JP3066301B2 - Recording medium reproducing apparatus, reproducing method, recording method, and recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reading and decoding recording information of a variable bit rate from a recording medium such as an optical disk, an optical disk which compresses data such as moving image data and encodes the data into variable bit rate data, etc. The present invention relates to a method or apparatus for recording on a recording medium, or an apparatus such as a multimedia terminal having the above functions.

[0002]

2. Description of the Related Art Moving Picture Experts Group (MPEG) is an international standard for compression encoding digital video data.
p). In MPEG, predictive coding with motion compensation,
Techniques such as discrete cosine transform, adaptive quantization, and Huffman coding are used. MPEG includes DSM (Data Strat
MP with transfer rate within 1.5 [Mbps] from ge Media)
EG1 (ISO11172) and higher MPEG2
(ISO 13818). In order to obtain high image quality higher than that of the standard TV such as the NTSC system, at least the MP
It is said that compression encoding by EG2 is necessary. In addition, as a video coding standard, for example, H.264, which is a video conference standard, may be used. 261 or JPEG (ISO / IEC 1091), which is an international standard for still image compression and encoding.
8) used for all images. There is also JPEG.

In MPEG1, the bit rate is fixed, but in MPEG2, a variable bit rate is allowed. The variable bit rate is, for example, 2 [Mbps] to 4 [M
bps], which is such that the average is 3 [Mbps]. This variable bit rate is used for scenes with complicated patterns and intense motion, taking into account the fact that image quality degradation is hardly noticeable even when the compression level is increased, and that the image quality is significantly degraded when the compression level is increased. In a scene where image quality degradation is conspicuous, compression encoding is performed to increase the bit rate, and in a scene where image quality degradation is not conspicuous such as a monotonous pattern or a scene with little movement, compression encoding is performed so as to reduce the bit rate. By doing so, the overall image quality is made uniform. A device for performing such variable bit rate compression encoding is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-141.
No. 298. FIG. 2 shows an example of data encoded at a variable bit rate.

In recent years, various devices corresponding to multimedia have been proposed or being provided. This type of apparatus not only has a function of reading out compressed moving image data recorded on a storage medium such as an optical disk and decoding it into video / audio data, but also has other functions such as data received from a network. Has a function corresponding to data from various sources, such as decoding the data by a data decoder and executing application software.

[0005]

When reading and decoding compressed data of a variable bit rate recorded on a recording medium such as an optical disk, the transfer rate at which compressed data is read from the recording medium and the read compressed data are determined by the following. Since there is a difference in decoding speed and the difference is not constant, a buffer memory is used to reduce the difference. That is, once the compressed data read from the recording medium at a certain transfer rate is temporarily stored in the buffer memory, the compressed data in the buffer memory is read in response to a read request from the decoder side. The reading speed from the buffer memory increases in a scene with a high bit rate and decreases in a scene with a low bit rate.

When the transfer rate at which the encoded data is transferred from the recording medium to the buffer memory is higher than the read rate at which the encoded data is read from the buffer memory and sent to the decoder, the read control is easy. That is, when the buffer memory becomes full (to be exact, a default value close to full), the reading from the recording medium is interrupted, and the data amount of the buffer memory is reduced to a predetermined value (the free space of the buffer memory is sufficiently recovered). The value may be controlled so that reading from the recording medium is resumed when the value becomes equal to or less than (value).

On the other hand, if the read speed at which the encoded data is read from the buffer memory and sent to the decoder is higher than the transfer rate at which the encoded data is transferred from the recording medium to the buffer memory, in other words, the bit rate of the encoded data However, if the transfer rate to the buffer memory is higher than the transfer rate to the buffer memory, the encoded data stored in the buffer memory in the early stage of the reproduction of the recording medium is exhausted, and the data cannot be decoded continuously. This causes a problem of becoming unsuitable. In order to eliminate this problem, a sufficient amount of data is stored in the buffer memory at the initial stage of reproduction of the recording medium (= in the case of a fixed bit rate, the difference between the transfer rate and the bit rate is multiplied by the recording time. A certain amount of data).

However, in the case of variable bit rate data, since the difference between the transfer rate and the bit rate is not uniform, the amount of data to be stored at the beginning of reproduction of the recording medium cannot be determined. For this reason, there is a possibility that the decoding may be interrupted due to lack of data in the buffer memory during decoding. SUMMARY OF THE INVENTION It is an object of the present invention to prevent interruption of decoding due to loss of data in a buffer memory when variable bit rate data is read from a recording medium and decoded. It is still another object of the present invention to enable output of decoded data to be continued even when data in the buffer memory runs out during decoding.

In order to achieve the above object, according to the present invention, information indicating directly or indirectly a capacity of a buffer memory necessary for continuously decoding the encoded data and a transfer speed corresponding to the capacity is stored in the code. The above problem is solved by comparing the information with the transfer speed and the capacity of the buffer memory provided in the device, by multiplexing the information with the encoded data. However, this method cannot cope with a device in which the capacity of a usable buffer memory fluctuates irregularly depending on the operation status of another application, such as a device compatible with multimedia. A further object of the present invention is to solve the above-mentioned disadvantages with respect to a multimedia-compatible device.

