JP2008135133A - Bit stream reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize a reproducing device which has an input buffer management device dispensing with securement of a memory buffer for making encoded data retreat and copy processing to the memory buffer for retreat. <P>SOLUTION: A bit stream reproducing device has a plurality of read pointers (101, 102), an invalid area table 105 on which invalid areas 108 for prohibiting read-out of respective read pointers can be registered and a read-out position control device 104 for skipping read-out of the invalid areas when the read pointers enter the invalid areas. The read pointer 101 is assigned to acquisition of a header and control information, the read pointer 102 is assigned to acquisition of encoded data, and an area the read pointer 101 acquires is registered on the invalid area table 105 as an invalid area with respect to the read pointer 102. Thereby, the read pointer 102 can perform data acquisition in the same manner with acquisition from a continuous area and encoded data can be decoded without being retreated to the memory buffer for retreat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bit stream playback device that controls reading from a memory buffer in a device that decodes an encoded stream of audio, music information, and moving images, and plays back a bit stream such as encoded music information or moving image information. .

  With reference to FIG. 10, a conventional configuration will be described as a configuration of an input buffer for supplying data to a decoder in an apparatus for decoding an encoded bit stream of audio, audio, or moving picture.

  FIG. 12 shows a conventional bitstream decoding apparatus. In FIG. 12, 1000 is an input buffer in FIFO format that accumulates a certain amount of bit stream, and 1001 is acquired from the input buffer 1000 when decoding a bit stream in which control information and encoded data as shown in FIG. This is a save buffer for temporarily saving the data.

12, when decoding the stream of FIG. 11, the control information A is acquired for decoding the encoded data A, and the encoded data A is sequentially acquired from the input buffer 1000 based on the acquired control information A and decoded. However, in order to decode the encoded data B (B-1, B-2), the control information B is stored after the encoded data B-1, and is necessary for decoding the encoded data B. In order to obtain the correct control information B, it is necessary to obtain the encoded data B-1 from the input buffer 1000. However, since the acquired encoded data B-1 is the data to be decoded, it cannot be discarded and is temporarily saved in the save buffer. Further, even if the data is not data as shown in FIG. 11, the input buffer 1000 has a FIFO structure, so it is difficult to confirm the reliability of the frame to be decoded by the presence of the synchronization word of the next frame at a predetermined position. There is a possibility that noise may be generated by decoding based on an erroneous synchronization word, or an underflow may occur because data supply to the input buffer 1000 is not in time. Furthermore, when an error occurs during decoding, there is a possibility that the data that should be decoded cannot be resumed from the point in time when the error occurred and the data that should be decoded can be discarded. Therefore, when this method is adopted, a decoding apparatus corresponding to various types of encoded data can be configured at low cost. However, when decoding encoded data as shown in FIG. 11 or after checking the reliability of the data. When attempting to decrypt data, the copy to the save buffer always occurs, increasing the memory capacity and processing load (see, for example, Patent Document 1).
JP-A-8-65170 (page 10, first figure)

  Since the conventional bit stream decoding apparatus is configured as described above, the input encoded stream is not synchronized with the header information and the encoded data, and the encoded data to be decoded is the header information of the frame. In the case of an encoded stream that is also included in a previous or subsequent frame, it is necessary to save the encoded data stored in the frame before the header information of the frame to be decoded. In addition, when decoding after confirming that the synchronization word of the next frame following the frame exists at a predetermined position in order to confirm the reliability of the data, it is necessary to save the data of the frame, A memory buffer and a copy process to the memory buffer are required, and many resources and processing performance are required.

  In addition, since there are two input paths to the decoder, buffer memory management in the event of an error and switching of the input buffer during decoding processing has become complicated.

  Therefore, an object of the present invention is to secure and save a memory buffer for saving encoded data even in the case of a stream in which encoded data to be decoded is stored before control information such as MP3. It is an object of the present invention to provide a bitstream reproducing device having an input buffer management device that does not require copying to a memory buffer.

  In order to solve the above-described problem, a bit stream reproducing device according to a first aspect of the present invention is a bit stream capable of processing encoded data from a bit stream having encoded data and control information for decoding the encoded data. A playback device for receiving and storing a bitstream; a plurality of read pointers for reading data from the memory buffer; an invalid area table for registering invalid areas for skipping data for each of the read pointers; Read out information from the invalid area table, automatically determine that the read pointer has reached the invalid area, and control the read position so as to skip over the invalid area data and memory using the read pointer Decoder that reads and decodes bitstream from buffer An invalid area that analyzes the encoded data and registers the invalid area in the invalid area table based on the result, and also registers the invalid area in the invalid area table in accordance with an instruction from the decoder and matches the already registered information. An information registration device is provided, and a plurality of read pointers are allocated for control information acquisition and encoded data decoding, respectively, and an area in which control information is stored by the invalid area information registration apparatus is registered in the invalid area table as an invalid area. Thus, the control is performed so that the encoded data stored discontinuously by being positioned before or after the control information can be handled as stored in the continuous area.

