JP5712631B2 - Video recording apparatus and video recording method - Google Patents

Description

  The present invention relates to a video recording apparatus and a video recording method for recording video information on an information recording medium such as a hard disk device or an optical disk device.

  In general, a video recording apparatus for recording a digital broadcast program on a hard disk or an optical disk drive is known. When recording a broadcast program or the like, encoded video stream information and playback control information used when playing back the video stream information are recorded on a hard disk or an optical disk. In recording such a broadcast program, it is very systematic to update the playback control information as needed while recording video stream information in real time. In particular, in embedded devices, CPU performance (frequency and cache) is a weak CPU in order to suppress an increase in cost, and the influence of the reproduction control information update processing on the system becomes large.

  Therefore, in order to reduce the system load, a method of updating the reproduction control information at a constant cycle is generally employed. If the playback control information update cycle is too short, responsiveness of user operations may be degraded, or playback video may be disturbed during simultaneous processing, such as viewing playback images during recording. is there. In particular, since a plurality of simultaneous processes may be performed during recording in an embedded device as described above, even though it is an inexpensive CPU, the update control information update cycle is usually set to a long time such as 3 minutes. . In this case, the reproduction control information for managing the video stream information is updated every three minutes. In such a setting that the playback control information is updated every three minutes, if a power failure occurs at the time when the playback control information is acquired, even if the video stream information can be acquired after the power failure is restored, the video stream information Since corresponding playback control information could not be acquired, there was a problem that a video section of up to 3 minutes could not be played back.

  As one method for solving such a problem, the data during the update period of the reproduction control information is stored in another nonvolatile memory, and the video stream information recorded at the time of power failure recovery and the backup data stored in the nonvolatile memory are stored. There is known a method of reconstructing reproduction control information for video stream information by correcting inconsistencies with the reproduction control information (see, for example, Patent Document 1).

  As another method, the data during the playback control information update cycle is interleaved as backup information between the video stream information being recorded, and interleaved with the video stream information recorded at the time of power failure recovery. A method of reconstructing playback control information for video stream information by correcting inconsistencies with backup information is known (see, for example, Patent Document 2).

JP 2002-84498 A (page 5, FIG. 5) JP 2004-178788 A (page 4-8, FIG. 1)

  However, in the conventional method of storing the backup information of the reproduction control information during the update cycle in the nonvolatile memory, it is necessary to separately provide an expensive nonvolatile memory, leading to an increase in the cost of the apparatus. In addition, it is necessary to reconstruct the playback control information when the power failure is restored, and there arises a problem that the recording process cannot be resumed promptly when the power failure is restored.

  Further, in the conventional method in which the data during the update period of the playback control information is interleaved and recorded as backup information between the video stream information being recorded, the backup data interleaved and recorded in the video stream information is a normal Since a lot of unnecessary information is recorded at the time of reproduction, video stream information with very poor compression efficiency is recorded. Further, since the video stream information is not sequentially recorded as a physical recording position, useless seek processing also occurs in read processing during reproduction. Furthermore, it is necessary to reconstruct the playback control information when the power failure is restored, which causes a problem that the recording process cannot be resumed promptly when the power failure is restored.

  The present invention has been made to solve the above-described problems, and reduces the loss of video information that can be reproduced when a power failure occurs without increasing the cost of the video recording apparatus and reducing the compression efficiency. It is an object of the present invention to provide a video recording apparatus that can resume recording processing smoothly when a power failure is restored. Further, since it can be implemented with a simple algorithm, it can be applied to an embedded device equipped with an inexpensive CPU.

The video recording apparatus according to the present invention is
A stream control unit that receives video stream information, separates playback control information used in playback of the video stream information from the video stream information, and records the playback control information in the recording / playback drive unit;
A system state acquisition unit for acquiring an operation state indicating a power state including a standby state and an operation state ;
An update cycle management unit for setting an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired by the system state acquisition unit,
The update cycle management unit sets the update cycle to the first cycle shorter than the normal update cycle when the power state is determined to be the standby state and the operation state is the low load state , and the power state is set to the standby state. When the operation state is determined to be a high load state, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle .
Further, the video recording method according to the present invention includes:
A video recording method performed by a video recording apparatus for recording video stream information on an information recording medium,
A stream acquisition step of receiving video stream information, separating playback control information used in playback of the video stream information from video stream information, and recording the playback control information in a recording / playback drive unit;
A system state acquisition step for acquiring a power state including a standby state and an operating state indicating an operating state ;
An update cycle management step for setting an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired in the system state acquisition step,
The update cycle management step sets the update cycle to the first cycle shorter than the normal update cycle when the power status is determined to be the standby status and the operation status is the low load status , and the power status is set to the standby status. When the operation state is determined to be a high load state, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle .

  The present invention limits the playback control information to a time zone in which responsiveness to a user operation is not required by changing the acquisition cycle of the playback control information based on system state information including a power supply state and an operating state. Can be shortened. For this reason, there is no increase in the cost of the video recording apparatus, the number of video information lost sections that can be reproduced when a power failure occurs can be reduced, and the recording process can be smoothly resumed when the power failure is restored. In addition, since it can be implemented with a simple algorithm, processing can be performed by an inexpensive CPU used in an embedded device.