[0010]

According to a first aspect of the present invention, there is provided a transfer means for reading record information of a variable bit rate of a recording medium and transferring the read information to a buffer memory, and a data transfer to the buffer memory so that the buffer memory does not overflow. Buffer control means for controlling transfer of data, a decoder for reading and decoding data in the buffer memory, an output memory for storing data decoded by the decoder, and reading and outputting data in the output memory. Means for repeatedly outputting, from the output memory, data decoded immediately before the buffer memory becomes empty until the buffer memory becomes empty when the buffer memory becomes empty. In the first aspect, when the buffer memory becomes empty, data decoded immediately before and stored in the output memory is repeatedly output.

According to a second aspect of the present invention, there is provided a transfer means for reading record information at a variable bit rate of a recording medium and transferring the read information to a buffer memory, and a buffer for controlling transfer of data to the buffer memory so that the buffer memory does not overflow. Control means, a decoder for reading and decoding data in the buffer memory, a capacity of the memory necessary for reading and decoding the variable bit rate data transferred to the memory without interruption, and a transfer of data to the memory. Extracting means for extracting index information indicating a rate from the recorded information on the recording medium; and determining whether or not the recorded information can be reproduced based on the index information, the capacity of the buffer memory, and the maximum transfer rate of data to the buffer memory. And a determining means for determining. In the second aspect, index information is extracted from the record information read from the recording medium, and it is determined whether or not the record information can be reproduced based on the index information. The determination is made, for example, in disk units, program units, or the like.

According to a third aspect of the present invention, there is provided a transfer means for reading record information of a variable bit rate of a recording medium and transferring the read information to a buffer memory, and a buffer for controlling transfer of data to the buffer memory so that the buffer memory does not overflow. Control means; a decoder for reading and decoding data in the buffer memory; and a rate difference indicating a temporal change in a rate difference between a transfer rate of data to the memory and a bit rate of variable bit rate data read from the memory. Extracting means for extracting characteristics from the recording information of the recording medium; and a capacity of the memory necessary for seamlessly decoding variable bit rate data transferred to the memory based on the rate difference characteristic, and an amount of data to the memory. Means for calculating index information indicating a transfer rate, the index information and the buffer Determination means for determining whether reproduction of the record information based on the memory capacity and the maximum transfer rate of data to the buffer memory, which is a recording medium reproducing apparatus having a. In the third invention, data for calculating the index information is extracted, the index information is calculated based on this data, and the processing is performed in the same manner as in the second invention.

In the second and third aspects of the present invention, if the buffer memory becomes empty during the reproduction of the recorded information determined to be unreproducible by the determining means, the decoding is performed immediately before the empty. It may be configured to have a means for repeatedly outputting data until the data is cleared. Further, in the second and third inventions and the above configuration, the index information may be a plurality of transfer rates and a plurality of memory capacities corresponding to the plurality of transfer rates. Further, in the above configuration, the variable bit rate data may be a bit stream compliant with the MPEG2 standard obtained by compressing moving image data.

According to a fourth aspect of the present invention, there is provided a rate difference indicating a temporal change in a rate difference between a bit rate of variable bit rate data to be recorded and a transfer rate when data is transferred from a recording medium to a buffer memory of a reproducing apparatus. A recording method for calculating a characteristic, multiplexing the rate difference characteristic with variable bit rate data to be recorded in association with the transfer rate to generate a bit stream, and recording the bit stream on a recording medium.

According to a fifth aspect of the present invention, the data in the buffer memory is decoded without interruption based on the bit rate of the variable bit rate data to be recorded and the transfer rate when the data is transferred from the recording medium to the buffer memory of the reproducing apparatus. To calculate the capacity of the buffer memory required to perform the operation, multiplex the capacity with the variable bit rate data to be recorded in association with the transfer rate to generate a bit stream, and record the bit stream on a recording medium. It is a recording method.

According to a sixth aspect of the present invention, there is provided an encoder for compressing and encoding moving image data to generate data of a variable bit rate, a transfer rate for transferring data from a recording medium to a buffer memory of a reproducing apparatus, and the variable bit rate. Means for calculating a rate difference characteristic indicating a temporal change in a rate difference from a bit rate of data; and generating a bit stream by multiplexing the rate difference characteristic with the variable bit rate data in association with the transfer rate. And a means for recording the bit stream on a recording medium.

According to a seventh aspect of the present invention, there is provided an encoder for compressing and encoding moving image data to generate data of a variable bit rate, a transfer rate for transferring data from a recording medium to a buffer memory of a reproducing apparatus, and the variable bit rate. Means for calculating the capacity of the buffer memory necessary for seamlessly decoding the data in the buffer memory based on the data, and multiplexing the capacity to the variable bit rate data to be recorded in association with the transfer rate. A recording apparatus comprising: means for generating a bit stream by means of a digital camera; and means for recording the bit stream on a recording medium.

