JP4719506B2 - Terminal device, content reproduction method, and computer program - Google Patents

Description

The present invention relates to a terminal device , a content reproduction method , and a computer program. More specifically, the present invention relates to a waiting time such as buffering when multimedia files including moving image data and audio data are reproduced via a network. In order to shorten the time, it is suitable for use in order to enable quick reproduction without file conversion, various server settings, and generation of a server program.

  In recent years, digital devices such as digital video, digital cameras, PDAs, and mobile phones are rapidly spreading. Also, with the progress of digitalization in television broadcasting, various data such as video, audio, still images, and characters can be handled as digital data (digital data). Against this background, development of multimedia technology that handles various data in an integrated manner is thriving. Among multimedia technologies, information compression technology for digital data is important. Among them, video and interactive media with a very wide range covering high-definition image quality from low-speed lines. ISO (International Organization for Standardization) is working on the standardization of MPEG-4, the standard for reproducing images. The details of the MPEG-4 information compression technique are not directly related to the present invention, and thus the description thereof is omitted.

  The “MP4 file format” is standardized by ISO / IEC 14496-14 as a file format format for storing content that complies with the MPEG-4 standard. The MP4 file format is composed of metadata describing information about media and media data that is encoded data such as video and sound. All information is stored in a structure called “Box” (or “Atom”).

  FIG. 4 shows the data structure of the Box. As shown in FIG. 4, the Box 101 is composed of a size field 102, a type field 103, and a data field 104. The size field 102 stores the size (number of bytes) of the entire Box 101 including the size field 102, and the type field 103 stores the identifier of the Box 101 (usually an alphabet of 4 characters). The data field 104 stores actual header information and media data.

  This is the basic data structure of Box 101. In addition, a version field (1 byte) and a flags field (3 bytes) may exist before data field 104, and the Box in which these exist is called FullBox. Call. The metadata part that makes up the above-described MP4 file format using such a Box structure is called MovieBox (hereinafter referred to as moov), and the media data part is referred to as MediaDataBox (hereinafter referred to as mdat).

  In addition, the MP4 file format box defined in ISO / IEC 14496-14 includes not only an essential box but also an optional box that can be used as needed or a box that can be freely defined by the user. . Among them, for example, there is FileTypeBox (hereinafter referred to as ftyp). ftyp must be at the beginning of the MP4 file. FIG. 5 shows an example of the MP4 file Box configuration using ftyp. The ftyp 202 must be arranged at the head, but the arrangement order of other boxes such as the moov 203 and the mdat 204 is free.

  Further, the details of moov and mdat will be described with reference to FIG. For the convenience of explanation, the mdat 620 will be described. The mdat 620 is composed of a series of data units called chunks. In the example of FIG. 6, the mdat 620 includes a first audio chunk (Audio chunk 1) 621, a first Video chunk (Video chunk 1) 622, a second Video chunk (second Audio chunk 2), and a second As shown in the video chunk (Video chunk 2),..., The audio chunk and the video chunk are alternately arranged.

  The order of chunks and the number of chunks in mdat 620 are set free. One chunk is composed of a series of data units corresponding to one frame of video or audio data called a sample. Referring to the first video chunk (Video chunk 1) 622 in FIG. 6 as an example, a first Video sample (Video sample 1) 623, a second Video sample (Video sample 2) 624, a third Video sample ( As shown in video sample 3),...

  Next, the configuration of the moov 601 will be described. The moov 601 further has a hierarchical structure based on a Box. The essential Box is a MovieHeaderBox (mvhd) 602 that stores header information as a whole, a trak (Audio) 603 exemplified in FIG. 6, and a trak (Video). A plurality of TrackBoxes 604. Furthermore, this TrackBox also has a Box hierarchical structure, and the structure of the lower layer will be described by taking trak (Video) 604 as an example.

  Tracing the lower layer of trak (Video) 604 in FIG. 6, it can be seen that SampleTableBox (stbl) 605 exists. In this Box, information of at least one of each chunk or each sample of mdat 620 is stored in association with each item. The items included in the stbl 605 will be briefly described below. stts 606 is a sample duration, stsd 607 is sample detailed information, stsz 608 is a sample size, stsc 609 is the number of samples included in a chunk, that is, the number of frames, and stco 610 is a chunk offset, which are stored in association with each sample. .