  According to the first invention, a plurality of read pointers are allocated for control information acquisition and encoded data decoding, respectively, and the area where the control information is stored by the invalid area information registration device is set as an invalid area in the invalid area table. By registering, control was performed so that encoded data stored discontinuously by being positioned before or after the control information can be handled as stored in a continuous area, so control for decoding the bitstream Even in the case of a bit stream in which encoded data to be decoded is stored before or after the control information or before and after the control information, the information is not synchronized with the encoded data. Copy processing can be reduced. In other words, since there are multiple read pointers, a read pointer for acquiring control information and a read pointer for decoding encoded data are allocated, and the start address and size of the area where the control information is stored are registered in the invalid area table. By doing so, it can be handled as data stored in a pseudo continuous area in the same manner as a bit stream in which control information and encoded data are synchronized. In addition, the registration information in the invalid area table may be such that the start address and size of the area in which the control information is stored can be calculated, and the start address and end address may be registered.

  The bit stream reproducing apparatus according to the second aspect is the bit stream reproducing apparatus according to the first aspect, wherein the bit stream is composed of a header including a unique synchronization word and encoded data, and is decoded in a certain decoding unit composed of a frame. Means for analyzing the header and calculating a frame length necessary for decoding as a first threshold, and determining whether or not data exceeding the first threshold exists in the memory buffer A data amount detection device comprising: a frame length calculated from a header in each frame as a second threshold; and a means for determining that data greater than or equal to the second threshold exists in the memory buffer; And a next frame detection device that detects a synchronization word of the next frame of the frame based on the data amount detection device. When it is issued, the header analysis permission is given to the decoder, the amount of data greater than or equal to the second threshold value is detected, and if the frame is not the final frame, the next frame synchronization word exists at a predetermined position in the next frame detection device. In such a case, the decoder is given permission to decode, and when the frame is the last frame, if the amount of data equal to or greater than the second threshold is detected, the decoder is given permission to decode.

  According to the second invention, in the case of a bit stream that consists of a header including a unique sync word and encoded data and can be decoded in a certain decoding unit such as a frame, the bit stream is written to the memory buffer and the decoder Even when the bit stream is read asynchronously from the memory buffer, there is data in the memory buffer that is equal to or larger than the data amount having the first threshold value that can determine the amount of data in the memory buffer and calculate the frame length from the control information. For example, the synchronization word of the current frame is detected and the frame length is calculated, and if the amount of data equal to or larger than the second threshold determined by the calculated frame length exists in the memory buffer, the synchronization word of the next frame is placed at a predetermined position. After confirming that it exists, establish synchronization of the current frame and allow the decoder to decode By performing, it can prevent generation of noise when the decoding is based on sound interruption or incorrect synchronization word by underflow occurs in the middle of decoding.

  According to a third aspect of the present invention, there is provided a bitstream reproducing device obtained by the effective data amount detecting device for calculating an effective data size between any two read pointers and the effective data amount detecting device in the bitstream reproducing device of the first invention. An effective data amount determination device that compares a predetermined data size with a predetermined threshold value, and a read pointer position control device that controls a read pointer position based on a determination result of the effective data amount determination device. When the control device advances only a specific read pointer among a plurality of read pointers and other read pointers do not advance due to an error or data skip at the time of decoding, control is performed so that the data amount between the read pointers is less than the threshold value. Prevents memory buffer overflow and ensures a certain amount of data between each read pointer. Decoded by can be resumed.

  According to the third aspect of the present invention, even when decoding errors occur continuously or even when a specific read pointer is advanced and other read pointers are not advanced due to data skipping in the memory buffer, etc., the control information By using the maximum value of the data size that can be stored earlier as a threshold value and controlling the read pointer so that the amount of data between each read pointer is less than or equal to the threshold value, memory buffer overflow can be prevented and controlled. If the information and encoded data are not synchronized, and the data stream of the bit stream that stores the encoded data to be decoded before or after the control information is stored, the amount of data between each read pointer By ensuring the above, decoding can be resumed promptly after the reproduction resume command.

  According to a fourth aspect of the present invention, there is provided a bitstream reproducing device that can process encoded data in a certain decoding unit composed of frames from a bitstream having encoded data and control information for decoding the encoded data. A stream reproduction device for registering control information together with a memory buffer for receiving and storing a bit stream, a plurality of read pointers for reading data from the memory buffer, and an invalid area for skipping data to each of the read pointers A control information area table, a read position control device that automatically reads out information from the control information area table and automatically determines that the read pointer has reached an invalid area and skips the invalid area, and a read pointer Bitstream from memory buffer using A decoder for reading and decoding, and analyzing the encoded data and registering the invalid area and control information in the control information area table based on the result, and also registering the invalid area and control information in the control information area table in response to an instruction from the decoder The control information area registration device that matches the already registered information, and the control information registered in the control information area table by the information notification from the readout position control device is read, and the decoder control information used for decoding the next frame is obtained. A decoder control information rewriting device for rewriting, assigning a plurality of read pointers for control information acquisition and encoded data decoding, respectively, and using the control information area registration device as an invalid area as an area for storing control information And register it in the control information area table together with the readout position control device from the decoder Characterized by being controlled to rewrite the control information decoder by the decoder control information rewriting device at a break in the frame corresponding to the invalid region when there is information notifying the control information rewriting device.

