JP2007150845A - Data reproducing apparatus, data reproducing method, and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce images without a sense of incongruity by maintaining the transmission time of images, even when the data are formed as the AV data to which the time information is added only to a part of the packet such as MPEG2-TS format. <P>SOLUTION: The data reproducing apparatus comprises a data reader 206 for reading AV data; a timing controller 208 for outputting a time information packet based on the time information when the packet of AV data obtained is the time information packet to which the time information is added, and outputting an ordinary packet in the predetermined timing interval from the time information packet when the packet is the ordinary packet other than the time information packet; and an interface 214 for relaying the time information packet and ordinary packet outputted to the external side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data reproduction device, a data reproduction method, and a program thereof, and, for example, relates to a data reproduction device, a data reproduction method, and a program thereof that reproduce AV data packets.

  Digital video compression technology that digitizes video and audio AV (Audio and Visual) signals and reduces the amount of video data using digital compression technology is widely used for broadcasting AV signals and storing them in storage media . Examples of using such digital video compression technology include BS (Broadcast Satellite) digital broadcasting, terrestrial digital broadcasting, and video software using a so-called DVD (Digital Versatile Disc).

  A typical example of the digital video compression technique is the MPEG-2 (Motion Picture Experts Group-2) system. Here, MPEG is a general term for data compression methods standardized by the Motion Picture Experts Group. In digital broadcasting, MPEG2-TS (Transport Stream) format is used as a method for transmitting compressed digital data.

  In the MPEG2-TS format, compressed video or audio data is divided into units called, for example, 188-byte packets, and data is transmitted in units of packets (TS packets). By packetizing data in this way, it becomes easy to multiplex and transmit data of a plurality of channels.

  A data reproducing apparatus for recording and reproducing the MPEG2-TS broadcast has been put into practical use. For example, a 188-byte packet input as an AV signal is stored in a storage medium while being padded with NULL packet data, the boundary of MPEG data is matched with the sector boundary of the disk, and the video progresses on the file system. Has been disclosed (for example, Patent Document 1). In such a technique, a packet is read and reproduction processing is performed without performing complicated disk access during reproduction.

  Thus, storing 188-byte packets obtained by dividing AV data simply and continuously in a file is widely used in PCs (Personal Computers) having a digital broadcast receiving function.

  Also, in so-called AV equipment, a time stamp indicating the transmission time of each packet is added to and stored in all packets in the MPEG2-TS format, and at the time of reproduction, the output timing of the packet is controlled using this time stamp, A technique for outputting packets at the same packet interval as at the time of input is known (for example, Patent Document 2). With such a technique, it is possible to prevent the internal buffer from overflowing and depleting and the time information in the stream from being shifted due to early arrival or delay of packet transmission inside the AV device.

JP 2005-25919 A Japanese Patent No. 3119116

  However, data such as a PC that inserts a NULL packet and stores it so that the boundary of the MPEG data and the sector boundary of the disk coincide with each other, and data such as the AV device that stores the time stamp indicating the transmission time of all packets. With the playback device, the following problems occur depending on the storage form.

  That is, in the data reproducing apparatus, time stamps can be added to the data of all packets, whereas in the PC, time stamps cannot be added or managed due to hardware limitations. The file format will be different and data compatibility will be lost. This is a particular problem when the PC and the data reproducing apparatus are connected and the data reproducing apparatus is used as a peripheral device of the PC.

  Also, since the file stored in the PC does not include information regarding the output time in all packets, the packet output interval cannot be accurately grasped or controlled. Therefore, the packet cannot be output from the PC to the outside at an accurate timing, and data transmission from the PC to the data reproducing apparatus is difficult. MPEG2-TS packets contain various time information, but once the transmission time of the packet deviates, the time information becomes meaningless, so even when data is transmitted from the PC to the data reproduction device, it is decoded. Need to be processed.

  The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to maintain a video transmission time and to provide a video with no sense of incongruity even when time information is not added to all packets. It is intended to provide a new and improved data reproducing apparatus, data reproducing method and program thereof that can be reproduced.

  In order to solve the above-described problem, according to an aspect of the present invention, a data reading unit that reads AV data; and a packet of the read AV data is a time information packet to which time information is added, The time information packet is output based on the time information, and when the read AV data packet is a normal packet other than the time information packet, the normal packet is output at a predetermined time interval from the time information packet. There is provided a data reproducing device comprising: an output timing control unit; and an interface unit that relays the output time information packet and normal packet to the outside.

  The data reproduction device reproduces AV data obtained by packetizing video and audio data that have been compressed by digital compression technology. In this AV data, a time information packet and a normal packet are mixed. The timing control unit first detects a time information packet and outputs the time information packet at a specific time based on the time information. In addition, the timing control unit sequentially outputs normal packets included in the time information packet at predetermined time intervals with reference to the output timing of the time information packet. With this configuration, it is possible to maintain a video transmission time and obtain a reproduced video without a sense of incongruity.

  The AV data is data stored in advance on a storage medium, the time difference between the time information in two successive time information packets of the AV data in the storage medium, and the normal packet between the two time information packets An interval calculation unit for calculating the predetermined time interval from the number of the above may be further provided.

