JP4436617B2 - Demultiplexer - Google Patents

Description

【０１９５】
ここで、ランダムアクセス処理部４００は、時間長ａが目標時間Ｘと等しいか否かを判別し（ステップＳ４０８）、等しいと判別したときには（ステップＳ４０８のＹ）、目的サンプルはｍｏｏｆ時間長Ｃ_Ｎに対応する最後のサンプルであると判別する（ステップＳ４１０）。
【０１９６】
また、ランダムアクセス処理部４００は、時間長ａが目標時間Ｘと等しくないと判別したときには（ステップＳ４０８のＮ）、さらに、時間長ａが目標時間Ｘよりも大きいか否かを判別する（ステップＳ４１２）。
【０１９７】
ランダムアクセス処理部４００は、時間長ａが目標時間Ｘよりも大きくないと判別したときには（ステップＳ４１２のＮ）、Ｎ＝Ｎ＋１として（ステップＳ４１４）、さらにステップＳ４０６からの動作を繰り返し実行する。なお、上記数式は、基本コンテンツ時間長Ａとｍｏｏｆ時間長Ｃ_１〜Ｃ_Ｎとの総和を表しているが、ランダムアクセス処理部４００は、Ｎの増加の度に上記数式の加算処理を全て実行することはなく、加算処理結果を一時保存しておき、Ｎが１増加する度に、前記Ｎに相当するＣ_Ｎを上記保存された加算処理結果にさらに加算することで上記数式の解を求める。
【０１９８】
そして、時間長ａが目標時間Ｘよりも大きいと判別したときには（ステップＳ４１２のＹ）、ランダムアクセス処理部４００は、まず変数ＭをＭ＝１として（ステップＳ４１６）、基本コンテンツ時間長Ａ及びｍｏｏｆ時間長Ｃ_ｎ並びにｔｒａｆ時間長Ｄ_ｍを用いて時間長ｂを下記数式により算出する（ステップＳ４１７）。
【数２】

【０１９９】
ここで、ランダムアクセス処理部４００は、時間長ｂが目標時間Ｘと等しいか否かを判別し（ステップＳ４１８）、等しいと判別したときには（ステップＳ４１８のＹ）、目的サンプルはｔｒａｆ時間長Ｄ_Ｍに対応する最後のサンプルであると判別する（ステップＳ４２０）。
【０２００】
また、ランダムアクセス処理部４００は、時間長ｂが目標時間Ｘと等しくないと判別したときには（ステップＳ４１８のＮ）、さらに、時間長ｂが目標時間Ｘよりも大きいか否かを判別する（ステップＳ４２２）。
【０２０１】
ランダムアクセス処理部４００は、時間長ｂが目標時間Ｘよりも大きくないと判別したときには（ステップＳ４２２のＮ）、Ｍ＝Ｍ＋１として（ステップＳ４２４）、さらにステップＳ４１７からの動作を繰り返し実行する。そして、時間長ｂが目標時間Ｘよりも大きいと判別したときには（ステップＳ４２２のＹ）、ランダムアクセス処理部４００は、まず変数ＬをＬ＝１として（ステップＳ４２６）、基本コンテンツ時間長Ａ、ｍｏｏｆ時間長Ｃ_ｎ、ｔｒａｆ時間長Ｄ_ｍ、サンプル時間Ｅ_ｌを用いて時間長ｃを下記数式により算出する（ステップＳ４２８）。
【数３】

【０２０２】
ここで、ランダムアクセス処理部４００は、時間長ｃが目標時間Ｘと等しいか否かを判別し（ステップＳ４３０）、等しいと判別したときには（ステップＳ４３０のＹ）、目的サンプルはサンプル時間長Ｅ_Ｌに対応するサンプルであると判別する（ステップＳ４３２）。
【０２０３】
また、ランダムアクセス処理部４００は、時間長ｃが目標時間Ｘと等しくないと判別したときには（ステップＳ４３０のＮ）、さらに、時間長ｃが目標時間Ｘよりも大きいか否かを判別する（ステップＳ４３４）。
【０２０４】
ランダムアクセス処理部４００は、時間長ｃが目標時間Ｘよりも大きくないと判別したときには（ステップＳ４３４のＮ）、Ｌ＝Ｌ＋１として（ステップＳ４３６）、さらにステップＳ４２８からの動作を繰り返し実行する。そして、時間長ｃが目標時間Ｘよりも大きいと判別したときには（ステップＳのＹ）、ランダムアクセス処理部４００は、エラーが発生したものと判断する（ステップＳ４３８）。
【０２０５】
そして、ステップＳ４０２、ステップＳ４１０、ステップＳ４２０、又はステップＳ４３２で目的サンプルが特定された後、ランダムアクセス処理部４００は、その目的サンプルを示す目的サンプル識別情報を出力する（ステップＳ４４０）。
【０２０６】
このように本変形例では、拡張領域のｍｏｏｆ１３０’のｍｆｈｄ１３１に、ｍｏｏｆ時間長情報を格納するｍｏｏｆ時間長フィールド１３１ｄを設け、さらに、ｔｆｈｄ１３３に、ｔｒａｆ時間長情報を格納するｔｒａｆ時間長フィールド１３５を設けるとともに、ランダムアクセス時において目標時間から目的サンプルを探すときには、まず拡張コンテンツ時間長を用い、次に、拡張コンテンツ時間長よりも短いｍｏｏｆ時間長を用い、さらに次に、ｍｏｏｆ時間長よりも短いｔｒａｆ時間長を用い、そして最後に、ｔｒａｆ時間長よりも短いサンプル時間長を用いるため、図２８に示す従来のランダムアクセス処理部８１２の動作と比べて、計算量を少なくし、迅速に目的サンプルを探し出すことができる。
【０２０７】
そして、ランダムアクセス処理部４００は、ＭＰ４ファイルデータ１００’と目的サンプル識別情報とを復号部２１３に出力して、その目的サンプル識別情報により示される目的サンプルからのコンテンツの再生を復号部２１３及び再生部２１４に実行させる。
【０２０８】
図２０は、ｔｆｈｄ１３３のシンタックスを示す表示図である。
この図２０に示すように、ｔｒａｆ１３２のｔｒａｆ時間長フィールド１３５には、例えば３２ビットが割り当てられる。
【０２０９】
なお、ランダムアクセス処理部４００の主制御部４１０は、ｍｏｏｆ時間長処理部４２０からのｍｏｏｆ時間長情報の出力状況や、ｍｏｏｆ時間長情報により示されるｍｏｏｆ時間長の有効性を判別しており、ｍｏｏｆ時間長を用いようとする場合に、ｍｏｏｆ時間長情報が出力されなかったとき、又はｍｏｏｆ時間長が有効でないと判別したときには、ｔｒａｆ時間長処理部４３０にｍｏｏｆ１３０’に格納されている全てのｔｒａｆ時間長情報を出力させて、これらｔｒａｆ時間長の和をｍｏｏｆ時間長の代わりに用いても良い。さらに、ランダムアクセス処理部４００の主制御部４１０は、ｔｒａｆ時間長処理部４３０からのｔｒａｆ時間長情報の出力状況や、ｔｒａｆ時間長情報により示されるｔｒａｆ時間長の有効性を判別しており、ｔｒａｆ時間長を用いようとする場合に、ｔｒａｆ時間長情報が出力されなかったとき、又はｔｒａｆ時間長が有効でないと判別したときには、サンプル時間長処理部４４０にｔｒａｆ１３２に格納されている全てのサンプル時間長情報を出力させて、これらサンプル時間長の和をｔｒａｆ時間長の代わりに用いても良い。
【０２１０】
また、上記変形例では、各サンプルにシーク可能か否かを示すフラグを含めたが、ｍｏｏｆ１３０に対応する複数のサンプルに対して１つのフラグを含めたり、ｔｒａｆ１３２に対応する複数のサンプルに対して１つのフラグを含めたりしても良い。これにより、各サンプル毎にフラグをチェックする処理を省くことができる。
【０２１１】
【発明の効果】
以上の説明から明らかなように、本発明に係る逆多重化装置によれば、処理手段で多重化データが各組ごとに逆多重化処理されるため、ストリームとして配信される多重化データからコンテンツをダウンロード再生することができるとともに、多重化データの先端部に含まれる総時間長情報に基づいて総時間長が総時間長特定手段で特定されてその総時間長が表示手段により表示されるため、ダウンロード再生中にでも総時間長をユーザに知らせることができ、コンテンツのダウンロード再生時の利便性を向上することができる。また、本発明に係る逆多重化装置は、ＭＰ４ファイルデータをダウンロードして再生するパーソナルコンピュータや携帯電話などに用いるのに適し、本発明に係る多重化装置は、画像や音声などのマルチメディアデータを取得してＭＰ４ファイルデータを作成して記録するデジタルビデオカメラや録画機能付き携帯電話などに用いるのに適している。
【図面の簡単な説明】
【図１】実施の形態における逆多重化装置及び多重化装置が扱うＭＰ４ファイルデータのファイルフォーマットを示すデータ構成図である。
【図２】同上のＭＰ４ファイルデータに基づいて再生を行う逆多重化装置の構成を示す構成図である。
【図３】同上の時間処理部のコンテンツ時間長特定部の内部構成を示すブロック図である。
【図４】同上の時間処理部のトラック時間長特定部の内部構成を示すブロック図である。
【図５】同上の逆多重化装置のコンテンツ時間長特定部の特徴的な動作を示すフロー図である。
【図６】同上の逆多重化装置の再生部により表示される画像を示す画像表示図である。
【図７】同上の逆多重化装置の再生部により表示される他の画像を示す画像表示図である。
【図８】同上の多重化装置の構成を示す構成図である。
【図９】同上の多重化装置の動作を示すフロー図である。
【図１０】同上のｔｒｅｘのシンタックスを示す表示図である。
【図１１】同上のｍｅｈｄを含むＭＰ４ファイルデータを扱うコンテンツ時間長特定部の内部構成を示すブロック図である。
【図１２】同上のコンテンツ時間長特定部の特徴的な動作を示すフロー図である。
【図１３】同上のｍｅｈｄのシンタックスを示す表示図である。
【図１４】同上の変形例に係る逆多重化装置が取り扱うＭＰ４ファイルデータのｍｏｏｆのファイルフォーマットを示すデータ構成図である。