  According to the fourth invention, the area in which the control information is stored by the control information area registration device is registered as an invalid area in the control information area table together with the control information, and the information notification is sent from the reading position control device to the decoder control information rewriting device. In this case, the decoder control information rewriting device controls the decoder to rewrite the control information at the frame break corresponding to the invalid area, so that control information is added to each frame and the packet storing the input stream is stored. Decoding is possible without reconfiguration. That is, even when decoding a bitstream having control information asynchronously with the decoding unit without having the control information for each decoding unit such as a frame, the control information area for registering the area where the control information is stored as an invalid area Control information can be registered in the table, and when invalid area information is read, control information used for the next decoding is rewritten, so that the consistency between the control information and the data to be decoded can be guaranteed. Can be. For this reason, decoding can be performed without adding control information to each frame or reconfiguring a decoding unit when a plurality of frames are decoded together.

  A bit stream reproducing device according to a fifth aspect of the present invention is a bit stream capable of processing a plurality of encoded data from a plurality of bit streams having a plurality of encoded data and control information for decoding the plurality of encoded data. A playback device, a memory buffer for receiving and storing a bitstream, a plurality of read pointers for reading data from the memory buffer, and an area for skipping data for each of the read pointers as a first invalid area, An invalid area table for registering information on the first invalid area, an area information table for registering area information of the bitstream stored in the memory buffer, and reading the area information from the area information table to each of the read pointers The bit stream area to be automatically skipped is judged and output as the second invalid area. A read area control device that performs control, and a read pointer that automatically reaches the first invalid area obtained by reading information from the invalid area table or the second invalid area notified from the read area control device A read position control device that determines and controls a read position so as to skip the first or second invalid area, a plurality of decoders that read and decode a bit stream from a memory buffer using a plurality of read pointers, and a bit The first invalid area and the area information are registered in the invalid area table and the area information table based on the result of analyzing the stream, and the first invalid area and the area information table are registered in the invalid area table and the area information table according to an instruction from the decoder. Register each area information and align with the already registered information. When a plurality of bit streams are mixed and stored in the memory buffer, each of the read pointers uses a read area control device as a continuous area for only one kind of bit stream. By performing control so that the data can be read out, only data necessary for decoding can be obtained for each decoder, and a plurality of bit streams can be decoded simultaneously.

  According to the fifth invention, when a plurality of bit streams are mixed and stored in the memory buffer, each of the read pointers can read only one desired type of bit stream as a continuous area using the read area control device. By controlling in this way, only the data necessary for decoding can be obtained for each decoder and a plurality of bit streams can be decoded at the same time. Therefore, the process of separating the multiplexed data using the demultiplexer, A more power-saving bitstream reproduction system can be constructed by omitting the process of copying moving images, audio data, and the like to respective dedicated input buffer devices. In other words, even when decoding a bitstream in which multiple types of encoded data such as moving images and audio are multiplexed, an area information table for registering the type information and start position of data stored in the memory buffer is provided. When it is detected that the next read position of each of the plurality of read pointers is the start position of the encoded data different from the type information of the encoded data (bit stream) to be read notified from the decoder, By controlling to check the information and skipping to the next area of the encoded data to be read out, a plurality of input buffer devices for various encoded data are prepared, and demultiplexing processing of the multiplexed bit stream is performed. Thus, decoding can be performed without copying data to each input buffer device.

  A bit stream reproduction device according to a sixth aspect is the bit stream reproduction device according to the first, second, third, fourth or fifth aspect, wherein the bit stream is reproduced from the recording medium, written to the memory buffer, read from the memory buffer, and decoded. To do.

  According to a seventh aspect of the present invention, there is provided a bit stream reproducing apparatus according to the first, second, third, fourth or fifth aspect of the present invention, which receives a bit stream transmitted via a wired or wireless transmission path. have.

  According to the sixth and seventh inventions, a bit stream can be read and reproduced from a recording medium, a wired or wireless transmission path, and a memory and power saving bit stream reproduction system can be constructed as described above.

  The bit stream reproduction device according to an eighth aspect of the present invention is the bit stream reproduction device according to the sixth or seventh aspect, wherein the bit stream is a stream in which music information is encoded.

  A bit stream reproduction device according to a ninth aspect is the bit stream reproduction device according to the sixth or seventh aspect, wherein the bit stream is a moving image encoded stream encoded at a variable bit rate.

  According to the eighth and ninth inventions, it is possible to reproduce music information and an encoded stream of moving images.

  According to a tenth aspect of the present invention, there is provided a bitstream reproducing apparatus according to the sixth or seventh aspect of the present invention, wherein the bitstream is a moving image encoded stream encoded according to the MPEG standard, and the control information is included in the encoded stream. Multiplexed.

  The bit stream reproducing apparatus of the present invention provides a common input buffer management method for streams encoded by various encoding methods, thereby reducing the amount of extra memory area and copying processing, Low power and low cost are possible.

(Embodiment 1)
Regarding the bit stream reproducing apparatus according to the first embodiment of the present invention, a read pointer control method will be described with reference to FIG.

