JP3747904B2 - Reference system and method for AV data stored in AV server - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a system and method for a plurality of editing terminals to refer to materials stored in an AV server.
[0002]
[Prior art]
Nowadays, broadcasting stations generally store AV (Audio and / or Video) data, which is a material, in a large capacity AV server.
[0003]
The AV server generally has a RAID (Redundant Array of Inexpensive Disks) configured by using a plurality of hard disk drives and a plurality of input / output ports such as an SDI (Serial Digital Interface) port.
[0004]
AV data sent to the AV server from the outside (VTR in the broadcasting station, video camera at the interview site connected to the broadcasting station through a wide area network, etc.) is input to one of the input / output ports, and its input / output Compression processing is performed at the port. Then, the data is sent from the input / output port to the RAID and recorded in the RAID.
[0005]
AV data read from the RAID and sent to any of the input / output ports is subjected to decompression processing or the like at the input / output port. Then, it is output from the input / output port and sent from the AV server to the outside (on-air server, backup server, etc.).
[0006]
By the way, the broadcasting station does not send the material stored in the AV server as it is when it is on the air, but edits the material with an editing terminal (non-linear editing machine) and sends the editing result (so-called “complete packet”). It is normal.
[0007]
Conventionally, as a method of referencing (reading) material stored in an AV server with an editing terminal for editing, for example, an input / output port of an AV server and an editing terminal are connected in a one-to-one correspondence, A method of directly referencing the material from the AV server via the connected input / output port has been adopted (for example, see Patent Document 1).
[0008]
[Patent Document 1]
JP-A-8-221951 (paragraph numbers 0003 to 0006, FIG. 3)
[0009]
[Problems to be solved by the invention]
  However, in this method, the input / output ports of the AV server and the editing terminal are connected in a one-to-one correspondence, so the materials stored in the AV server can be simultaneously processed in parallel.InThe number of editing terminals that can be referred to is limited by the number of input / output ports of the AV server.
[0010]
In broadcasting stations, various and large amounts of materials stored in AV servers are often edited in parallel by a plurality of editing terminals. In such a case, it is very inconvenient that the number of editing terminals that can simultaneously refer to the material is restricted in this way.
[0011]
  This method also includes an AV server.InsideIn RAID, since AV data is distributed and recorded in a plurality of hard disk drives, there is a waiting time when a large amount of AV data is referred to by the editing terminal or when AV data of a jump frame is referred to by the editing terminal. There was an inconvenience that the time was long.
[0012]
  In editing, a certain amount of AV data (for example, AV data sent from a video camera at a certain interview site to a broadcasting station via a wide area network and stored in an AV server) as a material to be edited is edited by an editing terminal. After the reference (preview), the portion of the AV data necessary for editing may be determined. Also, when editing, AV data of the jump frame is referenced on the editing terminal (deciding and correcting the IN point and OUT point while watching the video jumping in frame units)) ThisThere is also. In those cases, the long waiting time is very inconvenient.
[0013]
In view of the above, the present invention makes it possible to simultaneously refer to the material stored in the AV server on a plurality of editing terminals without being restricted by the number of input / output ports of the AV server. An object of the present invention is to shorten the waiting time when referring to the material stored in the server on the editing terminal.
[0014]
[Means for Solving the Problems]
  In order to solve this problem, the applicant of the present invention uses the same AV as this AV server (referred to as the first AV server) in a system for referencing AV data stored in the AV server with a plurality of editing terminals. The second AV server that compresses and stores data at a higher compression rate than the first AV server and the recording means in the first AV server can be accessed at a higher speed, and is connected to these editing terminals. Each editing terminal,A first operation screen for selecting a material to be edited, and a second operation for previewing the material to be edited selected on the first operation screen and determining a portion necessary for editing from the preview A process of displaying a screen and a third operation screen for editing with reference to the AV data of the portion determined on the second operation screen is performed, and the material to be edited is displayed on the first operation screen. Based on the selection, the entire selected material is taken from the second AV server.First processing means to be referenced;On the second operation screenSecond processing means for requesting transfer of AV data of the determined part from the first AV server to the recording device based on determination of a part necessary for editing;Based on the operation for referring to the AV data on the third operation screen, the AV data is read from this recording device.A reference system having a third processing means to be referred to is proposed.