  Since data is written in advance in the storage medium, the data reproducing apparatus can refer to the contents of the data at once or in a short time. Therefore, the interval calculation unit can read the time difference and the number of normal packets from the storage medium without the actual output of AV data, and the predetermined time can be read in advance or independently of the data transmission path. The interval or packet output rate can be calculated. Such a calculation may be a result of dividing the time difference by the number of normal packets + 1.

  A data buffer for temporarily holding the read AV data packet; a time difference between time information in two successive time information packets of the AV data held in the data buffer; and between the two time information packets An interval calculating unit that calculates the predetermined time interval from the number of normal packets may be further provided.

  The data buffer temporarily holds a part of AV data including at least two continuous time information packets. The interval calculation unit can refer to at least two time information packets held in the data buffer and a normal packet between them at once or in a short time. Therefore, the interval calculation unit can easily calculate the predetermined time interval or the packet output rate from the time difference and the number of normal packets.

  The interval calculation unit may update the predetermined time interval as needed according to the time difference or the change in the number of normal packets. With such a configuration, even if the time difference of AV data and the number of normal packets are irregularly arranged, a uniform output interval can be maintained, and a reproduced video with a more uncomfortable feeling can be obtained.

  The predetermined time interval may be set shorter than a value obtained by dividing the time difference by the number of normal packets + 1. With this configuration, it is possible to prevent a collision between a normal packet and a time information packet output immediately thereafter.

  The timing control unit includes: a packet buffer that temporarily holds an input packet; a PCR packet determination unit that determines whether the packet held in the packet buffer is a time information packet; and the packet buffer A PCR extracting unit for extracting time information of the packet held in the counter; a counter for counting clocks; a coincidence detecting unit for generating an output start signal when the time information and the count value of the counter coincide; A timer for generating an output start signal at the predetermined time interval based on an output start signal from the match detection unit; and switching an output start signal between the match detection unit and the timer based on the determination of the PCR packet determination unit A timing switching unit; outputting a packet in the packet buffer in response to the switched output start signal A force controlling section; may be provided with.

  A data writing unit for writing AV data may be further provided, and the interface unit may further relay audio data from an external device to the data writing unit.

  As described above, the data reproducing apparatus can also have a function of storing AV data input from the outside. Since the interface unit and the data writing unit store the input data format in the storage medium without adding redundant time information to the AV data, the interface unit and the data writing unit can be compatible with the storage medium stored in the PC. .

  The computer also provides a program that functions as the data reproduction device, and also provides a data reproduction method for reproducing AV data using the data reproduction device.

  As described above, according to the present invention, even with AV data in which time information is added to only a part of packets such as the MPEG2-TS format, the video transmission time can be maintained and the video without any sense of incongruity. Can be played.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  In the conventional data reproducing apparatus, regardless of whether the input packet is a PCR (Program Clock Reference) packet to which time information is added, the time information is added to all the packets independently and stored. , It was played back using the time information.

  On the other hand, since the PC is a general-purpose product, the hardware is limited, and there is no way to add time information uniquely to the packet to be stored or to refer to the added time information.

  Therefore, a format discrepancy occurs between the storage medium stored in the conventional data reproducing apparatus and the storage medium stored in the PC, and there is no compatibility.

(First embodiment: data reproduction system)
The data reproducing apparatus according to the present embodiment reproduces AV data obtained by packetizing video and audio data that has been data-compressed by a digital compression technique without feeling uncomfortable such as a transmission delay. The AV data is data obtained by digitizing audio and / or video and performing a predetermined data compression process. In the AV data, a time information packet and a normal packet are mixed.

  FIG. 1 is an image diagram for explaining the connection relation of the data reproduction system according to the present embodiment, and FIG. 2 is a block diagram schematically showing the function of the data reproduction system.

  The data reproduction system 100 in FIG. 1 includes an antenna 110, a broadcast receiver 120, a television monitor 130, and an HDD (Hard Disk Drive) recorder 140 that also functions as a data reproduction device.

  The antenna 110 receives a radio wave such as a television broadcast output from the television broadcast tower 150 over a wide area, and converts the received radio signal into an electric signal.

  The broadcast receiver 120 converts the AV data received by the antenna 110 into a format that can be reproduced by the television monitor 130, and transmits the AV data to the television monitor 130. Further, the AV data from the antenna 110 is output to be stored in the HDD recorder 140, and the AV data stored in the HDD recorder 140 is input.

  The television monitor 130 receives the video signal and the audio signal from the broadcast receiver 120, and reproduces the video on the monitor and the audio on the speaker.

  The HDD recorder 140 stores the AV data input from the broadcast receiver 120 in a storage medium such as an HDD or a DVD, and reads the AV data stored in the HDD or DVD to the broadcast receiver 120. Output.

  The broadcast receiver 120 may be integrally formed with the television monitor 130 or may be integrally formed with the HDD recorder 140. Furthermore, the broadcast receiver 120, the television monitor 130, and the HDD recorder 140 can all be integrally formed. Further, AV data read by the HDD recorder 140 may be directly transmitted to the television monitor 130 without using the broadcast receiver 120.

  Referring to FIG. 2, the broadcast receiver 120 includes a tuner 122, an interface unit 124, and a decoder 126.