It is a block diagram which shows the structure of the video recording device which concerns on Embodiment 1 of this invention. It is a logical file structure figure of the recording / reproducing drive part which concerns on Embodiment 1 of this invention. It is a figure which shows the syntax of the address management file which concerns on Embodiment 1 of this invention. It is a figure which shows the syntax of the reproduction | regeneration control information file which concerns on Embodiment 1 of this invention. It is a figure which shows the title structure which concerns on Embodiment 1 of this invention. It is explanatory drawing regarding the data update period which concerns on Embodiment 1 of this invention. It is the figure which showed the operation | movement flow of the video recording device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the video recording apparatus which concerns on Embodiment 2 of this invention. It is the stream processing load conversion table regarding the copyright protection information which concerns on Embodiment 2 of this invention. It is the stream processing load conversion table regarding the stream attribute information which concerns on Embodiment 2 of this invention. It is an update cycle correspondence table | surface which showed the response | compatibility with the system processing load point which concerns on Embodiment 2 of this invention, and an update cycle. It is the figure which showed the operation | movement flow of the video recording device which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a video recording apparatus 100 according to Embodiment 1 for carrying out the present invention. In FIG. 1, a system control unit 101 is a collective term for a storage unit that stores a CPU, firmware, and the like, and integrally controls the entire video recording apparatus 100. The video recording apparatus 100 includes a recording / reproducing drive unit 102 capable of reading and writing information records such as a hard disk device. In the present embodiment, the description will be given assuming that the recording / reproducing drive unit 102 is a hard disk device, but an optical disk drive device or an SD media drive may be used instead of the hard disk device. In that case, stream information and reproduction control information are recorded on the optical disk medium or SD medium, and are read and written through the recording / reproduction drive unit 102.

  The recording / playback drive unit 102 stores stream information in which encoded video, which will be described later, is multiplexed, and playback control information for the stream information. The playback control information includes video and audio attribute information related to the encoded video / audio stream separated from the stream information recorded in the recording / playback drive unit 102, and playback start time information in stream information access units (usually GOP units). And information indicating the correspondence between the playback start position information and the like.

  The broadcast receiving unit 103 receives a digital broadcast wave that has been encoded and compressed in advance with MPEG-2 Transport Stream (hereinafter referred to as MPEG-2 TS). The digital broadcast wave may be multiplexed with video and audio of a plurality of programs. In this case, the broadcast receiving unit 103 extracts only the MPEG-2 TS of the selected program.

  The network receiving unit 104 receives a digital broadcast program from a receiver such as a set top box via a network. The network receiving unit 104 has a function of receiving MPEG-2 TS and MPEG-4 AVC programs transmitted from the set top box.

  The stream control unit 110 performs overall control of the stream flow of the entire system. In the stream control unit 110, a decryption unit 111, a stream information acquisition unit 112, and an encryption unit 113 exist. Generally, when the video transmitted from the broadcast receiving unit 103 or the network receiving unit 104 is a copyright-protected program, the stream information is encrypted according to a predetermined copyright protection rule. Therefore, the received program is decrypted by the decryption unit 111, the copy information is read from the stream information by the stream information acquisition unit 112, and an appropriate encryption process is performed by the encryption unit 113 based on the copy control information. The stream information is written into the recording / reproducing drive unit 102 above.

  The predetermined copyright protection system is a CAS system when receiving terrestrial digital broadcasting, a DTCP-IP system for information distributed via a network, an AACS system when writing to an optical disk, and a C2 system when writing to a hard disk. The decryption process and the encryption process are performed by each method. Since the encryption strength and the device authentication method differ depending on these copyright protection methods, the influence of the decryption process and the encryption process on the system load also differs.

  Next, the flow of recording processing in the present embodiment will be described. When recording a terrestrial digital broadcast program, the MPEG-2 TS received by the broadcast receiving unit 103 is supplied to the stream control unit 110. The MPEG-2 TS stream information supplied to the stream control unit 110 is sequentially subjected to the above-described decryption processing, stream analysis processing, and encryption processing based on an instruction from the system control unit 101, and the recording / reproduction drive unit 102. Is recorded on the hard disk.

  In the stream information acquisition unit 112, in the course of the stream recording process, for each access unit (GOP unit), the system control unit 101 is provided with playback start time information and playback start position that are information constituting playback control information. Information, video information attribute information, etc. are notified. The system control unit 101 stores the reproduction start time information, the reproduction start position information, the attribute information of the video information, and the like in a data format suitable for recording in the memory unit 120 managed by the system control unit 101. The data format at this time is information for temporary recording for constituting the reproduction control information, and is called reproduction control information (temporary recording). The reproduction control information (temporary recording) may be recorded in a database so that the next access is easy.