【図１５】同上の変形例に係る逆多重化装置のランダムアクセス処理部の内部構成を示すブロック図である。
【図１６】同上の変形例に係るｍｏｏｆ時間長処理部の内部構成を示すブロック図である。
【図１７】同上の変形例に係るｔｒａｆ時間長処理部の内部構成を示すブロック図である。
【図１８】同上の変形例に係るランダムアクセス処理部の概略的な動作を説明するための説明図である。
【図１９】同上の変形例に係るランダムアクセス処理部の動作を示すフロー図である。
【図２０】同上の変形例に係るｔｆｈｄのシンタックスを示す表示図である。
【図２１】従来例におけるＭＰ４ファイルデータの基本的なファイルフォーマットを示すデータ構成図である。
【図２２】同上のｍｏｏｖの詳細な構成を示すデータ構成図である。
【図２３】同上のｍｏｏｆの詳細な構成を示すデータ構成図である。
【図２４】同上のＭＰ４ファイルデータを生成する従来の多重化装置の構成を示す構成図である。
【図２５】同上の多重化装置のｍｏｏｖデータ及びｍｏｏｆデータの生成に関する動作を示すフロー図である。
【図２６】同上のＭＰ４ファイルデータに基づいて再生を行う従来の逆多重化装置の構成を示す構成図である。
【図２７】同上の時間長特定部の内部構成を示すブロック図である。
【図２８】同上のランダムアクセス処理部の構成を示す構成図である。
【図２９】同上のトラック制御部の内部構成を示すブロック図である。
【図３０】同上のランダムアクセス処理部の概略的な動作を説明するための説明図である。
【図３１】同上の従来の逆多重化装置での問題点を説明するための説明図である。
【符号の説明】
１００ ＭＰ４ファイルデータ
１００ａ 基本領域
１００ｂ 拡張領域
１１０ ｍｏｏｖ
１１３ａ ｍｈｅｘ
１１３ｂ ムービー時間長フィールド
１２０ ｍｄａｔ
１３０ ｍｏｏｆ
１４０ ｍｄａｔ
２００ 逆多重化装置
２１０ データ取得部
２１１ 時間処理部
２１１ａ コンテンツ時間長特定部
２１１ｂ トラック時間長特定部
２１１ｃ 再生時間特定部
２１２ ランダムアクセス処理部
２１３ 復号部
２１４ 再生部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a demultiplexer that demultiplexes multiplexed data obtained by multiplexing multimedia data such as image data and music data, and a multiplexer that multiplexes multimedia data.
[0002]
[Prior art]
In recent years, MP4 has attracted attention as a file format for multiplexing and storing multimedia data (content such as moving images, audio, text, or still images).
[0003]
MP4 is used as a file format of MPEG-4, which is a compression encoding method for moving images, and JPEG 2000, the next generation version of JPEG, which is a compression encoding method for natural images.
[0004]
Initially, the MP4 file format was composed of one data box for storing multiplexed contents and one header box for storing information related to the contents of the data area.
[0005]
Therefore, a multiplexing device that generates MP4 file data from multimedia data acquires the multimedia data, performs encoding and multiplexing processing, and creates the header box after all the multimedia data has been processed. The MP4 file data was completed.
[0006]
In such a multiplexing apparatus, when the amount of information of multimedia data is large, it takes some time to create the header box after the acquisition of multimedia data and the processing for the multimedia data are completed.
[0007]
For example, in a multiplexing device configured as a mobile phone with a recording function, when an incoming call is received during recording, a time lag is added to the incoming call in order to create a header box that includes information related to the entire recorded content. Occurs. In addition, when priority is given to incoming calls, the creation of the header box is interrupted and the MP4 file data cannot be completed.
[0008]
Therefore, the MP4 file format has been improved so that a plurality of sets of data boxes and header boxes are connected (see, for example, Non-Patent Document 1).
[0009]
FIG. 21 is a data structure diagram showing a basic file format of conventional MP4 file data improved as described above.
[0010]
The MP4 file data 900 is composed of a basic area 900a and an extended area 900b.
[0011]
The basic area 900a includes a movie box (hereinafter referred to as “moov”) 910 as a header box and a media data box (hereinafter referred to as “mdat”) 920 as a data box.
[0012]
The moov 910 further includes a movie header box (hereinafter referred to as “mvhd”) 911, a plurality of track boxes (hereinafter referred to as “trak”) 912, and a movie extend box (hereinafter referred to as “mvex”) 913. It consists of.
[0013]
The extension area 900b includes a plurality of sets of a movie fragment box (hereinafter referred to as “moof”) 930 serving as the header box and a media data box (hereinafter referred to as “mdat”) 940 serving as the data box. It is configured as a combination.
[0014]
The moof 930 further includes one movie fragment header box (hereinafter referred to as “mfhd”) 931 and a plurality of track fragment boxes (hereinafter referred to as “traf”) 932.