  The tuner 122 selects a desired frequency band from the radio wave received by the antenna 110, and extracts a signal in the frequency band using a BPF (Band Pass Filter) or the like. In addition, information on a desired channel is extracted as data in the MPEG2-TS format from the frequencies thus extracted.

  In digital broadcasting, in order to effectively use a limited carrier (frequency), packets of a plurality of channels are multiplexed on a signal of one frequency. The tuner 122 first demodulates a signal included in a predetermined frequency, performs error correction processing, and generates a plurality of packets. Since a program of a plurality of channels is multiplexed in this packet group, the tuner 122 extracts only a packet of a desired channel from the packet and outputs it to the interface unit 124.

  FIG. 3 is an explanatory diagram showing a transmission form of an MPEG2-TS format packet output from the tuner 122. FIG. 3A shows all packets included in the predetermined frequency. Here, a 188-byte packet 200 obtained by dividing AV data is received, and a plurality of channels are mixed in one frequency. The tuner 122 sequentially determines whether or not the packet included in the predetermined frequency is the packet 202 of the desired channel, and extracts only the packet 202 of the predetermined channel as shown in FIG. The extracted packet 202 has an irregular and discontinuous output timing as shown in FIG.

  The interface unit 124 transmits the packet 202 from the tuner 122 to the decoder 126, and also outputs the packet 202 to the HDD recorder 140 when the HDD recorder 140 is connected.

  The decoder 126 extracts a video packet from the packet 202 transmitted from the interface unit 124, subsequently performs a decoding process into a format that can be reproduced by the television monitor 130, generates a video signal, and supplies the video signal to the television monitor 130.

  The decoder 126 also extracts audio packets, performs decoding processing to generate audio signals, and supplies them to the television monitor 130 together.

The data reproducing apparatus in the data reproducing system is exemplified by the HDD recorder 140, but is not limited to such a case. DVD, CD (Compact Disc), FD (Floppy (registered trademark) Disk), MO (Magnetic-optical Disk). Any device capable of reproducing AV data on a storage medium such as a flash memory, a card memory, a USB memory, a RAM, an E ² PROM, and a non-volatile RAM may be used, and various AV devices such as a DVD recorder can be used. .

  In the above-described data reproduction system, the connection between the broadcast receiver and the data reproduction device has been described. However, the present invention is not limited to this, and an imaging device (such as a video camera) or a digital camera capable of capturing a moving image can be used. The above-described functions can be implemented by connecting a data reproducing device.

  Therefore, it is possible to form a data reproducing device integrally with the video camera and view the recorded data directly on the television monitor 130.

(Data reproducing apparatus 200)
Next, a detailed description will be given of the data reproducing apparatus described using the HDD recorder 140 as an example.

  FIG. 4 is a block diagram showing a schematic function of the data reproducing apparatus 200 according to the present embodiment. The data reproduction apparatus 200 includes a data reproduction control unit 202, a data holding unit 204, a data reading unit 206, a timing control unit 208, an interval calculation unit 210, a data buffer 212, an interface unit 214, and a data writing. A part 216 and a remote control receiving part 218 are formed.

  The data reproduction control unit 202 manages and controls the entire data reproduction apparatus 200 by a semiconductor integrated circuit including a central processing unit (CPU).

  The data holding unit 204 is composed of a storage medium such as an HDD or a DVD, and can store AV data input from the outside.

  FIG. 5 is an explanatory diagram showing a data storage format of AV data stored in the data holding unit 204. On the HDD as the data holding unit 204, 188-byte long packets 150 in the MPEG-TS format are continuously stored and managed as one file.

  In the MPEG2-TS system, such AV data is divided into PES (Packetized Elementary Stream) packets, and time information such as PTS (Present Time Stamp) and DTS (Decord Time Stamp) is attached to the header portion of the PES packet. Further, as described above, the TS packet 150 is divided into 188 bytes.

  Each packet 150 includes a synchronization byte 152 indicating the head of the packet, a 13-bit PID (Packet ID) 154 for identifying the packet type, a packet body 156 including the divided AV data, and the like.

  The packet 150 includes video data packets, audio data packets, PAT (Program Association Table) packets, PMT (Program Map Table) packets, PCR packets, and the like, which can be identified by the PID 154. .

  The data reading unit 206 sequentially reads AV data packets for reproduction processing of AV data stored in the data holding unit 204 and transfers the AV data packets to the timing control unit 208 directly or via the data buffer 212. Further, the data reading unit 206 may directly read the time difference and the number of packets from the data holding unit 204 and transmit the time difference and the number of packets to the interval calculation unit 210 via a route independent of the data transmission route.

  The timing control unit 208 determines whether the AV data packet read by the data reading unit 206 is a time information packet to which reproduction information including the reproduction time of the AV data is added, which is represented as a PCR packet. If the packet is a PCR packet, the PCR packet is output to the interface unit 214 at a specific time when the PCR packet is to be output based on the time information. If the packet is a normal packet other than the PCR packet, the PCR packet is output. Normal packets are sequentially output to the interface unit 214 at predetermined time intervals from the time.

  For example, at least one PCR packet may be included in 100 msec of video time. The timing control unit 208 can maintain the transmission time of the video, and can obtain a playback video without a sense of incongruity.