  FIG. 1 is a block diagram showing a bit stream decoding apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, 11 is a bit stream input buffer device, and 100 is a ring-type memory buffer of the bit stream input buffer device 11. The memory buffer 100 receives and stores the bit stream. 101 and 102 are read pointers for reading data from the memory buffer 100, two or more read pointers can be set, and 103 is a write pointer for writing data to the memory buffer 100. Reference numeral 104 denotes a reading position control device that controls the reading position of the read pointer (101, 102). Reference numeral 105 denotes an invalid area table that registers invalid areas for which reading is prohibited for each read pointer (101, 102). The invalid area table 105 registers an invalid area 108 for skipping data for each of the read pointers. The read position control device 104 controls the read position of the read pointer 101 or the read pointer 102 based on the information registered in the invalid area table 105. At this time, it is automatically determined that the read pointer has reached the invalid area, and the reading position is controlled so as to skip over the invalid area 108. Reference numeral 106 denotes a decoder that decodes the bit stream. The decoder 106 reads and decodes data from the memory buffer 100 using the read pointer 101 or 102. Reference numeral 107 denotes an invalid area information registration device that analyzes a bit stream and registers an invalid area for the read pointer 101 or 102 in the invalid area table 105 in accordance with the analysis result or an instruction from the decoder 106. The invalid area information registration device 107 matches the invalid area 108 registered in the invalid area table 105 with information already registered.

  In the above configuration, when processing encoded data from a bit stream having encoded data and control information for decoding the encoded data, a plurality of read pointers (101, 102) are respectively used for obtaining control information and encoding. By registering the area in which the control information is stored by the invalid area information registration device 107 as the invalid area 108 in the invalid area table 105, the area is stored before or after the control information. Control is performed so that encoded data stored in succession can be treated as being stored in a pseudo continuous area.

  The stream in which the encoded data is arranged before or after the control information that can be input in this embodiment is as shown in FIG. 1 decodes encoded data A based on control information A, encoded data B-1 and B-2 are decoded based on control information B, and encoded data C is decoded based on control information C. The

  A stream is stored from the synchronization word A in the memory buffer 100, the decoder 106 uses the read pointer 101 to acquire the synchronization word and the control information, and the read pointer 102 uses to acquire the encoded data. Both read pointers are positioned at the head of the synchronization word A.

  When the encoded data A is decoded by the decoder 106, first, the control information A is obtained from the synchronization word A using the read pointer 101. However, since the memory buffer 100 does not have a FIFO structure, the synchronization information obtained using the read pointer 101 is acquired. The word A and the control information A also exist in the memory buffer 100 and are held in a state that can be acquired by the read pointer 102. Therefore, when a stream is acquired with the read pointer 101, either or both of the head address where the synchronization word A is stored in the invalid area table 105 and the size or the end address until the end where the control information A is stored Is registered as an invalid area for the read pointer 102. Thus, when data is to be acquired using the read pointer 102, the reading position control device 104 reads the information registered in the invalid area table 105 and moves the read pointer 102 to the head of the encoded data A. Thus, the read pointer 102 can read the encoded data A. Registration of invalid areas in the invalid area table 105 may be performed by analyzing and registering the bitstream using the invalid area information registration device 107 before the decoder 106 starts decoding.

Similarly, when the encoded data B is decoded, when the synchronization word B and the control information B are acquired using the read pointer 101, the start address and the control information B in which the synchronization word B is stored are stored. One or both of the size up to the end and the end address are registered as an invalid area for the read pointer 102. The encoded data B is stored as encoded data B-1 and encoded data B-2 before and after the control information B. When the read pointer 102 has completely acquired the encoded data B-1, the read position control is performed. The device 104 reads data from the invalid area table 105 and moves the read pointer 102 to the head of the encoded data B-2. For this reason, the decoder 106 can acquire the encoded data B stored discontinuously in the same manner as the data arranged in the continuous area using the read pointer 102.
(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS.

  FIG. 2 is a block diagram showing a bit stream decoding apparatus according to Embodiment 2 of the present invention. The same reference numerals as those in FIG. 1 denote the same or corresponding parts. FIG. 3 is a flowchart showing the operation in the second embodiment of the present invention.

  In FIG. 2, 21 is a bit stream input buffer device, 200 is a data amount detection device for detecting the effective data size stored from the read pointer 101 or 102 to the write pointer 103, and 201 is calculated by the decoder 106. The next frame detection device detects whether or not the synchronization word of the next frame of the frame is present at a predetermined position based on the frame length. The valid data size is a size obtained by subtracting the data size registered as an invalid area from the data size actually stored from the read pointer 101 or 102 to the write pointer 103.

  The bit stream is composed of a header including a unique synchronization word and encoded data, and can be decoded in a certain decoding unit such as a frame. The data amount detection apparatus 200 uses the data amount necessary for analyzing the header and calculating the frame length necessary for decoding as the first threshold value, and whether or not there is data in the memory buffer 100 that is equal to or greater than the first threshold value. And a means for determining that there is data in the memory buffer 100 that is equal to or greater than the second threshold, with the frame length calculated from the header in each frame as the second threshold.