  Since the configuration and information as described above are stored, the MP4 file can be reproduced while manipulating the actual encoded data of mdat 620 by the management information of the encoded data of moov 601. Therefore, when playing a file, it is better to read moov 601 before mdat 620 and play it than to read mdat 620 first, store it in a buffer, etc., then read moov, and play based on moov 601. It can be seen that it is played faster.

  Therefore, consider the case of playback of moving image content via a network. There are a streaming type and a download type as a method for distributing content according to a user request from a server device to a client terminal via a network. In the streaming type, a streaming server is required, and it is necessary to set a server program that enables streaming on the server side. In the download type, no special server software is required for the server device, and distribution is possible in a very standard computer environment.

  In addition, when the download type HTTP protocol is used, data is sequentially transferred from the top of a normal content file. Therefore, when considering the MP4 file structure described above, the mdat data is placed at the top of the file. In the case where it is arranged, after all the data has been acquired and the moov information has been acquired, reproduction is not possible.

  With reference to FIG. 7, the concept of download type distribution via a network of conventional MP4 files will be described. In FIG. 7, the left side is Client 301 and the right side is Server 302. When a reproduction request “http: //xxx/a.mp4” is transmitted from the client 301 to the server 302 in step 303, the server 302 starts from the top of the content file a.mp4 specified in step 303 in step 304. The data in the file is sent sequentially. That is, it is transmitted from encoded data of mdat. When all the data of mdat is transmitted, the management information of moov is transmitted at step 305. On the client 301 side, reproduction is possible only after analyzing the moov data sent in step 305. Therefore, during the acquisition of mdat data in step 304, the client 301 is kept in the wait state.

  However, when moov is at the beginning of the file, when moov has been acquired, it is not possible to wait until all mdat has been acquired, and at the stage where the reproducible unit of encoded data in mdat has been acquired. Sequential playback is possible. That is, even in the download type, depending on the file format, quick playback close to the streaming type is possible. In addition, when compared with the file having mdat at the top as described above, it is considered that the difference in playback start time increases as the size of mdat increases.

  As described above, in the case of using the streaming type in the distribution of multimedia contents via the network, it is necessary to set the streaming server. In the download type, the content file format is set so that quick playback is possible in advance. In the case of MP4, it is necessary to arrange and create in the order of moov and mdat. In the unlikely event that such a file format is not used, for example, a server process such as CGI is prepared, and the file is converted in the order of moov and mdat, or the contents of the file are analyzed, and moov's It is conceivable to perform a process of acquiring the part in advance. However, in both cases, the work of preparing the server process on the server side is necessary in both cases.

  It is desirable that the waiting time be as short as possible for any content from the client side, that is, the user side. Although it is well known that the content can be quickly played back using various methods if some modification is made on the server side, the file format of what content is driven by the client using standard protocols and computer environments. Even so, it could not be played back more quickly.

  The present invention has been made in view of such a problem, and in the reproduction of multimedia contents via a network, standard functions without performing various settings of the server, conversion of multimedia contents files, and the like. The purpose is to realize quick playback using

In order to achieve the above-described object, the present invention is a terminal device that receives and plays back a content file including metadata and media data that can be played back using the metadata. Type information indicating the type of data following the data, and size information corresponding to the data amount from the top of the content file to the next type information of the type information. An acquisition unit that requests and acquires data including the server device, and the media data of the content file is reproduced in the predetermined amount of data of the content file based on the type information acquired by the acquisition unit. Determination means for determining whether or not the metadata to be used continues, and the acquisition means includes the acquisition procedure. When the determination unit determines that the metadata follows the predetermined amount of data acquired by the server, the data following the predetermined amount of data is acquired as metadata from the server device, and the acquisition unit acquires the data. If the determination means determines that the predetermined amount of data does not follow the metadata, the subsequent predetermined amount of data corresponding to the size information from the beginning of the content file is transferred to the predetermined amount of data. There is provided a terminal device that is obtained from the server device for determining whether or not metadata follows data of a data amount .

  According to the present invention, it is possible to perform client-driven video playback using a standard protocol and computer environment without requiring various settings on the server side, and quick playback is possible regardless of the file format format. Become.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
With reference to FIG. 1, a description will be given of download-type delivery of an MP4 file having the simplest configuration, that is, an MP4 file in which moov and mdat are each composed of only one box, via a network.