  The interval calculation unit 210 calculates a predetermined time interval from the time difference of time information in two consecutive PCR packets of AV data in the data holding unit 204 and the number of normal packets between the two PCR packets. Such calculation may be performed by dividing the time difference by the number of normal packets + 1.

  Specifically, the interval calculation unit 210 temporarily holds the packet group from the data holding unit 204 in the data buffer 212, extracts the time difference and the number of normal packets related to the PCR packet from the packet group, and performs a predetermined time interval or packet The output rate is calculated.

  Further, since AV data is stored in the data holding unit 204 in advance, the data reading unit 206 can refer to the contents at a time. Therefore, it is possible to directly extract the time difference and the number of normal pads by the data reading unit 206 and obtain the packet output timing from the actual data amount without depending on a single bit rate.

  In this way, the packet output timing can be accurately controlled, and the problem of partially opening the packet interval can be avoided.

  The predetermined time interval may be set shorter (for example, about 10 to 20%) than the value obtained by dividing the time difference between PCR packets by the number of normal packets + 1. With this configuration, it is possible to prevent a collision between the normal packet to be output and the PCR packet immediately after that, and to guarantee the output of the PCR packet.

  The interval calculation unit 210 may update the predetermined time interval as needed according to the time difference or the change in the number of normal packets. For example, if the output rate is constant even when the time difference of AV data and the number of normal packets are irregularly arranged, if there are more normal packets than the specified value among the PCR packets, And a PCR packet immediately after that cause a video loss or a video output timing delay. With such a configuration that adjusts the output rate as needed, it is possible to maintain an output interval according to the time difference, and to obtain a reproduced video with a more uncomfortable feeling.

  However, if it is known beforehand that the PCR packet of the AV data stored in the data holding unit 204 and the regular packet have regularity and the output rate is constant, the function of the interval calculation unit 210 Can be stopped or not used.

  The interface unit 214 relays the output PCR packet and normal packet to the outside.

  The data writing unit 216 writes AV data input from the external device (peripheral device) to the interface unit 214 in the data holding unit 204.

  The remote control receiving unit 218 receives a command desired by the user from the remote controller and a command related to AV data recording and reproduction, and transmits the command to the data reproduction control unit 202. The data reproduction control unit 202 performs each function in response to the command.

  With the above-described configuration, video data and audio data that have been compressed by digital compression technology are packetized data, and AV data in which PCR packets and normal packets are mixed is stored in the data holding unit 204 and reproduced. Can do. The operation of storing and reproducing such AV data will be briefly described below.

  Assume that a user records a television program being viewed while the user is receiving a television broadcast in the data reproduction system. In order to record the video being broadcast, the user uses a remote controller (not shown) to instruct the data playback device to prepare for recording, for example, to change the channel. The command signal output from the remote control is received by the remote control receiving unit 218 in the data playback device, and a recording preparation command is input to the data playback control unit 202.

  The data reproduction control unit 202 switches the interface unit 214 to the recording mode, instructs the data writing unit 216 to prepare for recording, and further sends, for example, stream data to the broadcast receiver 120 via the interface unit 214. Request.

  At this time, in the broadcast receiver 120, the stream data received by the tuner 122 is supplied to the decoder 126 via the interface unit 124, and the stream data is decoded by the decoder 126 and displayed on the television monitor 130. .

  The interface unit 124 in the broadcast receiver 120 receives a stream data transmission request from the data reproduction device 200 and supplies the stream data supplied to the decoder to the data reproduction device 200 side.

  As an interface between the interface unit 124 of the broadcast receiver 120 and the interface unit 214 of the data reproduction device 200, a digital interface defined by IEEE 1394 can be used, as shown in FIG. Such MPEG2-TS format TS packets can be transmitted as they are.

  On the data playback device 200 side, the stream data input from the broadcast receiver 120 is input to the interface unit 214 through the input / output terminal of the data playback device 200 and input to the data writing unit 216 in a packet format.

  Thereafter, when the user instructs to start recording with the remote control, a signal from the remote control is received by the remote control receiving unit 218 and input to the data reproduction control unit 202. The data reproduction control unit 202 instructs the recording process of the stream data in accordance with the recording start instruction, and the data writing unit 216 converts the packet input from the interface unit 214 into a file as continuous data, and sends it to the data holding unit 204. I will remember it.

  At the end of the desired stream, the user issues a recording stop command via the remote control. In response to this, the data reproduction control unit 202 controls the data writing unit 216 and, after completing the packet writing, rewrites the file management information area of the data holding unit 204, for example, in the HDD, and stores the stored information as a file. Register in management information.

  Through the above processing, a packet group input from the outside can be stored as a file on the HDD as the data holding unit 204. The data format on the HDD is a continuous form of 188 byte packets as shown in FIG.

  Next, the reproduction process of AV data stored in the data holding unit 204 will be described.

  The user operates the remote controller to select AV data to be played back and gives an instruction to start playback. When receiving the reproduction start signal, the remote control receiving unit 218 transmits a reproduction start command to the data reproduction control unit 202.

  The data playback control unit 202 switches the interface unit 214 to the playback mode in accordance with the playback start command, and switches the broadcast receiver 120 to the stream data input mode via the interface unit 214. That is, the interface unit 124 in the broadcast receiver 120 switches the operation so that the packet received from the data reproduction device 200 is supplied to the decoder 126.