  When the data amount detection apparatus 200 detects data greater than or equal to the first threshold value, the header analysis permission is given to the decoder 106 to detect the data amount greater than or equal to the second threshold value, and the next frame if the frame is not the final frame. When the detection device 201 can detect that the synchronization word of the next frame exists at a predetermined position, the decoder 106 is given decoding permission, and when the frame is the last frame, the data amount equal to or greater than the second threshold is detected. Then, the decoder 106 is controlled to give decoding permission.

That is, as shown in FIG. 3, the data amount detection device 200 has data in the memory buffer 100 that is equal to or larger than the data amount having a data size necessary for calculating the frame length defined by each standard as a first threshold. Then, the control information analysis permission is given to the decoder 106 to calculate the frame length (steps 300, 301, 302, 303). The data amount detection device 200 sets the frame length calculated by the decoder 106 as the second threshold value, and if there is a data amount equal to or larger than the second threshold value in the memory buffer 100, the data amount detection device 200 notifies the next frame detection device 201 of the next frame synchronization word A detection instruction is issued, and if the next frame synchronization word is present at a predetermined position, the next frame detection device 201 controls the decoder 106 to establish synchronization as a correct frame and give the decoder 106 permission to decode ( Steps 304, 305, and 306) can prevent generation of noise when decoding based on an erroneous synchronization word and generation of noise due to underflow during decoding.
(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 is a block diagram showing a bit stream decoding apparatus according to Embodiment 3 of the present invention. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts. FIG. 5 is a diagram showing the transition of the effective data amount between two read pointers in the third embodiment of the present invention.

  In FIG. 4, 41 is a bit stream input buffer device, 400 is a valid data amount detection device for detecting the valid data size between read pointers for data stored between the read pointers 101 and 102, and 401 is a read. An effective data amount determination device that determines whether the valid data size between pointers exceeds a predetermined threshold. 402 is an effective data amount determination device 401 that determines that the effective data amount between read pointers exceeds the threshold. In this case, the read pointer position control device controls the advance of the other read pointer so that the effective data amount between the read pointers is equal to or less than the threshold value based on the preceding read pointer.

  The valid data size between read pointers is a size obtained by subtracting the data size registered as an invalid area from the data size actually stored between the read pointers 101 and 102. Further, the threshold value is set to be equal to or larger than the maximum size of the encoded data defined in the standard, and in the case of a stream as shown in FIG.

  In the above configuration, when the read pointer position control device 402 advances only a specific read pointer among a plurality of read pointers due to an error during decoding or data skip, and the other read pointer does not advance, the data amount between the read pointers is a threshold value. Decoding can be resumed by controlling so as to be as follows and securing a certain amount of data between the read pointers.

That is, in FIG. 4, when 101 is the preceding read pointer and the effective data size up to the read pointer 102 with reference to the read pointer 101 exceeds the threshold, the effective data size between the read pointers 101 and 102 is the threshold. By advancing the read pointer 102 as follows, it is possible to prevent the memory buffer 100 from overflowing due to the read pointer 102 not moving as shown in FIG. Further, by securing a certain amount of data necessary for decoding between the read pointers 101 and 102, data stored before the control information can be guaranteed even in the case of data as shown in FIG. Decryption can be resumed quickly with the instruction.
(Embodiment 4)
A fourth embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 is a block diagram showing a bit stream decoding apparatus according to Embodiment 4 of the present invention. The same reference numerals as those in FIG. 1 denote the same or corresponding parts. FIG. 7 is a diagram showing an example of an input stream in Embodiment 4 of the present invention.

  In FIG. 6, 61 is a bit stream input buffer device, and 600 is a stream that does not have control information for each frame, and is read to each read pointer when it is read out at a timing asynchronous with the frame like a multiplexed stream packet. On the other hand, this is a control information area table in which control information itself can be registered in the table together with the control information area of the multiplexed stream. That is, the control information area table 600 registers control information together with the invalid area 108 for skipping data for each of the read pointers. Reference numeral 601 denotes a decoder control information rewriting device for notifying that the read pointer has passed through the registered area from the control information area table 600 and updating the control information in the decoder used for decoding the next frame. That is, the decoder control information rewriting device 601 reads the control information registered in the control information area table 600 by the information notification from the reading position control device 104 and rewrites the control information of the decoder. Reference numeral 602 denotes a control information area registration apparatus that analyzes a bit stream and registers in the control information area table 600 information indicating the invalid area for the read pointer 101 or 102 and information for controlling the operation of the decoder 106 according to the analysis result or an instruction from the decoder 106. . The control information area registration device 602 matches the invalid area registered in the control information area table 600 with the information already registered.

  In the above configuration, when the information is notified from the reading position control device 104 to the decoder control information rewriting device 601, the control means for rewriting the control information of the decoder 106 by the decoder control information rewriting device 601 at the frame break corresponding to the invalid area. It has.

