JP2014182853A - Disk reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk reproducing apparatus that hinders freeze and discontinuation of video.SOLUTION: If data recorded in a disk 10 is not correctly read, an error recovery processing section 5c in a decoder 5 performs an error recovery process in which the reading position of a pickup 2 is skipped to a readable area of the disk 10. A reproduction speed control section 5e makes the reproduction speed of a decoding part 5a lower than usual during error recovery processing, thereby restricting data freeze in a buffer memory 4. Accordingly, a video is not liable to freeze. Since data freeze in the buffer memory 4 can be restricted, a skip width can be made narrow, thus hindering a discontinuous video.

Description

  The present invention relates to a disk reproducing apparatus having an error recovery function that repeats skipping to a readable area when a disk data read error occurs.

  The disk playback device mounted on the vehicle skips the read position to the readable area of the disk by the error recovery function when it takes time to read data due to vibrations peculiar to the vehicle and fingerprints and scratches attached to the disk. . However, if the data in the buffer memory is depleted while skipping is repeated, the output (image output) of the video signal to the display device stops and the video freezes.

  To deal with this problem, for example, Patent Document 1 proposes a disk playback device that dynamically changes the upper limit of the number of read retries in accordance with the remaining amount of data in the buffer memory. As a result, if there is a lot of data in the buffer memory and the video does not freeze even after retrying the readout, a lot of retries are performed, and when the buffer memory is low, the readout position is skipped. Since the next data is read out, the video can be reproduced without freezing.

JP 2002-140875 A

  Since the conventional disc reproducing apparatus is configured as described above, it is possible to reproduce the video without freezing, but there is a problem that discontinuity of the video occurs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a disc reproducing apparatus that suppresses video freeze and discontinuity.

  A disc playback apparatus according to the present invention includes a reading unit for reading data recorded on a disc, a buffer memory for temporarily storing data read by the reading unit, and a decoding for decoding and reproducing the data in the buffer memory into video or audio Recovery unit that executes error recovery processing for skipping the reading position of the reading unit to the readable area of the disc when the data recorded on the disc and the data recorded on the disc cannot be read correctly, and during error recovery processing And a playback speed control section that makes the playback speed of the decoding section slower than normal.

  According to the present invention, since the reproduction speed is made slower than usual during the execution of the error recovery process, the data usage of the buffer memory is reduced, and the video is hardly frozen. In addition, by reducing the amount of buffer memory used, the skip width of error recovery processing can be reduced, and video discontinuity is less likely to occur. Therefore, it is possible to provide a disc reproducing apparatus that suppresses video freeze and discontinuity.

1 is a block diagram showing a disc playback apparatus according to Embodiment 1 of the present invention. FIG. FIG. 6 is a diagram for explaining error recovery processing by an error recovery processing unit of the disk reproducing device according to Embodiment 1; FIG. 10 is a diagram for explaining the relationship between the remaining amount of buffer memory and the amount of use during error recovery processing of the disk playback apparatus according to Embodiment 1; The relationship between the residual amount of the buffer memory of the disc reproducing | regenerating apparatus concerning Embodiment 1 and reproduction | regeneration speed is shown. 4 is a flowchart showing an operation of the disc reproducing apparatus according to the first embodiment.

Embodiment 1 FIG.
As shown in FIG. 1, the drive 1 of the disk reproducing apparatus according to the first embodiment reads data recorded on the disk 10 by a pickup (reading unit) 2, demodulates the data by a demodulator 3, and then buffers The memory 4 is temporarily cached. Thereafter, the decoder 5 expands and decodes the cache data of the buffer memory 4 in the main memory 6, encodes it with the D / A converter 7, and outputs video and audio. A microcomputer (hereinafter referred to as “microcomputer”) 8 controls the decoder 5 in accordance with a user input operation, and executes reproduction, stop, skip, search, and the like of the disk 10.

  The disk 10 is, for example, a CD (Compact Disc), a DVD (Digital Versatile Disc), or a BD (Blu-ray Disc; registered trademark / hereinafter, description is omitted). In addition, when making a disc reproducing | regenerating apparatus respond | correspond to BD, the local storage 9 for corresponding to BD profile 1.1 or more is added.

  The decoder 5 includes a decoding unit 5a that decompresses the cache data of the buffer memory 4 into the main memory 6 and decodes the data into video and audio, and a control unit 5b that controls the operation of the decoding unit 5a. The control unit 5b includes an error recovery processing unit 5c that executes error recovery processing when data recorded on the disk 10 cannot be read correctly, and a buffer memory monitoring unit that monitors the remaining amount of cache data in the buffer memory 4. 5d and a playback speed for instructing the decoding unit 5a to control the playback speed of video and audio (that is, the speed at which the cache data of the buffer memory 4 is expanded in the main memory 6 and decoded and output to the D / A converter 7). A control unit 5e, an audio output control unit 5f that controls audio output of the decoding unit 5a, and a caption display control unit 5g that controls subtitle display of the decoding unit 5a are provided.