  Further, the system control unit 101 reconstructs the reproduction control information (temporary recording) developed in the memory unit 120 into reproduction control information in accordance with an update instruction from the update period management unit 152 described later, and then passes through the stream control unit 110. Thus, the process of updating the playback control information for the recording / playback drive unit 102 is performed.

  Next, the flow of reproduction processing in the video recording apparatus 100 of the present embodiment will be described. When playing back the stream information recorded in the recording / playback drive unit 102, the system control unit 101 first reads the playback control information related to the stream information to be played back from the recording / playback drive unit 102 and holds it in the memory unit 120. To do. Based on the read reproduction control information, the system control unit 101 instructs the stream control unit 110, the video / audio decoder unit 114, and the like to prepare for reproduction.

  Thereafter, the stream control unit 110 reads the stream information recorded in the recording / reproducing drive 102 and supplies the stream information to the video / audio decoder unit 114.

  The video / audio decoder unit 114 sequentially captures the stream information, and then separates it into a video stream or audio stream that has been encoded and compressed. Further, the video / audio decoder unit 114 decodes the video stream encoded by MPEG-2 to decode the output video signal, and also decodes the audio stream encoded by AC-3. Decode to output audio signal. Finally, the video / audio decoder unit 114 sends the output video signal and the output audio signal to the display device 116.

  As shown in FIG. 1, the block composed of the recording / playback drive unit 102, the broadcast receiving unit 103, the network receiving unit 104, the stream control unit 110, and the video / audio decoder unit 114 is a video / audio stream recording / playback function. One block having the above is called a decoder block 115. The decoder block 115 performs stream information recording processing and reproduction processing based on an instruction from the system control unit 101.

  The video recording apparatus 100 includes an operation unit 130 connected to the system control unit in order to accept a request from the user to the video recording apparatus 100. In general, the operation unit 130 refers to an operation panel, a remote control, or the like disposed on the front panel of the video recording apparatus 100. The system control unit 101 interprets the content of the command requested by the operation unit 130 and controls the decoder block 115 to perform recording processing and reproduction processing of arbitrary stream information.

  The video recording apparatus 100 includes a power control unit 140 that performs power management. The video recording apparatus 100 has three power states: a power-on state, a standby state, and a power-off state. In the power-on state, power is supplied to the entire video recording apparatus 100 and video output is also performed. At this time, the video recording apparatus 100 is in a state where all user requests can be received immediately, and the user can view the video. The power OFF state refers to a state where power is not supplied to the entire video recording apparatus 100.

  The standby state is a state in which only a part of the blocks constituting the video recording apparatus 100 is operable, and indicates a state in which the acceptance of user requests is limited. Normally, the standby state is entered when the power key is pressed by the operation unit 130.

  The standby state means, for example, that the stream control unit 110 and the video / audio decoder unit 114 constituting the video recording apparatus 100 are not energized and no video / audio output is performed, or the recording / reproduction drive unit 102 constituting the video recording apparatus 100 is performed. Is turned off and recording / reproduction is not performed, or firmware that operates the video recording apparatus 100 is partially terminated to indicate a state in which the amount of computation of the CPU of the system control unit 101 is reduced. The standby state is intended to suppress the power supplied to the video recording apparatus 100 by performing such restrictions.

  The power control unit 140 performs switching between the power OFF state / power ON state / standby state according to an instruction from the system control unit 101. The power supply control unit 140 manages the power supply state and has a function of notifying the system control unit 101 of the information. The power OFF state indicates a state in which no power is physically supplied to the video recording apparatus 100 such as insertion / removal of an AC plug, and it is not necessary to consider in the present invention. The operation of the video recording apparatus 100 in the two power supply states of the state and the standby state will be described.

  The video recording apparatus 100 includes a system state acquisition unit 151 that acquires a system operation state. The system operating state indicates whether or not the standby state is possible and the simultaneous operating state. Note that recording in the standby state means a reserved recording state, which means that there is little possibility that a user operation is performed, and that responsiveness is not required so much.

  The simultaneous operation state described above refers to a state in which video recording and reproduction are simultaneously performed in the video recording apparatus 100. Specific examples of the simultaneous operation state include “no recording and reproduction operation”, “reproducing one program”, “recording one program”, “recording two programs” ”,“ Recording one program while playing the program (chock playback) ”, and“ recording two programs while playing one program ” . Note that the amount of CPU calculation in the video recording apparatus 100 increases as more processes are performed at the same time, so the processing load applied to the system also increases. This simultaneous operation state can be determined by the system state acquisition unit 151 even when the power control unit 140 is in the standby state.

  In the video recording apparatus 100, based on the information obtained by the system state acquisition unit 151, playback control information (temporary recording) stored in the memory unit 120 during recording is stored in the recording / playback drive unit 102. The update cycle management unit 152 determines the update cycle to be written as. As a specific example, since the responsiveness to the user operation is not required for the recording in the standby state, the system processing load can be distributed with priority over the update of the reproduction control information, so the update cycle is set short. Conversely, for recording in the power-on state, in order to prioritize responsiveness to user operations, a long update cycle is set to distribute the system processing load to the responsiveness (control instructed by the operation unit 130).