The stream input in FIG. 7 is stored in a packetized state with a constant size, and the packet size is not necessarily synchronized with the frame. Frames 4-1 and 4-2 are states in which one frame data is stored across two packets. In the stream as shown in FIG. 7, when decoding is performed based on the control information described in the control information area of the packet including the head of each frame, the frames 4-1 and 4-2 are decoded based on the control information A. Conventionally, it is necessary to add control information to each frame or reconfigure the packet so that the frames 4-1 and 4-2 do not straddle a plurality of packets. Analysis is performed by the area registration device 602, and the control information area and the control information are registered in the control information area table 600. The read pointer passes through the control information B area, and the decoder control information rewriting apparatus 601 is used. By updating the control information for decoding the next frame to the control information B, the frame 4 is decoded based on the control information A. Since during decoding of the frame 5 it can be decoded based on the control information B, thereby enabling decoding without reconstruction of addition and packet control information to each frame.
(Embodiment 5)
Embodiment 5 of the present invention will be described with reference to FIG.

  FIG. 8 is a block diagram showing a configuration example of a bit stream reproduction system according to Embodiment 5 of the present invention.

  That is, in the first to fourth embodiments, an encoded bit stream transmitted from a recording medium, a wired or wireless transmission path is reproduced, written to a memory buffer, read from the memory buffer, and decoded.

  In FIG. 8, reference numeral 800 denotes an antenna for receiving radio waves for broadcasting or the like. Reference numeral 803 denotes broadcast reception for taking out a stream in which moving images and audio are multiplexed from the radio waves received by the antenna 800 and passing them to the demultiplexing device 804. Device. Reference numeral 801 denotes a recording medium capable of recording music information and moving images. Reference numeral 802 denotes a data reading device that reads a stream from the recording medium 801 and passes the stream to the demultiplexing device 804. The stream is a stream in which music information is encoded or a moving image encoded stream encoded at a variable bit rate. The moving image encoded stream is encoded according to the MPEG standard, and the control information is multiplexed in the stream.

In this case, the demultiplexing device 804 analyzes the streams sent from the data reading device 802 and the broadcast receiving device 803 and separates them into moving image data and audio / audio data. The stream passed to the demultiplexer 804 is not only a case where a moving image and audio / audio are multiplexed as one stream, but also an audio / audio only. In the stream analyzed and separated by the demultiplexer 804, the moving image data portion is temporarily stored in the video stream input buffer device 805, decoded by the video decoder 807, and visually displayed by the display device 809. In the stream analyzed and separated by the demultiplexer 804, the audio / audio data portion is temporarily stored in the audio stream input buffer device 806, decoded by the audio decoder 808, and output by the speaker device 811. Each of the video stream input buffer device 805 and the audio stream input buffer device 806 includes any one of the above-described 11, 21, 41, and 61 bit stream input buffer devices. Reference numeral 810 denotes a synchronization control device that synchronizes the decoding timings of moving images and audio / audio data based on information stored in the multiplexed stream. By configuring in this way, no matter what type of bit stream is input, there is no copy processing for securing and saving unnecessary save memory areas, and a memory-saving and power-saving bit stream playback system is constructed. it can.
(Embodiment 6)
A sixth embodiment of the present invention will be described with reference to FIGS.

  FIG. 9 is a block diagram showing a bit stream decoding apparatus according to Embodiment 6 of the present invention. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

  In FIG. 9, reference numeral 71 denotes a bit stream input buffer device, 701 denotes an area information table for registering area information of data stored in the memory buffer 100, and 702 denotes information registered in the area information table 701. This is a read area control device that controls the positions of a plurality of read pointers (101, 102) based on the read area control device. At this time, the invalid area 108 to be automatically skipped for each of the read pointers is determined, and the reading position is controlled so as to skip the invalid area. Only two (101, 102) read pointers are shown, but they may be added as necessary. Reference numeral 706 denotes an area information registration apparatus that analyzes a bit stream and registers area information in the invalid area table 105 or the area information table 701 in accordance with the analysis result and an instruction from the decoder 106 or 703. The area information registration device 706 matches the invalid area registered in the invalid area table 105 and the area information table 701 with the information already registered. Information registration in the region information table 701 is performed according to the analysis result of the bit stream analyzed by the region information registration device 706 before the decoder 106 or 703 starts decoding. The decoder 703 is a decoder that decodes a bitstream different from that of the decoder 106, and not only reads and decodes data from the memory buffer 100 using a plurality of read pointers similarly to the decoder 106, but also creates invalid areas for the plurality of read pointers. A registration instruction can be given to the area information registration device 706 and registered in the invalid area table 105. 704 represents the state of the bit stream A stored in the memory buffer 100, and 705 represents the state of the bit stream B as in 704.

  In the above configuration, when a plurality of bit streams are mixed and stored in the memory buffer 100, each of the plurality of read pointers uses the read area control device 702 to pseudo-continue only one desired type of bit stream. By performing control so that it can be read out as an area, only data necessary for decoding can be acquired for each decoder, and a plurality of bit streams can be decoded simultaneously.

  In this case, when transmitting the bit stream to the memory buffer 100, the region information registration device 706 analyzes the type information for identifying the write start position of the various bit streams and the type of the bit stream, and registers them in the region information table 701. Keep it. Also, the various decoders notify the read area control device 702 of type information indicating which bitstream is to be acquired. In decoding the bit stream A 704, the decoder 106 notifies the read area control device 702 so that the bit stream A 704 can be acquired using the read pointer 101. The read area control device 702 confirms the information in the area information table 701, and the next read position of the read pointer 101 is the start position of the bit stream B 705 different from the type information (bit stream A 704) notified from the decoder 106. Is detected from the area information table 701, and information is read so that the read position control device 104 that controls the read position of the read pointer 101 skips to the write start position. By performing the notification control, the decoder 106 can acquire the bit stream A 704 stored discontinuously in the memory buffer 100 using the read pointer 101 as if it is a continuous area, and can perform decoding.

