JP2006270829A - Motion picture reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optimal reproduced screen page depending on characteristics of a screen page change of contents at the time of reproducing motion picture data at fast forward, at fast rewind and at a special mode or the like. <P>SOLUTION: In the reproduction of picture data created by using MPEG or the like, a picture changing amount for every given block data is set by using a spare time by foreseeing picture data and by creating a management table. At the time of fast-forward and fast-rewind reproduction, picture changing amount small portions are controlled by applying fast-forward and fast-rewind reproduction, a viewer is allowed to grasp easily the contents even at the time of the fast-forward and fast-rewind reproduction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique which is effective when applied to reproduction at the time of fast-forwarding and rewinding moving image data.

  Many video data playback technologies have fast-forward and rewind functions, but such fast-forward and rewind control is performed in units of time or at a constant speed. Therefore, in the case of a scene where screen switching is intense, there is a problem that the viewer cannot recognize the screen when fast-forwarding or rewinding.

  As technologies relating to such moving image reproduction, there are JP-A-9-31695 (Patent Document 1) and JP-A-2001-101063 (Patent Document 2).

  The former (Patent Document 1) decodes encoded data recorded in units of frames having a predetermined length of time in a semiconductor memory and performs fast-forward reproduction. In the fast-forward reproduction process, the encoded data recorded in the semiconductor memory is used. Data is read at predetermined frame intervals, and time axis compression processing is performed using the read encoded data of the first frame and the encoded data of the second, third, and fourth frames following the first frame. It has been reproduced.

The latter (Patent Document 2) is a communication system in which data communication occurs intermittently, and when the communication is in a disconnected state, the idle time is used to obtain data that may be requested next from the terminal. Based on the set prefetch attribute value, prefetching is performed from the data providing side.
JP-A-9-311695 JP 2001-101063 A

  The former (Patent Document 1) has an advantage that the apparatus can be stopped at a desired position because time-based compression can distinguish between sound and silence even if the reproduced content cannot be understood. In general, the viewer grasps the content by the change of the screen rather than the voice.

  The latter (Patent Document 2) simply describes a technique for prefetching data from a server or the like by using the idle time in a disconnected state when data is intermittently received via a network. However, when this is moving image data, the screen recognition at the time of fast forward and rewind is not considered.

  It is an object of the present invention to provide an optimal playback screen according to the characteristics of the content screen change even when fast-forwarding, rewinding, or special playback during playback of moving image data.

  In order to solve the above problems, the present invention employs the following means.

That is, a video playback device that plays back video data in a compressed format, the first storage means for storing video data in a compressed format, and the video data from the first storage means, A second storage unit that stores a change amount of data as change amount information; a decoding unit that reads and decodes the moving image data from the first storage unit; and the decoded moving image data for display A conversion unit that converts the data into data; and a control unit that controls the first and second storage units, a decoding unit, and the conversion unit. The control unit stores the decoded moving image data in the conversion unit. At the time of transmission, the moving image data to be transmitted to the conversion means is controlled with reference to the change amount information stored in the second storage means (claim 1).

  As described above, by reproducing the moving image data using the change amount information of the moving image data, it is possible to realize the reproduction control optimum for the change of the change amount.

  Further, the change amount information is the amount of change of the screen per unit time (claim 2).

  As described above, by controlling the reproduction of the moving image data according to the amount of change in the screen per unit time, it becomes possible to reproduce the moving image data in a state optimal for the change in the screen.

  The change amount information is information indicating whether the change amount of the screen per unit time is larger or smaller than a preset reference value, and the reference value may be arbitrarily set.

  Further, the reference value is an intermediate value between the maximum and minimum data per unit time.

  Thus, by distinguishing the magnitude of the screen change amount based on the reference value, it is possible to reproduce the moving image data in a state that is optimal for the screen change with a simple reference.

  Further, the control means increases the fast-forward playback speed (or rewind playback speed) in the data portion where the data change amount per unit time is smaller than the reference value, and the data portion where the data change amount per unit time is large. Then, the fast-forward playback speed (or rewind playback speed) is lowered, and the decoded moving image data is sent to the conversion means (claim 5).

  As a result, fast-forward playback is performed at high speed in scenes with small image changes, and fast-forward playback at low speed is performed in scenes with large screen changes. It becomes easy.

