JP6334452B2 - Playback speed adjustment device, playback speed adjustment method, and playback speed adjustment program - Google Patents

Description

  The present invention relates to a technique for controlling the playback speed of digital content.

  In recent years, the fusion of education and ICT has progressed, and the online education service market has expanded. As described in Non-Patent Document 1, many learners take notes using the keyboard while watching online educational material contents, take notes using a stylus pen or fingers, or underline, etc. Perform the input operation. When such an input operation is performed, the learner's cognitive load is likely to increase, so the consciousness tends to concentrate on the act of writing, and the attention to the act of listening is reduced.

  As a technique for solving this problem, Non-Patent Document 2 proposes a technique for detecting a learner's input operation and temporarily stopping the content or slowing the reproduction speed.

Masahiro Ando, Masaomi Ueno, “Analysis of writing effect using tablet PC in e-learning”, Journal of Japan Society for Educational Technology, Japan Society for Educational Technology, 2011, Vol. 35, No. 2, pp.109-123 Masahiro Taniuchi, “Video lecture player that dynamically adjusts playback state from learner's note description information”, Media Education Research, 2008, Vol. 5, No. 2, pp.85-94 Daniel Szafir, Bilge Mutlu, “ARTFul: Adaptive Review Technology for Flipped Learning”, CHI2013, 2013, pp.1001-1010 Hidekazu Ito, Rei Kajikawa, “Effective method for shortening video within a limited viewing time”, IEICE Technical Report, IEICE, 2009, HIP2008-153, pp.23- 28

  However, Non-Patent Document 2 has a problem that the longer the input operation is performed by the learner, the longer it takes to view the content to the end. According to Non-Patent Document 3, the viewing time of content in online education is preferably about 15 to 20 minutes from the viewpoint of maintaining the concentration of learners. That is, if the viewing time of the content becomes long, it becomes difficult for the learner to maintain concentration.

  As in Non-Patent Document 4, there is an existing technique for setting a viewing time at the start of content viewing and adjusting the playback speed of the content according to the setting, but the playback speed is calculated based on the characteristics of the content. In many cases, the time required for the input operation of the learner and the cognitive load due to the input operation are not considered.

  The present invention has been made in view of the above, and an object of the present invention is to control the playback speed of content so as not to increase the viewing time of the content while reducing the increase in the cognitive load of the learner during the input operation. To do.

  A playback speed adjusting device according to a first aspect of the present invention is a playback speed adjusting device that adjusts the playback speed of content, and receives the playback time of the content when the user starts an input operation while viewing the content. The receiving means, the elapsed time required for the user to view the content up to the playback time, the remaining playback time required to play the remaining content after the playback time at a constant speed, and the entire content at the same speed Upper limit value determining means for determining an upper limit value of the remaining viewing time based on the total playback time required for playback, and input operation time estimation for estimating the input operation time required for the user to perform an input operation in the remaining content And a playback speed so that the content that takes time that is the sum of the remaining playback time and the input operation time can be played within the upper limit. Calculation means for output, characterized by having a.

  The playback speed adjustment apparatus further includes a storage unit that stores a score representing a correlation between scenes obtained by dividing the content into a plurality of pieces, and the input operation time estimation unit corresponds to the playback time based on the score. A scene group having a high correlation with the scene is extracted, and the input operation time is obtained by estimating and totaling the time required for the input operation by the user in each scene belonging to the scene group.

  In the playback speed adjustment apparatus, the calculation means uses the remaining playback time obtained by playing back the playback speed of each scene not belonging to the scene group at a playback speed faster than a constant speed.

  In the playback speed adjustment apparatus, the receiving unit receives a type of the input operation of the user, and the calculation unit calculates the playback speed using a coefficient corresponding to the type of the input operation. To do.

  In the reproduction speed adjusting device, the type of the input operation is an input operation other than a character, a character input operation that matches the content content, or a character input operation that does not match the content content. .

  A playback speed adjustment method according to a second aspect of the present invention is a playback speed adjustment method executed by a computer for adjusting the playback speed of content, wherein the content at the time when the user starts an input operation while viewing the content is displayed. A step of receiving a playback time, an elapsed time that the user took to view the content up to the playback time, a remaining playback time required to play the remaining content after the playback time at a constant speed, and the entire content Determining the upper limit value of the remaining viewing time based on the total playback time required when playing the video at a constant speed, estimating the input operation time required by the user for the input operation in the remaining content, Content that requires time that is the sum of the remaining playback time and the input operation time can be played within the upper limit. And having the steps of: calculating the playback speed.