  Similarly, when decoding the bit stream B 705, if the type information is notified to the read area control device 702 so that the decoder 703 can acquire the bit stream B 705 using the read pointer 102, the read area control is performed. Under the control of the device 702, the bit stream B705 in the memory buffer 100 can be read as a continuous area and decoded.

  In the configuration of FIG. 9, the read pointer 101 is assigned to the decoder 106 and the read pointer 102 is assigned to the decoder 703 to decode two types of bitstreams. However, a new decoder and a read pointer assigned to the new decoder are shown. Can be applied to decoding of three or more types of bitstreams. Further, by adding a read pointer to be assigned to each of a plurality of decoders and assigning them respectively for obtaining control information and decoding encoded data, the control shown in the first embodiment can be realized simultaneously by a plurality of decoders. be able to.

  FIG. 10 is a block diagram showing a configuration example of a bit stream reproduction system according to Embodiment 6 of the present invention. The same reference numerals as those in FIG. 8 indicate the same or corresponding parts.

  In FIG. 12, reference numeral 1200 denotes the video / audio input buffer device 71 that stores a stream in which moving images and audio data transmitted from the data reading device 802 or the broadcast receiving device 803 are multiplexed. If information such as the start position of each moving image and audio data is registered when the multiplexed stream is stored in the input buffer device 1200, the multiplexed data stored in the input buffer device 1200 is stored. From the data, moving image data can be directly supplied to the video decoder 807 and audio data can be directly supplied to the audio decoder 808 for decoding. By adopting such a configuration, the process of separating the multiplexed data using the demultiplexer, and the process of copying the separated moving images and audio data to the respective dedicated input buffer devices are omitted. A power-saving bitstream playback system can be constructed.

  The bitstream reproduction apparatus according to the present invention is a large-scale reproduction apparatus for reproducing compressed data of audio and images, for example, a data stream such as MPEG (Moving Picture Experts Group) -1/2 standardized by ISO (International Organization for Standardization). It is effective as hardware in a scale integrated circuit, software by a microcomputer, or the like.

1 is a block diagram of a bit stream playback device according to a first embodiment of the present invention. The block diagram of the bit stream reproducing | regenerating apparatus of Embodiment 2 of this invention. The flowchart explaining operation | movement of Embodiment 2 of this invention. The block diagram of the bit stream reproducing | regenerating apparatus of Embodiment 3 of this invention. The graph which shows transition of the data amount between the read pointers of Embodiment 3 of this invention. The block diagram of the bit stream reproducing | regenerating apparatus of Embodiment 4 of this invention. The figure which shows the example of the stream which does not have control information in each flame | frame. The block diagram of the moving image reproduction | regeneration system of Embodiment 5 of this invention. The block diagram of the bit stream reproducing | regenerating apparatus of Embodiment 6 of this invention. The block diagram of the moving image reproduction | regeneration system of Embodiment 6 of this invention. The figure which shows the example of the stream from which control information and data become asynchronous. The block diagram of the conventional bit stream reproducing | regenerating apparatus.

Explanation of symbols

11, 21, 41, 61, 71 Bit stream input buffer device 100 Memory buffer 101, 102 Read pointer 103 Write pointer 104 Read position control device 105 Invalid region table 106 Decoder 107 Invalid region information registration device 200 Data amount detection device 201 Next frame Detection apparatus 400 Effective data amount detection apparatus 401 Effective data amount determination apparatus 402 Read pointer position control apparatus 600 Control information area table 601 Decoder control information rewriting apparatus 602 Control information area registration apparatus 701 Area information table 702 Read area control apparatus 706 Area information registration Device 805 Video stream input buffer device 806 Audio stream input buffer device 1000 FIFO buffer 1001 Data saving buffer 1200 Video / Audio stream input buffer Ffer device

Claims (10)