  In the example of FIG. 1, the decoding unit 5a is configured by a dedicated circuit, and the control unit 5b is configured by a microcomputer, the error recovery processing unit 5c, the buffer memory monitoring unit 5d, the playback speed control unit 5e, and the audio output of the control unit 5b. The functions of the control unit 5f and the caption display control unit 5g are all realized by software, but the present invention is not limited to this configuration.

  FIG. 2 is a diagram for explaining error recovery processing by the error recovery processing unit 5c, and shows an area in which data of the disk 10 is recorded. When the pickup 2 fails to read data due to vibration, or when reading data from a data area having fingerprints or scratches on the disk 10 fails, a read error is notified from the demodulator 3 to the decoder 5. When the read error is notified, the error recovery processing unit 5c instructs the pickup 2 via the demodulator 3 to read the position skipped by a predetermined skip width, and causes the data at that position to be read. In other words, the error recovery process is to repeat the error skip process with a fixed skip width until the readable area is reached and no read error is notified.

  The smaller the skip width of the error skip process, the higher the possibility that the continuity of the video is maintained when reaching the readable area, but the number of repetitions of the error skip process increases and it takes time to read the data. When it takes time to read data, even if the error recovery processing unit 5c executes error recovery processing and skips to a readable area, the data in the buffer memory 4 (buffer memory remaining amount) may be exhausted during that time. There is sex. When the data in the buffer memory 4 is depleted, the output (image display) of the video signal from the decoding unit 5a to the display device (not shown) stops and the video freezes.

  FIG. 3 is a diagram for explaining the relationship between the remaining amount of the buffer memory 4 and the usage amount during the error recovery process. By sufficiently increasing the capacity of the buffer memory 4, data depletion of the buffer memory 4 during error recovery processing can be prevented, so that the skip width can be set small. However, increasing the capacity of the buffer memory 4 leads to an increase in cost.

  Therefore, in the first embodiment, without increasing the capacity of the buffer memory 4, how to minimize the skip width of the error recovery process to prevent discontinuity of the video, and how to use the buffer memory Consider whether to minimize the video freeze.

  FIG. 4 shows the relationship between the remaining amount of the buffer memory 4 and the reproduction speed. The vertical axis on the left side of the graph represents the remaining capacity of the buffer memory 4, the vertical axis on the right side represents the video and audio playback speed, and the horizontal axis represents the usage amount of the buffer memory 4. As shown in the figure, the playback speed is set according to the remaining amount of the buffer memory 4. In addition, the buffer memory monitoring unit 5d starts the monitoring of the remaining amount of the buffer memory 4 according to the remaining amount of the buffer memory 4, and the buffer memory remaining amount at which the monitoring of the remaining amount of the buffer memory 4 ends. A monitoring end point and a fine slow playback start point for reducing the playback speed of the decoder 5 are set. Furthermore, an audio output section for outputting audio from the decoder 5 and an audio mute & subtitle display section for superimposing subtitles on video instead of outputting audio are set according to the playback speed. Details of these setting items will be described later.

  In the first embodiment, during the error recovery process, fine slow playback is performed with the playback speed reduced by a small amount from the normal playback speed (100%), the amount of use of the buffer memory 4 is reduced, and the output time is reduced. extend. This prevents data depletion in the buffer memory 4 and makes it difficult to freeze the video. Further, by reducing the amount of use of the buffer memory 4, the skip width is reduced without increasing the capacity of the buffer memory 4, thereby making it difficult for video discontinuities to occur.

A specific implementation method will be described with reference to the flowchart of FIG.
When a read error notification is received from the demodulator 3, the error recovery processing unit 5c resets the number of error skips (step ST1) and starts error recovery processing. Thereafter, the error recovery processing unit 5c performs error skip processing and the following operations in parallel.

  The error recovery processing unit 5c determines whether or not the number of error skips is greater than or equal to a predetermined N times (step ST2). If the number of error skips is N or more (step ST2 “YES”), data cannot be read out, that is, the number of error skips is large and the remaining change (decrease amount) in the buffer memory 4 is large. Monitoring of the remaining amount of the buffer memory 4 is started (step ST3). On the other hand, when the number of error skips is less than N (step ST2 “NO”), the process proceeds to step ST11.