  Further, the data reproduction control unit 202 reads a desired file from the data holding unit 204 in accordance with the reproduction start instruction. The read file is extracted in a 188-byte packet format and input to the timing control unit 208 directly or via the data buffer 212. The timing control unit 208 controls the packet output timing so that time information does not contradict, and outputs the packet at a predetermined timing. The detailed operation of the timing control unit 208 will be described below.

(Timing control unit 208)
FIG. 6 is a block diagram illustrating schematic functional blocks of the timing control unit 208. Here, the timing control unit 208 includes a packet input terminal 300, a packet buffer 302, a PCR packet determination unit 304, a PCR extraction unit 306, a counter 308, a coincidence detection unit 310, a timer 312, and a parameter input terminal. 314, a timing switching unit 316, an output control unit 318, and a packet output terminal 320.

  The packet input from the data reading unit 206 is temporarily held in the packet buffer 302 via the packet input terminal 300. The PCR packet determination unit 304 and the PCR extraction unit 306 analyze the contents of the packet input to the packet buffer 302.

  The PCR packet discriminating unit 304 discriminates whether the packet input to the packet buffer 302 is a PCR packet as a time information packet or another normal packet.

  The PCR extracting unit 306 extracts a PCR value as time information attached to the packet input to the packet buffer 302. If the packet is a PCR packet, the PCR extraction unit 306 transfers the extracted PCR value to the match detection unit 310. If such a packet is not a PCR packet, the PCR value has no meaning.

  The counter 308 counts a count value in a format that can be synchronized with the PCR using, for example, a 27 MHz clock. The counter 308 transmits the count value thus counted to the coincidence detection unit 310.

  The coincidence detection unit 310 compares the PCR value input from the PCR extraction unit 306 with the count value generated by the counter 308, and outputs a packet output start signal to the timing switching unit 316 when the values match. Output.

  The timer 312 outputs a packet output start signal to the timing switching unit 316 at a predetermined cycle based on the output start signal from the coincidence detection unit 310. The output period of the packet output start signal by the timer 312 can be controlled from the data reproduction control unit 202 via the parameter input terminal 314.

  The timing switching unit 316 causes the output control unit 318 to output the PCR packet in response to the output start signal of the coincidence detection unit 310 when the PCR packet determination unit 304 determines that the determination target packet is a PCR packet, When the PCR packet determining unit 304 determines that the packet is a normal packet other than the PCR packet, for example, the packet is output according to the output start signal of the timer 312.

  The detailed operation of the timing control unit 208 will be described below.

  7A and 7B are timing charts for explaining the packet output timing by the timing switching unit 316. 7A shows the timing of the packet input to the packet input terminal 300, and FIG. 7B shows the timing of the packet output from the packet output terminal 320.

  When the reproduction of the AV data is started, the timing control unit 208 reads the AV data packet from the data holding unit 204. The read timing may be read for every predetermined number of packets (in this case, four) as shown in FIG. 7A, or may be read one by one at predetermined intervals. It is read at a faster timing and held in the packet buffer 302. When reading such a packet, it does not matter whether the packet is a PCR packet or any other packet.

  The packet buffer 302 acquires one packet 350 from the data holding unit 204. The PCR packet discriminating unit 304 discriminates whether or not the packet is a PCR packet. In FIG. 7A, a packet with diagonal lines is a PCR packet. Accordingly, the PCR packet determining unit 304 determines that the packet 350 is a PCR packet, and notifies the timing switching unit 316 to that effect.

  The timing switching unit 316 receives the signal from the PCR packet determination unit 304 and switches the timing input of the timing switching unit 316 to the coincidence detection unit 310 side. As a result, the output start signal of the packet output from the match detection unit 310 is input to the output control unit 318.

The PCR extraction unit 306 extracts the PCR value of the packet acquired by the packet buffer 302 in parallel with the PCR packet determination unit 304 and transfers it to the match detection unit 310. The coincidence detection unit 310 compares the PCR value extracted by the PCR extraction unit 306 with the count value generated by the counter 308, and outputs an output start signal to the timing switching unit 316 when they match. In this way, the packet (PCR packet) 350 is output from the packet output terminal 320 at the time when the PCR value and the count value coincide, that is, when the PCR packet should be output (time T ₁ in FIG. 7B). .

  The packet buffer 302 acquires the next packet 352 from the data holding unit 204. The PCR packet discriminating unit 304 discriminates whether or not the packet is a PCR packet, as described above. Since the packet 352 is a normal packet that is not a PCR packet, the PCR packet determination unit 304 notifies the timing switching unit 316 to that effect.

  The timing switching unit 316 receives the signal from the PCR packet determination unit 304 and switches the timing input of the timing switching unit 316 to the timer 312 side. As a result, the output start signal of the packet output from the timer 312 is input to the output control unit 318.

  The timer 312 waits for a predetermined time interval k from the previous packet (here, the packet 350), and outputs a packet output start signal to the timing switching unit 316 when the predetermined time interval k is reached. In this way, the packet 352 is output from the packet output terminal 320 at a predetermined time interval k from the packet 350 that is a PCR packet.