  A reproduction speed adjustment program according to a third aspect of the present invention is characterized by operating a computer as each means of the reproduction speed adjustment apparatus.

  According to the present invention, it is possible to control the playback speed of the content so that the viewing time of the content is not prolonged while reducing the increase in the learner's cognitive load during the input operation.

It is a functional block diagram which shows the structure of the content reproduction system in 1st Embodiment. It is a figure which shows the example of the data which the content database with which the server of the said content reproduction system is provided is hold | maintained. It is a flowchart which shows the flow of a process of the content reproduction system in 1st Embodiment. It is a flowchart which shows the flow of the process which calculates reproduction | regeneration speed. It is a flowchart which shows the flow of the process which produces | generates the scene information stored in a content database, and a network graph. It is a figure which shows a mode that the character of "A" is input by handwriting. It is a figure explaining a mode that the set of a series of event groups is made into 1 scene. It is a functional block diagram which shows the structure of the content reproduction system in 2nd Embodiment.

[First Embodiment]
FIG. 1 is a functional block diagram showing the configuration of the content reproduction system according to the first embodiment. The content reproduction system shown in the figure includes a server 1 and a client terminal 2. The client terminal 2 receives content from the server 1 and plays it. The client terminal 2 reproduces content at a reproduction speed designated by the server 1 when the user is performing an input operation. The server 1 receives the playback time of the content when the user starts an input operation from the client terminal 2, and considers the time required for the user's input operation, and the viewing time after the received playback time is within a predetermined range. The content reproduction speed is calculated so as to be within the range and transmitted to the client terminal 2. Hereinafter, each device will be described.

  The client terminal 2 includes a content request transmission unit 21, a content reception unit 22, an input operation detection unit 23, and a playback speed change unit 24.

  The content request transmission unit 21 transmits a content acquisition request to the server 1. The content is specified by a user who uses the client terminal 2, for example.

  The content receiving unit 22 receives content from the server 1 and causes the client terminal 2 to reproduce the received content. A general video playback player can be used for content playback.

  The input operation detection unit 23 detects a user input operation on the client terminal 2 and transmits the playback time of the content being played back to the server 1 at the start of the input operation. The input operation is, for example, a character input operation using a keyboard or a stylus pen, or an operation for modifying a character such as underlining. For example, an input operation is detected based on the occurrence of an event such as an input event by a mouse such as mousedown, mousemove, or mouseup, or an input event by a stylus pen or a finger.

  The input operation detection unit 23 transmits the event to the playback speed change unit 24 when the event that has occurred is an event indicating the start of the input operation or an event indicating the end of the input operation. For example, as an event indicating the start of an input operation, “mouseddown”, “touchdown”, or the like can be considered. As an event indicating the end of the input operation, mouseup, touchup, or the like can be considered. An event corresponding to an event indicating the start of the input operation or an event indicating the end of the input operation may be manually set in advance.

  The playback speed changing unit 24 receives an event from the input operation detecting unit 23. When the received event is an event indicating the start of the input operation, the playback speed change flag is set to 1, and in the case of an event indicating the end of the input operation. The playback speed change flag is set to 0. The playback speed changing unit 24 receives the playback speed from the server 1 and adjusts the playback speed of the content so that the content is played back at the received playback speed while the playback speed change flag is 1. For example, the playback speed may be changed by using a playback speed changing function of a general video player.

  The server 1 includes a content request reception unit 11, a content database (DB) 12, a correlation graph construction unit 13, an input operation reception unit 14, a playback speed calculation unit 15, and a playback speed notification unit 16.

  The content request receiving unit 11 receives a content acquisition request from the client terminal 2, acquires the content from the content DB 12, and transmits the content to the client terminal 2.

  The content DB 12 holds content and information related to the content. FIG. 2 shows an example of data stored in the content DB 12. In the example of the figure, the data stored in the content DB 12 is composed of a content ID column, a visual information column, an auditory information column, a scene column, and a graph column.