  In step ST2, monitoring of the remaining capacity of the buffer memory 4 based on the number of error skips starts because the decoder 5 executes a process such as skip or search through the microcomputer 8 by a user operation, and the buffer memory 4 caches. This is for distinguishing between when data is temporarily cleared and error recovery processing.

  Subsequently, when the buffer memory monitoring unit 5d determines that the remaining amount of the buffer memory 4 has decreased to the fine slow playback start point ("YES" in step ST4), the playback speed control unit 5e instructs the decoding unit 5a. Then, the slow slow playback is started with the playback speed reduced by a minute amount from the normal playback speed (100%) (step ST5). By reducing the playback speed, the amount of use of the buffer memory 4 is reduced, and video freeze due to the depletion of cache data is less likely to occur.

  Subsequently, when the buffer memory monitoring unit 5d determines that the remaining amount of the buffer memory 4 is equal to or less than the fine slow playback start point ("YES" in step ST6), the playback speed control unit 5e responds to the remaining amount of the buffer memory 4. (Fine slow) The reproduction speed is reset and an instruction is given to the decoding unit 5a (step ST7). In this step ST7, when the error recovery process reaches the readable area and the remaining capacity of the buffer memory 4 increases, the playback speed is increased, while the readable area cannot be reached and the remaining capacity of the buffer memory 4 is reduced. When it decreases, the playback speed is lowered.

  As shown in FIG. 4, the playback speed relative to the remaining amount of the buffer memory 4 is non-linear. At the start of the slow slow playback, the playback speed is gradually decreased (that is, the playback speed is reduced at a low rate). It is desirable that the playback speed is rapidly decreased (that is, the rate of decrease in playback speed is large) immediately before the remaining amount of the buffer memory 4 is exhausted. This is because if the playback speed is lowered too much, a sense of incongruity in sound is generated, so that the slow slow playback is performed as close to 100% of the normal playback speed as possible. Thereby, from the user's viewpoint, since the image output time is extended, the time of the video freeze state is shortened, and the video can be continuously viewed.

  The playback speed control unit 5e determines whether or not the reset playback speed is in the audio mute section (step ST8). When the playback speed corresponds to the audio mute section (step ST8 “YES”), the audio output control unit 5f instructs the decoding unit 5a to stop the audio output (step ST9). If the content of the disc 10 includes subtitle data, the subtitle display control unit 5g instructs the decoding unit 5a to output a video in which the same subtitle language as the audio language code is displayed (step ST9). On the other hand, when the playback speed does not correspond to the audio mute section (step ST8 “NO”), the audio output control unit 5f instructs the decoding unit 5a to cancel the audio mute and output the audio (step ST10).

  After steps ST9 and ST10, the process returns to step ST6 again, and the buffer memory monitoring unit 5d checks the remaining capacity of the buffer memory 4. When the error recovery process reaches the readable area and the remaining capacity of the buffer memory 4 exceeds the slightly slow playback start point (step ST6 “NO”), the buffer memory monitoring unit 5d buffers the remaining capacity of the buffer memory 4 It is compared with the memory remaining amount monitoring end point (step ST11).

  If the buffer memory monitoring unit 5d determines that the remaining amount of the buffer memory 4 has increased to the buffer memory remaining amount monitoring end point ("YES" in step ST11), the remaining amount monitoring of the buffer memory 4 is ended (step ST11). ST12). On the other hand, when the remaining amount of the buffer memory 4 is smaller than the buffer memory remaining amount monitoring end point (step ST11 “NO”), the process returns to step ST2.

  When monitoring of the remaining amount of the buffer memory 4 is completed (step ST12), the error recovery processing unit 5c resets the number of error recovery (step ST13), and whether or not the read error from the demodulator 3 continues, that is, error skip. It is determined whether or not to repeat the process (step ST14). If there is no notification of a read error from the demodulator 3 (step ST14 “NO”), it is determined that the readable area has been reached, and the error recovery processing unit 5c ends the error recovery process. On the other hand, if the notification of the read error is continued from the demodulator 3 (“YES” in step ST14), the error recovery processing unit 5c continues the error recovery process and repeats the processes in and after step ST2 in parallel.

  As described above, according to the first embodiment, the disk reproducing apparatus includes the pickup 2 that reads the data recorded on the disk 10, the demodulator 3 that demodulates the read data, and the buffer memory 4 that temporarily stores the demodulated data. If the data recorded in the disk 10 cannot be read correctly, the decoding unit 5a that decodes and reproduces the data in the buffer memory 4 into video or audio, and if the data recorded in the disk 10 cannot be read correctly, An error recovery processing unit 5c that executes an error recovery process to be skipped and a playback speed control unit 5e that slows down the playback speed of the decoding unit 5a during the execution of the error recovery process are provided. For this reason, the amount of data used in the buffer memory 4 is reduced during the execution of the error recovery process, and the video is difficult to freeze. Further, since the amount of data used in the buffer memory 4 is reduced, the skip width of the error recovery process can be reduced, so that discontinuity of video is less likely to occur. Therefore, it is possible to provide a disc reproducing apparatus that suppresses video freeze and discontinuity.