An eighth invention is a reproducing apparatus having a function of reading encoded data recorded on a recording medium, temporarily storing the encoded data in a buffer memory, and reading and decoding the encoded data from the buffer memory. Extracting means for extracting, from the encoded data, environment information indicating an environment necessary for continuously decoding the encoded data; and environmental information extracted by the extracting means and the capability of the reproducing apparatus. A reproducing apparatus comprising: a deciding unit that decides a required capacity of the buffer memory based on the memory; and a memory control unit that secures the capacity determined by the deciding unit in the memory and allocates the capacity to the buffer memory.

A ninth invention is a reproducing apparatus having a function of reading encoded data recorded on a recording medium, temporarily storing the encoded data in a buffer memory, and reading and decoding the encoded data from the buffer memory. Extracting means for extracting, from the encoded data, environment information indicating an environment necessary for continuously decoding the encoded data; and environmental information extracted by the extracting means and the capability of the reproducing apparatus. Determining means for determining a required capacity of the buffer memory based on the output, outputting means for securing the capacity determined by the determining means in the memory and allocating the allocated capacity for the buffer memory; and Output to the effect that the allocation is performed as described above, and when a response indicating that the allocation is permitted is input in response to the output, a memory that executes the allocation. And control means, a reproducing apparatus having a.

Further, in the eighth and ninth aspects, the coded data is obtained by compressing a moving image
A bit stream conforming to the EG2 standard may be used. In the eighth and ninth inventions and each of the above configurations, the environment information may include a plurality of transfer rates from the recording medium to the buffer memory and a plurality of memory capacities corresponding to the respective transfer rates. Is also good.

According to a tenth aspect of the present invention, there is provided a type buffer memory for temporarily storing input encoded data in a system buffer memory, reading encoded data from the system buffer memory, and determining the type of the encoded data. A playback device having a function of temporarily storing the encoded data in the type buffer memory and decoding the encoded data in a format corresponding to the type. Extracting means for extracting environment information indicating an environment necessary for decoding from the encoded data, the system buffer memory and the type based on the environment information extracted by the extracting means and the capability of the playback device. Determining means for determining the total capacity required for the buffer memory, and securing the total capacity determined by the determining means in the memory to determine A memory control means for allocating a system buffer memory for the type buffer memory, a reproducing apparatus having a.

According to an eleventh aspect of the present invention, there is provided a type buffer memory for temporarily storing input encoded data in a system buffer memory, reading the encoded data from the system buffer memory, and determining the type of the encoded data. A playback device having a function of temporarily storing the encoded data in the type buffer memory and decoding the encoded data in a format corresponding to the type. Extracting means for extracting environment information indicating an environment necessary for decoding from the encoded data, the system buffer memory and the type based on the environment information extracted by the extracting means and the capability of the playback device. Determining means for determining the total capacity required for the buffer memory, and securing the total capacity determined by the determining means in the memory to determine An output means for outputting a message to the effect that the system buffer memory and the type buffer memory are to be allocated; and a response to the effect that the allocation is permitted is input in response to the output by the output means. And a memory control means for executing the assignment in the event of such a situation.

Further, in the tenth and eleventh aspects,
The encoded data may be a bit stream conforming to the MPEG2 standard, and the type buffer memory may be a buffer memory for a video decoder and a buffer memory for an audio decoder for decoding the bit stream conforming to the MPEG2 standard. In the tenth, eleventh, and the above configurations,
The environment information may be a plurality of transfer rates of the encoded data and a plurality of memory capacities corresponding to the respective transfer rates.

According to a twelfth aspect of the present invention, in a reproducing method in which input encoded data is temporarily stored in a buffer memory and then read and decoded, an environment necessary for continuously decoding the encoded data is provided. From the encoded data, determine the capacity required for the buffer memory based on the environment information, secure the determined capacity in the memory and allocate it to the buffer memory, Is the way.

According to a thirteenth aspect of the present invention, in a reproducing method of temporarily storing input encoded data in a buffer memory and then reading and decoding the encoded data, an environment necessary for continuously decoding the encoded data is provided. Is extracted from the encoded data, the capacity required for the buffer memory is determined based on the environment information, and the determined capacity is secured in the memory and allocated to the buffer memory. Output, and execute the assignment when a response to permit the assignment is input in response to the output.
It is a reproduction method.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

1. First Embodiment (Recording Apparatus) FIG. 1 shows an example in which a recording method and apparatus according to the present invention are embodied.
In the illustrated circuit, a video signal and an audio signal are input to an encoder 11, converted into compressed video data and compressed audio data, respectively, and then multiplexed by a multiplexer 12. The processing in the encoder 11 and the multiplexer 12 is the same as the processing in the well-known MPEG encoder, and a description thereof will be omitted.