  First, on the client side, the distribution method (protocol http) and the extension (.mp4) of the content file are determined from the URL of the content to be reproduced input by the user in step S501. In the case of the above combination, next, in step S502, the client requests the acquisition of the URL of the content file to be reproduced and the first 8 bytes of the file. The first 8 bytes correspond to both the size field (4 bytes) and the type field (4 bytes) in the description of the Box described above. In step S503, the server sends the first 8 bytes of the content file and the total file size of the content file to the client.

  The client analyzes the first 8 bytes, and determines whether the type field is moov in step S504. If it is not moov, that is, in the case of mdat in the present embodiment, the type, size, and acquisition start position (first) are once stored in a memory or the like in step S505. After that, in step S506, 8 bytes are acquired from the position plus the size already acquired from the top. In other words, as described above, in order to obtain moov data in advance, if there is an mdat at the beginning, it skips that part and obtains the next Box.

  The 8 bytes acquired in step S506 are analyzed, and the process of step S504 is performed again. If the type acquired for the second time is moov, it is determined in step S507 whether or not it is the top box. In the case of the top box, since 8 bytes have already been acquired from the top, all data from the 9th byte to the end of the file are acquired in step S508.

  If it is not the first box in the determination in step S507, in step S509, the size obtained by subtracting 8 bytes from the size acquired second time is acquired from the position obtained by adding 8 bytes to the previous acquisition position. . When the data part is acquired, the acquisition size is set to GetSIZE, and size is added to this. In step S510, the above-described GetSIZE is compared with the total file size acquired in step S503. If this is not the case, in step S511, data corresponding to the size obtained by subtracting 8 bytes from size is acquired from the position obtained by adding 8 bytes from the stored acquisition position. In addition, size is added to GetSIZE. In step S512, when the data has been acquired with the stored information such as type, the information is deleted.

  Finally, in step S510, GetSIZE is compared with the total file size. If they match, the process ends. Although the file acquisition flowchart is as described above, the reproduction start point corresponds to the mdat data acquisition timing in step S508 or step S512.

  FIG. 2 shows a conceptual diagram of processing in the present embodiment. In FIG. 2, the left side is Client 401 and the right side is Server 402. First, the URL input from the user is analyzed on the client 401 side, the distribution method (http) and the extension (.mp4) are determined, and in the case of this combination, “http: //xxx/a.mp4 Range: 0 -7 ”, a request for acquiring the first 8 bytes of the content file a.mp4 (a reproduction request for content range specification) 403 is transmitted from the client 401 to the server 402. A response 404 including the first 8 bytes of the content file a.mp4 requested for acquisition and the total file size is transmitted from the server 402. The client 401 discriminates the value of the type field included in the first 8 bytes, and transmits the acquisition request 405 for specifying the range of the moov position (download request specifying the position of moov) from the client 401 in the same manner as in the previous step. A moov portion 406 is transmitted from the server 402. Next, an acquisition request (download request specifying the mdat position) 407 is performed from the client 401 by specifying the range of the mdat position, and the mdat portion 408 is transmitted from the server 402. After the client 401 acquires and analyzes the moov portion 406, the playback starts when the client 401 acquires a reproducible unit in the acquisition of the mdat portion 408.

  As described above, in this embodiment, when specifying the URL of the content to download and play, it is determined whether the data is encoded data or management information by specifying the download range and determining the data type. Then, management information is acquired in advance. When the management information has been acquired, encoded data is acquired sequentially. Other file information is completely acquired by repeating the comparison of the acquisition size and the total file size. In reproduction, management information is first obtained and analyzed, and reproduction is started when the corresponding encoded data is obtained in a reproducible unit, and quick reproduction is possible regardless of the file configuration order.

(Second Embodiment)
In the first embodiment, description has been made using the example of an MP4 file in which mdat and moov, which are the simplest configurations, are each composed of only one Box, but as described above, there are other ftyp for MP4 files. In some cases, a user-defined box or a plurality of mdats exist. Such a complicated case will be described with reference to FIG.