  In addition, the control means lowers the fast-forward playback speed (or rewind playback speed) in the data portion where the data change amount per unit time is smaller than the reference value, and in the data portion where the data change amount per unit time is large. The fast-forward playback speed (or rewind playback speed) may be increased to send the decoded moving image data to the conversion means (claim 6).

  In this case, the dialogue part of the performer is important, for example, in a drama, etc., and the content of moving scenes etc. is not related to the synopsis of the story. It becomes easy.

  In addition, when the data portion whose data change amount per unit time is smaller than the reference value becomes longer than a predetermined time set in advance, the control means performs fast forward playback (or rewind playback) of the data portion in the middle. It may be interrupted and the fast forward playback (or rewind playback) may be resumed from the next portion with the large amount of data change.

  According to this, when a scene with a small screen change amount continues, the reproduction can be interrupted and skipped to a scene with a large screen change amount, and the contents of the viewer can be easily understood.

  In addition, when resuming reproduction after skipping in the above, the control means performs fast forward reproduction (or rewind reproduction) of a data portion whose data change amount per unit time is smaller than the reference value. Alternatively, the decrypted moving image data may be sent to the conversion means at a higher rewind speed (claim 8).

  Even during skip playback, fast-forward playback is performed at high speed in scenes where image changes are small, and fast-forward playback is performed at low speeds in scenes where changes in the screen are large. Becomes easy.

  Further, the set time until the fast-forward reproduction or the rewind reproduction is interrupted may be arbitrarily set.

  In addition, the control unit may send the decoded moving image data to the conversion unit only for a data portion whose data change amount per unit time is smaller than the reference value. ).

  In other words, in fast-forward playback, etc., only the data part with a small screen data change amount is played back without playing the data part with a large screen data change amount. It is possible to grasp the entire content without making it happen.

  In addition, the control unit may send the decoded moving image data to the conversion unit only for a data portion having a data change amount per unit time larger than the reference value. ).

  This makes it possible to realize fast-forward playback of content that can be grasped only by screen changes such as action movies.

  In addition, when only a data portion having a large data change amount per unit time than the reference value continues for a certain time, the control means extracts a data portion having a small data change amount per unit time from the large data portion. Thus, the decrypted moving image data is sent to the converting means for reproduction (claim 12).

  As a result, even if the content of the screen changes for a long time, it is possible to prevent the inconvenience that a reproduced image is not extracted at all due to only a large data portion during fast-forward reproduction.

  In the control means, when the moving image data periodically thinned out is sent to the converting means, the data portion for restarting the fast forward reproduction after the thinning is more than the reference value per unit time. When the data portion has a large data change amount, the fast-forward reproduction is resumed from the data portion having a small data change amount before and after the data portion.

  According to this, when skip reproduction is performed, the restart position of data reproduction can always be set to a position where the amount of change of the image is small, and it is possible to prevent the image from changing suddenly during fast-forward reproduction.

In the control means, when the moving image data periodically thinned out is sent to the converting means, the data portion for restarting the fast forward reproduction after the thinning is more per unit time than the reference value. If the data portion has a small data change amount, fast-forward reproduction may be resumed from the data portion having a large data change amount before and after the data portion.

  Further, in the rewinding reproduction or specific double speed reproduction in the control means, when the moving image data periodically thinned is sent to the conversion means, the data portion for restarting the reproduction after the thinning is more than the reference value. If the data change amount per unit time is a small (or large) data portion, reproduction may be resumed from a data portion having a large (or small) data change amount before and after the data portion.

  Thus, by applying the present invention also in the case of rewind playback or special playback such as 1.5 times speed, the same effect as fast forward playback can be obtained.

  According to the present invention, an optimal playback screen is realized according to the characteristics of the content screen change during fast-forward playback, rewind playback, special playback, and the like of moving image data.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a system configuration of the present embodiment. As shown in the figure, in the present embodiment, the main bus 1 is the center, the central controller 10 and the interface 2 via the storage medium 3, RAM 4, ROM 5, temporary storage area 6, decoder 7, display data conversion unit. 8 etc. are connected.

  The ROM 5 is an area for storing initial programs and initial data, and the central controller 10 reads these programs through the main bus 1 and executes them. Although not shown, the display data converter 8 is connected to a display device such as a liquid crystal display.