In this example, the bit rate of the data compressed by the encoder 11 is sent to the buffer capacity calculator 21. Here, as shown in FIG. 2, compression encoding is performed so that the bit rate of the compressed data becomes a variable bit rate. That is, in a scene where the deterioration of the image quality is conspicuous, such as a complicated pattern or a scene with a lot of movement, compression encoding is performed so as to increase the bit rate. In the scene, compression encoding is performed so that the bit rate becomes low. This buffer capacity calculator 21
Is also input with information indicating a plurality of maximum transfer rates.

The buffer capacity calculator 21 calculates buffer capacities corresponding to a plurality of maximum transfer rates, and sends the calculation results to the multiplexer 12 in association with the respective transfer rates. The multiplexer 12 multiplexes this information with the compressed video data and the compressed audio data and outputs a bit stream.

In the above, the buffer capacity _Sn is:

(Equation 1) S _n and h _{n + 1} obtained by the above are compared and given by the larger one. As shown in FIG. 4, h _i is the area of the portion where the variable bit rate (curve) is larger than the maximum transfer rate (the dashed line), V _i is the area of the portion where the variable bit rate is smaller than the maximum transfer rate, B _i is the time when the variable bit rate changes from a portion larger than the maximum transfer rate to a smaller portion. In the figure, V ₀ can be ignored by starting decoding after the system buffer (see FIG. 3) is full.

As the maximum transfer rate, for example, eight rates are prepared in units of 1 [Mbps] from 3 [Mbps] to 10 [Mbps], and the buffer capacity (buffer on the reproduction apparatus side) is set for each of them. May be obtained. By preparing a plurality of types of maximum transfer rates and buffer capacities corresponding to the respective maximum transfer rates in this way, it is possible to support various transfer rates depending on the playback device. For example, if the transfer rate of the playback device is 5.4 [Mbp
s], the transfer rate may refer to the required buffer capacity of 5 [Mbps].

Buffer capacity and transfer rate (= index information)
Are recorded at the beginning of each program, in an area where data is multiplexed, and application information is recorded. Furthermore, in the case of an optical disk, a lead-in area may be used.

In the above description, the compressed video data and the compressed audio data are multiplexed with the transfer rate and the buffer capacity corresponding to the transfer rate. FIG. 3 shows a reproducing apparatus corresponding to this case. Instead of this method, as shown by broken lines and parentheses in FIG. 1, a rate difference characteristic corresponding to the transfer rate (a characteristic indicating a temporal change in the difference between the variable bit rate and the transfer rate) is calculated by the rate difference characteristic calculator 22. , The rate difference characteristic and the corresponding transfer rate may be multiplexed on the compressed video data and the compressed audio data, and the reproducing apparatus may calculate the buffer capacity and the transfer rate. The reproducing apparatus in this case is shown in FIG.

2. Second Embodiment (Playback Apparatus) FIG. 3 shows an example in which a playback method and apparatus according to the present invention are embodied.
The information recorded on the optical disc D is read by a reader 51, and a CD decoder 52 and a CD-ROM decoder
The data is demodulated into CD format data (compressed data at a variable bit rate) by 53 and is temporarily stored in the system buffer 60. The data amount of the system buffer 60 is monitored by the buffer controller 60a (see FIG. 6), and when the data becomes full, reading from the optical disk D is interrupted. When the amount of data in the system buffer 60 falls below a certain lower limit, reading from the optical disk D is restarted. This control is shown in the figure as read control a.

The data stored in the system buffer 60 is read out in response to data requests b and c from the respective controllers of the video buffer 61 and the audio buffer 62, and stored in the video buffer 61 and the audio buffer 62, respectively. Thereafter, they are sent to the video decoder 81 and the audio decoder 82 and decompressed, respectively, and output as video data and audio data, respectively. Note that the video decoder 81 and the audio decoder 82 are synchronized by the synchronization control circuit 65.

In this embodiment, the buffer capacity required for the reproducing apparatus and the transfer corresponding to the buffer capacity are determined by the index information extracting unit 71 from the compressed data demodulated into CD format data by the CD-ROM decoder 53. The rate is extracted and sent to determination section 72. When it is determined that reproduction cannot be performed, the determination unit 72 sends an instruction e indicating that reading is not performed to the reading & transferring circuit 50, and that the decoding is not performed on the video decoder 81 and the audio decoder 82. Send the instructions f1 and f2.

It should be noted that simple reproduction may be performed when it is determined that reproduction is impossible. That is, similarly to the apparatus of FIG. 6 described later, when the video buffer 61 and the audio buffer 62 become empty, the video data and the audio data decoded immediately before may be repeatedly output. In that case, the output memory is video decoder 81
It is assumed that it is provided in the audio decoder 82.

3. Third Embodiment (Reproducing Apparatus) FIG. 5 shows another example different from FIG. 3 that embodies the reproducing method and apparatus of the present invention. The device of FIG. 5 is substantially the same as the device of FIG. 3, and therefore only different portions will be described, and portions having the same configuration will be denoted by the same reference numerals and description thereof will be omitted.