[0015]
In this reference system, the same AV data that is stored in the first AV server is also stored in the second AV server that compresses the AV data at a higher compression rate than the first AV server. Also, a recording device that can be accessed at a higher speed than the recording means in the first AV server is connected to a plurality of editing terminals.
[0016]
  In each editing terminal, a first operation screen for selecting a material to be edited and a material to be edited selected on the first operation screen are previewed, and a portion necessary for editing is determined from the preview. The second operation screen and a third operation screen for editing with reference to the AV data of the portion determined on the second operation screen are performed.
  When the material to be edited is selected on the first operation screen, the first processing unit refers to the entire material to be edited from the second AV server.
  After that, when the part necessary for editing is determined from the material to be edited on the second operation screen, the AV data of the part necessary for the editing is transferred from the first AV server to the recording device. Is requested by the second processing means.
  After that, when an operation for referring to the AV data of the part necessary for editing is designated on the third operation screen, for example, by specifying a frame, the third processing means converts the AV data of the designated frame to this AV data. Reference from recording device.
[0017]
Therefore, the AV data stored in the first AV server can be referred to from the recording device at each editing terminal. Thus, unlike the case of connecting the input / output port of the first AV server and the editing terminal in a one-to-one correspondence, the material stored in the first AV server is changed to the input / output of the first AV server. It can be referred to in parallel by a plurality of editing terminals regardless of the number of ports.
[0018]
Further, the entire material to be edited (the material for determining the portion necessary for editing) may be referred to (previewed) from the second AV server having a higher compression rate (lower resolution) than the first AV server. Therefore, the waiting time is shorter than that in the case of referring directly from the first AV server.
[0019]
Since it is sufficient to transfer only the AV data necessary for editing determined from the entire referenced material from the first AV server to the recording device, the entire material to be edited is transferred from the first AV server. Unlike the case of transferring to this recording apparatus, the time required for transfer can be short.
[0020]
Furthermore, since this recording apparatus can be accessed at a higher speed than the recording means in the first AV server, the waiting time when referring to the AV data of the jumping frame from the recording apparatus at the editing terminal at the time of editing is directly the first. This is shorter than the case where the AV data of the jump frame is referred from the AV server.
[0021]
  As a result, the waiting time when referring to the material stored in the first AV server on the editing terminalBetweenShorter.
[0022]
  In this reference system, as an example, the recording apparatus having a plurality of fiber channel ports is used.Each editing terminal and this recording device are connected by a fiber channel, andIn this recording deviceWith Fiber ChannelA gateway terminal connected to the first AV server and connected to the first AV server, and transferring AV data from the first AV server to the recording apparatus based on a request from the second processing means of the editing terminal; It is preferable that the second processing means of each editing terminal sends a request to this gateway terminal.
[0023]
As a result, transmission / reception of AV data among the gateway terminal, recording device, and editing terminal is performed by the fiber channel. Therefore, the AV data stored in the first AV server is obtained by performing network connection utilizing the characteristics of the fiber channel. Can be referred to in parallel by a larger number of editing terminals.
[0024]
  Also, AV data transmission / reception between gateway terminals, recording devices, and editing terminals in this wayTheIn the case of using the fiber channel, as an example, the gateway terminal has recorded the AV data in the file to which the recording device writes AV data.End ofThe third processing means of each editing terminal is recorded with this information in the file.Before this endIt is preferable to refer to AV data of a part.
[0025]
As a result, even when the recording device refers to AV data from the recording device at the editing terminal while the recording device is writing AV data to the file, the portion of the file to which AV data has not yet been written is referred to (reading). It will be possible to prevent the situation.
[0026]
  Next, in a method in which the applicant refers to AV data stored in the AV server with a plurality of editing terminals,A first operation screen for selecting a material to be edited is displayed. Based on the selection of the material to be edited on the first operation screen, the entire selected material is displayed.Is the second AV server storing the same AV data as the AV server (first AV server) compressed at a higher compression rate than the first AV server?RansanThe first step to illuminate and each editing terminalA material to be edited selected on the first operation screen is previewed, and a second operation screen for determining a portion necessary for editing is displayed, and the second operation screen is displayed.Based on the determination of the portion necessary for editing, the AV data of the determined portion can be accessed from the first AV server at a higher speed than the recording means in the first AV server, and the editing terminal A second step requesting transfer to a connected recording device, and each editing terminal,A third operation screen for performing editing with reference to the AV data determined in the second operation screen is displayed, and the operation for referring to the AV data is performed on the third operation screen. , The AV data from this recording deviceA reference method having a third step of referring to is proposed.