  The moving image data is stored in the storage medium 3. This storage medium 3 is an optical or magnetic storage medium such as CD, CD-R, CD-RW, DVD, DVD-RW, DVD-RAM, MO, hard disk, SD card (trade name), Memory Stick (trade name), A small portable memory such as MMC (trade name).

  The moving image data stored in the storage medium 3 is moving image data in a format such as MPEG1, MPEG2, MPEG4, ASF, MOV, AVI, WMV.

  In the system configuration described above, the central control device 10 causes the moving image data stored in the storage medium 3 to be read into the temporary storage area 6 via the interface 2 and the main bus 1. At this stage, the moving image data is in a compressed state of a predetermined format.

  Next, the central control device 10 causes the decoder 7 to sequentially read the moving image data in the temporary storage medium 3 via the main bus 1 and decode it. The decrypted moving image data is stored in the RAM 4 or the temporary storage area 6.

  Next, the central control device 10 transfers the decoded moving image data stored in the temporary storage area 6 or the RAM 4 to the display data conversion unit 8 via the main bus 1.

The display data converter 8 converts the decoded video data into an NTSC signal (Natio).
nal TV Standards Committe type signal) and sent to a display device (not shown).

  In this embodiment, the central control device 10 is characterized in that in parallel with the above-described processing, the compressed moving image data stored in the storage medium 3 or the temporary storage area 6 during the idle time is analyzed. This will be described in detail below.

2 and 3 are diagrams for explaining the concept of analyzing the amount of change of the screen in the present embodiment.
FIG. 2 shows data with a small change amount of data per unit time when the central control device 10 analyzes the compressed moving image data stored in the storage medium 3 or the temporary storage area 6. .

  Here, a data size threshold value Ds is set in advance, and as shown in the figure, the data size B changes the screen because the data amount for unit time (a time) is smaller than the threshold value Ds. The central controller 10 recognizes the moving image data with a small amount.

  On the other hand, FIG. 3 shows a data structure in which the amount of change in data per unit time is large. Here, the data size C is recognized by the central controller 10 as moving image data having a large screen change amount because the data amount for a unit time (a time) is larger than the threshold value Ds.

  For this threshold value Ds, the central controller 10 calculates a plurality of data amounts per unit time, extracts the largest and smallest data amounts, and sets the intermediate value as the threshold value Ds. can do. That is, in FIG. 2, when it is assumed that the data size B is the smallest and the data size C is the largest, this intermediate value is the threshold value Ds. That is, the threshold value Ds = (B + C) / 2 can be obtained.

  The example shown in the figure is effective for moving image data in a format in which data compression is performed by paying attention to the difference between the previous and next screens as in the MPEG system.

  A management table 11 (FIG. 15) for managing the moving image data stored in the storage medium 3 or the temporary storage area 6 is provided in the temporary storage medium 3 or the RAM 4, and the data of the addresses 1A to 1D are displayed on the screen. A data portion having a large change, addresses 1D to 1E, may be managed as data having a small screen change.

  According to this method, the central controller 10 generates the management table 11 (FIG. 15) using the idle time. When the moving image data is read from the storage medium 3 or the temporary storage area 6, it is possible to refer to the management table 11 to identify the magnitude of the screen change for each moving image data stored at the address.

  The central control device 10 may identify the magnitude of the screen change amount of the moving image data while performing the comparison with the threshold value Ds in real time without using the management table 11 (FIG. 15).

The process flow of FIG. 4 shows the procedure of such a process.
In the figure, first, when a free time occurs (START), the central controller 10 starts analysis of moving image data (MPEG) stored in the storage medium 3 or the temporary storage area 6 (401). Here, the analysis is processing for recognizing the data amount per unit time of the moving image data (402). Actually, the amount of data per unit time is counted by virtually decoding and reproducing the compressed moving image data in software by a program stored in the RAM 4. If there is enough hardware, analysis may be performed by connecting the analysis hardware decoder 7 to the main bus.

  Then, the central control device 10 compares the data amount per unit time counted in this way with a threshold value Ds preset in the RAM 4 or the temporary storage area 6 (403).