  In addition, although the system state acquisition unit 151 and the update cycle management unit 152 are illustrated as examples configured by firmware in the system control unit 101, hardware having the functions may be used. In addition, although the system state acquisition unit 151 and the update cycle management unit 152 are illustrated separately, they may be a single block in which functions are integrated.

  FIG. 2 is a structural diagram showing a logical file structure of the recording / reproducing drive unit 102 in the present embodiment. The directory structure of the highest hierarchy of the file structure forming the logical hierarchy is called the root directory 200, and the directory structure arranged in the lower hierarchy of the root directory 200 is called the disk directory 201. The disc directory 201 includes a playback control information file 221 that is content management information recorded in the recording / playback drive unit 102, an address management directory 202 that is a folder in which the address management file 222 is recorded together, and a stream information file 231. The stream management directory 203 is a folder recorded collectively. The reproduction control information file 221 and the address management file 222 are collectively referred to as reproduction control information.

  In FIG. 2, the description will be made assuming that the address management file 222 and the stream information file 231 are associated with each other by a 5-digit file name in a 1: 1 ratio. The file name may be a five-digit number and need not be a sequential number.

  2 shows an example in which the address management file 222 and the stream information file 231 are arranged in separate directories. However, the address management file 222 and the stream information file 231 are arranged in the same directory, or the files are arranged directly in the root directory 300. It does not matter. In this embodiment, the address management file 222 is recorded in a 1: 1 correspondence with the stream information file 231. However, the address management file 222 is recorded together in one address management file 222. It doesn't matter.

  FIG. 3 is a diagram showing the syntax of the address management file 222. “Start_PTS” (301) indicates the PTS (Presentation_Time Stamp) of the first video frame of the target stream information file 231, and “End_PTS” (302) indicates the PTS of the final video frame. The attribute information management table 310 records information such as video attribute information (resolution, bit rate, frame rate) and audio attribute information (number of channels, sampling rate) of the stream information file 231. The access point management table 320 describes information necessary for cue playback. For example, when video data is encoded with an MPEG-2 video stream, the head of GOP (Group of Pictures) corresponds to an access point. In this embodiment, it is described in which packet of the stream information file 231 the head of the GOP exists.

  “Num_of_entry” (321) is the total number of access points, and the next loop statement (for and below) is repeated by the number of “num_of_entry” (321). “PTS_GOP_Start” (331) indicates a display start PTS of the access point, and “SPN_GOP_Start” (332) is the relative number of packets from the head of the stream information file 231 to the head of the access point. Since the packet has a fixed length, the relative number of bytes from the head of the stream information file 231 to the head of the access point can be calculated by multiplying the value of “SPN_GOP_Start” (332) and the number of bytes per packet. The video recording apparatus 100 determines the position of the access point on the disk from the number of bytes from the beginning of the stream information file 231 and performs cue playback. Further, “I_Pic_Size” (333) describes the size of an I picture that is an intra frame in the access point. The I picture size is recorded as a relative packet number from “SPN_GOP_Start” (332) indicating the access point head position.

  FIG. 4 is a diagram showing the syntax of the playback control information file 221. As shown in FIG. “Num_of_Title” (401) is the total number of program programs recorded in the recording / playback drive unit 102, and the next loop statement is repeated by the number of “num_of_Title” (401). “Title_Attribute ()” (402) holds title attribute information such as total title time, title name, and recording date and time. “Num_of_Play_Interval” (403) indicates the total number of pieces of playback section information constituting the title, and is repeated by the number of “num_of_Play_Interval” (403) in the next loop statement. As the playback section information, information of “stream_name” (411), “Start_Time” (412), and “End_Time” (413) is recorded. “Stream_name” (411) indicates the file name of the stream information file 231 to be played back, and “Start_time” (412) and “End_time” (413) respectively play back a predetermined section of the stream information file 231 to be played back. Indicates the start time and playback end time. In the present embodiment, the PTS (Presentation Time Stamp) of the video data is “Start_time” (412) and “End_time” (413). From these pieces of information, the video recording apparatus 100 can determine which section of the stream information file 231 should be reproduced.

  FIG. 5 shows the title structure. The title corresponds to a program selected by the user, and information on the title is information described in the reproduction control information file 221. The title is a collection of a plurality of predetermined playback sections of the stream information file 231. The title is one playback section of one stream information file 231, or is composed of a plurality of playback sections in one stream information file 231, or a predetermined playback of each of different stream information files 231. It is configured in various forms such as when it is configured from sections.

  The predetermined playback section is determined by designating the name of the address management file 222 to be played, the playback start point (Start_Time), and the end point (End_Time). By combining this information with the information in the access point management table 320 in the address management file 222, the start position of an arbitrary access point in the stream information file 231 can be known. By utilizing this, it can be utilized for random access processing such as special reproduction of the stream information file 231 and time search.

  During recording, the stream information file 231 and the address management file 222 are recorded simultaneously. The stream information file 231 is written in real time, while the address management file 222 is written based on the update cycle from the update cycle management unit 152. That is, the video recording apparatus 100 can perform the reproduction process on the stream information file 231 up to the location where the address management file 222 is written.