[0027]
According to this reference method, in the same manner as in the reference system according to the present invention described above, a plurality of editing terminals can store the material stored in the AV server without being restricted by the number of input / output ports of the AV server. Can be referred simultaneously in parallel, and the waiting time when referring to the material stored in the AV server on the editing terminal is shortened.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 shows an example of the overall configuration of a reference system according to the present invention. This reference system is applied to, for example, a news production system of a broadcasting station, and includes an AV server 1, an AV server 2, a plurality of editing terminals 3 (3 (1) to 3 (N)), and editing. The same number of SSDs (Solid State Disks) 4 (4 (1) to 4 (N)) as the terminal 3 and the gateway terminal 5 are included.
[0029]
Although not shown in the figure, the AV server 1 communicates via a plurality of SDI ports, a RAID, a management system that lists and manages materials (AV data) recorded in the RAID, and Ethernet (registered trademark). A network interface for performing communication and an interface for transmitting / receiving AV data to / from the gateway terminal 5 (for example, a dedicated bus called MDR).
[0030]
Each SDI port of the AV server 1 includes an encoder that compresses input AV data into AV data (eg, 144 megabits / second) at a predetermined compression rate.
[0031]
AV data is supplied to the AV server 1 from the outside (a VTR in a broadcasting station, a video camera in a news gathering site connected to the broadcasting station through a wide area network, etc.). AV data supplied to the AV server 1 is input to one of the SDI ports and subjected to compression processing or the like at the SDI port. Then, it is sent from the SDI port to the RAID and recorded in the RAID.
[0032]
Although not shown, the AV server 2 also has a network interface for performing communication via an SDI port, RAID, or Ethernet.
[0033]
The SDI port of the AV server 2 includes an encoder that compresses the input AV data into AV data (for example, 4 to 8 megabits / second) having a higher compression rate (low resolution) than the SDI port of the AV server 1. Yes.
[0034]
The AV data that is supplied to the AV server 1 is supplied to the AV server 2. AV data supplied to the AV server 2 is input to the SDI port and subjected to compression processing and the like at the SDI port. Then, it is sent from the SDI port to the RAID and recorded in the RAID.
[0035]
The SSD 4 is a storage system having a solid state memory (SDRAM) and four fiber channel ports, and can be accessed at a higher speed than a hard disk drive.
[0036]
The editing terminals 3 (1) to 3 (N) and the SSDs 4 (1) to 4 (N) are connected one-to-one with fiber channels. The gateway terminal 5 is connected to the AV server 1 and is connected to each SSD 4 via a FC (fiber channel) switch 6 via a fiber channel.
[0037]
Each editing terminal 3, gateway terminal 5, AV server 1, and AV server 2 are connected by Ethernet 7.
[0038]
The editing terminal 3 is composed of a computer such as a workstation. The editing terminal 3 is installed with an editor which is application software for editing AV data. The operation screen displayed on the editing terminal 3 by the editor includes the following operation screens (1) to (4).
[0039]
(1) An operation screen for referring to a material list from the management system in the AV server 1 via Ethernet and selecting a material to be edited from the material list.
(2) An operation screen for previewing a material to be edited selected on the operation screen (1) and determining a portion necessary for editing from the previewed material.
[0040]
(3) An operation screen for editing (deciding / correcting in / out points, pasting on the timeline, etc.) with reference to the AV data determined in the operation screen (2).
(4) An operation screen for recording edited AV data in the AV server 1.
[0041]
  In addition to this editor, the editing terminal 3 includes the following:of(Software for processing as in a) to (c) is installed.
[0042]
(A) Processing for referring to the entire selected material from the AV server 2 via the Ethernet based on the selection of the material to be edited on the operation screen (1).
[0043]
(B) Based on the determination of the portion necessary for editing on the operation screen (2), the transfer of the determined portion of AV data from the AV server 1 to the corresponding SSD 4 is performed via the Ethernet gateway terminal. Processing required for 5.
[0044]
(C) A process of referring to the AV data from the SSD 4 based on the operation of referring to the AV data on the operation screen (3).