  If the result is smaller than the threshold value (in the case of data size B), the moving image data portion is recognized as a data portion having a small screen change amount (404). If it is larger than the threshold value (in the case of data size A), the moving image data portion is recognized as a data portion having a large screen change amount (405).

FIG. 5 is a diagram for explaining a data reproduction method in which the magnitude of the data change amount is identified as a result of the above.
In the figure, as a result of analysis by the central control device 10, it is determined that the moving image data addresses 1A to 1D and 1E to 2E have a large screen change amount, and 1D to 1E and 2E to have a small screen change amount. Yes. It is assumed that such determination result information is stored in the management table 11 (as the change amount flag in FIG. 15) set in the temporary storage area 6 or the RAM 4 described above.

  The central controller 10 reads the uncompressed moving image data from the storage medium 3 or the temporary storage area 6 and delivers it to the decoder 7. The decoder 7 decodes the moving image data and records it in the RAM 4 or the temporary storage area 6. Here, the central control device 10 registers the address after decoding corresponding to the address before compression (compression state data) in the management table 11 (FIG. 15). In the case of FIG. 5, specifically, EA is registered corresponding to DA, 2E corresponding to CA, 1E corresponding to BA, 1D corresponding to address 1A before decoding (compressed state data). ing.

  In the figure, the moving image data portion registered in the address area having the change amount flag of 1 has a large screen change amount. Therefore, during fast-forward playback, control is performed so that playback is performed at a speed lower than the normal fast-forward speed (low speed). The video data portion registered in the address area where the change amount flag is 0 is small in screen change amount, so that control is performed so that the fast-forward playback is performed at the normal fast-forward speed or faster than that (high speed / Usually fast forward).

  More specifically, as shown in the figure, the fast-forward control is a process of reading periodically thinned data (1 / n) from the temporary storage area 6 (or RAM 4) and sending it to the display data converter 8. However, the central controller 10 performs control to increase the thinning rate when reproducing low-speed fast-forward moving image data at this time. Specifically, the central control device 10 inserts a thinned portion (2 × 1 / n) twice per unit time into the decoded image data in the temporary storage area 6 (or RAM 4). The data is sent to the display data conversion unit 8.

  By such processing, a portion with a large screen change amount during a moving image is played back at a low speed during fast forward playback, and a portion with a small screen change amount is played back at a high speed / normal speed during fast forward playback.

  Control in which a portion with a small screen change amount is fast-forwarded in this way is particularly effective for fast-forward playback of content such as an action movie that has a large screen change.

In contrast to FIG. 5, in FIG. 6, a portion with a large screen change amount during a moving image is played back at high speed / normal speed during fast forward playback, and a portion with a small screen change amount is played back at low speed during fast forward playback This is an example. The configuration of the management table 11 is the same as that shown in FIG.

  That is, since the moving image data part registered in the address area having the change amount flag 1 has a large screen change amount, control is performed so that the fast-forward playback is performed at a speed higher than the normal fast-forward speed (high-speed / normal fast-forward). The video data part registered in the address area with the change amount flag set to 0 has a small change amount of the screen, so that the fast-forward playback is controlled so that it is played back at the normal fast-forward speed or higher (high speed / normal). Fast-forward).

  In such a playback method, the speech portion of the performer is important as in a drama, and moving scenes are effective for fast-forward playback of content that is not related to the synopsis of the story.

  More specifically, as shown in the figure, the fast-forward control is a process of reading periodically thinned data (1 / n) from the temporary storage area 6 (or RAM 4) and sending it to the display data converter 8. However, the central control device 10 performs control to increase the thinning rate when reproducing the high-speed fast-forward moving image data at this time. Specifically, the central control device 10 inserts a thinned portion (2 × 1 / n) twice per unit time into the decoded image data in the temporary storage area 6 (or RAM 4). This is done by sending the data to the display data converter 8.

  FIG. 7 shows that when the central control unit 10 recognizes that a part with a small screen change amount per unit time continues for a certain time or more as a result of prefetching moving image data, a fast-forward playback of a data part with a small screen change amount is in progress. FIG. 6 is a diagram for explaining a case where the fast-forward reproduction is continued after skipping to the next data change address and skipping fast-forward reproduction again.