In the apparatus shown in FIG. 5, the CD-ROM decoder 53
A plurality of rate difference characteristics (characteristics indicating a temporal change in the difference between the variable bit rate and the transfer rate) data and the plurality of rate difference characteristic data from the compressed data demodulated into the data in the CD format. The plurality of transfer rate data that have been extracted are extracted by the rate difference characteristic extraction unit 75, and are sent to the index information calculation unit 76. The index information calculation unit 76 calculates, based on Equation 1 (Equation 1) described above,
The buffer capacity required for the device and the transfer rate associated with the capacity are calculated, and the result is sent to the determination unit 72. The following processing is the same as that of the apparatus in FIG.

4. Fourth Embodiment (Reproducing Apparatus) FIG. 6 shows another example different from FIGS. 3 and 5 which embodies the reproducing method and apparatus of the present invention. In the apparatus shown in FIG. 6, the record information read from the optical disc D by the read & transfer circuit 50 is temporarily stored in the buffer memory 60b. The buffer controller 60a stops reading from the optical disk D when the buffer memory 60b becomes full of data (exactly, a predetermined value close to data full), and the buffer memory 60b
When the data amount becomes equal to or less than a certain lower limit value (the free space is a sufficient predetermined value), control is performed to restart reading from the optical disk D. This control is indicated as a in the figure.

The data (compressed data of variable bit rate) in the buffer memory 60b is read out in response to data requests b and c from the MPEG decoder 80, and
It is decoded at 80 and output to the outside via the output memory 80a. When the buffer memory 60b becomes empty, the buffer controller 60a outputs the output memory 80a.
Is sent to the buffer memory 60b, and the decoded data immediately before the buffer memory 60b becomes empty are repeatedly output until the empty state is eliminated. By controlling in this way, the output of data can be continued even though the moving image is in the frame drop state and the audio is in the mute state.

4. Fifth Embodiment (Reproducing Apparatus) FIG. 7 shows another example different from FIGS. 3, 5 and 6 that embodies the reproducing method and apparatus of the present invention. D is an optical disk which is an example of a recording medium. 500 is a data reading unit. If the recording medium is the optical disk D, the reading unit 500 includes a pickup, a CD-DA decoder, a CD-RO
An M decoder and the like are included. 600 is a system buffer. It is assumed that not only the encoded data sent from the reading unit 500 for the recording medium D but also other application software and data from the network are input to the system buffer 600.

Reference numeral 630 denotes a switching unit for reading data temporarily stored in the system buffer 600 and distributing the data to a media decoder corresponding to the data. Reference numeral 610 denotes a video buffer memory for temporarily storing the video data sent from the switching unit 630, and reference numeral 810 denotes a video decoder for reading and decoding the video data in the video buffer memory 610. Reference numeral 620 denotes an audio buffer memory for temporarily storing audio data sent from the switching unit 630, and 820 denotes an audio buffer memory.
620 is an audio decoder for reading and decoding audio data. Hereinafter, similarly, a buffer memory corresponding to another medium (application software, network, etc.) and a decoder corresponding to the other medium are provided for data sent from the switching unit 630. In the figure, a buffer memory 690 and a decoder 890 corresponding to the buffer memory 690 are shown as representatives of the other media described above.

Reference numeral 700 denotes an optical disc D by the reading unit 500.
Is a data extraction unit that extracts environmental information multiplexed on encoded data read from the encoded data from the encoded data. The environment information includes, for example, the capacity of a buffer memory required for a playback device to be able to decode encoded data without interruption, and a transfer rate corresponding to the capacity (a rate at which recording information on a recording medium is read and transferred to a system buffer). )
It consists of. FIG. 8 shows an example of the environment information. In addition, when the apparatus side corresponds as in the apparatus of FIG. 5 described above, a rate difference characteristic or the like can be used as environment information.

Reference numeral 701 denotes a data selection unit that determines the capacity of the buffer memory based on the environment information extracted by the data extraction unit 700. Here, the buffer memory includes a system buffer 600 and a buffer for a decoder for decoding the encoded data (for example, if the encoded data is MPEG2 data, the video buffer 610 and the audio buffer 610).
620). In determining the capacity, the maximum transfer rate of the apparatus shown in FIG.

Reference numeral 702 denotes a buffer amount control unit for securing the capacity of the buffer memory determined by the data selection unit 701 in the memory of the apparatus shown in FIG. At this time, the currently running application software and the memory capacity required for input from the network are referenced.

Next, the operation of the apparatus shown in FIG. 7 will be described. The encoded data is read from the optical disk D by the reading unit 500. Here, since the case where the recording medium is the optical disk D is described, as described above, the reading unit 500 includes a pickup, a CD-DA decoder, a CD-ROM decoder, and the like. It may be a tape medium,
In that case, the reading unit 500 is constituted by a reading head, a data decoder corresponding to the type of tape, and the like.