  In this way, the output interval of normal packets excluding PCR packets is controlled by the timer 312. Here, it is desirable that the packet output interval is substantially uniform including the PCR packet. In addition, if the packet interval is too short, the interface units 124 and 214 of both devices and the decoder 126 of the broadcast receiver 120 may be burdened, and the buffer may overflow during packet transmission. Should be as long as possible.

  Therefore, the packet interval k excluding the PCR packet can be obtained as follows. That is, the time interval k can be considered as the bit rate of the reproduction stream data divided by the number of bits for one packet. Here, as the bit rate, bit_rate information described in the sequence_extension in the MPEG stream can be used.

  However, if a bit rate is partially high for an arbitrary packet and the number of packets existing between PCR packets is large, the output timing of the PCR packet may be delayed. If the output timing of the PCR packet is later than the original output timing, the PCR value on the stream data is shifted, so it is desirable to output the packet at an interval slightly shorter than the calculated value k.

  Further, the packet interval k may be obtained from the actually stored stream data. Such calculation will be described in an embodiment described later.

  Even after the packet 352 is output, the packet buffer 302 obtains the next packet 354 from the data holding unit 204 in the same manner as described above, and if it is determined that the packet 354 is not a PCR packet, the packet 354 becomes the previous packet 352. Are output to the packet output terminal 320 at a predetermined time interval k. Such processing is repeated every time a packet is acquired, and a plurality of normal packets are output at a predetermined time interval k from one PCR packet.

When the packet 356, which is the next PCR packet, is recognized by the PCR packet discriminating unit 304, the packet (PCR packet) 356 should be output when the PCR value matches the count value, that is, the PCR packet should be output originally. The packet is output from the packet output terminal 320 at the time (time T ₂ in FIG. 7B). In this way, the packet output timing is made uniform as shown in FIG. 7B, and a reproduced video with no sense of incongruity can be obtained on the television monitor 130.

  Further, although the packet output timing shown in FIG. 7B is different from the packet output timing shown in FIG. 3B, the output timing of the PCR packet including the time information is accurately controlled. In the broadcast receiver 120 that has received the packet shown in FIG. 7B, the correct packet reception time can always be reproduced without the time information being shifted, and the decoding process is not hindered.

  In the example of FIGS. 7A and 7B, the number of packets is reduced to simplify the description. However, the number is not limited to the case of FIGS. There may be 10,000 packets.

(Interval calculator 210)
Next, a configuration for obtaining a time interval k for outputting a packet by using a PCR packet of AV data will be described.

  As described above, the interval calculation unit 210 determines the time difference between the PCR values in two consecutive PCR packets of AV data from the data holding unit 204 held in the data buffer 212, and between the two preceding and following PCR packets. The predetermined time interval is calculated from the number of normal packets.

  FIG. 8 is an explanatory diagram showing a packet held in the data buffer 212 for explaining the calculation of the predetermined time interval. Here, numerical values are assigned in the order of packets input to the data buffer 212.

  In the present embodiment, for example, 16 packets are read from the data holding unit 204 at a time, and the interval calculation unit 210 extracts PCR packets from the packet group. As a result, it is recognized that three PCR packets 400, 402, and 404 exist in the data buffer 212.

Subsequently, the interval calculation unit 210 selects two recent PCR packets (400, 402), and refers to the PCR values of the PCR packets 400, 402. Here, the PCR value of the PCR packet 400 includes the time of _{t 1,} the PCR value of the PCR packet 402 that contains the time _{t 2.}

  Next, the interval calculation unit 210 counts the number of packets (normal packets) between the two PCR packets. Here, five packets exist between the PCR packets 406.

Subsequently, the interval calculation unit 210 divides (divides) the time difference t ₂ −t ₁ of the PCR value by the numerical value 6 obtained by adding 1 to the number of normal packets 5 between the two previous and subsequent PCR packets. Thereby, the predetermined time interval k is derived. The predetermined time interval k may be set shorter than a value obtained by dividing the time difference t ₂ −t ₁ by the number of normal packets 5 + 1. This is implemented by rounding down the decimal point after division or by subtracting uniformly (1 to 20%). By such processing, it is possible to easily prevent a collision between the output normal packet and the PCR packet immediately after that. The predetermined time interval k thus obtained may be stored in the file as management information related to the stream file.

  Such calculation of the predetermined time interval k may be performed during the actual reproduction of the stream data, or may be performed for the purpose of obtaining the predetermined time interval k at the start of reproduction or before the start of reproduction. good. Here, the predetermined time interval k can be increased to such an extent that no problem occurs in transmission, and can be set in advance to a value calculated from the maximum bit rates of the interface units 124 and 214 and the decoder 126.

  The predetermined time interval k obtained as described above is set in the timer 312 in the timing control unit 208 by the data reproduction control unit 200, and the packet output interval is controlled. Accordingly, the packets in the stream file input to the timing control unit 208 are output at intervals as shown in FIG. 7B.

  The packet output from the timing control unit 208 is transmitted to the external broadcast receiver 120 via the interface unit 214 and input to the decoder 126 from the interface unit 124 on the broadcast receiver 120 side. The packet is decoded into a predetermined video signal by the decoder 126 and then displayed on the television monitor 130.