  FIG. 6 is an explanatory diagram regarding the data update cycle. The writing of the stream information file 231 and the writing of the reproduction control information are managed in synchronization, but the update timing is different. Since the stream information file 231 has a large data capacity and is written in a sequential manner, the stream information file 231 is written to the recording / reproducing drive unit 102 with real-time characteristics. On the other hand, the playback control information has a data structure defined in bit units to reduce the recording size, but is detected in information in byte units, so it needs to be reconfigured into a data structure in bit units. . Another feature is that the update cycle is fast, such as the need to update in units of GOP (about 0.5 seconds).

  Since the reproduction control information is data having the above-described configuration and an early update cycle, when the system control unit 101 records the reproduction control information (temporary recording) detected by the stream control unit 110 in the memory unit 120, It is constructed as byte-unit information suitable for recording without optimizing the size of the data structure. Thereafter, the system control unit 101 reads out reproduction control information (temporary recording) based on an instruction from the update cycle management unit 152, reconstructs it as reproduction control information, and records it in the recording / reproduction drive unit 102. By doing so, the stream information file 231 and the reproduction control information are synchronized, and the stream information file 231 up to the point can be reproduced.

  In FIG. 6, generally, an update period (TM_UPDATE) 601 is set to a time of about 3 minutes. When the update cycle is set to 3 minutes, the stream information file 231 and the reproduction control information are synchronized at intervals of 3 minutes such as 3 minutes, 6 minutes, 9 minutes,. At this time, as shown in FIG. 6, if it is assumed that a power failure has occurred at the point of 8 minutes from the start of recording, the stream information file 231 is recorded up to the point of 8 minutes, but the playback control information is written at the point of 6 minutes. It has only been done. For this reason, the stream information file 231 is recorded in the section from 6 minutes to 8 minutes, but there is no corresponding playback control information, so the recorded stream information file 231 cannot be played back. This section is defined as a lost section (TM_DEL) 602. The purpose of this embodiment is to set the optimal update cycle dynamically and shorten the lost section 602 by appropriately grasping the system state of the video recording apparatus 100.

  FIG. 7 is a diagram showing an operation flow of the video recording apparatus 100 in the present embodiment. The update cycle setting in the video recording apparatus 100 of the present embodiment will be described in detail with reference to FIGS. This operation is continued until the recording end determination (S701) is performed. If it is determined in S701 that the recording operation is being performed, the process proceeds to S702. In step S <b> 702, the system state acquisition unit 151 acquires the current power state information of the video recording apparatus 100 from the power control unit 140. That is, if the recording is in the standby state, it is highly likely that the recording is a reserved recording, and it is determined that the responsiveness to the user operation is not so necessary. On the other hand, if the power is on, there is a possibility that a reproduction request or a recording request for another program may be made by a user operation, and it is determined that it is necessary to have a certain response.

  If it is determined in step S702 that the power is on, the update cycle management unit 152 sets the update cycle of the playback control information to 3 minutes so that the playback control information is not updated too frequently in order to guarantee responsiveness to the user. The setting is made (S707). On the other hand, if it is determined in S702 that the camera is in the standby state, the process proceeds to S703. In S703, it is determined whether or not recording of another program that is simultaneously processed during reserved recording is being executed. In recent hard disk recorders, it is general that two programs can be simultaneously recorded. In this embodiment, both the program from the network receiver 104 and the program from the broadcast receiver 103 can be recorded. Proceed with the explanation as possible.

  If simultaneous program recording is being performed, it is determined that the system processing load is moderate, and the update cycle management unit 152 sets the update cycle of the playback control information to 2 minutes (S706). If it is determined in S703 that simultaneous recording is not being executed, the update cycle management unit 152 sets the update cycle of the playback control information to 1 minute (S705). After the update cycle setting unit 152 determines the update timing of the playback control information, the process proceeds to S701 and the recording process is continued.

  In this way, when the update cycle of the reproduction control information is changed from 3 minutes to 2 minutes or 1 minute, the lost section 602 shown in FIG. 6 changes. For example, if the update period is set to 3 minutes, the lost section 602 is a maximum of 3 minutes, but if the update period is set to 2 minutes or 1 minute, the lost section 602 is a maximum of 2 minutes or 1 minute. Become. That is, when there is simultaneous recording in the standby state (update cycle 2 minutes) and when there is no simultaneous recording in the standby state (update cycle 1 minute), when the power is on (update cycle 3 minutes), Lost section can be shortened.

  In the video playback device 100 configured as in the present embodiment, the update cycle of the playback control information can be optimized from the power supply state and the simultaneous operation processing status, and the loss of a stream that can be played back even when a power failure occurs Can be reduced. That is, since it is possible to easily grasp the processing load of the entire system from the contents of the simultaneous operation processing in the standby state, the update cycle of the reproduction control information can be dynamically set according to the system state.