The encoded data output from reading section 500 is temporarily stored in system buffer 600. The coded data in the system buffer 600 is read from the system buffer 600 in response to a data request DR from any of the buffers (the video buffer 610, the audio buffer 620, the buffer memory 690, etc.), and the switching unit 630
, The attribute of the encoded data is determined and sent to the corresponding buffer memory. The buffer memory to which the encoded data is sent may be switched according to a timing instruction from the outside. From switching unit 630,
For example, when the data is sent to the video buffer, it is temporarily stored in the video buffer 630, and then the video decoder 81
It is sent to 0, decoded into moving image data, and output to the outside.

In the above, the data extraction unit is selected from the encoded data sent from the read unit 500 to the system buffer 600.
700 extracts environmental information. This environment information includes various maximum transfer rates, as shown in FIG.
It is configured as a correspondence table of buffer memory capacities required at the various maximum transfer rates. Data selection section
701 selects the required capacity of the buffer memory based on this correspondence table and the maximum transfer rate which is the capability of the reading unit 500 of the device (the device of FIG. 7). For example, if the maximum transfer rate of the reading unit 500 is 2 [Mbps],
The capacity of the buffer memory required to decode the recording information on the optical disc D without interruption is 75 [Mbit].

When the capacity of the buffer memory is selected by the data selecting section 701, the buffer amount control section 702 secures the selected capacity in the memory as the capacity of the buffer memory for decoding the optical disk D. FIG. 9 shows this state. The left column of FIG. 9 shows a state in which a plurality of media data are being decoded. The capacity of the system buffer 600 is m1, the capacity of the medium 1 is m2, the capacity of the medium 2 is m3, and the capacity of the video 1 is m4. , A capacity m5 as a buffer for video 2 and a capacity m6 as a buffer for audio 1.

In this state, the total capacity M1 + M2 of the buffer memory (M1 in the buffer memory for video 1 and M1 in the system buffer 600) is required for the continuous decoding of the recorded information on the optical disk D by the data selection unit 701. Is determined, the memory allocation is changed by the buffer amount control unit 702 as shown in the right column of FIG. That is, here, the assignment of the media (media 1, media 2, and video 2) that are not currently in operation is canceled, and the above-described total capacity is secured in the memory. In addition, even if it is currently operating, the operation of the operating medium is stopped, for example, on condition of the user's permission, etc., and the memory capacity is secured by diverting the buffer capacity of the medium. Is also good. In this way, by changing the allocation in the memory, it is possible to increase the buffer memory that can be used for decoding the video 1 and to include a high bit rate like the encoded data recorded on the optical disc D. It is possible to continuously decode and reproduce the variable bit rate data.

5. Sixth Embodiment (Reproducing Apparatus) FIG. 10 shows another example different from FIGS. 3, 5, 6, and 7 that embodies the reproducing method and apparatus of the present invention. FIG. 10 is substantially the same as the device in FIG. 7, and thus a configuration different from the device in FIG. 7 will be described. The same components as those in FIG.

The apparatus shown in FIG. 10 is different from the apparatus shown in FIG. 7 in that the capacity of the buffer memory selected by the data selection unit 701 is insufficient just by diverting and allocating a buffer memory for a medium not currently in operation. This is a device that notifies the user of this fact and diverts the buffer memory for the currently operating medium permitted by the user and allocates it to the buffer memory for the optical disk D.

For this reason, in the apparatus shown in FIG. 10, the decision of the data selection section 701 is output to the display output section 901 to inform the user, and the user's permission response from the operation input section 902 is waited.
Similar to the device of FIG. 7, memory allocation is performed. The permission of the user may be made for each medium or may be made collectively.

If the answer of the user to the display output of the display output unit 901 is "NO", the memory allocation is not changed. In this case, other currently running media are not stopped. Regarding the optical disc D,
The fact that the optical disc D cannot be continuously played back may be displayed on the display output unit 901. And / or the optical disc D may be ejected from the drive.

[0055]

According to the first aspect of the present invention, when the buffer memory becomes empty, the data decoded immediately before is repeatedly output, so that interruption of the output data can be prevented. In the second invention, index information is extracted from the recorded information, and it is determined whether or not reproduction is possible based on the extracted index information. In the third invention, the rate characteristic is extracted and the index information is calculated,
Based on this, it is determined whether reproduction is possible. Therefore, it is possible to prevent a recording medium whose reproduction is interrupted halfway from being reproduced. In the fourth to seventh aspects, the index information and the rate characteristics used as described above can be recorded on a recording medium such as a CD. In the eighth, tenth, and twelfth inventions, the allocation in the memory is changed based on the environment information extracted from the encoded data read from the recording medium to secure the capacity of the buffer memory. Encoded data recorded on a medium can be decoded continuously without interruption. In the ninth, eleventh, and thirteenth inventions, in the eighth invention, when it is necessary to stop the currently operating medium when changing the allocation in the memory, the user is informed of the need. Since the allocation of the memory is changed after the user's permission, there is no possibility that the stoppage of the medium may be stopped by mistake.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a recording apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of variable bit rate data.