[0015]
FIG. 22 is a data configuration diagram showing a detailed configuration of the moov 910.
The mvhd 911 includes a movie time length field 911a that stores basic content time length information indicating a time length (basic content time length) required for reproduction of the content included in the basic area 900a.
[0016]
The track 912 further includes a track header box (hereinafter referred to as “tkhd”) 914. The tkhd 914 includes a track ID field 916 for storing track identification information for identifying a track, and a track time length field 917. And are included. The track time length field 917 stores basic track time length information indicating the time length (basic track time length) required for playback of the track included in the basic area 900a indicated by the track identification information.
[0017]
Here, the track is a kind of content and means a moving image, sound, text, or the like.
[0018]
The mvex 913 includes a number of track extend boxes (hereinafter referred to as “trex”) 915 corresponding to the number of tracks included in the extension area 900b.
[0019]
The trex 915 indicates a track ID field 918 for storing track identification information for identifying a track, and a time length set by default for a sample of a track in the extension area 900b specified by the track identification information. A first default time length field 919 in which default sample time length information is stored is included.
[0020]
Here, the sample is the minimum unit of the MP4 file format, and means one frame or picture if the track is a moving image, and means sound information for 20 (msec) if the track is sound. .
[0021]
FIG. 23 is a data configuration diagram showing a detailed configuration of the moof 930.
The traf 932 included in the moof 930 further includes one track fragment header box (hereinafter referred to as “tfhd”) 933 and a plurality of track fragment run boxes (hereinafter referred to as “trun”) 936.
[0022]
In the tfhd 933, the track ID field 934 that stores the track identification information for identifying the track, and the traf 932 that stores the tfhd 933 among the samples of the track in the extension area 900b specified by the track identification information. A second default time length field 935 in which default sample time length information indicating a time length set by default is stored for the associated sample is included. Here, the second default time length field 935 may be omitted, and in this case, the first default time length field 919 is referred to.
[0023]
The run 936 includes a sample time length field 937 for storing sample time length information indicating the time length (sample time length) of each sample included in the track of the extension area 900b specified by the track identification information.
[0024]
As described above, the MP4 file format includes one set of mdat 920 and moov 910, and further includes a plurality of sets of mdat 940 and moof 930, that is, a box for storing multiplexed contents and the contents included in the box. The conventional multiplexing apparatus completes the MP4 file data 900 each time it sequentially acquires and processes multimedia data, and in real-time recording. It is effective. The conventional multiplexing device configured as a mobile phone with a recording function can prevent an incoming time lag even during recording.
[0025]
FIG. 24 is a configuration diagram showing a configuration of a conventional multiplexing device that generates the MP4 file data 900. As shown in FIG.
[0026]
The multiplexing apparatus 700 includes an image data analysis unit 701, an audio data analysis unit 702, a first changeover switch 703, a second changeover switch 704, a control unit 708, a moof generation unit 705, and a moov generation unit 706. And a file generation unit 707.
[0027]
The image data analysis unit 701 obtains image data and analyzes the image data, thereby generating image specifying information having contents indicating a time stamp and a size of the image data. Then, the image data analysis unit 701 generates image encoded data by encoding the image data, and outputs the image encoded data and image specifying information.
[0028]
The voice data analysis unit 702 acquires voice data and analyzes the voice data, thereby generating voice specifying information having contents indicating a time stamp, a size, and the like of the voice data. Then, the voice data analysis unit 702 generates voice encoded data by encoding the voice data, and outputs the voice encoded data and the voice specifying information.
[0029]
The moov generation unit 706 generates and outputs data (moov data) stored in the moov 910 according to control from the control unit 708.
[0030]
The moof output unit 705 generates and outputs data (moof data) stored in the moof 930 in accordance with control from the control unit 708.
[0031]
The control unit 708 acquires the image specifying information from the image data analyzing unit 701, acquires the sound specifying information from the sound data analyzing unit 702, and based on the image specifying information and the sound specifying information, the first changeover switch 703 and By switching the second changeover switch 704, the data to be stored in the basic area 900a including the moov data is first output from the second changeover switch 704, and then the data to be stored in the extension area 900b including the moof data is output. Output.
[0032]
The file generation unit 707 performs multiplexing processing on each data output from the second changeover switch 704 to generate MP4 file data 900, and outputs this.
[0033]
FIG. 25 is a flowchart showing operations related to generation of moov data and moof data in the conventional multiplexing apparatus 700.
[0034]
First, the multiplexing apparatus 700 generates moov data (step S100).
Next, the multiplexing apparatus 700 creates moof data (step S102).
[0035]
Then, the multiplexing apparatus 700 determines whether there is unprocessed data for encoding and multiplexing of the input image data and audio data (step S104). Here, when it is determined that there is unprocessed data (Y in step S104), the operation from step S102 is repeatedly executed, and when it is determined that there is no unprocessed data (N in step S104), the process ends. To do.
[0036]
As described above, the conventional multiplexing apparatus 700 using the MP4 file data 900 is effective for real-time recording because it sequentially creates moof data.
[0037]
By the way, the MP4 file data 900 is suitable for streaming because it is configured such that a plurality of sets of data boxes and header boxes are connected as shown in FIGS. In other words, the demultiplexer that reproduces the content by acquiring the MP4 file data 900 and performing the demultiplexing process sequentially reproduces (downloads) all the MP4 file data 900 distributed as a stream before the download is completed. Play).
[0038]
FIG. 26 is a block diagram showing the configuration of a conventional demultiplexer that reproduces content based on the MP4 file data 900.
[0039]
The demultiplexer 800 acquires and reproduces MP4 file data 900. The data acquisition unit 810 that acquires the MP4 file data 900 and the MP4 file data 900 acquired by the data acquisition unit 810 are reproduced. A decoding unit 813 that performs demultiplexing and decoding, a time processing unit 811 that performs temporal processing based on the acquired MP4 file data 900, and a process for randomly accessing the acquired MP4 file data 900 A random access processing unit 812 that performs the above and a reproduction unit 814 that outputs an image and sound based on the data output from the decoding unit 813.
[0040]
The time processing unit 811 includes a time length specifying unit 811a that specifies the time length required to play a part of content included in the MP4 file data 900, and a playback time specifying unit 811b that specifies the playback time. Here, the reproduction time refers to the time taken for reproduction from the reproduction start time to the present time when the content is reproduced from the beginning.
[0041]
FIG. 27 is a block diagram showing an internal configuration of the time length specifying unit 811a.
The time length specifying unit 811 a includes a first separation unit 821, a second separation unit 822, a third separation unit 823, a first analysis unit 824, and a second analysis unit 825.
[0042]
Upon obtaining the MP4 file data 900, the first separation unit 821 separates and outputs moov data from the MP4 file data 900.
[0043]
When obtaining the moov data, the second separation unit 822 separates and outputs the data (mvhd data) stored in the mvhd 911 and the data (trak data) stored in the trak 912 from the moov data.
[0044]
When the third separation unit 823 acquires the trak data, the third separation unit 823 separates and outputs the data (tkhd data) stored in the tkhd 914 from the trak data.
[0045]
When the first analysis unit 824 acquires mvhd data from the second separation unit 822, the first analysis unit 824 analyzes the mvhd data and outputs basic content time length information stored in the movie time length field 911a.
[0046]
When the second analysis unit 825 acquires the tkhd data from the third separation unit 823, the second analysis unit 825 analyzes the tkhd data, outputs the track identification information stored in the track ID field 916, and corresponds to the track identification information. Then, the basic track time length information stored in the track time length field 917 is output.