[0045]
(D) Based on the fact that the edited AV data is recorded on the AV server 1 on the operation screen (4), the gateway terminal 5 records the edited AV data on the AV server 1 via the Ethernet. Processing requested for.
[0046]
  The gateway terminal 5 is also composed of a computer such as a workstation. The gateway terminal 5 has the followingof(Software for processing such as e) and (f) is installed.
[0047]
(E) A process of transmitting AV data from the AV server 1 to the gateway terminal 5 based on the request from the editing terminal 3 by the process (b), and transmitting the AV data to the SSD 4 and recording it on the SSD 4.
[0048]
(F) Processing that causes the edited AV data to be transmitted from the SSD 4 based on the request from the editing terminal 3 by the process (d), and that the edited AV data is transmitted to the AV server 1 and recorded in the AV server 1.
[0049]
In the process (e) of the gateway terminal 5, end-of-data (information indicating the end of the portion of the file in which the AV data has been written in the metadata area of the file in which the SSD 4 writes the AV data. EOD) is also recorded.
[0050]
In the process (c) of the editing terminal 3, the AV data of the portion before the end indicated by the EOD in the metadata area is referred to in the file in which the SSD 4 has written the AV data.
[0051]
Next, in this reference system, an operator's operation when referring to AV data stored in the AV server 1 by each editing terminal 3 and a flow of processing based on this operation will be described.
[0052]
FIG. 2 shows the flow of operations and processing. First, the operator of each editing terminal 3 refers to the material list of the AV server 1 on the above-described operation screen (1), and in the material list. To select a material to be edited (for example, AV data transmitted from a video camera at a certain interview site to a broadcasting station via a wide area network and stored in the AV server 1) (step S1).
[0053]
Then, when the editing terminal 3 executes the above-described process (a), the entire selected material to be edited is referred to from the AV server 2 via the Ethernet 7 (step S2).
[0054]
Subsequently, the operator of the editing terminal 3 previews the selected material to be edited on the operation screen (2) described above, and determines a portion necessary for editing from the previewed material (step S3).
[0055]
Then, when the editing terminal 3 executes the process (b), the AV data of the determined part is transferred from the AV server 1 to the SSD 4 corresponding to the editing terminal 3 via the Ethernet 7. Requested to the gateway terminal 5 (step S4).
[0056]
Then, the gateway terminal 5 executes the process (e) based on this request, so that the AV data of the determined part (part necessary for editing) is transmitted from the AV server 1 to the gateway terminal 5, It is recorded on the SSD 4 (At this time, the above-mentioned EOD is also recorded in the metadata area of the file to which the SSD 4 writes AV data) (step S5).
[0057]
Subsequently, when the operator of the editing terminal 3 performs an operation on the above-described operation screen (3) to refer to the AV data of the portion necessary for the editing by designating a jump frame, for example, the editing terminal 3 3 executes the above-described processing (c), and the AV data of the jump frame is referred to from the SSD 4 (in this case, the SSD 4 indicates the EOD in the metadata area among the files to which the AV data has been written. The AV data of the part before the terminal to be referred is referred to (step S6).
[0058]
In this way, the AV data stored in the AV server 1 is referred to by each editing terminal 3. FIG. 3 is a diagram showing the AV data transferred from the AV server 1 to the SSD 4 for reference to the AV data in comparison with the entire material to be edited. After the entire material to be edited is referenced from the low-resolution AV server 2 as shown in FIG. 5A (step S2 in FIG. 2), it is necessary for editing from the entire material to be edited as shown in FIG. Are determined (step S3 in FIG. 2). Then, as shown in FIG. 6C, only the part necessary for this editing out of the entire material to be edited is transferred from the AV server 1 to the SSD 4.
[0059]
The operator of each editing terminal 3 performs an operation of recording the edited AV data in the AV server 1 on the operation screen (4) after editing with reference to the AV data on the operation screen (3). Then, the editing terminal 3 executes the above-described process (d), and the gateway terminal 3 executes the above-described process (f) based on this, so that the edited AV data is transferred from the SSD 4 to the gateway terminal 5. To the AV server 1 and recorded in the AV server 1.
[0060]
The edited AV data recorded in the AV server 1 in this way is output from any SDI port of the AV server 1 and sent from the AV server 1 to the outside (on-air server, backup server, etc.).