  The central control device 10 refers to the management table 11, and when fast-forwarding playback of moving image data at an address set with a small screen change amount (change amount flag = 0), the fast-forward playback is performed at the reference time Tc. When the time elapses, the fast-forward reproduction is temporarily interrupted, and the management table 11 is referred to search for an address where the next screen change amount becomes large (change amount flag = 1), and the moving image data is obtained from this address. Read out and continue fast-forward playback again.

  On the other hand, FIG. 8 shows that when the central controller 10 recognizes that a portion with a small screen change amount per unit time continues for a certain time or more as a result of prefetching moving image data, fast-forward reproduction of a data portion with a small screen change amount 7 is the same as in FIG. 7 except that the moving image data at the address from the address (change amount flag = 1) where the next screen change amount becomes large is changed to low-speed fast-forward reproduction (see FIG. 5). Is different.

  The setting of the reference time Tc does not have to be fixed, for example, 0.5 seconds or 1 second, and is set to ½ of the entire reproduction time of the data portion having a small screen change amount. Is also possible. Such setting of the reference time Tc may be arbitrarily set by the user using an external input means (keyboard or operation button).

  FIG. 9 shows a screen change when the central control device 10 analyzes the moving image data (before decoding) read into the temporary storage area 6 or the RAM 4 and generates the management table 11 and when fast-forward playback is in progress. This is an example in which only a data portion with a small amount (an address portion with a change amount flag = 0) is decoded.

That is, after the management table 11 is generated, the central controller 10 refers to the management table 11 and reads only the moving image data in the address area with the change amount flag = 0 from the temporary storage medium 3 or the temporary storage area 6 again. Then, the process of handing over to the decoder 7 is performed.

  By performing such control, only a data portion with a small screen change amount is fast-forwarded during fast-forward playback, and playback control suitable for fast-forward playback of content such as a drama with little screen change is possible. In addition, since a data portion having a large screen change amount is not decoded, fast-forward playback without fatigue of the viewer's eyes is possible.

  On the other hand, FIG. 10 is the reverse of FIG. 9 and the central control unit 10 analyzes the moving image data (before decoding) read into the temporary storage area 6 or the RAM 4 to generate the management table 11 and fast forwards. This is an example of decoding only a data portion having a large screen change amount (an address portion with a change amount flag = 1) when playback is in progress.

  That is, after the management table 11 is generated, the central controller 10 refers to the management table 11 and reads only the moving image data in the address area with the change amount flag = 1 from the temporary storage medium 3 or the temporary storage area 6 again. Then, the process of handing over to the decoder 7 is performed.

  By performing such control, only the data portion with a large screen change amount is fast-forwarded during fast-forward playback, and playback control suitable for fast-forward playback of important content such as action movies where the screen change is large Is possible. If the fast-forward playback of the data portion having a large screen change is performed by the low-speed fast-forward playback (see FIG. 5), it is possible to perform the data playback that is easy for the viewer to see even if the screen changes severely.

  By the way, as shown in FIG. 9, when control is performed that does not reproduce a portion with a large image change amount during fast-forward reproduction, in a content where a scene with a large image change amount always continues, data to be decoded is There may be cases where it does not exist.

  Therefore, in FIG. 11, the screen change amount is analyzed in more detail, and only the block with the smaller data change amount (the fourth block from the left) among the blocks with the large image change amount within the predetermined time Tt is decoded. Is allowed to do.

  In order to realize this, specifically, instead of the change amount flag in the management table 11, the data change amount is digitized and registered for each predetermined data block, and the central control device 10 stores the data change amount. The data area to be decoded may be determined by referring to it.

  Further, the change amount flag of the management table 11 may be set to about 3 to 5 levels, and only the smallest flag value among them may be decoded within a predetermined data reproduction time (Tt).

  Further, the central control device 10 may dynamically change the threshold value Ds (see FIG. 2) so that it is always regenerated (flag value = 0) within a certain time (Tt). Further, a plurality of threshold values Ds may be held in the temporary storage area 6 or the RAM 4.

  12 and 13 are diagrams showing an example in which moving image data is thinned out in units of time and transferred to the decoder 7 during fast-forward playback.