  First, on the client side, the distribution method (protocol http) and the extension (.mp4) of the content file are determined from the URL of the content to be reproduced input by the user in step S701. In the case of the above combination, next, in step S702, the client makes a request for acquiring the URL of the content file to be reproduced and the first 8 bytes of the file. The first 8 bytes correspond to both the size field (4 bytes) and the type field (4 bytes) in the description of the Box described above.

  In step S703, the server sends the first 8 bytes of the content file and the total file size of the content file to the client. At this time, the size of the portion corresponding to the 8-byte box acquired in advance is added as the extracted size. This is for grasping the analyzed Box, and is used to determine whether there is a Box that is extracted by comparing all file sizes later and forgot to analyze the type.

  The client analyzes the first 8 bytes acquired in step S703, and determines whether the type field is moov in step S704. If it is not moov, in step S705, the type, size, and acquisition start position (first) are once stored in a memory or the like. Thereafter, in step S706, 8 bytes are acquired from the position plus the size already acquired from the top. That is, as described above, since it is desired to obtain moov data in advance, if there is an mdat at the beginning, the portion is skipped and the next box is obtained. At this time, size is added to the extracted size.

  If the acquired type is moov in step S704, it is determined in step S707 whether or not it is the top box. In the case of the top box, since 8 bytes have already been acquired from the top, all data from the 9th byte to the end of the file are acquired in step S708. In this case, the process ends here. If the 8 bytes acquired in step S706 are analyzed, the process of step S704 is performed again.

  If it is determined in step S704 that it is moov and it is not the top box in step S707, in step S709, a size obtained by subtracting 8 bytes from size is acquired from the position obtained by adding 8 bytes to the previous acquisition position. When the data part is acquired, the acquisition size is set to GetSIZE, and size is added to this. Since moov has been acquired at this point, mdat is acquired from the part near the beginning of the file. Therefore, in step S710, it is determined whether the type field stored in the memory or the like is mdat. The data portion corresponding to the mdat portion of the information stored in step S711 is acquired from the server from the size and acquisition information.

  In step S712, the stored information on the memory for which acquisition has been completed is deleted. By performing the operations in steps S710 to S712, mdat is detected from the storage information that has already acquired 8 bytes of type and size, and all data is acquired from the server. In step S713, the extracted size is compared with the total file size. If they do not match, 8 bytes are acquired from the previous extraction position in step S714, and whether or not type is mdat is compared in step S715. If it is not mdat, it is added to the information stored in the memory in step S716.

  In the case of mdat in step S715, the data portion is acquired from the server in step S717. In the processing of steps S713 to S717, all mdats are acquired from the server from the unanalyzed box for the type in the content file. If the extracted size matches the total file size in step S713, it is checked in step S718 whether there is information stored in the memory or the like, and if it exists in step S719, the data portion is obtained from the server. In step S720, the stored information is deleted. By repeating these steps S718 to S720, data other than the previously analyzed types moov and mdat are acquired. When all of the files have been acquired, it is confirmed that GetSIZE matches all the file sizes, and the processing ends.

  Although the file acquisition flowchart is as described above, the reproduction start point corresponds to the acquisition timing of mdat data in step S708, step S711, or step S717.

(Third embodiment)
In the first and second embodiments, when determining the content file of the URL input from the user on the client side, the MP4 file is determined using the file extension (.mp4). Take the following two points as an example.
(1) Analysis by type field (2) Analysis by media type of HTTP header fold

(1) The analysis by the type field means that in the “MP4 file format” standard of ISO / IEC 14496-14, ftyp, moov, and mdat exist in the type field in the box. When these types are detected, there is a method of determining as an MP4 file.

(2) The analysis by media type includes a Content-Type entity header field in the header field definition when the HTTP protocol is used. This indicates the media type of the entity body that is sent when a GET request is made. In the case of an MP4 file, a media type such as “Content-Type: video / mpeg4” can be acquired.

(Fourth embodiment)
The playback method described in the first embodiment, the second embodiment, and the third embodiment described above is capable of always quick playback in a content file in which moov is not stored in advance in the file. Judging from factors such as video content shooting time, content file size, mdat size, content data rate, etc., by holding means for selecting the conventional method and the method of the present invention, It becomes possible to realize a quick reproduction more effectively.
That is, the first to third embodiments are not exclusive, and various methods including a conventional method can be switched according to an arbitrary condition.