[0061]
As described above, in this reference system, the same AV data that is stored in the AV server 1 is also stored in the AV server 2 that compresses AV data at a higher compression rate than the AV server 1. Further, an SSD 4 that can be accessed at a higher speed than the RAID in the AV server 1 is connected to a plurality of editing terminals 3.
[0062]
Then, after each editing terminal 3 refers to the entire material to be edited from the AV server 2, the portion necessary for editing is determined from the AV server 2, and the AV data of the determined portion is stored in the AV server 1. Is requested to be transferred from the SSD 4 to the SSD 4, and the AV data of the portion necessary for the editing is referenced from the SSD 4.
[0063]
Accordingly, the AV data stored in the AV server 1 can be referred to from the SSD 4 at each editing terminal 3. As a result, unlike the case where the SDI port of the AV server 1 and the editing terminal are connected in a one-to-one correspondence, the material stored in the AV server 1 is not limited by the number of SDI ports of the AV server 1. Reference can be made simultaneously by a plurality of editing terminals 3 in parallel.
[0064]
Further, since the entire material to be edited (material for determining a portion necessary for editing) is referenced (previewed) from the AV server 2 having a higher compression rate (low resolution) than the AV server 1, the AV server 1 is directly used. The waiting time is shorter than when referencing from.
[0065]
Then, it is sufficient to transfer only the AV data of the part necessary for editing determined from the entire referenced material from the AV server 1 to the SSD 4, so that the entire material to be edited is transferred from the AV server 1 to the SSD 4. In contrast, the time required for transfer is short.
[0066]
Furthermore, since the SSD 4 can be accessed at a higher speed than the RAID in the AV server 1, the waiting time when the editing terminal 3 refers to the AV data of the jump frame from the SSD 4 at the time of editing is directly from the AV server 1. This is shorter than when referring to the AV data of the frame.
[0067]
This shortens the waiting time when the editing terminal 3 refers to the material stored in the AV server 1.
[0068]
Since SSD uses solid-state memory, it is generally more expensive than RAID. However, SSD 4 only needs to have a minimum necessary capacity for storing only AV data for editing. Further, the increase in cost due to the provision of the SSD can be minimized.
[0069]
Also, since AV data is transmitted / received between the gateway terminal 5 / SSD 4 / editing terminal 3 by the fiber channel, the AV data stored in the AV server 1 can be obtained by performing a network connection utilizing the characteristics of the fiber channel. A larger number of editing terminals 3 can be referred simultaneously.
[0070]
Further, the gateway terminal 5 records end-of-data (EOD), which is information indicating the end of the portion in which the AV data has been written, in the metadata area of the file in which the SSD 4 writes the AV data, Since each editing terminal 3 refers to the AV data of the portion of the file before the end indicated by this EOD in the metadata area, the editing terminal 3 from the SSD 4 in the middle of writing the AV data to the file. When referring to AV data, it is possible to prevent a situation in which a portion of the file to which AV data has not yet been written is referred (excessively read).
[0071]
In the above example, one editing terminal 3 is connected to each SSD 4. However, since the SSD 4 has four fiber channel ports, two or three editing terminals 3 may be connected to each SSD 4 using unused ports.
[0072]
In the above example, AV data stored in an AV server having an SDI port is used as a reference target. However, the present invention is not limited to this, and AV data stored in an AV server having an input / output port other than the SDI port may be referred to by the present invention.
[0073]
In the above example, the SSD 4 is interposed between the AV server 1 and the editing terminal 3. However, as another example, a recording device other than an SSD that can be accessed at a higher speed than the RAID in the AV server 1 may be interposed between the AV server 1 and the editing terminal 3.
[0074]
In the above example, the present invention is applied to a news production system. However, the present invention is not limited to this, and an appropriate system (for example, a program production system other than news, a CM production system, or a movie production system) that requires AV data stored in an AV server to be referred to by an editing terminal. ) May be applied to the present invention.
[0075]
Further, the present invention is not limited to the above examples, and it is needless to say that various other configurations can be taken without departing from the gist of the present invention.
[0076]
【The invention's effect】
As described above, according to the present invention, the material stored in the AV server can be referred to in parallel by a plurality of editing terminals without being restricted by the number of input / output ports of the AV server. In addition, there is an effect that the waiting time when the material stored in the AV server is referred to by the editing terminal is shortened.