[0047]
The time length specifying unit 811a outputs basic content time length information to the playback unit 814, and also includes track identification information and basic track time length information corresponding to the track in the basic area 900a indicated by the track identification information. Is output to the playback unit 814.
[0048]
When the playback unit 814 acquires the basic content time length information, the track time length information, and the track identification information, the playback unit 814 displays the basic content time length or displays the basic track time length for each track as necessary. To do. Further, the playback unit 814 displays the playback time while playing back an image or sound based on the result of specification by the playback time specifying unit 811b.
[0049]
FIG. 28 is a configuration diagram showing the configuration of the random access processing unit 812.
When the random access processing unit 812 acquires target time information indicating the target time from the outside, the random access processing unit 812 searches the accumulated MP4 file data 900 for a sample corresponding to the target time as a target sample. The data storage unit 830a, the first separation unit 830, the second separation unit 831, the third separation unit 832, the fourth separation unit 835, the fifth separation unit 834, the first analysis unit 836, A second analysis unit 837, a third analysis unit 838, a track control unit 833, a determination unit 839, and a control unit 840. Here, the target time refers to a halfway playback start time when the user tries to play the content halfway. For example, when the user tries to reproduce the content with a total time length of 10 minutes without looking at the top 2 minutes, the target time is 2 minutes. The data storage unit 830a stores the MP4 file data 900 acquired by the data acquisition unit 810.
[0050]
When acquiring the MP4 file data 900 from the data storage unit 830a, the first separation unit 830 separates and outputs moov data and moof data from the MP4 file data 900.
[0051]
When acquiring the moov data, the third separation unit 832 separates and outputs the data (mvex data) stored in the mvex 913 from the moov data.
[0052]
When acquiring the moov data from the first separation unit 830, the track control unit 833 outputs track identification information based on the moov data.
[0053]
When the second separation unit 831 obtains the moof data from the first separation unit 830 and obtains the track identification information from the track control unit 833, the second separation unit 831 stores in the traf 932 corresponding to the track specified by the track identification information from the moof data. Separated data (traf data) is output.
[0054]
When the fourth separation unit 835 obtains the traf data from the second separation unit 831, the data stored in the tfhd 933 (tfhd data) and the data (trun data) stored in the run 936 are obtained from the traf data. Separate and output.
[0055]
When the fifth separation unit 834 obtains the mvex data from the third separation unit 832 and obtains the track identification information from the track control unit 833, the fifth separation unit 834 stores the mvex data in the trex 915 corresponding to the track specified by the track identification information. Separated data (trex data) is output.
[0056]
When acquiring the trex data from the fifth separation unit 834, the first analysis unit 836 analyzes the trex data and outputs the default sample time length information included in the trex data as the first time length information.
[0057]
When the second analysis unit 837 acquires the tfhd data from the fourth separation unit 835, the second analysis unit 837 analyzes the tfhd data and outputs the sample time length information included in the tfhd data as the second time length information.
[0058]
When the third analysis unit 838 acquires the run data from the fourth separation unit 835, the third analysis unit 838 analyzes the run data and outputs the sample time length information included in the run data as the third time length information.
[0059]
The determination unit 839 includes the first time length information acquired from the first analysis unit 836, the second time length information acquired from the second analysis unit 837, and the third time length information acquired from the third analysis unit 838. , Select one of them, and output it as time length information. Here, the determination unit 839 first gives priority to the third time length information. When the third time length information is omitted and cannot be obtained, the second time length information is given priority and the second time length information is given. If it is omitted and cannot be obtained, the first time length information is selected and output.
[0060]
Further, when outputting the time length information, the determination unit 839 also outputs sample identification information for identifying a sample corresponding to the time length information.
[0061]
When acquiring the target time information indicating the target time, the control unit 840 sequentially adds the time lengths indicated in the time length information sequentially output from the determination unit 839. The control unit 840 performs the addition until the addition result reaches the target time indicated by the target time information, and outputs the sample identification information acquired from the determination unit 839 when the target time is reached as the target sample identification information. To do.
[0062]
FIG. 29 is a block diagram showing the internal configuration of the track control unit 833.
The track control unit 833 acquires the moov data and separates the trak data therefrom, the sixth separation unit 841 acquires the trak data and further separates the tkhd data therefrom, and the tkhd And an analysis unit 843 that identifies the track identification information by analyzing the data and outputs the track identification information.
[0063]
FIG. 30 is an explanatory diagram for explaining a schematic operation of the random access processing unit 812.
[0064]
As shown in FIG. 30, the conventional random access processing unit 812 specifies a target sample corresponding to the target time by sequentially adding the sample time lengths.
[0065]
Then, the random access processing unit 812 outputs the MP4 file data 900 and the target sample identification information to the decoding unit 813, and reproduces the content from the target sample indicated by the target sample identification information by using the decoding unit 813 and the reproduction unit. 814.
[0066]
When the conventional demultiplexing apparatus 800 obtains the MP4 file data 900 distributed as a stream, the MP4 file data 900 can be downloaded and reproduced based on the acquired MP4 file data 900, and is stored by being provided with the random access processing unit 812. Random access to all the MP4 file data 900 is possible.
[0067]
[Non-Patent Document 1]
`` INTERNATIONAL ORGANIZATION FOR STANDARDISATION ORGANISATION INTERNATIONALE DE NORMALISATION ISO / IEC JTC1 / SC29 / WG11 CODING OF MOVING PICTURES AND AUDIO '', ISO / IEC JTC1 / SC29 / WG11, MPEG01 / N4270-1, 2001.1.20
[0068]
[Problems to be solved by the invention]
However, in the conventional demultiplexing apparatus 800, when the MP4 file data 900 is downloaded and played back, the entire length including the extended area 900b can be displayed even though the time length required for playing back the content contained in the basic area 900a can be displayed. There was a problem that the total time length of the contents of could not be displayed and it was not easy to use.
[0069]
FIG. 31 is an explanatory diagram for explaining a problem in the conventional demultiplexer 800.
[0070]
The demultiplexer 800 configured as a mobile phone downloads the MP4 file data 900 distributed as a stream via the base station 990, and sequentially plays back the downloaded MP4 file data 900. At this time, although the demultiplexer 800 displays the playback time, the time length required to play back all the contents cannot be specified unless all the MP4 file data 900 is acquired. The total time length of the content cannot be displayed during downloading or playback. For example, in the charge system charged according to the usage time, the user of the demultiplexing apparatus 800 is worried that the guide of the usage charge is not known, or when the remaining capacity of the battery is low, the power is cut off halfway. You may feel anxiety that you might end up. As described above, in the conventional demultiplexing apparatus 800, the user cannot know the total time length of the content and lacks convenience.
[0071]
Therefore, in view of such problems, the present invention has an object to provide a demultiplexing apparatus and a multiplexing apparatus that improve the convenience of content download and playback while maintaining the effectiveness of download playback and real-time recording. To do.
[0072]
[Means for Solving the Problems]
In order to achieve the above object, a demultiplexing apparatus according to the present invention is a demultiplexing apparatus that obtains demultiplexed data obtained by multiplexing content that is a digital work from its head and demultiplexes the multiplexed data. The multiplexed data includes a plurality of sets of a content storage box that stores a part of the multiplexed content and a related information storage box that stores related information related to the part of the content. Total time length information for specifying the total time length required for reproduction of all contents is configured to be included in the head portion, and the demultiplexer includes an acquisition unit that acquires the multiplexed data, A demultiplexing unit for each set of the multiplexed data acquired by the acquiring unit, and included in a head portion of the multiplexed data acquired by the acquiring unit. Based on the total time length information that comprises the a total time length specifying means for specifying the total length of time, and display means for displaying the total time length specified by the total time length specifying means. Here, the multiplexed data is composed of first and second areas each having the set, and the total time length information is a content indicating a time length required for reproducing the content included in the first area. The first time length information and second time length information indicating the time length required for playing the content included in the second region, and the total time length specifying means includes the The total time length may be specified by adding the time length indicated by the first time length information and the time length indicated by the second time length information.