  The content ID column stores a content ID that can uniquely identify the content. The visual information column stores visual information of content, for example, teaching material data in a slide format. The file format of the teaching material data is not limited, and for example, a file format such as PDF, word, and html is conceivable. The auditory information column stores the auditory information of the content, for example, voice data of the lecturer included in the content. The file format of the audio data is not limited, and a file format such as mp3 can be considered. In this embodiment, the content is composed of visual information and auditory information. A moving image file may be stored as content.

The scene column and the graph column are information related to content generated by the correlation graph construction unit 13 described later. In the scene column, scene information including the start time and end time of each scene obtained by dividing the content or each scene extracted from the content is stored. The graph column stores a network graph representing the relationship between scenes. As the format of the network graph, for example, a data structure such as an array or a dictionary can be considered. In the example of FIG. 2, the score representing the correlation between the first scene and the second scene of the content C ₁ is expressed as C ₁ (1,2): 0.3.

  The correlation graph construction unit 13 divides the content into a plurality of scenes, stores the scene information in the content DB 12, creates a network graph representing the relationship between each scene, and stores it in the graph column of the content DB 12.

  The input operation receiving unit 14 receives the playback time of the content from the client terminal 2 and transmits it to the playback speed calculation unit 15.

  The playback speed calculation unit 15 is a time required for the user to view the content up to the playback time, a time required to view the remaining content after the playback time at a constant speed, and a time when the entire content is viewed at a constant speed. The upper limit value of the remaining viewing time is determined based on the time required for. The playback speed calculation unit 15 refers to the content DB 12 to extract a scene highly relevant to the scene corresponding to the playback time, estimates the time required for the input operation by the user in the highly relevant scene, and inputs the user The playback speed is calculated so that the viewing time including the time required for the operation is within the upper limit of the viewing time determined.

  The playback speed notification unit 16 transmits the playback speed calculated by the playback speed calculation unit 15 to the client terminal 2.

  Each unit included in the server 1 and the client terminal 2 may be configured by a computer including an arithmetic processing device, a storage device, and the like, and the processing of each unit may be executed by a program. This program is stored in a storage device included in the server 1 and the client terminal 2, and can be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or provided through a network.

  Next, the operation of the content reproduction system in the first embodiment will be described.

  FIG. 3 is a flowchart showing the flow of processing of the content reproduction system in the first embodiment.

  When the user selects content that the user wants to view, the content request transmission unit 21 transmits an acquisition request including the content ID of the content selected by the user to the server 1 (step S11).

  When receiving the acquisition request, the content request receiving unit 11 acquires content (visual information and auditory information) corresponding to the content ID included in the acquisition request from the content DB 12, and transmits the content to the client terminal 2 (step S12). The client terminal 2 receives the content and starts reproducing the content. Further, the client terminal 2 accepts an input operation from the user during the reproduction of the content.

  When the input operation detection unit 23 detects a user input operation, the input operation detection unit 23 transmits the content reproduction time at the start of the input operation to the server 1 (step S13).

  The playback speed calculation unit 15 estimates the input operation time required for the input operation by the user after the received playback time, determines the upper limit value of the remaining viewing time, and the viewing time including the input operation time is within the upper limit value. The reproduction speed is calculated so as to be within the range (step S14). Details of the process of calculating the playback speed by the playback speed calculation unit 15 will be described later.

  The playback speed changing unit 24 receives the playback speed and plays back the content at the received playback speed while the user is performing an input operation (step S15). When the user finishes the input operation, the playback speed changing unit 24 plays the content at a constant speed. When the input event does not occur for a predetermined time or more, it may be determined that the user has finished inputting the operation.

  Thereafter, the processes in steps S13 to S15 are repeated. During the input operation, the content is played back at the playback speed calculated by the server 1, and when no operation is input, the content is played back at a normal speed.

  Next, processing of the playback speed calculation unit 15 will be described.

  FIG. 4 is a flowchart showing a processing flow of the reproduction speed calculation unit 15.

  The playback speed calculation unit 15 identifies the scene s corresponding to the playback time t from the playback time t when the user started the input operation, and selects the scene group S that is related to the scene s and has a playback start time later than the scene s. Obtain (step S21). The playback speed calculation unit 15 refers to the network graph stored in the content DB 12 and sets a scene having a score of N or more indicating a correlation with the scene s as a scene related to the scene s. The score N is set in advance by hand, for example.