[0077]
Further, by performing network connection utilizing the characteristics of the fiber channel, it is possible to obtain an effect that a larger number of editing terminals can simultaneously refer to AV data stored in the AV server.
[0078]
Further, when AV data is referred to from the recording device at the editing terminal while the recording device is writing AV data to the file, a situation in which the AV data is not yet written in the file is prevented. The effect that it is possible is also acquired.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a reference system according to the present invention.
FIG. 2 is a diagram showing a flow of operations / processes in the system of FIG. 1;
FIG. 3 is a diagram showing AV data transferred from the AV server 1 to the SSD 4 in the system of FIG. 1;
[Explanation of symbols]
1 AV server, 2 low resolution AV server, 3 (1) -3 (N) editing terminal, 4 (1) -4 (N) SSD, 5 gateway terminal, 6 FC switch, 7 Ethernet

Claims (6)

In a system for referencing AV data stored in an AV server with a plurality of editing terminals,
A second AV server that stores the same AV data as the AV server after being compressed at a higher compression rate than the AV server;
A recording device connected to the editing terminal, capable of higher speed access than the recording means in the AV server,
Each of the editing terminals
A first operation screen for selecting a material to be edited;
A second operation screen for previewing a material to be edited selected on the first operation screen and determining a portion necessary for editing from the preview;
A third operation screen for performing editing with reference to the AV data of the portion determined on the second operation screen;
And processing to display
First processing means for referring to the entire selected material from the second AV server based on the selection of the material to be edited on the first operation screen ;
Second processing means for requesting transfer of AV data of the determined part from the AV server to the recording device based on the determination of the part necessary for editing on the second operation screen ;
Stored in an AV server, comprising: third processing means for referring to the AV data from the recording device based on an operation for referring to the AV data on the third operation screen . AV data reference system. In the reference system for AV data stored in the AV server according to claim 1,
The recording apparatus has a plurality of fiber channel ports,
Each of the editing terminals and the recording device are connected by a fiber channel,
A gateway that is connected to the recording device via a fiber channel and connected to the AV server, and that transfers AV data from the AV server to the recording device based on a request from the second processing means of the editing terminal A terminal,
A reference system for AV data stored in an AV server, wherein the second processing means of each of the editing terminals sends a request to the gateway terminal. In the reference system for AV data stored in the AV server according to claim 2,
The gateway terminal records information indicating an end of a portion in which AV data has been written in the file in which the recording device writes AV data,
Referencing AV data stored in an AV server, wherein the third processing means of each of the editing terminals refers to AV data of the portion of the file before the end indicated by the information system. In a method of referring to AV data stored in an AV server with a plurality of editing terminals,
Each of the editing terminals displays a first operation screen for selecting a material to be edited, and based on the selection of the material to be edited on the first operation screen, the entire selected material and a first step of the second or et references AV server that accumulates the compressed at a higher compression rate than the AV server to the same AV data and the AV server,
Each of the editing terminals displays a second operation screen for previewing the material to be edited selected on the first operation screen and determining a part necessary for editing from the previewed material. Based on the determination of the part necessary for editing on the operation screen, the AV data of the determined part can be accessed from the AV server at a higher speed than the recording means in the AV server, and the editing terminal can be accessed. A second step requiring transfer to a connected recording device;
Each of the editing terminals displays a third operation screen for performing editing with reference to the AV data of the portion determined on the second operation screen, and refers to the AV data on the third operation screen. And a third step of referring to the AV data from the recording device based on the operation, and a method of referring to the AV data stored in the AV server. The method for referring to AV data stored in the AV server according to claim 4,
Each of the editing terminals and the recording device having a plurality of Fiber Channel ports are connected by Fiber Channel,
A gateway terminal connected to the recording device via a fiber channel and connected to the AV server;
In the second step, each of the editing terminals sends a request to the gateway terminal ;
The method for referencing AV data stored in an AV server, further comprising the step of causing the gateway terminal to transfer AV data from the AV server to the recording device based on a request from the editing terminal. The method for referring to AV data stored in the AV server according to claim 5,
The gateway terminal further includes a step of recording information indicating an end of a portion of the file in which the AV data has been written in the file into which the recording device writes the AV data,
In the third step, the AV data stored in the AV server is referred to by referring to AV data of the portion of the file before the end indicated by the information.

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