[0073]
As a result, the multiplexed data is demultiplexed for each set by the processing means, so that the content can be downloaded and reproduced from the multiplexed data distributed as a stream, and included in the leading end of the multiplexed data. Since the total time length is specified by the total time length specifying means based on the total time length information and the total time length is displayed by the display means, it is possible to inform the user of the total time length even during download playback. Convenience at the time of download reproduction of can be improved.
[0074]
Further, the multiplexed data is composed of a first area or a second area having the set, respectively, according to the content included therein, and the multiplexed data is from the first area. When configured, the total time length information indicates a time length required for reproduction of the content included in the first area, and when the multiplexed data is composed of the first and second areas, the total time length information The time length information includes the first time length information indicating the time length required for reproducing the content included in the first area and the time length required for reproducing the content included in the second area, or Second time length information indicating that the time length is unknown, and the total time length specifying means is configured such that the multiplexed data acquired by the acquiring means is from the first area. It is configured Determining whether it is composed of the first and second areas, and when determining that it is composed of the first area, specify the time length indicated by the total time length information as the total time length, When it is determined that the first area is composed of the first and second areas, whether the time length required for reproducing the content included in the second area is unknown based on the second time length information. If it is determined that it is not unknown, the total time length is obtained by adding the time length indicated by the first time length information and the time length indicated by the second time length information. When it is determined that the total time length cannot be specified, the display means determines that the total time length cannot be specified by the total time length specifying means. ,in front It may be characterized in that the total length of time is to inform that it is the unknown.
[0075]
Thereby, if there is no second area in the multiplexed data, the time length required to play the content included in the first area is specified as the total time length, and the multiplexed data is identified from the first and second areas. When configured, the time length required for reproduction of the contents included in the first and second areas is added, and the addition result is specified as the total time length, so that the total time length is accurately specified. It is possible to determine whether or not the time length required for reproducing the content included in the second area is unknown based on the second time length information included in the multiplexed data. Since this is notified, only the reliable total time length can be notified to the user.
[0076]
The demultiplexing apparatus further includes a reproducing unit that reproduces the content that has been demultiplexed by the processing unit, and a reproduction time specifying unit that specifies a reproduction time during which the content is being reproduced by the reproducing unit. The display means calculates a ratio of the playback time specified by the playback time specifying means to the total time length specified by the total time length specifying means, and determines a predetermined figure according to the ratio It is good also as moving and displaying.
[0077]
As a result, the graphic moves in accordance with the ratio of the playback time to the total time length, so that the user can easily grasp the playback status of the content.
[0078]
The present invention relates to a data structure of multiplexed data handled by the demultiplexer, a storage medium for storing the multiplexed data, a multiplexer for generating the multiplexed data, the demultiplexer, The present invention can also be realized as a demultiplexing method and a multiplexing method performed by the multiplexing apparatus, and a program for causing a computer to execute the method.
[0079]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a demultiplexing apparatus and a multiplexing apparatus according to embodiments of the present invention will be described with reference to the drawings.
[0080]
FIG. 1 is a data configuration diagram showing a file format of MP4 file data handled by the demultiplexer and the multiplexer in the present embodiment.
[0081]
The MP4 file data 100 is composed of a basic area 100a and an extended area 100b, and is characterized in that content information indicating the total time length of contents included in the data 100 is stored in the basic area 100a. With this information, the user can know the total time length in the demultiplexer, and convenience is improved. In addition, a device that is difficult to give this information, such as a multiplexing device that records in real time, may be able to omit the information.
[0082]
The basic area 100a includes a media data box (hereinafter referred to as “mdat”) 120 in which multiplexed content is stored, and a movie box (hereinafter referred to as “moov”) in which information related to the content of the mdat 120 is stored. 110).
[0083]
The moov 110 further includes a movie header box (hereinafter referred to as “mvhd”) 111, a plurality of track boxes (hereinafter referred to as “trak”) 112, and a movie extend box (hereinafter referred to as “mvex”) 113. It consists of.
[0084]
The extension area 100b includes one media data box (hereinafter referred to as “mdat”) 140 that stores multiplexed content and one movie fragment box (hereinafter referred to as “mdat 140”) that stores information related to the content of the mdat 140. The group is composed of a combination of a plurality of pairs with each other (referred to as “moof”) 130. Here, like the conventional example, the moof 130 further includes one movie fragment header box (hereinafter referred to as “mfhd”) and a plurality of track fragment boxes (hereinafter referred to as “traf”). That is, such an extension region 100b has a structure similar to that of the conventional extension region 900b.
[0085]
The mvhd 111 in the moov 110 of the basic area 100a includes a movie time length field 111a for storing basic content time length information indicating the time length required to reproduce the content included in the basic area 100a (basic content time length). Yes.
[0086]
The trak 112 includes a track header box (hereinafter referred to as “tkhd”) 114. Here, the tkhd 114 includes a track ID field 116 for storing track identification information for identifying a track, and a time length (basic track time) required for reproducing a track in the basic area 100a indicated by the track identification information. And a track time length field 117 for storing basic track time length information indicating (length).
[0087]
The mvex 113 includes a number of track extend boxes (hereinafter referred to as “trex”) 115 corresponding to the number of tracks included in the extended area 100b, and further includes one movie extend header box (hereinafter “mhex”). 113a) is included.
[0088]
The mhex 113a includes a movie time length field 113b for storing extended content time length information indicating a time length (extended content time length) required for reproduction of the content included in the extended area 100b. Here, the extended content time length information may indicate “0”. In this case, the extended content time length information indicates that the extended content time length is unknown.
[0089]
The trex 115 includes a track ID field 118 for storing track identification information for identifying a track in the extension area 100b, and a time set by default for a sample of the track in the extension area 100b specified by the track identification information. A first default time length field 119 in which default sample time length information indicating the length is stored, and a content indicating a time length (extended track time length) required for reproduction of the track in the extended area 100b specified by the track identification information And a track time length field 115a in which extended track time length information is stored.
[0090]
That is, in the MP4 file data 100 of the present embodiment, the mvex 113a in which the extended content time length information is stored is included in the mvex 113, and the extended track time length information is stored in the trex 115 of the mvex 113, compared to the conventional example. The track time length field 115a is included.
[0091]
Note that the MP4 file data 100 may be composed of only the basic area 100a when the information amount of the content included therein is small. In this case, the move 110 movex 113 is omitted. FIG. 2 is a configuration diagram showing the configuration of the demultiplexing apparatus 200 according to the present embodiment that reproduces content based on the MP4 file data 100.
[0092]
The demultiplexer 200 acquires and reproduces the MP4 file data 100. The data acquisition unit 210 that sequentially acquires the MP4 file data 100 from the basic area 100a and the data acquisition unit 210 acquire the MP4 file data 100. Based on the MP4 file data 100 acquired by the data acquisition unit 210, a decoding unit 213 that sequentially demultiplexes and decodes the MP4 file data 100 for each set of moov 110 and mdat 120 and a set of moof 130 and mdat 140. Based on the data output from the decoding unit 213, the random access processing unit 212 that performs random access processing on the acquired MP4 file data 100, and the time processing unit 211 that performs general processing Is provided.