Playback speed calculation unit 15, for each scene of the scene group S, the user estimates the time required for input operation, obtains the input operation time t ₁ which is the sum of time required for input operation by each scene (step S22). As a method of estimating the input operation time, for example, there is a method of calculating the average input operation time of each scene using the viewing history and operation history of other users who have viewed the same content. Alternatively, using the viewing history and operation history of other users who viewed the same content, the type and ratio of input operations performed on each scene are provided as data in the graph column of the content DB 12, and the scene group The type of input operation expected to occur in each scene of S may be acquired from the graph column of the content DB 12, and the input operation time may be estimated based on the type of input operation. The type of input operation is determined based on the cognitive load applied to the user, as will be described in a second embodiment described later. For example, an operation for underlining is a simple input operation, and an operation for inputting a handwritten character is an input operation requiring a cognitive load. As another method, the input operation time may be estimated based on the input operation speed of the user who is viewing the content. For example, the input operation time after the reproduction time is estimated based on the time used for the input operation before the reproduction time.

When the user watches the remaining content at the playback speed V (constant speed) determined by the content creator in consideration of the elapsed time t ₀ required for viewing the content up to the playback time t, the playback speed calculation unit 15 M times (M × t ₂ ) times the viewing time t ₂ required for the above is set as the upper limit value of the remaining content viewing time (step S23).

  M is a real number that satisfies the following condition.

ここで、Ｔはコンテンツ全体を等速で再生した場合の視聴時間であり、αは１＜αを満たす実数で予め人手によって設定される。経過時間ｔ_０が長ければ、残りのコンテンツの視聴に要する時間が短くなるように実数Ｍが小さくなる。

Here, T is a viewing time when the entire content is reproduced at a constant speed, and α is a real number satisfying 1 <α and is set in advance by hand. The longer the elapsed time t _0, the real number M such that the time required for viewing the remaining content shortens decreases.

The reproduction speed calculation unit 15 reproduces the input operation time t ₁ required for the input operation by the user and the remaining contents at a constant speed when viewing the remaining contents so that the remaining contents can be reproduced within the upper limit value. The playback speed v _s is calculated based on the time (t ₁ + t ₂ ) that is the sum of the viewing time t ₂ required for (step S24). Specifically, to calculate a playback speed v _s using the following equation (1).

なお、条件を満たす実数Ｍが存在しない場合はｖ_ｓ＝Ｖとする。つまり、再生速度を変更しない。

If there is no real number M that satisfies the condition, v _s = V. That is, the playback speed is not changed.

Of viewing time t ₂ required when watching remaining content, since the expected value is not included in the scene group S scene input operation is performed is small, constant speed of playback speed V slightly faster rate than, for example, it may calculate the viewing time t ₂ as to reproduce the content at 120% of the speed of the playback speed V. According to Non-Patent Document 2, it is considered that the user does not feel uncomfortable with the speed change up to 120%. By slightly increasing the playback speed of scenes not included in the scene group S, the number of cases where the real number M does not exist can be reduced.

  Next, the process of the correlation graph construction part 13 is demonstrated.

  FIG. 5 is a flowchart showing a process flow of the correlation graph construction unit 13 in the present embodiment.

The correlation graph construction unit 13 acquires the unprocessed content C _n from the content DB 12, divides the content C _n into a plurality of scenes (or extracts a plurality of scenes), and sets the start time and end time of each scene to the content DB 12 (Step S31). The content C _n can be divided by the following method.

(1) Set the time of one scene and divide (2) Set the number of divisions and divide the scene at equal intervals (3) Divide in units of slides so that one scene corresponds to one slide (4) Analyzing the contents of the content and determining the division point or extraction point based on the analysis result. (5) Deciding the division point or extraction point based on the operation history of the user who has viewed in the past.

Here, (5) a method of dividing a scene based on the operation history will be described. Assume that the client terminal 2 notifies the server 1 of the occurrence of an event related to input, and the server 1 holds the notified event as an operation history. The correlation graph construction unit 13 acquires the time when the input operation to the client terminal 2 is started and the time when the input operation is completed from the operation history, and divides or extracts the time between them from the content C _n as one scene. For example, a series of event groups such as “moused event → more than one move move event → mouse up event” notified from the client terminal 2 is detected, and a period during which these events occur is defined as one scene.