A bitstream reproduction device capable of processing the encoded data from a bitstream having encoded data and control information for decoding the encoded data,
A memory buffer for receiving and storing the bitstream;
A plurality of read pointers for reading data from the memory buffer;
An invalid area table for registering invalid areas for skipping data for each of the read pointers;
A read position control device that reads information from the invalid area table and automatically determines that the read pointer has reached the invalid area and controls the read position so as to skip the invalid area data; and
A decoder that reads and decodes a bitstream from the memory buffer using the read pointer;
Analyzing the encoded data and registering the invalid area in the invalid area table based on the result, and registering the invalid area in the invalid area table in accordance with an instruction from the decoder and matching with the already registered information An invalid area information registration device that takes
The plurality of read pointers are allocated for control information acquisition and encoded data decoding, respectively, and the area where the control information is stored by the invalid area information registration device is registered in the invalid area table as the invalid area. Thus, the bit stream reproducing apparatus is controlled so that the encoded data stored discontinuously by being positioned before or after the control information can be handled as stored in the continuous area. The bitstream is composed of a header including a unique synchronization word and encoded data, and can be decoded in a certain decoding unit consisting of a frame,
Means for analyzing the header and determining a data amount necessary for calculating a frame length necessary for decoding as a first threshold value, and determining whether or not data exceeding the first threshold value exists in the memory buffer; A data amount detection device comprising: means for determining, in each frame, the frame length calculated from the header as a second threshold value and determining that data equal to or greater than the second threshold value exists in the memory buffer; A next frame detection device for detecting a synchronization word of the next frame of the frame based on the frame length;
When the data amount detection device detects data greater than or equal to the first threshold value, the header analysis permission is given to the decoder, the data amount greater than or equal to the second threshold value is detected, and the frame is not the final frame. When the next frame detection device can detect the presence of a synchronization word of the next frame at a predetermined position, the decoder is permitted to decode, and when the frame is the last frame, the data equal to or higher than the second threshold value 2. The bit stream reproducing apparatus according to claim 1, wherein when the amount is detected, the decoder has a control for giving a decoding permission. An effective data amount detection device for calculating an effective data size between any two read pointers;
An effective data amount determination device that compares a data size obtained by the effective data amount detection device with a predetermined threshold value, and a read pointer position that controls a read pointer position based on a determination result of the effective data amount determination device A control device,
When the read pointer position control device advances only a specific read pointer among the plurality of read pointers due to an error during decoding or data skip, and the other read pointer does not advance, the data amount between the read pointers is less than a threshold value. 2. The bit stream reproducing apparatus according to claim 1, wherein the bit stream reproducing apparatus according to claim 1, wherein the decoding can be resumed by controlling so as to prevent overflow of the memory buffer and securing a certain amount of data between the read pointers. A bitstream reproducing apparatus capable of processing the encoded data in a certain decoding unit composed of frames from a bitstream having encoded data and control information for decoding the encoded data,
A memory buffer for receiving and storing the bitstream;
A plurality of read pointers for reading data from the memory buffer;
A control information area table for registering the control information together with an invalid area for skipping data for each of the read pointers;
A read position control device that reads information from the control information area table and automatically determines that the read pointer has reached the invalid area and controls the read position so as to skip the invalid area;
A decoder that reads and decodes a bitstream from the memory buffer using the read pointer;
Analyzing the encoded data and registering an invalid area and control information in the control information area table based on the result, and also registering the invalid area and control information in the control information area table according to an instruction from the decoder. A control information area registration device that matches the registered information;
A decoder control information rewriting device that reads the control information registered in the control information area table by information notification from the read position control device and rewrites the control information of the decoder used for decoding the next frame;
The plurality of read pointers are assigned for control information acquisition and encoded data decoding, respectively, and the control information area is stored in the control information area together with the control information, with the area storing the control information as the invalid area. The decoder control information rewriting device rewrites the control information of the decoder at the break of the frame corresponding to the invalid area when there is information notification from the read position control device to the decoder control information rewriting device. A bit stream reproducing apparatus characterized by being controlled to A bitstream reproducing device capable of processing a plurality of encoded data from a plurality of bitstreams having a plurality of encoded data and control information for decoding the plurality of encoded data,
A memory buffer for receiving and storing the bitstream;
A plurality of read pointers for reading data from the memory buffer;
An area for skipping data for each of the read pointers is a first invalid area, and an invalid area table for registering information on the first invalid area;
An area information table for registering area information of the bitstream stored in the memory buffer;
A read area control device that reads out the area information from the area information table and automatically controls the read pointer to be read out and determines a bit stream area to output as a second invalid area;
It is automatically determined that the read pointer has reached the first invalid area obtained by reading information from the invalid area table or the second invalid area notified from the read area control device, and A reading position control device for controlling the reading position so as to skip the first or second invalid area;
A plurality of decoders that read and decode a bitstream from the memory buffer using the plurality of read pointers, respectively;
Based on the result of analyzing the bit stream, the first invalid area and area information are registered in the invalid area table and area information table, respectively, and also in the invalid area table and area information table in response to an instruction from the decoder. An area information registration device that registers each of the first invalid area and the area information and matches the already registered information,
When a plurality of bit streams are mixed and stored in the memory buffer, each of the read pointers performs control so that only one desired type of bit stream can be read as a continuous area using the read area control device. Thus, a bit stream reproducing apparatus characterized in that only the data necessary for decoding can be obtained for each of the decoders and a plurality of bit streams can be decoded simultaneously.   6. The bit stream reproducing apparatus according to claim 1, wherein a bit stream is reproduced from a recording medium, written to a memory buffer, read from the memory buffer, and decoded.   6. The bit stream reproducing apparatus according to claim 1, further comprising a stream receiving apparatus that receives a bit stream transmitted via a wired or wireless transmission path.   The bit stream reproducing apparatus according to claim 6 or 7, wherein the bit stream is a stream in which music information is encoded.   The bit stream reproducing apparatus according to claim 6 or 7, wherein the bit stream is a moving image encoded stream encoded at a variable bit rate.   8. The bit stream reproducing device according to claim 6, wherein the bit stream is a moving image encoded stream encoded in accordance with an MPEG standard, and the control information is multiplexed in the encoded stream.

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