  In addition, since the update cycle can be reduced only during a time period during which no user operation is performed, such as during scheduled recording, the system processing capability can be assigned to the update processing of the playback control information without responsiveness. Therefore, the reproduction control information can be updated with a very short update cycle, and the possibility of loss of stream information can be reduced. In addition, since it is not necessary to have special hardware, there is an effect that it is not necessary to increase the cost of the device itself.

  Furthermore, in the video playback apparatus 100 configured as in the present embodiment, it is not necessary to reconstruct the playback control information when the power failure is restored, so that the recording process can be resumed immediately. Further, since it is not necessary to record the difference information of the reproduction control information in the stream information, there is an effect that the compression efficiency is not lowered.

  In the present embodiment, an example is shown in which the update control information update cycle is set to 1 minute when there is no simultaneous recording in the standby state. However, when the playback control information update cycle is set short, the system processing Since there is a possibility of exceeding the limit amount, there is a possibility of data writing failure or unintentional hang-up during recording. Therefore, it is desirable to set an update cycle suitable for the system state. On the other hand, when the operating frequency of the CPU is high, the update period of the reproduction control information can be set to 1 minute or less.

  In this embodiment, the case where the update cycle of the playback control information is shorter than that of the video stream information has been described. Conversely, the update cycle of the video stream information may be longer than the update cycle of the playback control information. . Further, as an example in which the responsiveness to the user operation is unnecessary, the recording process in the standby state is described. However, it is sufficient that the number of user operation requests is smaller than that in the normal state, and the power may be on.

Embodiment 2. FIG.
In the first embodiment, based on the system state of the video recording apparatus 100, the stream information lost section that can be played back at the time of a power failure is set by shortening the update cycle of the playback control information in a time zone when no user operation is performed. The purpose was to shorten. In the second embodiment, focusing on the fact that the attribute of stream information to be recorded affects the system processing load, the system load is calculated based on the copyright protection information and stream attribute information of the stream information, and the power is turned on. The purpose is to finely control the update cycle of the reproduction control information even in the state.

  FIG. 8 is a block diagram showing the configuration of the video recording apparatus 100 according to the second embodiment. In FIG. 8, the same components as those described in Embodiment 1 are denoted by the same reference numerals. In the video recording apparatus 100 according to the present embodiment, the copyright protection information (encryption method, authentication method, encryption strength) and stream attribute information (bit rate, resolution, codec) of stream information to be recorded are determined based on the system processing load. Is provided with a stream processing load acquisition unit 801 for determining how much it affects. This stream processing load acquisition unit 801 is provided in the system control unit 101.

  The stream processing load determination unit 801 calculates a system processing load amount based on information obtained by the decryption unit 111, the stream information acquisition unit 112, and the encryption unit 113 in the stream control unit 110 during recording. The information obtained by the stream information acquisition unit 801 is mainly determined by program information on the transmission side such as a broadcasting station. For example, copyright protection information such as an encryption method and a decryption method is defined in the stream information to be transmitted, and stream attribute information such as the bit rate, resolution, and codec of the stream information is also transmitted. Is determined by. Such information has a great influence on the writing process and the arithmetic process.

  In the present embodiment, the system state acquisition unit 151, the update cycle management unit 152, and the stream processing load acquisition unit 801 are examples configured by firmware in the system control unit 101. You may be the hardware which has. In addition, the system state acquisition unit 151, the update cycle management unit 152, and the stream processing load acquisition unit 801 are described as separate configurations, but may be a single block in which functions are integrated.

  FIG. 9 is a stream processing load conversion table regarding copyright protection information. This stream processing load conversion table is composed of a decryption load list 900 and an encryption load list 910. Next, the decryption load list 900 and the encryption load list 910 will be described respectively.

  The decryption load list 900 indicates the degree of influence on the system load when decrypting an encrypted stream, and includes a decryption method 901 and a stream processing load point (decryption) 902. The The decryption method 901 shows a list of decodable copyright protection methods supported by the video recording apparatus 100. For example, there are a CAS system that is a digital broadcasting standard, a DTCP system that is a copyright protection standard for network transmission, an HDCP system, an AACS system that is a disk encryption system, and a C2 system. A stream processing load point (decoding) 902 indicates a converted value of the system processing amount when the decoding method is executed, and the larger the numerical value, the higher the system processing load. In general, the higher the encryption strength in the copyright protection regulations, the higher the system processing load. FIG. 9 shows that the processing load is the highest when DTCP encryption (full authentication), which is a copyright protection rule at the time of network transmission, is applied.

  Note that the stream processing load point (decryption) 902 does not simply indicate the encryption strength but indicates the height of the system processing load. For example, when there is hardware assist when performing the decoding process in the video recording apparatus 100, the amount of CPU calculation is reduced. Therefore, in this case, the stream processing load point (decryption) 902 is a small value even in a decryption method with high encryption strength. Even with the same decryption method, the CPU processing load varies even when the authentication method and the authentication cycle between devices are different.