  However, when a character is input by handwriting using a pointing device such as a mouse, there may be a plurality of series of event groups for the input of one character. Therefore, a set of series of event groups may be one scene. For example, as illustrated in FIG. 6, when inputting the character “A” by handwriting, “A” is composed of three strokes, and therefore, a series of three event groups input the character “A”. Corresponds to the operation. One character may be input as one scene, or a plurality of characters may be input as one scene. When making a series of event groups the same scene, as shown in FIG. 7, when the time from detecting a series of event groups to detecting the next series of event groups is less than a predetermined time, It is determined that it is appropriate to set a series of these consecutive events as the same scene. At this time, a section in which no event occurs may be included in any of the scenes before and after the section. Alternatively, a section where no event occurs may be an independent scene.

When the correlation graph construction unit 13 finishes dividing the scene, any two scenes S _i and S _j ( _assuming that the scene S _i is reproduced earlier than the scene S _j in the content C _n ) A score (a real number between 0 and 1) representing the correlation between the scenes S _i and S _j is calculated (step S32). For example, a method of calculating a score based on a viewing history of a user who has viewed content in the past can be considered. Specifically, it is calculated what percentage of the users who performed the input operation in the scene S _i performed the input operation in the scene S _j . That is, the score a user u is sought conditional probability that event B occurs that the user u under the condition that has occurred events A that performs an input operation in the scene S _i performs an input operation in the scene S _j To do.

Alternatively, a method of converting the utterance of the lecturer in each scene into character information and quantifying the correlation between scenes using a well-known document structure analysis technique can be considered. For example, there is a saying that "important point There are three" in the scene S _k, in the scene S _l "is the first one is the ○○", in the scene S _m "the second is ○○", scene If there is a saying of the "third is ○○" in the S _n, scene S _k and each scene S _l, S _m, the correlation between the S _n is large, is considered. Further, each scene _{S l,} S m, greater correlation between _{S n,} is considered.

  The correlation graph construction unit 13 constructs a directed graph (Bayesian network) having the scene created in step S31 as a node and the score created in step S32 as a weight, and stores the graph in the graph column of the content DB 12 (step S33).

  The correlation graph construction unit 13 may execute the above processing at a timing when new content is stored in the content DB 12, or may construct a network graph based on the viewing history of the user who has viewed the content in the past. Good. When the network graph is variable, the network graph may be updated by executing processing for each content stored in the content DB 12 at a predetermined timing.

As described above, according to the present embodiment, the server 1 considers the elapsed time t ₀ required for viewing the content up to the playback time t when the user started the input operation, and the remaining content viewing time. For each scene of the scene group S related to the scene s corresponding to the reproduction time t, the user estimates the input operation time t ₁ required for the input operation, and the remaining content is within the upper limit value. By calculating the playback speed v _s based on the time (t ₁ + t ₂ ) that is the sum of the input operation time t ₁ and the viewing time t ₂ required when the remaining content is played back at a constant speed so that playback is possible. The content reproduction speed can be controlled so that the viewing time of the content does not become longer while considering the user's input operation.

[Second Embodiment]
FIG. 8 is a functional block diagram showing the configuration of the content reproduction system according to the second embodiment. The content playback system shown in FIG. 1 is different from the content playback system of the first embodiment in that the client terminal 2 includes an input operation type determination unit 25 and the server 1 uses a playback speed adjustment unit instead of the playback speed calculation unit 15. The difference is that 17 is provided. In the second embodiment, the playback speed is adjusted according to the type of user input operation. For example, when the user is performing an operation of writing characters, the content reproduction speed is made slower than when the user is simply performing an underline operation. Hereinafter, differences from the first embodiment will be described.

  The input operation type determination unit 25 determines the type of input operation from the input event that has occurred in the client terminal 2, and transmits the determined type of input operation to the server 1. For example, the following three types of input operations are discriminated based on the occurrence of an input event with a mouse such as “mouseddown”, “mousemove”, “mouseup”, or an input event with a stylus pen or a finger.

Type1 Marks other than characters such as underline and circle are drawn Type2 The instructor's remarks in the content are copied Type3 The user's own words are used to write notes and diagrams

  For example, a known character recognition technique can be used to determine the type of input operation. Character recognition is performed on a point set drawn by an input operation after a predetermined time has elapsed after detecting an event indicating the start of the input operation. If the recognition result is other than a character, the type of input operation is determined as Type1. If the recognized character string matches the sound in the content, it is determined as Type 2, and if it does not match the sound in the content, it is determined as Type 3. The voice in the content can be converted into a character string using a known voice recognition technique.