(Other embodiments of the present invention)
The present invention has been described based on the preferred embodiments. However, such embodiments are merely examples of the present invention and do not limit the present invention. For example, a file generated according to the present invention is not limited to an MP4 file, and can be applied to other arbitrary file playback having metadata information such as moov and data information such as mdat. . Further, although described using the HTTP protocol, the present invention can also be applied to other protocols that can specify an acquisition range in a file.

  In order to operate various devices to realize the functions of the above-described embodiments, program codes of software for realizing the functions of the above-described embodiments are provided to an apparatus or a computer in the system connected to the various devices. What is implemented by operating the various devices according to a program supplied and stored in a computer (CPU or MPU) of the system or apparatus is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, the program code are stored. The recorded medium constitutes the present invention. As a recording medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer, etc. It goes without saying that the program code is also included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with the embodiment.

  Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the CPU provided in the function expansion board or function expansion unit based on the instruction of the program code Needless to say, the present invention includes a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.

It is a flowchart of the download type delivery via the network which shows the 1st Embodiment of this invention and is an MP4 file. It is a conceptual diagram of the download type delivery via the network of the MP4 file, showing the first embodiment of the present invention. It is a flowchart of the download type | mold delivery via the network of the complicated MP4 file which shows the 2nd Embodiment of this invention and is the range of an international standard. It is a block diagram which shows the prior art and shows the structure of Box which is a basic unit of MP4 file. It is a block diagram which shows the prior art and shows the structure of the Box of MP4 file. It is a block diagram which shows the prior art and shows the structure of moov and mdat of MP4 file. It is a conceptual diagram of a download type distribution through a network of MP4 files, showing a conventional technique.

Explanation of symbols

401 Client 402 Server 403 Playback request 404 Response 405 Download request 406 Content moov part 407 Download request 408 Content mdat part

Claims (13)