  The encryption load list 910 indicates the degree of influence on the system load when stream encryption is performed according to the copyright protection regulations, and includes an encryption method 911 and a stream processing load point (encryption) 912. . Generally, when recording a copyright-protected program, it is necessary to record the video recording apparatus 100 with encryption. Therefore, the once decrypted stream must be encrypted again. The encryption method 911 indicates a list of copyrightable protection methods that can be encrypted by the video recording apparatus 100. For example, there are AACS method and C2 method which are disk encryption methods. Similarly to the stream processing load point (decryption) 902, the stream processing load point (encryption) 912 indicates the system processing load.

  The decryption load list 900 and the encryption load list 910 shown in FIG. 9 are stored in advance in the program by the system control unit 101, and the stream processing load point is determined by the hardware and software constituting the system. ing.

  FIG. 10 is a stream processing load conversion table regarding stream attribute information of stream information to be recorded. The stream processing load conversion table includes a bit rate load list 1001. In the present embodiment, the description is made on the bit rate as the stream attribute information of the stream information to be recorded, but a codec or resolution may be used instead of the bit rate. The bit rate load list 1001 indicates the influence of the bit rate, which is stream attribute information to be recorded, on the system load, and includes a bit rate category 1011 and a stream processing load point (bit rate) 1012. It is assumed that the bit rate category 1011 is divided in units of 5 Mbps this time. The stream processing load point (bit rate) 1012 indicates the degree of influence on the system processing load, and the higher the numerical value, the higher the system processing load.

  When the bit rate is high, many writings to the recording / reproducing drive unit 102 are performed per unit time. Therefore, a high bit rate means that the CPU calculation amount and hardware access are high, and the stream processing load point 1012 related to the recording stream is also set high.

  FIG. 11 is an update cycle correspondence table showing correspondence between system processing load points and update cycles. This update cycle correspondence table 1100 includes system processing load points 1101 and setting update cycles 1102. The system processing load point is a total value of the stream processing load point (decryption) 902, the stream processing load point (encryption) 912, and the stream processing load point (bit rate) 1012 described above. That is, the system processing load point is calculated from the copyright protection information and the stream attribute information.

  Next, an example of calculating the system processing load point 1101 will be described. For example, when a stream received from the network is recorded in the recording / playback drive unit 102, the decryption method 901 employs DTCP encryption (full authentication), and the encryption method 911 employs C2 encryption. If the bit rate category 1011 is 18 Mbps, the system processing load point 1101 is 15 points + 3 points + 8 points = 26 points. Therefore, from the update cycle correspondence table 1100, when the system processing load point 1101 is 26 points, the setting update cycle 1102 is set to 2 minutes 30 seconds.

  FIG. 12 is a diagram showing an operation flow of the video recording apparatus 100 according to the present embodiment. The update cycle setting in the second embodiment will be described in detail with reference to FIG. 12 and FIGS. 2 to 6 and FIGS. 8 to 12 used in the description of the first embodiment. In FIG. 12, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  If it is determined in S702 that the recording is being performed while the power is on, the process proceeds to S1201. If it is determined that the state is the standby state, the same operations as those described in the first embodiment are performed from S703 onward, and thus the description thereof is omitted.

  In step S1201, the stream processing load acquisition unit 801 acquires stream processing load information of a recording target (CH1: channel 1). For the stream processing load information, a stream processing load point (decryption / encryption) is calculated from the copyright protection information described in FIG. Thereafter, the stream processing load point (bit rate) of the stream attribute information (bit rate) described in FIG. 10 is calculated. The system control unit 101 stores the sum of these load points as the system processing load point.

  Next, it is determined whether there is another recording channel in the same time zone (S1202). If there is no other recording channel, the process proceeds to S1204. On the other hand, if another recording channel exists, the same processing as that performed in S1201 is performed for the recording channel (CH2: channel 2), and a stream processing load point is calculated for channel 2 (S1203). Thereafter, the stream processing load acquisition unit 801 adds the stream processing load points as the above-described system processing load points, and after determining the final system processing load points, the process proceeds to S1204.

  In S1204, the update cycle of the reproduction control information is determined by comparing the system processing load point held by the system control unit 101 with the update cycle correspondence table 1100 shown in FIG. For example, when the system processing load point 1101 is 35 points so far, the update cycle is set to 2 minutes and 40 seconds. Then, as described above, after the update cycle setting unit 152 determines the update cycle of the playback control information, the process proceeds to S701 and the recording process is continued.

  In the video recording apparatus 100 configured in this way, the load of the entire system can be calculated from the processing load information related to the stream that is recorded by the video recording apparatus 100, so an optimum update cycle is set even when the power is turned on. can do. With this configuration, even when the power is on, the system processing load can be properly grasped, so that the playback control information can be updated at an optimal cycle without sacrificing the responsiveness of the user operation. It can be carried out. Therefore, it is possible to provide the encoded video recording apparatus 100 that can reduce the loss time of the reproducible stream as much as possible even during a power failure when the power is turned on.

  In the present embodiment, the update cycle correspondence table 1100 is divided in units of 10 points, but may be further subdivided.

  In this embodiment, the bit rate is used as the stream attribute information. However, in addition to the bit rate, a codec or a resolution that is an attribute of the stream information may be used as the stream attribute information.