[0093]
The random access processing unit 212 stores all the MP4 file data 100 acquired by the data acquisition unit 210. When the target time information having the content indicating the target time is acquired from the outside, the random access processing unit 212 stores the MP4 file data 100 stored therein. A sample corresponding to the target time is searched as a target sample, and the playback of the content from the target sample is executed by the decoding unit 213 and the playback unit 214.
[0094]
In addition, the time processing unit 211 is based on the MP4 file data 100, a content time length specifying unit 211a that specifies the total time length required for reproduction of all the contents included therein, and all the tracks included in the MP4 file data 100. A track time length specifying unit 211b for specifying the time length required for playback for each track, and a playback time specifying unit 211c for specifying the playback time.
[0095]
FIG. 3 is a block diagram illustrating an internal configuration of the content time length specifying unit 211 a of the time processing unit 211.
[0096]
The content time length specifying unit 211a includes a first separation unit 221, a second separation unit 222, a third separation unit 224, a first analysis unit 223, a second analysis unit 225, and an addition unit 226. Yes.
[0097]
The first separation unit 221 acquires the MP4 file data 100, separates the data (moov data) stored in the moov 110 from the MP4 file data 100, and outputs the data.
[0098]
When obtaining the moov data, the second separation unit 222 separates and outputs the data (mvhd data) stored in the mvhd 111 and the data (mvex data) stored in the mvex 113 from the moov data.
[0099]
When the third separation unit 224 acquires the mvex data, the third separation unit 224 separates and outputs the data (mhex data) stored in the mhex 113a from the mvex data.
[0100]
When the first analysis unit 223 acquires the mvhd data from the second separation unit 222, the first analysis unit 223 analyzes the mvhd data and outputs basic content time length information stored in the movie time length field 111a.
[0101]
When the second analysis unit 225 acquires the mhex data from the third separation unit 224, the second analysis unit 225 analyzes the mhex data and outputs the extended content time length information stored in the movie time length field 113b.
[0102]
When the addition unit 226 acquires the basic content time length information and the extended content time length information from the first analysis unit 223 and the second analysis unit 225, the addition unit 226 and the basic content time length information indicated by the basic content time length information and the extended content time The extended content time length indicated by the length information is added, and content total time length information indicating the added time length (content total time length) is output. Further, when the extended content time length information indicates “0”, the adding unit 226 outputs the basic content time length information as the total content time length information.
[0103]
As described above, the content time length specifying unit 211a according to the present embodiment specifies the total time length of the content included in the basic area 100a and the extended area 100b of the MP4 file data 100 and indicates the total content time length. The total content time length information is output.
[0104]
FIG. 4 is a block diagram showing an internal configuration of the track time length specifying unit 211b of the time processing unit 211.
[0105]
The track time length specifying unit 211b includes a first separation unit 231, a second separation unit 232, a third separation unit 233, a fourth separation unit 235, a first analysis unit 234, a second analysis unit 236, And an adder 237.
[0106]
The first separation unit 231 acquires the MP4 file data 100, separates the moov data from the MP4 file data 100, and outputs it.
[0107]
When obtaining the moov data, the second separation unit 232 separates and outputs the data (trak data) stored in the trak 112 from the moov data and the mvex data.
[0108]
When the third separation unit 233 acquires the trak data, the third separation unit 233 separates and outputs the data (tkhd data) stored in the tkhd 114 from the trak data.
[0109]
When the first analysis unit 234 acquires the tkhd data from the third separation unit 233, the first analysis unit 234 analyzes the tkhd data and outputs the track identification information stored in the track ID field 116 of the tkhd 114. Further, the first analysis unit 234 extracts basic track time length information corresponding to the track specified by the track identification information from the track time length field 117 of the tkhd 114, and outputs this.
[0110]
When the fourth separation unit 235 acquires the mvex data from the second separation unit 232 and acquires the track identification information from the first analysis unit 234, the trex 115 corresponding to the track specified by the track identification information from the mvex data. The data (trex data) stored in is separated and output.
[0111]
When the second analysis unit 236 acquires the trex data from the fourth separation unit 235, the second analysis unit 236 analyzes the trex data and outputs the extended track time length information stored in the track time length field 115a.
[0112]
When the addition unit 237 acquires the basic track time length information from the first analysis unit 234 and acquires the extended track time length information from the second analysis unit 236, the time length indicated by the basic track time length information and the extended track time The time length indicated by the length information is added, and track total time length information indicating the added time length (track total time length) is output.
[0113]
As described above, the track time length specifying unit 211b according to the present embodiment specifies the total time length of tracks included in the basic area 100a and the extended area 100b of the MP4 file data 100 for each track, and indicates the track. The identification information and track total time length information indicating the total track time length of the track are output.
[0114]
FIG. 5 is a flowchart showing a characteristic operation of the content time length specifying unit 211a of the demultiplexing apparatus 200 in the present embodiment.
[0115]
First, the content time length specifying unit 211a acquires the MP4 file data 100 (step S200), analyzes the mvhd 111 of the data 100, and specifies the basic content time length T1 (step S202).
[0116]
Next, the content time length specifying unit 211a determines whether or not the mvex 113 is included in the moov 110 of the data 100 acquired in step S200 (step S204).
[0117]
Here, when the content time length specifying unit 211a detects the mvex 113 (Y in step S204), the content time length specifying unit 211a determines that the MP4 file data 100 includes the basic area 100a and the extended area 100b, and further includes the mvex 113. By analyzing the mhex 113a (step S206), it is determined whether or not the extended content time length information stored in the movie time length field 113b indicates “0” (step S208).
[0118]
When the content time length specifying unit 211a determines that the extended content time length information does not indicate “0” (N in Step S208), the content time length specifying unit 211a specifies the extended content time length T2 from the extended content time length information (Step S210). .
[0119]
Then, the content time length specifying unit 211a calculates the total content time length T by adding the basic content time length T1 and the extended content time length T2 (step S212), and displays the content total time length T. Content total time length information is output (step S214).
[0120]
On the other hand, when mvex 113 is not detected in step S204 (N in step S204), the content time length specifying unit 211a determines that the MP4 file data 100 is composed of the basic area 100a, and sets the basic content time length T1 as the content. Treated as the total time length T (step S220), the content total time length information is output (step S214).
[0121]
When it is determined in step S208 that the extended content time length information indicates “0” (Y in step S208), the content time length specifying unit 211a determines that the total content time length T cannot be calculated. Then, the total time length unknown information indicating that the total content time length T is unknown is output (step S218).
[0122]
Here, the playback unit 214 of the demultiplexing apparatus 200 according to the present embodiment outputs an image and audio based on the data from the decoding unit 213, and displays the playback time specified by the playback time specifying unit 211c. When the content total time length information is output from the content time length specifying unit 211a, the total content time length indicated by the total content time length information is displayed, and the total time length unknown information is output from the content time length specifying unit 211a. When it is done, it is notified that the total content time length is unknown.
[0123]
FIG. 6 is an image display diagram showing an image displayed by the reproduction unit 214 when the total content time length information is output.
The reproduction unit 214 displays a screen P1 for displaying a reproduction image. On the screen P1, a reproduction image display unit P2 that displays the reproduction image, a slider bar P3, an operation button P4, and a time display unit. P5 is displayed.
[0124]
In the time display part P5, the total content time length is displayed on the right side in the figure as “00:02:00”, for example, and the playback time is displayed on the left side in the figure as “00:00:30”, for example. Is displayed.
[0125]
The slider bar P3 slides on the line Ln1 from the left side to the right side in the drawing according to the ratio of the playback time to the total content time length.
[0126]
FIG. 7 is an image display diagram showing an image displayed by the playback unit 214 when the total time length unknown information is output.