  In the fast forward reproduction, as shown in FIG. 12, the central control apparatus 10 reproduces only data A, C, E. Here, for example, if the moving image data of A to E is playback data for 21 seconds, A is a portion of 0 to 1 second, B is 10 to 11 seconds, and C is a portion of 20 to 21 seconds from the start position. It becomes fast-forward playback data for a total of 3 seconds.

  Here, after the fast-forward playback of the portion A is completed, at the stage where playback of the portion C is started (address BBB), the data change amount of the image C is large (change amount flag) as shown in FIG. When the block data of = 1) is at the head position, the central controller 10 verifies the last data block of the portion B existing before it, and the screen change amount of this portion is small (change amount flag). = 0), the image data from the head address (address AAA) of the last block of the portion B is sent to the decoder 7, and fast-forward playback is resumed. At this time, the central control device 10 can determine the magnitude of the image change amount of the block from the value of the change amount flag with reference to the management table 11.

  In this description, the example in which fast-forward playback is resumed from a portion where the screen change amount is small has been described. However, the present invention is not limited to this.

  FIG. 14 illustrates an example in which the control of FIG. 13 is performed by rewind playback.

  In FIG. 12, at the stage (address CCC) at which the rewinding reproduction of the portion A is started after the rewinding reproduction of the portion C is completed (the address CCC), as shown in FIG. When the block data of (change amount flag = 1) is at the rewinding reproduction start position, the central control device 10 verifies the data block of the portion B existing before that (the head position of B in the figure). If the screen change amount in this portion is small (change amount flag = 0) (refer to the change amount flag in the management table 11), the image from the last address (address DDD) of the first block in the B portion Data is sent to the decoder 7 to resume the rewind playback.

  As described above, in the present embodiment, the central control device 10 pre-reads image data during idle time, generates the management table 11, and sets an image change amount flag for each predetermined block data. Fast forward playback and rewind playback according to the amount of change can be performed.

  In the present embodiment, fast forward playback and low speed fast forward playback have been described by taking fast forward playback as an example, but it is needless to say that rewind playback may be used. In this case, high speed fast forward playback is replaced with high speed rewind playback, and low speed fast forward playback is replaced with low speed rewind playback.

  Needless to say, the fast-forward playback according to the present embodiment may be applied to normal playback or special playback (1.5 times speed playback or the like). In this case, “fast forward playback” in the present embodiment may be read as “normal playback” and “special playback (for example, 1.5 × speed playback)”. That is, the central control device 10 can refer to the management table 11 even during normal reproduction, so that the reproduction method can be changed between a data portion having a large screen change amount and a data portion having a small screen change amount.

  The present invention can be used for special playback such as fast-forward playback and rewind playback of moving image data.

It is a block diagram which shows the system configuration | structure of the moving image reproducing device of this invention. It is a figure (1) which shows the data size for demonstrating the variation | change_quantity of a screen. It is a figure (2) which shows the data size for explaining the amount of change of a screen. It is a flowchart which shows the judgment procedure of the magnitude of the screen change amount by a central control unit. It is explanatory drawing (1) which shows the relationship between moving image data (compression state) and decoded data. It is explanatory drawing (2) which shows the relationship between moving image data (compression state) and decoded data. It is a figure (1) for demonstrating skip reproduction | regeneration at the time of fast-forward reproduction | regeneration of moving image data. It is FIG. (2) for demonstrating skip reproduction | regeneration at the time of fast-forward reproduction | regeneration of moving image data. It is explanatory drawing in the case of reproducing | regenerating only the data part with a small variation | change_quantity of a screen at the time of fast-forward reproduction | regeneration of moving image data. It is explanatory drawing in the case of reproducing | regenerating only a data part with the big variation | change_quantity of a screen at the time of fast-forward reproduction | regeneration of moving image data. It is a figure which shows a response | compatibility in case only the data part with the big variation | change_quantity of a screen continues at the time of fast-forward reproduction | regeneration of moving image data. It is a figure for demonstrating skip reproduction | regeneration of moving image data. It is a figure (1) which shows the control method when reproduction | regeneration is restarted in skip reproduction | regeneration of moving image data. It is a figure (2) which shows the control method when reproduction | regeneration is restarted in skip reproduction | regeneration of moving image data. It is a figure which shows an example of a management table.