DESCRIPTION OF SYMBOLS 100 Video recording device 101 System control part 102 Recording / reproducing drive part 103 Broadcast receiving part 104 Network receiving part 110 Stream control part 111 Decoding part 112 Stream information acquisition part 113 Encryption part 114 Video / audio decoder part 115 Decoder block 116 Display apparatus 120 Memory unit 130 Operation unit 140 Power supply control unit 151 System state acquisition unit 152 Update cycle management unit 200 Root directory 201 Disk directory 202 Address management directory 203 Stream management directory 221 Playback control information file 222 Address management file 231 Stream information file 301 Start_PTS
302 End_PTS
310 attribute information management table 320 access point management table 321 num_of_entry
331 PTS_GOP_Start
332 SPN_GOP_Start
333 I_Pic_Size
401 num_of_Title
402 Title_Attribute
403 num_of_Play_Interval
411 stream_name
412 Start_Time
413 End_Time
601 Update cycle 602 Lost section 801 Stream processing load acquisition unit 900 Decoding load list 901 Decoding method 902 Stream processing load point (decoding)
910 Encryption load list 911 Encryption method 912 Stream processing load point (encryption)
1001 Bit rate load list 1011 Bit rate category 1012 Stream processing load point (bit rate)
1100 Update cycle correspondence table 1101 System processing load point 1102 Setting update cycle

Claims (6)

A stream control unit that receives video stream information, separates playback control information used in playback of the video stream information from the video stream information, and records the playback control information in a recording / playback drive unit;
A system state acquisition unit for acquiring an operation state indicating a power state including a standby state and an operation state;
An update cycle management unit that sets an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired by the system state acquisition unit;
The update cycle management unit sets the update cycle to a first cycle shorter than a normal update cycle when the power state is determined to be a standby state and the operation state is a low load state, When it is determined that the power supply state is a standby state and the operation state is a high load state, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle A video recording apparatus characterized by: A stream control unit that receives video stream information, separates playback control information used in playback of the video stream information from the video stream information, and records the playback control information in a recording / playback drive unit;
A system state acquisition unit that acquires a power state including a standby state and an operation state indicating an operation state, and determines whether or not the stream control unit is in a recording state in which the video stream information is recorded in the recording / playback drive unit; ,
An update cycle management unit that sets an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired by the system state acquisition unit;
The update cycle management unit updates the update when the stream control unit determines that the system state acquisition unit is in a recording state and the power supply state is in a standby state and the operation state is in a low load state. The cycle is set to a first cycle shorter than the normal update cycle, the stream control unit is determined to be in a recording state by the system state acquisition unit, the power state is a standby state, and the operation state is a high load state. When it is determined that there is a video recording apparatus, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle. A stream processing load acquisition unit that calculates a system processing load based on copyright protection information and stream attribute information included in the video stream information;
The update cycle management unit sets the update cycle to the normal update cycle and the second update cycle based on the system processing load amount calculated by the stream processing load acquisition unit when the power state is not a standby state. the video recording apparatus according to claim 1 or claim 2, characterized in that to set the third period between cycles. A video recording method performed by a video recording apparatus for recording video stream information on an information recording medium,
A stream acquisition step of receiving video stream information, separating playback control information used in playback of the video stream information from the video stream information, and recording the playback control information in a recording / playback drive unit;
A system state acquisition step for acquiring a power state including a standby state and an operating state indicating an operating state;
An update cycle management step for setting an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired in the system state acquisition step;
The update cycle management step sets the update cycle to a first cycle shorter than a normal update cycle when the power supply state is determined to be a standby state and the operation state is a low load state, When it is determined that the power supply state is a standby state and the operation state is a high load state, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle And a video recording method. A stream acquisition step of receiving video stream information, separating playback control information used in playback of the video stream information from the video stream information, and recording the playback control information in a recording / playback drive unit;
A system state obtaining step for obtaining a power state including a standby state and an operating state indicating an operating state and determining whether the stream obtaining step is a recording state in which the video stream information is recorded in the recording / reproducing drive unit; ,
An update cycle management step for setting an update cycle for recording the playback control information in the recording / playback drive unit based on the power supply state and the operation state acquired in the system state acquisition step;
In the update cycle management step, the update is performed when the stream acquisition step is determined to be a recording state by the system state acquisition step, and the power state is determined to be a standby state and the operation state is a low load state. The cycle is set to a first cycle shorter than a normal update cycle, the stream acquisition step is determined to be a recording state by the system state acquisition step, the power state is a standby state, and the operation state is a high load state. When it is determined that there is a video recording method, the update cycle is set to a second cycle shorter than the normal update cycle and longer than the first cycle. A stream processing load acquisition step of calculating a system processing load based on copyright protection information and stream attribute information included in the video stream information;
In the update cycle management step, when the power supply state is not in the standby state, the update cycle is set to the normal update cycle and the second update cycle based on the system processing load amount calculated in the stream processing load acquisition step. 6. The video recording method according to claim 4, wherein the third period is set to a third period.

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