  First, the playback speed adjustment unit 17 receives the playback time of the content at the start of the user's input operation, as in the playback speed calculation unit 15 of the first embodiment, and relates to the scene s corresponding to the playback time. The playback speed is calculated in consideration of the input operation time required for the input operation by the user in a high scene, and the calculated playback speed is transmitted to the client terminal 2.

  When receiving the type of input operation from the client terminal 2, the playback speed adjustment unit 17 recalculates the playback speed according to the received type of input operation, and transmits the recalculated playback speed to the client terminal 2. Specifically, the reproduction speed is recalculated using the following equation (2) in which the type of input operation is added to the equation (1) of the first embodiment.

ここで、βは０＜β≦１の実数であり、入力操作の種類に応じて例えば予め人手により設定しておく。

Here, β is a real number of 0 <β ≦ 1, and is set in advance manually, for example, according to the type of input operation.

  The cognitive load on the user depending on the type of input operation is considered to be Type3> Type2> Type1, so β is set to be the smallest when the type of input operation is Type3, and is the largest when Type1 (Where β <1). Until the type of input operation is received from the client terminal 2, the playback speed is calculated with β = 1.

  As described above, according to the present embodiment, the server 1 receives the type of the user's input operation from the client terminal 2, and recalculates the playback speed according to the type of the input operation, thereby performing the input operation. The playback speed can be adjusted according to the magnitude of the cognitive load on the user.

DESCRIPTION OF SYMBOLS 1 ... Server 11 ... Content request receiving part 12 ... Content DB
DESCRIPTION OF SYMBOLS 13 ... Correlation graph construction part 14 ... Input operation reception part 15 ... Reproduction speed calculation part 16 ... Reproduction speed notification part 17 ... Reproduction speed adjustment part 2 ... Client terminal 21 ... Content request transmission part 22 ... Content reception part 23 ... Input operation detection Unit 24 ... reproduction speed changing unit 25 ... input operation type discrimination unit

Claims (7)

A playback speed adjustment device for adjusting the playback speed of content,
Receiving means for receiving the playback time of the content when the user starts an input operation while viewing the content;
Elapsed time required for the user to view the content up to the playback time, remaining playback time required for playback of the remaining content after the playback time at a constant speed, and playback of the entire content at the same speed An upper limit determining means for determining an upper limit of the remaining viewing time based on the total playback time required;
Input operation time estimating means for estimating an input operation time required for the user by the remaining content in the remaining content;
Calculating means for calculating a playback speed so that content that takes a time that is the sum of the remaining playback time and the input operation time can be played within the upper limit;
A playback speed adjusting device comprising: Storing means for storing a score representing a correlation between scenes obtained by dividing the content into a plurality of parts;
The input operation time estimating means extracts a scene group having a high correlation with the scene corresponding to the reproduction time based on the score, and estimates the time required for the input operation by the user in each scene belonging to the scene group. The playback speed adjusting apparatus according to claim 1, wherein the input operation time is obtained by summing up.   3. The playback speed adjustment device according to claim 2, wherein the calculating means uses the remaining playback time obtained by playing back each scene not belonging to the scene group at a playback speed faster than a constant speed. . The receiving means receives the type of input operation of the user,
The playback speed adjusting apparatus according to claim 1, wherein the calculation unit calculates the playback speed using a coefficient corresponding to a type of the input operation.   5. The playback speed according to claim 4, wherein the type of the input operation is an input operation other than a character, an input operation of a character that matches the content content, or an input operation of a character that does not match the content content. Adjustment device. A playback speed adjustment method executed by a computer to adjust the playback speed of content,
Receiving the playback time of the content when the user starts an input operation while viewing the content;
Elapsed time required for the user to view the content up to the playback time, remaining playback time required for playback of the remaining content after the playback time at a constant speed, and playback of the entire content at the same speed Determining an upper limit for remaining viewing time based on the total playback time required;
Estimating the input operation time required for the input operation by the user in the remaining content;
Calculating a playback speed so that content that takes time that is the sum of the remaining playback time and the input operation time can be played within the upper limit;
A playback speed adjustment method characterized by comprising:   6. A reproduction speed adjustment program for operating a computer as each means of the reproduction speed adjustment apparatus according to claim 1.

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