[0127]
As described above, the playback unit 214 displays a screen P1 including a playback image display unit P2, a slider bar P3, an operation button P4, and a time display unit P5. On the right side of the time display unit P5 in FIG. A character or symbol indicating that the time length is unknown is displayed as, for example, “-:-:-”. In addition, the playback unit 214 displays the playback time on the right side of the time display unit P5 in the drawing, for example, “00:00:30”.
[0128]
For example, the slider bar P3 slides on the line Ln1 from the left end to the right side in the figure in accordance with the ratio of the playback time to a predetermined time. Repeat the slide.
[0129]
Further, when acquiring the track identification information and the track total time length information from the track time length specifying unit 211b, the playback unit 214 uses the track total time length information for each track indicated in the track identification information as necessary. Displays the total track length shown.
[0130]
As described above, the demultiplexing apparatus 200 according to the present embodiment can perform the download reproduction when the download of the MP4 file data 100 is started, and it is not necessary to complete the download of the MP4 file data 100. The total content time length can be displayed based on the total content time length information stored in the moov 110 of the MP4 file data 100, and convenience can be improved.
[0131]
Next, the multiplexing apparatus 300 that creates the MP4 file data 100 in this embodiment will be described.
[0132]
FIG. 8 is a configuration diagram showing a configuration of multiplexing apparatus 300 in the present embodiment. The multiplexing apparatus 300 according to the present embodiment includes an image data analysis unit 301, an audio data analysis unit 302, a first changeover switch 303, a second changeover switch 304, a control unit 308, and a moof generation unit 305. , A moov generation unit 306 and a file generation unit 307. The image data analysis unit 301 acquires image data and analyzes it to generate image specifying information having contents indicating a time stamp, a size, and the like of the image data. The image data analysis unit 301 then encodes the image data to create encoded image data, and outputs the encoded image data and image specifying information.
[0133]
The voice data analysis unit 302 acquires voice data and analyzes the voice data, thereby generating voice specifying information having contents indicating a time stamp, a size, and the like of the voice data. Then, the audio data analysis unit 302 generates audio encoded data by encoding the audio data, and outputs the audio encoded data and the audio specifying information.
[0134]
The moov generation unit 306 generates and outputs moov data in accordance with control from the control unit 308. Here, the moov generation unit 306 in the present embodiment creates the mhex 113a in the movex 113 of the moov data.
[0135]
The moof generation unit 305 generates and outputs moof data in accordance with the control from the control unit 308.
[0136]
The control unit 308 acquires the image specifying information from the image data analyzing unit 301 and the sound specifying information from the sound data analyzing unit 302. Based on the image specifying information and the sound specifying information, the control unit 308 By switching the second changeover switch 304, the data to be stored in the basic area 100a including the moov data is first output from the second changeover switch 304, and then the data to be stored in the extension area 100b including the moof data is output. Output.
[0137]
Here, when outputting the moov data from the moov generation unit 306, the control unit 308 in the present embodiment, first, the extended content time length information stored in the movie time length field 113b of the mhex 113a indicates “0”. The moov data is generated by the moov generation unit 306 and output.
[0138]
Then, the control unit 308 sequentially adds the time lengths of the samples stored in the extended area 100b of the encoded image data and the encoded audio data based on the image specifying information and the audio specifying information.
[0139]
Next, when the control unit 308 causes the moof data to be output from the moof generation unit 305 with respect to all of the input audio data and image data, the time length added as described above is set as the extended content time length. The extended content time length information indicating the length is output to the moov generation unit 306.
[0140]
Then, the moov output unit 306 that has acquired the extended content time length information from the control unit 308 determines the position information of the extended content time length information and the content indicating the position of the movie time length field 113b of the mhex 113a in which the information is stored. Are output to the file generation unit 307.
[0141]
When the file output unit 307 acquires the extended content time length information and the position specifying information from the moov generation unit 306, the file output unit 307 stores the acquired extended content time length information in the movie time length field 113b of the mhex 113a indicated by the position specifying information. Overwrite. That is, the file generation unit 307 changes the extended content time length information indicating “0” to the extended content time length information acquired later to complete the MP4 file data 100.
[0142]
FIG. 9 is a flowchart showing the operation of multiplexing apparatus 300 in the present embodiment.
First, the multiplexing apparatus 300 generates moov data including extended content time length information indicating “0” (step S300). That is, the multiplexing apparatus 300 first generates temporary moov data.
[0143]
Next, the multiplexing apparatus 300 creates moof data (step S302).
[0144]
Then, the multiplexing apparatus 300 determines whether or not there is unprocessed data for encoding and multiplexing of the input image data and audio data (step S304). Here, when it is determined that there is unprocessed data (Y in step S304), the operation from step S302 is repeatedly executed, and when it is determined that there is no unprocessed data (N in step S302), the sample time The extended content time length information based on the length addition result is overwritten on the moov data (step S306), and the process is terminated.
[0145]
The multiplexing apparatus 300 according to the present embodiment generates MP4 file data 100 configured such that a set of moov 110 and mdat 120 and at least a set of moof 130 and mdat 140 are connected in accordance with the amount of content information. Therefore, it is effective for real-time recording, and the extended content time length information required for improving the convenience of the demultiplexer 200 can be stored in the moov 110.
[0146]
FIG. 10 is a display diagram showing the syntax of trex.
Depending on the version, 32 bits or 64 bits are assigned to the track time length field 115a of trex 115, and 32 bits are assigned to the first default time length field 119. The time scale is indicated by mvhd111.
[0147]
In this embodiment, mhex 113a including the extended content time length information is stored in mvex 113 of MP4 file data 100. Instead of this mhex 113a, a box including the total content time length information (hereinafter referred to as “mehd”). ) May be stored.
[0148]
FIG. 11 is a block diagram illustrating an internal configuration of a content time length specifying unit that specifies the total content time length based on MP4 file data including mehd.
[0149]
The content time length specifying unit 211a ′ includes a first separation unit 211 ′, a second separation unit 222 ′, a third separation unit 224 ′, and an analysis unit 225 ′. The first separation unit 221 ′ acquires the MP4 file data, separates the moov data from the MP4 file data, and outputs it. When obtaining the moov data, the second separation unit 222 ′ separates and outputs the mvex data from the moov data. When acquiring the mvex data, the third separation unit 224 ′ separates and outputs the mehd data stored in the above-described mehd from the mvex data. When the analysis unit 225 ′ acquires the mehd data from the third separation unit 224 ′, the analysis unit 225 ′ analyzes the mehd data and outputs content total time length information.
[0150]
FIG. 12 is a flowchart showing a characteristic operation of the above-described content time length specifying unit 211a ′.
[0151]
First, the content time length specifying unit 211a ′ acquires the above-described MP4 file data (step S260), and determines whether or not mehd is included in the data (step S262).
[0152]
When the content time length specifying unit 211a ′ detects mehd (Y in step S262), the content time length specifying unit 211a ′ analyzes the mehd (step S264), and the content total time length information stored in mehd is “0”. Whether or not it is shown is determined (step S266).
[0153]
Then, when it is determined in step S266 that the total content time length information does not indicate “0” (N in step S266), the content time length specifying unit 211a ′ outputs the total content time length information (step S268). ). On the other hand, the content time length specifying unit 211a ′ determines that the data does not contain mehd in step S262 (N in step S262), or the content total time length information indicates “0” in step S266. Is determined (Y in step S266), it is determined that the total content time length cannot be specified (step S270), and the total time length unknown information indicating that the total content time length is unknown is output. (Step S272).