FIG. 3 is a block diagram showing a reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing the magnitude of a variable bit rate and a transfer rate.

FIG. 5 is a block diagram showing a reproducing apparatus according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 8 is an explanatory diagram showing data (environmental data) used for selection (determination of buffer capacity) in a data selection unit 701 of the apparatus of FIG. 7;

FIG. 9 is a memory map of a memory whose allocation can be switched by switching control of a switching unit 603 of the apparatus of FIG. 7;

FIG. 10 is a block diagram showing a reproducing apparatus according to a sixth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 MPEG encoder 50 Transfer means (read & transfer circuit) 60 System buffer 70 Controller b, c Data request e, f1, f2 Information on reproduction / non-reproduction

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-165125 (JP, A) JP-A-7-336640 (JP, A) JP-A-6-76470 (JP, A) JP-A-6-76470 141298 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 5/91-5/956 H04N ^7/ 24-7/68 G11B 20/10-20/12

Claims (20)

(57) [Claims] 1. A buffer capacity required for a reproducing apparatus,
The transfer rate corresponding to the buffer capacity and the data
Recording medium reproduction for reproducing recorded information from recorded recording medium
In the apparatus, a transfer unit that reads record information of a variable bit rate from a recording medium and transfers the read information to a buffer memory; a buffer control unit that controls transfer of data to the buffer memory so that the buffer memory does not overflow; A decoder for reading and decoding data from a memory; an output memory for storing data decoded by the decoder; an output memory for reading and outputting data from the output memory; and an empty memory when the buffer memory becomes empty. Means for repeatedly outputting previously decoded data from the output memory until the empty state is eliminated. 2. A buffer capacity required for a reproducing apparatus,
The transfer rate corresponding to the buffer capacity and the data
Recording medium reproduction for reproducing recorded information from recorded recording medium
In the apparatus, a transfer unit that reads record information of a variable bit rate from a recording medium and transfers the read information to a buffer memory; a buffer control unit that controls transfer of data to the buffer memory so that the buffer memory does not overflow; a decoder for decoding by reading the data in the memory, required to decode uninterrupted reading the variable bit rate data that is transferred to the buffer memory the
Extraction means for extracting said data transfer rate to the buffer space and the buffer memory from information recorded on the recording medium, wherein said buffer capacitor extracted by the extraction means
Determining means for determining whether or not the recorded information can be reproduced based on a transfer rate . 3. A transfer means for reading record information of a variable bit rate from a recording medium and transferring the read information to a buffer memory; a buffer control means for controlling transfer of data to the buffer memory so that the buffer memory does not overflow; A decoder for reading and decoding the data in the buffer memory; and a rate difference characteristic indicating a temporal change in a rate difference between a transfer rate of the data to the buffer memory and a bit rate of the variable bit rate data read from the buffer memory. Extracting means for extracting from the recording information of the recording medium; and a capacity of the buffer memory necessary for seamlessly decoding the variable bit rate data transferred to the buffer memory based on the rate difference characteristic, and an amount of data to the buffer memory. Means for calculating index information indicating transfer rate , The recording medium reproducing apparatus having a determination means for determining whether the reproduction of the record information on the basis of the maximum data transfer rate of the index information to the capacity and the buffer memory of the buffer memory. 4. The apparatus according to claim 2, wherein when the buffer memory becomes empty during reproduction of the record information determined to be non-reproducible by the determination means, decoding is performed immediately before the empty. Means for repeatedly outputting the data until the empty is eliminated. 5. The recording medium reproducing apparatus according to claim 3, wherein the index information is a plurality of transfer rates and a plurality of memory capacities corresponding to the plurality of transfer rates. 6. The recording medium reproducing apparatus according to claim 1, wherein the variable bit rate data is a bit stream compliant with the MPEG2 standard obtained by compressing moving image data. 7. A rate difference characteristic indicating a temporal change in a rate difference between a bit rate of variable bit rate data to be recorded and a transfer rate when data is transferred from a recording medium to a buffer memory of a reproducing apparatus is calculated. A recording method for generating a bit stream by multiplexing the rate difference characteristic with variable bit rate data to be recorded in association with the transfer rate, and recording the bit stream on a recording medium. 8. A method for decoding data in said buffer memory without interruption based on a bit rate of variable bit rate data to be recorded and a transfer rate when data is transferred from a recording medium to a buffer memory of a reproducing apparatus. A recording method for calculating a required capacity of the buffer memory, multiplexing the capacity with variable bit rate data to be recorded in association with the transfer rate to generate a bit stream, and recording the bit stream on a recording medium. 9. An encoder for compressing and encoding moving image data to generate variable bit rate data, a transfer rate for transferring data from a recording medium to a buffer memory of a reproducing apparatus, and a bit rate of the variable bit rate data Means for calculating a rate difference characteristic indicating a temporal variation of a rate difference between the rate difference characteristic and a means for generating a bit stream by multiplexing the rate difference characteristic with the variable bit rate data in association with the transfer rate; Means for recording a bit stream on a recording medium. 