A terminal device that receives and reproduces a content file including metadata and media data that can be reproduced using the metadata from a server device,
A type of data corresponding to a predetermined amount of data from the beginning of the content file, the type information indicating the type of data following the data, and a size corresponding to the amount of data from the beginning of the content file to the next type information of the type information Obtaining means for requesting and obtaining data including information from the server device;
Determination means for determining whether or not the metadata used for reproducing the media data of the content file follows the predetermined amount of data of the content file based on the type information acquired by the acquisition means; And
The acquisition means includes
When the determination unit determines that the metadata continues to the data of the predetermined data amount acquired by the acquisition unit, the data following the data of the predetermined data amount is acquired as metadata from the server device,
When the determination unit determines that metadata does not follow the data of the predetermined data amount acquired by the acquisition unit, the predetermined data amount after the data amount corresponding to the size information from the top of the content file The terminal device is characterized in that the data is acquired from the server device for determining whether or not the metadata follows the predetermined amount of data. Determining means for determining whether or not the type of the content file to be reproduced is a predetermined type from the extension of the content file to be reproduced;
When the determination unit determines that the type of the content file to be reproduced is the predetermined type, the acquisition unit requests the server device for data of the predetermined data amount from the top of the content file. The terminal device according to claim 1, wherein the terminal device is acquired. Whether or not the type of the content file to be reproduced is a predetermined type based on whether or not the type information included in the predetermined amount of data from the beginning of the content file to be reproduced matches the predetermined type information Having a determining means for determining
The acquisition unit determines that the type of the content file to be reproduced is the predetermined type by the determination unit, and the determination unit determines that metadata follows the predetermined amount of data. The terminal device according to claim 1, wherein data following the predetermined data amount is acquired as metadata from the server device. Determining means for determining from the URL of the content file to be reproduced whether or not the combination of the distribution protocol and extension of the content file is a predetermined combination;
The acquisition unit acquires the predetermined amount of data from the head of the content file when the determination unit determines that the combination of the distribution protocol and extension of the content file to be reproduced is the predetermined combination. The terminal device according to claim 1, wherein: Determining means for determining whether or not a character string indicating a media type acquired from the server device before requesting a content file to be reproduced is a predetermined character string;
The acquisition unit acquires the data of the predetermined data amount from the head of the content file when the determination unit determines that the character string indicating the media type is the predetermined character string. The terminal device according to claim 1. A content reproduction method performed by a terminal device that receives and reproduces a content file including metadata and media data that can be reproduced using the metadata from a server device,
A type of data corresponding to a predetermined amount of data from the beginning of the content file, the type information indicating the type of data following the data, and a size corresponding to the amount of data from the beginning of the content file to the next type information of the type information An acquisition step of requesting and acquiring data including information from the server device;
A determination step for determining whether or not the metadata used for reproducing the media data of the content file follows the data of the predetermined data amount of the content file based on the type information acquired by the acquisition step. And
The acquisition step includes
If it is determined by the determination step that metadata follows the data of the predetermined data amount acquired by the acquisition step, data following the data of the predetermined data amount is acquired as metadata from the server device,
If the determination step determines that metadata does not follow the data of the predetermined data amount acquired by the acquisition step, the predetermined data amount after the data amount corresponding to the size information from the top of the content file The content reproduction method is characterized in that the data is acquired from the server device for determining whether or not the metadata follows the predetermined amount of data. A determination step of determining whether or not the type of the content file to be reproduced is a predetermined type from the extension of the content file to be reproduced;
When the determination step determines that the type of the content file to be reproduced is the predetermined type, the acquisition step requests the server device for data of the predetermined data amount from the top of the content file. The content reproduction method according to claim 6, wherein the content reproduction method is obtained. Whether or not the type of the content file to be reproduced is a predetermined type based on whether or not the type information included in the predetermined amount of data from the beginning of the content file to be reproduced matches the predetermined type information Having a discrimination process for discriminating
In the acquisition step, the determination step determines that the type of the content file to be played is the predetermined type, and the determination step determines that metadata follows the predetermined amount of data. The content reproduction method according to claim 6, wherein data following the predetermined amount of data is acquired as metadata from the server device. A determination step of determining whether or not a character string indicating a media type acquired from the server device before requesting a content file to be reproduced is a predetermined character string;
In the obtaining step, when the character string indicating the media type is determined as the predetermined character string by the determining step, the predetermined amount of data is acquired from the head of the content file. The content reproduction method according to claim 6. A computer program for causing a computer to execute a procedure for receiving and reproducing a content file including metadata and media data that can be reproduced using the metadata from a server device,
A type of data corresponding to a predetermined amount of data from the beginning of the content file, the type information indicating the type of data following the data, and a size corresponding to the amount of data from the beginning of the content file to the next type information of the type information An acquisition procedure for requesting and acquiring data including information from the server device;
A determination procedure for determining whether or not the metadata used for reproducing the media data of the content file follows the data of the predetermined data amount of the content file based on the type information acquired by the acquisition procedure; To run
The acquisition procedure is as follows:
If it is determined by the determination procedure that metadata follows the data of the predetermined data amount acquired by the acquisition procedure, data following the data of the predetermined data amount is acquired as metadata from the server device,
If the determination procedure determines that metadata does not follow the data of the predetermined data amount acquired by the acquisition procedure, the predetermined data amount after the data amount corresponding to the size information from the beginning of the content file The computer program for obtaining the data of the predetermined amount of data from the server device for determining whether or not the metadata follows the predetermined amount of data. Causing the computer to further execute a determination procedure for determining whether or not the type of the content file to be reproduced is a predetermined type from the extension of the content file to be reproduced;
When the determination procedure determines that the type of the content file to be reproduced is the predetermined type, the acquisition procedure requests the server device for data of the predetermined data amount from the beginning of the content file. The computer program according to claim 10, wherein the computer program is acquired. Whether or not the type of the content file to be reproduced is a predetermined type based on whether or not the type information included in the predetermined amount of data from the beginning of the content file to be reproduced matches the predetermined type information The computer further executes a determination procedure for determining whether or not
When the determination procedure determines that the type of the content file to be played is the predetermined type by the determination procedure, and the determination procedure determines that metadata follows the predetermined data amount The computer program according to claim 10, wherein data following the predetermined amount of data is acquired as metadata from the server device. Causing the computer to further execute a determination procedure for determining whether or not the character string indicating the media type acquired from the server device before the request for the content file to be reproduced is a predetermined character string;
In the acquisition procedure, when the determination procedure determines that the character string indicating the media type is the predetermined character string, the predetermined amount of data is acquired from the beginning of the content file. The computer program according to claim 10.

Images