  Further, according to the first embodiment, the disk reproducing device includes the buffer memory monitoring unit 5d that monitors the remaining amount of data in the buffer memory 4, and the reproduction speed control unit 5e detects the data detected by the buffer memory monitoring unit 5d. The reproduction speed of the decoding unit 5a is changed according to the remaining amount. For this reason, it is possible to make the video output time as long as possible and to shorten the time for the video to freeze.

  Further, according to the first embodiment, the playback speed control unit 5e changes the playback speed of the decoding unit 5a in a non-linear manner with respect to the data remaining amount of the buffer memory 4, and the playback speed decreases when the remaining data amount is large. The rate is reduced, and the rate of decrease is increased immediately before the remaining data is exhausted. For this reason, the playback speed during the error recovery process can be maintained as close to the normal playback speed as possible, and the user can appreciate without any sense of discomfort.

  Further, according to the first embodiment, the buffer memory monitoring unit 5d is configured to start monitoring the remaining amount of data in the buffer memory 4 in accordance with the skip amount of error recovery processing (number of error skips). For this reason, it is possible to distinguish between when the buffer memory 4 is cleared and when a read error occurs according to a skip or search by a user operation.

  Further, according to the first embodiment, the disc playback apparatus is configured to include the audio output control unit 5f that controls the audio output from the decoding unit 5a in accordance with the playback speed during execution of the error recovery process. As a result, the user can comfortably mute the audio when the playback speed is lower than the threshold level (boundary between the audio output section and the audio mute & caption display section in FIG. 4) that causes a sense of discomfort due to the slow slow playback. It will help to appreciate.

  Further, according to the first embodiment, the disc playback apparatus allows caption display to output a video on which captions are superimposed from the decoding unit 5a while the decoding unit 5a stops audio output under the control of the audio output control unit 5f. It was set as the structure provided with the control part 5g. This helps the user to enjoy the video comfortably.

  As described above, the disc playback apparatus according to the present invention reduces the playback speed and reduces the data usage of the buffer memory when it takes time to read data from the disc, and suppresses freeze and discontinuity of the video. Therefore, it is particularly suitable for use in an in-vehicle disk reproducing device that is easy to vibrate.

  In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.

  1 drive, 2 pickup, 3 demodulator, 4 buffer memory, 5 decoder, 5a decoding unit, 5b control unit, 5c error recovery processing unit, 5d buffer memory monitoring unit, 5e playback speed control unit, 5f audio output control unit, 5g Subtitle display control unit, 6 main memory, 7 D / A converter, 8 microcomputer, 9 local storage, 10 disks.

Claims (6)

A reading unit for reading data recorded on the disc;
A buffer memory for temporarily storing data read by the reading unit;
A decoding unit that decodes and reproduces data in the buffer memory into video or audio; and
If the data recorded on the disc could not be read correctly, an error recovery processing unit that executes an error recovery process for skipping the reading position of the reading unit to the readable area of the disc;
A disc playback apparatus comprising: a playback speed control unit that makes the playback speed of the decoding unit slower than normal during execution of the error recovery process. A buffer memory monitoring unit for monitoring the remaining amount of data in the buffer memory;
2. The disk playback apparatus according to claim 1, wherein the playback speed control unit changes the playback speed of the decoding unit according to the remaining amount of data detected by the buffer memory monitoring unit.   The playback speed control unit changes the playback speed of the decoding unit non-linearly with respect to the remaining amount of data in the buffer memory, and when the remaining amount of data is large, the rate of decrease in the playback speed is reduced and the remaining amount of data disappears. 3. The disk reproducing apparatus according to claim 2, wherein the rate of decrease is increased immediately before.   4. The disk reproducing apparatus according to claim 2, wherein the buffer memory monitoring unit starts monitoring the remaining amount of data in the buffer memory in accordance with a skip amount of the error recovery process.   5. The audio output control unit according to claim 1, further comprising an audio output control unit configured to control audio output from the decoding unit in accordance with a reproduction speed during execution of the error recovery process. Disc player.   6. The disc according to claim 5, further comprising a subtitle display control unit that outputs a video on which subtitles are superimposed from the decoding unit while the decoding unit stops audio output under the control of the audio output control unit. Playback device.

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