Depending on the result of the determination, a process for changing the frame rate, and the determined assigned code amount is determined by the change in the frame rate. If it meets the quality, a process of performing a second encoding, a series of processes including, is characterized in that a read by a computer, and can execute the command of.

  In this way, it is determined whether the allocated code amount per frame satisfies the required image quality, and the frame rate is changed according to the determination result. Therefore, the quantization parameter and the frame rate are appropriately set with the limited code amount. Can be controlled. As a result, the subjective moving image quality can be improved. For example, in a low bit rate environment, subjective image quality can be improved by lowering the image quality of a certain level or more in each image frame, that is, by reducing the quantization parameter and reducing the encoding degradation. Also, in a high bit rate environment, the subjective image quality can be improved by reducing the image quality, which is more than necessary, by increasing the quantization parameter and increasing the time resolution.

  As described above, according to the present embodiment, it is determined whether the allocated code amount in units of frames satisfies the required image quality, and the frame rate is changed according to the determination result. Thus, the quantization parameter and the frame rate can be controlled appropriately. As a result, the subjective moving image quality can be improved.

It is a block diagram which shows schematic structure of the moving image encoder which concerns on this embodiment. It is a flowchart which shows operation | movement of the moving image encoder which concerns on this embodiment. It is a figure which shows the determination method using a PSNR value. It is a figure which shows the determination method using QP value. It is a figure which shows the method in the case of reducing a frame rate. It is a figure which shows the method in the case of raising a frame rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Moving image encoder 11 Database 12 Input / output interface 13 1st encoding part 14 Code amount estimation part 15 Allocation code amount determination part 16 Determination part 17 Frame rate change part 18 VBV check part 19 Allocation code quantity correction part 20 2nd Encoder 30 Control bus

Claims (9)

A video encoding method for changing a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required image quality,
Performing first encoding on image material constituting a moving image input from a database;
Estimating a generated code amount of each frame in all quantization parameters based on the first encoded image data;
Using the estimated generated code amount of each frame and a set frame rate to determine an allocated code amount in units of frames according to encoding conditions;
Determining whether or not the determined code amount of the determined frame unit satisfies a required image quality;
As a result of the determination, when the determined allocated code amount satisfies the required image quality, the second encoding is performed on the image data that is the target of the first encoding, and the second encoding is performed. A step of outputting the selected image material,
As a result of the determination, when the determined allocated code amount does not satisfy the required image quality, the set frame rate is changed, and as a result, determined based on the first encoded image data. Re-determining whether or not the allocated code amount per frame satisfies the required image quality. If the determined allocation code amount does not satisfy the required image quality as a result of the determination, the setting is performed by a method of uniformly reducing the frame rate or excluding only frames that do not satisfy the required image quality. 2. The moving picture encoding method according to claim 1, wherein the frame rate is changed .   The image quality of the entire image sequence is calculated based on the determined code amount allocated for each frame, and when the image quality is less than a first threshold value indicating the required image quality, the frame rate is uniformly applied to the entire image sequence. The moving picture encoding method according to claim 1 or 2, wherein the moving picture encoding method is reduced.   When the image quality calculated from the assigned code amount of any frame unit among the determined assigned code amounts of each frame unit is less than the first threshold value indicating the required image quality, it is less than the first threshold value 3. The moving picture encoding method according to claim 1, wherein the frame rate is lowered by excluding frames that are.   Of the determined allocation code amount for each frame, the image quality calculated from the allocation code amount of any frame unit or the image quality calculated from the allocation code amount of a frame unit equal to or greater than a predetermined ratio is the required image. 3. The moving picture encoding method according to claim 1, wherein when the quality is less than the first threshold value indicating the quality, the frame rate is uniformly reduced over the entire image sequence.   The image quality of the entire image sequence is calculated based on the determined allocated code amount in frame units, and when the image quality exceeds a second threshold value indicating the required image quality, the frame rate is uniformly set for the entire image sequence. 3. The moving picture coding method according to claim 1, wherein the moving picture coding method is increased.   Of the determined allocation code amount for each frame, the image quality calculated from the allocation code amount of any frame unit or the image quality calculated from the allocation code amount of a frame unit equal to or greater than a predetermined ratio is the required image. 3. The moving picture encoding method according to claim 1, wherein when the second threshold value indicating quality is exceeded, the frame rate is uniformly increased over the entire image sequence. A video encoding device that changes a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required image quality,
A first encoding unit that performs first encoding on an image material constituting a moving image input from a database;
A code amount estimating unit that estimates the generated code amount of each frame in all quantization parameters based on the first encoded image data;
An allocation code amount determination unit that determines an allocation code amount in units of frames according to encoding conditions, using the estimated generated code amount of each frame and a set frame rate;
A determination unit that determines whether the determined code amount of the determined frame unit satisfies a required image quality;
As a result of the determination, when the determined allocated code amount satisfies the required image quality, the second encoding is performed on the image data that is the target of the first encoding, and the second encoding is performed. A second encoding unit for outputting the obtained image material,
The code amount determination unit changes the set frame rate when the determined allocation code amount does not satisfy the required image quality as a result of the determination, and as a result, the determination unit A moving picture coding apparatus which judges again whether or not an allocated code amount per frame determined based on one coded image data satisfies a required picture quality. A video encoding program for changing a frame rate so that an allocated code amount determined in units of frames satisfies a predetermined required image quality,
A process of performing first encoding on image material constituting a moving image input from a database;
A process of estimating the generated code amount of each frame in all quantization parameters based on the first encoded image data;
Using the estimated generated code amount of each frame and a set frame rate, a process of determining an allocated code amount in units of frames according to encoding conditions;
A process of determining whether or not the determined code amount of the determined frame unit satisfies a required image quality;
As a result of the determination, when the determined allocated code amount satisfies the required image quality, the second encoding is performed on the image data that is the target of the first encoding, and the second encoding is performed. Output the processed image material,
As a result of the determination, when the determined allocated code amount does not satisfy the required image quality, the set frame rate is changed, and as a result, determined based on the first encoded image data. A moving image encoding program characterized in that a series of processes including a process of re-determining whether or not an allocated code amount in frame units satisfies a required image quality is read by a computer and converted into an executable command.