10. An encoder for compressing and encoding moving image data to generate variable bit rate data, based on a transfer rate for transferring data from a recording medium to a buffer memory of a reproducing apparatus and the variable bit rate data. Means for calculating the capacity of the buffer memory required to decode the data in the buffer memory without interruption, and multiplexing the capacity with variable bit rate data to be recorded in association with the transfer rate to form a bit stream. A recording device, comprising: means for generating; and means for recording the bit stream on a recording medium. 11. A reproducing apparatus having a function of reading encoded data recorded on a recording medium, temporarily storing the encoded data in a buffer memory, and reading encoded data from the buffer memory and decoding the encoded data. Extracting means for extracting environment information indicating an environment necessary for continuously decoding encoded data from the encoded data; and the buffer based on the environment information extracted by the extracting means and the capability of the reproducing apparatus. A reproducing apparatus, comprising: a deciding unit for deciding a capacity required for a memory; and a memory control unit for allocating a capacity determined by the deciding unit to the memory and allocating it to the buffer memory. 12. A reproducing apparatus having a function of reading encoded data recorded on a recording medium, temporarily storing the encoded data in a buffer memory, and reading encoded data from the buffer memory to decode the encoded data. Extracting means for extracting environment information indicating an environment necessary for continuously decoding encoded data from the encoded data; and the buffer based on the environment information extracted by the extracting means and the capability of the reproducing apparatus. Deciding means for deciding the capacity required of the memory; output means for securing the capacity determined by the deciding means in the memory and outputting that the buffer memory is to be allocated; and allocating as described above by the output means. Is output, and when a response indicating that the allocation is permitted is input in response to the output, a memory control for executing the allocation is performed. Reproducing apparatus having a stage, a. 13. The reproduction according to claim 11, wherein the encoded data recorded on the recording medium is a bit stream conforming to the MPEG2 standard obtained by compressing moving image data. apparatus. 14. The environment information according to claim 11, wherein the environment information includes a plurality of transfer rates from the recording medium to the buffer memory and a plurality of memories corresponding to the transfer rates. The capacity of the playback device. 15. An input coded data is temporarily stored in a system buffer memory, and the coded data is read from the system buffer memory and temporarily stored in a type buffer memory determined according to a type of the coded data. A reproducing apparatus having a function of storing, reading encoded data from the type buffer memory, and decoding the encoded data in a method corresponding to the type, wherein the reproducing apparatus continuously decodes the encoded data in a method corresponding to the type. Extracting means for extracting, from the encoded data, environment information indicating an environment necessary for the system; requesting the system buffer memory and the type buffer memory based on the environment information extracted by the extracting means and the capability of the playback device; Determining means for determining the total capacity to be determined, and securing the total capacity determined by the determining means in a memory to the system A memory control means for allocating the buffer memory and the type buffer memory. 16. The coded data to be inputted is temporarily stored in a system buffer memory, the coded data is read from the system buffer memory, and temporarily stored in a type buffer memory determined according to the type of the coded data. A reproducing apparatus having a function of storing, reading encoded data from the type buffer memory, and decoding the encoded data in a method corresponding to the type, wherein the reproducing apparatus continuously decodes the encoded data in a method corresponding to the type. Extracting means for extracting, from the encoded data, environment information indicating an environment necessary for the system; requesting the system buffer memory and the type buffer memory based on the environment information extracted by the extracting means and the capability of the playback device; Determining means for determining the total capacity to be determined, and securing the total capacity determined by the determining means in a memory to the system Output means for outputting the information to be allocated for the buffer memory and the type buffer memory; output to the effect that the output means allocates as described above; and a response to permit the allocation is input in response to the output. In such a case, a memory control means for executing the assignment. 17. The coded data according to claim 14, wherein the coded data is a bit stream compliant with the MPEG2 standard obtained by compressing moving image data. A playback device, which is a buffer memory for a video decoder and an audio decoder for decoding a bit stream conforming to the standard. 18. The environment information according to claim 15, wherein the environment information corresponds to a plurality of transfer rates of encoded data input to the system buffer memory and the respective transfer rates. The playback device has a plurality of memory capacities. 19. A reproduction method for temporarily storing input coded data in a buffer memory and then reading and decoding the coded data, wherein environment information indicating an environment necessary for continuously decoding the coded data. From the encoded data, determining a required capacity of the buffer memory based on the environment information, securing the determined capacity in the memory, and allocating the determined capacity to the buffer memory. 20. In a reproducing method for temporarily reading input encoded data after temporarily storing the encoded data in a buffer memory, decoding environment information indicating an environment necessary for continuously decoding the encoded data. Is extracted from the encoded data, a capacity required for the buffer memory is determined based on the environment information, and a message that the determined capacity is secured in the memory and allocated to the buffer memory is output; A reproduction method for executing the assignment when a response to permit the assignment is input in response to the output.