  As described above, even when only a predetermined percentage of packets are stream data (stream file) having an output timing, the output timing of each packet can be kept substantially constant and output. Further, since the output timing of the PCR packet is output in synchronization with the time information in the stream, it is possible to realize the output of the stream having accurate time information.

  As a result, the time information is correctly managed in the interface unit 124 and the decoder 126 in the broadcast receiver 120, the management of the buffer for storing the packets is facilitated, and a problem occurs in the reproduction in the data reproducing apparatus 200. Disappear.

  Further, in the present embodiment, not only when AV data packets are regularly arranged as shown in FIGS. 7A and 8, but also when PCR packets and normal packets are irregularly arranged. Can also provide appropriate output timing of packets.

  Based on the time difference between the PCR values in two consecutive PCR packets of the AV data in the data holding unit 204 and the number of normal packets between the two preceding and following PCR packets, the interval calculation unit 210 holds the data buffer 212. The above processing for calculating the predetermined time interval is always continued as long as the time difference or the number of normal packets changes.

  Therefore, even if the AV data to be viewed is AV data with irregular time difference or number of normal packets, it is possible to derive an optimum predetermined time interval k according to the time, and the predetermined time interval k. Thus, the timing control unit 208 can provide an optimum output rate of packets. In this way, it is possible to maintain a uniform output interval, and to obtain a reproduced image that is more comfortable.

  In addition, the storage content of the data holding unit 204 is not attached with unique time information and the like, and is the same as the state stored in the PC, so that the compatibility with the format with the PC can be maintained. In this way, the storage medium stored in the PC can be used as it is in the data reproducing apparatus, and vice versa.

  In addition, a program that functions as the above-described data reproduction device and a storage medium that stores the program are also provided.

(Second Embodiment: Modification of Data Reproducing Device)
In addition, the data reproduction device 200 described above can be formed integrally with the broadcast receiver 120.

  FIG. 9 is a block diagram showing a modified example of the data reproducing device 200. A data reproduction device 300, which is a modification of the data reproduction device 200, includes a tuner 122, a decoder 126, a data reproduction control unit 202, a data holding unit 204, a data reading unit 206, a timing control unit 208, and an interval calculation. A unit 210, a data buffer 212, a data writing unit 216, and a remote control receiving unit 218 are included.

  Since the above-described components have substantially the same functions as the components in the first embodiment, redundant description will be omitted, and only the points that differ in the functions will be described here.

  The data reproduction apparatus 300 includes a tuner 122 and a decoder 126 as a broadcast receiver, converts AV data received by the antenna 110 into a format that can be reproduced by the television monitor 130, and transmits the converted data to the television monitor 130. At the same time, the data reproduction device 300 can store AV data received by the antenna 110 and can reproduce the stored AV data.

  In such a configuration, a packet whose output timing is adjusted by the timing control unit 208 is directly transmitted to the television monitor 130 via the decoder 126 without any processing such as addition of data. High-quality video playback can be performed.

  In addition, since the timing is adjusted at the time of output of the data reproduction device 300, it is possible to obtain a video with no sense of incompatibility even when connected to a personal computer other than the television monitor 130, for example.

(Third embodiment: data reproduction method)
FIG. 10 is a flowchart showing the flow of the data reproducing method according to the third embodiment.

  First, when reproduction of stored AV data is started by a user's remote control operation (S500), the data reading unit 206 reads AV data (S502), and the timing control unit 208 reads the AV data that has been read. If the packet is a PCR packet, the PCR packet is output based on the PCR value. If the packet is a normal packet, the normal packet is output at a predetermined time interval from the PCR packet. (S504).

  Such a predetermined time interval is obtained by dividing the time difference between the PCR values of two consecutive PCR packets of AV data in the data holding unit 204 by the number of normal packets between the two PCR packets + 1. The predetermined time interval may be updated as needed according to a time difference or a change in the number of normal packets.

  The interface unit 214 relays the PCR packet and the normal packet output from the timing control unit 208 to the outside (S506).

  Next, the output timing adjustment (S504) process will be described in detail.

  FIG. 11 is a flowchart showing the flow of the output timing adjustment method in the third embodiment. Here, the output timing of the packet input to the packet buffer 302 is determined according to the type of each packet.

  First, when the reproduction of stored AV data is started (S550), the packet buffer 302 acquires one packet from the data holding unit 204 (S552).

  Next, the PCR packet determining unit 304 determines whether or not the acquired packet is a PCR packet (S554). When the acquired packet is a PCR packet, the PCR packet determination unit 304 selects the coincidence detection unit 310 as an input of the output timing of the timing switching unit 316, and the packet output start signal output from the coincidence detection unit 310 is Control is performed so as to be input to the output control unit 318.

  In parallel with this, the PCR extraction unit 306 extracts the PCR value of the packet acquired by the packet buffer 302 and inputs it to the match detection unit 310. The coincidence detection unit 310 compares the PCR value extracted by the PCR extraction unit with the count value generated by the counter, and waits until they match (S556). When the PCR value and the count value match, a packet output start signal is output from the match detection unit 310 and input to the output control unit 318 via the timing switching unit 316.

  If the acquired packet is a normal packet other than the PCR packet, the PCR packet determination unit 304 selects the timer 312 side as the output timing input of the timing switching unit 316 and outputs the packet output from the timer 312. Control is performed so that the output start signal is input to the output control unit 318.