Explanation of symbols

1 Main bus 2 Interface 3 Storage medium 4 RAM
5 ROM
6 Temporary storage area 7 Decoder 8 Display data converter 10 Central controller 11 Management table

Claims (15)

A video playback device that plays back compressed video data,
First storage means for storing compressed video data;
Second storage means for reading out the moving image data from the first storage means and storing a change amount of the data every predetermined time as change amount information;
Decoding means for reading out and decoding the moving image data from the first storage means;
Conversion means for converting the decrypted moving image data into display data;
The first and second storage means, decoding means and control means for controlling the conversion means,
The control means controls the moving picture data to be sent to the converting means with reference to the change amount information stored in the second storage means when the decoded moving picture data is sent to the converting means. A video playback device characterized by the above. 2. The moving image reproducing apparatus according to claim 1, wherein the change amount information is a magnitude of a change amount of the screen per unit time. The change amount information is information indicating whether a change amount of the screen per unit time is larger or smaller than a preset reference value, and the reference value can be arbitrarily set. Or the moving image reproducing device according to 2. 4. The moving image reproducing apparatus according to claim 1, wherein the reference value is an intermediate value between a maximum value and a minimum value of a plurality of pieces of data per unit time. The control means increases the fast-forward playback speed (or rewind playback speed) in the data portion where the data change amount per unit time is smaller than the reference value, and fast-forwards in the data portion where the data change amount per unit time is large. 5. The moving image reproducing apparatus according to claim 1, wherein the decoded moving image data is sent to the conversion unit at a lower reproduction speed (or rewind reproduction speed). 6. The control means lowers the fast-forward playback speed (or rewind playback speed) in the data portion where the data change amount per unit time is smaller than the reference value, and fast-forwards in the data portion where the data change amount per unit time is large. 5. The moving image reproducing apparatus according to claim 1, wherein the decoded moving image data is sent to the conversion unit at a higher reproduction speed (or rewind reproduction speed). 6. The control means interrupts fast-forward playback (or rewind playback) of a data portion whose data change amount per unit time is smaller than the reference value longer than a predetermined time set in advance. 5. The moving picture reproducing apparatus according to claim 1, wherein fast-forward reproduction (or rewind reproduction) is resumed from a portion where the next data change amount is large. The control means increases the fast-forward playback speed (or rewind playback speed) when the data portion whose data change amount per unit time is smaller than the reference value is fast-forward playback (or rewind playback). 8. The moving image reproducing apparatus according to claim 7, wherein the converted moving image data is sent to the converting means. 9. The moving image reproducing apparatus according to claim 7, wherein the set time can be arbitrarily set. 5. The control unit according to claim 1, wherein the control unit sends the decoded moving image data to the conversion unit only for a data portion whose data change amount per unit time is smaller than the reference value. The moving image reproducing apparatus according to any one of the above. 5. The control unit according to claim 1, wherein the control unit sends the decoded moving image data to the conversion unit only for a data portion having a data change amount per unit time larger than the reference value. The moving image reproducing apparatus according to any one of the above. When only a data portion having a large data change amount per unit time than the reference value continues for a predetermined time, the control means extracts a data portion having a small data change amount per unit time from the large data portion, 11. The moving image reproducing apparatus according to claim 10, wherein the decoded moving image data is sent to the converting means for reproduction. The control means, when performing fast-forward playback periodically by sending out the moving image data to the conversion means, the data portion for restarting fast-forward playback after the thinning-out data change per unit time from the reference value 5. The moving image reproducing apparatus according to claim 1, wherein when the amount is a data portion having a large amount, fast-forward reproduction is resumed from a data portion having a small data change amount before and after the data portion. The control means, when performing fast-forward playback periodically by sending out the moving image data to the conversion means, the data portion for restarting fast-forward playback after the thinning-out data change per unit time from the reference value 5. The moving image reproducing apparatus according to claim 1, wherein when the amount is a data portion having a small amount, fast-forward reproduction is resumed from a data portion having a large amount of data change before and after the data portion. In the rewinding reproduction or specific double speed reproduction, the control means performs the data portion for resuming the reproduction after thinning out by sending the thinned moving image data to the conversion means in units of the reference value. 5. The reproduction is resumed from a data portion having a large (or small) data change amount before and after the data portion having a small (or large) data change amount per time. The moving image reproducing apparatus according to any one of the above.