  In parallel with this, the timer 312 waits for the predetermined time interval obtained from the previous PCR packet (S558). When the predetermined time interval elapses, the timer 312 outputs a packet output start signal, and the timing switching unit 316 Is input to the output control unit 318.

  The output control unit 318 outputs a packet in response to the output start signal from the timing switching unit 316 (S560), and repeats this process until the reproduction of the stored AV data is completed.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, it is described that the reproduction speed of the video is maintained by making the normal packets between the PCR packets uniform. However, the present invention is not limited to this, and for example, supplementation of NULL packets is appropriately performed. It is also possible to cope with a case where the predetermined time interval is constant and there is a remaining interval other than the normal packet between the PCR packets.

  Note that the steps in the data reproduction method of the present specification do not necessarily have to be processed in time series in the order described in the flowchart, but are executed in parallel or individually (for example, parallel processing or object-based processing). Processing).

  The present invention relates to a data reproducing apparatus and method thereof, and can be applied to, for example, a data reproducing apparatus and method for reproducing AV data packets.

It is an image figure for demonstrating the connection relation of the data reproduction system by 1st Embodiment. It is the block diagram which showed the function of the data reproduction system roughly. It is explanatory drawing which showed the transmission form of the packet of the MPEG2-TS format output from a tuner. It is the block diagram which showed the schematic function of the data reproduction apparatus by 1st Embodiment. It is explanatory drawing which showed the data storage format of AV data memorize | stored in a data holding part. It is a block diagram showing the schematic functional block of a timing control part. It is a timing chart for demonstrating the output timing of the packet by a timing switching part. It is a timing chart for demonstrating the output timing of the packet by a timing switching part. It is explanatory drawing which showed the holding | maintenance packet of the data buffer for demonstrating the calculation of a predetermined time interval. It is a block diagram which shows the modification of a data reproduction apparatus. It is the flowchart which showed the flow of the data reproduction method in 3rd Embodiment. It is the flowchart which showed the flow of the adjustment method of the output timing in 3rd Embodiment.

Explanation of symbols

200, 300 Data reproduction device 206 Data reading unit 208 Timing control unit 210 Interval calculation unit 212 Data buffer 124, 214 Interface unit 216 Data writing unit 302 Packet buffer 304 PCR packet discrimination unit 306 PCR extraction unit 308 Counter 310 Match detection unit 312 Timer 316 Timing switching unit 318 Output control unit

Claims (9)

A data reading unit for reading AV data;
When the read AV data packet is a time information packet to which time information is added, the time information packet is output based on the time information, and the read AV data packet is the time information packet. A timing control unit for outputting the normal packet at a predetermined time interval from the time information packet when the normal packet is other than the information packet;
An interface unit that relays the output time information packet and normal packet to the outside;
A data reproducing apparatus comprising: The AV data is data stored in advance on a storage medium,
An interval calculation unit that calculates the predetermined time interval from the time difference between the time information in two continuous time information packets of the AV data of the storage medium and the number of normal packets between the two time information packets is further provided. The data reproducing apparatus according to claim 1, wherein: A data buffer for temporarily holding the read AV data packet;
An interval calculation unit for calculating the predetermined time interval from a time difference between time information in two continuous time information packets of AV data held in the data buffer and the number of normal packets between the two time information packets The data reproducing apparatus according to claim 1, further comprising:   4. The data reproducing apparatus according to claim 2, wherein the interval calculation unit updates the predetermined time interval as needed according to the time difference or a change in the number of normal packets.   4. The data reproducing apparatus according to claim 2, wherein the predetermined time interval is set shorter than a value obtained by dividing the time difference by the number of normal packets + 1. The timing controller is
A packet buffer that temporarily holds an input packet;
A PCR packet determining unit for determining whether or not the packet held in the packet buffer is a time information packet;
A PCR extractor for extracting time information of the packet held in the packet buffer;
A counter for counting clocks;
A coincidence detection unit that generates an output start signal when the time information coincides with the count value of the counter;
A timer for generating an output start signal at the predetermined time interval based on an output start signal from the coincidence detection unit;
A timing switching unit that switches output start signals of the coincidence detection unit and the timer based on the determination of the PCR packet determination unit;
An output control unit for outputting a packet of the packet buffer according to the switched output start signal;
The data reproducing apparatus according to claim 1, further comprising: A data writing unit for writing AV data;
The data reproducing apparatus according to claim 1, wherein the interface unit further relays audio data from an external device to the data writing unit. Computer
A data reading unit for reading AV data;
When the read AV data packet is a time information packet to which time information is added, the time information packet is output based on the time information, and the read AV data packet is the time information packet. A timing control unit for outputting the normal packet at a predetermined time interval from the time information packet when the normal packet is other than the information packet;
An interface unit that relays the output time information packet and normal packet to the outside;
A program characterized by functioning as Reading AV data;
When the read AV data packet is a time information packet to which time information is added, the time information packet is output based on the time information, and the read AV data packet is the time information packet. Outputting the normal packet at a predetermined time interval from the time information packet if it is a normal packet other than an information packet;
Relaying the output time information packet and normal packet to the outside;
A method for reproducing data, comprising:

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