[0154]
In this way, by storing mehd in the MP4 file data instead of mhex 113a, the content time length specifying unit 211a ′ allows the content time length of the basic area 100a and the extended area 100b to specify the total content time length. By analyzing the mehd data without adding the time length of the content, it is possible to easily specify the total content time length.
[0155]
On the other hand, when the control unit 308 of the multiplexing apparatus 300 causes the moov generation unit 306 to generate moov data, first, the moov generation unit generates moov data whose total time length information stored in mehd indicates “0”. The time length of each sample stored in the basic area 100a and the extended area 100b of the image encoded data and the audio encoded data is sequentially added based on the image specifying information and the audio specifying information. When the control unit 308 causes the moof data to be output from the moof generation unit 305 for all of the input audio data and image data, the time length added as described above is set as the total content time length, and the time length Is output to the moov generation unit 306. As a result, the file generation unit 307 of the multiplexing apparatus 300 generates the MP4 file data 100 that stores the above-mentioned mehd.
[0156]
FIG. 13 is a display diagram showing the syntax of mehd.
Depending on the version, 32 bits or 64 bits are assigned to the movie time length field storing the total content time length information of mehd. For example, 32 bits are assigned when the version indicates 0, and 64 bits are assigned when the version indicates 1. The time scale is indicated by mvhd.
[0157]
The mhex 113a may have a syntax as shown in FIG.
[0158]
In the above embodiment, when the extended content time length information indicates “0”, the extended content time length is unknown, but the value may be, for example, a negative number other than “0”. .
[0159]
(Modification) Next, a modification of the demultiplexer 200 in the present embodiment will be described.
[0160]
The demultiplexing apparatus 200 described above handled MP4 file data having a basic area structure different from that of the conventional file format. However, the demultiplexing apparatus according to the present modification also has a conventional file format and an extended area structure. Handle different MP4 file data.
[0161]
FIG. 14 is a data configuration diagram showing a moof file format of MP4 file data handled by the demultiplexer according to the present modification.
[0162]
The moof 130 ′ is composed of one mfhd 131 and a plurality of trafs 132.
[0163]
The mfhd 131 includes an entry counter field 131a and a plurality of time length entry fields 131b. The time length entry field 131b further includes a track ID field 131c for storing track identification information for identifying a track, In the mdat 140 paired with the moof 130 ′, a moof time length field 131d for storing moof time length information indicating the time length (moof time length) of the track specified by the track identification information is formed.
[0164]
The traf 132 includes a single track fragment header box (hereinafter referred to as “tfhd”) 133 and a plurality of track fragment run boxes (hereinafter referred to as “trun”) 136, and the traf time length information is stored in tfhd 133. A stored traf time length field 135 and a second default time length field 134 in which default sample time length information is stored are included.
[0165]
The traf time length information stored in the traf time length field 135 indicates the sum of the time lengths of the samples (traf time length) indicated by the sample time length information included in the trun 136 of the traf 132, and the second default time length field 134 The stored default sample time length information indicates a time length set by default for the traf time length.
[0166]
FIG. 15 is a block diagram illustrating an internal configuration of a random access processing unit of the demultiplexing apparatus according to the present modification.
[0167]
The random access processing unit 400 can quickly search for a target sample with a smaller calculation amount than the conventional random access processing unit 812, and the MP4 file data 100 ′ having the moof 130 ′ shown in FIG. A data storage unit 401 for storing the data, a moof time length processing unit 420 for specifying the moof time length, a traf time length processing unit 430 for specifying the traf time length, a sample time length processing unit 440 for specifying the sample time length, The main control unit 410 controls these processing units.
[0168]
When the main control unit 410 acquires the MP4 file data 100 ′ and the target time information indicating the target time, the main control unit 410 analyzes the configuration of the MP4 file data 100 ′, and the moof time length processing unit 420 and the traf time length processing unit 430. And the sample time length processing unit 440, and the objective time sample according to the target time is obtained by integrating the moof time length, the traf time length, and the sample time length specified by each processing unit. Output sample identification information.
[0169]
FIG. 16 is a block diagram showing an internal configuration of the moof time length processing unit 420. The moof time length processing unit 420 includes a first separation unit 421, a second separation unit 423, a track control unit 422, and an analysis unit 424.
[0170]
When obtaining the MP4 file data 100 ′ having the moof 130 ′ in FIG. 14, the first separation unit 421 separates and outputs the moov data and the moof data from the MP4 file data 100 ′.
[0171]
When obtaining the moof data from the first separation unit 421, the second separation unit 423 separates the data (mfhd data) stored in the mfhd 131 from the moof data and outputs the separated data.
[0172]
When acquiring the moov data from the first separation unit 421, the track control unit 422 outputs track identification information based on the moov data.
[0173]
When the analysis unit 424 acquires the mfhd data from the second separation unit 423 and acquires the track identification information from the track control unit 422, the analysis unit 424 analyzes the mfhd data and uses the mfhd data to identify the track specified by the track identification information. The moof time length information is extracted and output.
[0174]
FIG. 17 is a block diagram illustrating an internal configuration of the traf time length processing unit 430.
The traf time length processing unit 430 includes a first separation unit 431, a second separation unit 433, a third separation unit 434, a track control unit 432, and an analysis unit 435.
[0175]
When acquiring the MP4 file data 100 ′, the first separation unit 431 separates and outputs moov data and moof data from the MP4 file data 100 ′.
[0176]
When the track control unit 432 obtains moov data from the first separation unit 431, the track control unit 432 outputs track identification information based on the moov data.
[0177]
When the second separation unit 433 obtains the moof data from the first separation unit 431 and obtains the track identification information from the track control unit 432, the second separation unit 433 analyzes the moof data and is specified by the track identification information from the moof data. The traf data corresponding to the track is separated and output.
[0178]
When the third separation unit 434 acquires the traf data from the second separation unit 433, the third separation unit 434 separates and outputs the tfhd data from the traf data.
[0179]
When the analysis unit 435 acquires the tfhd data from the third separation unit 434, the analysis unit 435 analyzes the tfhd data, extracts the traf time length information from the tfhd data, and outputs it.
[0180]
The sample time length processing unit 440 separates the run data for each track by performing a predetermined separation process from the MP4 file data 100 ′, and extracts and outputs the sample time length information from the run data.
[0181]
FIG. 18 is an explanatory diagram for explaining a schematic operation of the random access processing unit 400.
[0182]
FIG. 18A is a data configuration diagram showing a stream of MP4 file data 100 ′. Such a stream is configured in units of samples, and a flag indicating that seeking is possible (reading first) is included in the samples.
[0183]
FIG. 18B is a data configuration diagram showing the segment structure of the MP4 file data 100 ′.
[0184]
As described above, the file format of the MP4 file data 100 ′ includes the moov 110 and the moof 130 ′, and the moof 130 ′ includes the traf 132.
[0185]
The total content time length included in the MP4 file data 100 ′ is represented by the sum of the basic content time length A and the extended content time length B.
[0186]
Further, the extended content time length B is the moof time length C indicated by each moof 130 ′ of the extended area. ₁ , C ₂ , ..., expressed as the sum of moof time length C ₁ , C ₂ ,... Are the traf time length D indicated by each traf 132 in the respective moof 130 ′. ₁ , D ₂ It is expressed as the sum of.
[0187]
FIG. 18C is an explanatory diagram for explaining a seek operation of the random access processing unit 400.
[0188]
When the random access processing unit 400 acquires the target time information indicating the target time, first, the random content processing unit 400 adds the extended content time length B to the basic content time length A. If the addition result is equal to the target time, the random access processing unit 400 identifies the sample acquired at the end of the MP4 file data 100 ′ as the target sample, and outputs target sample identification information indicating the target sample.
[0189]
On the other hand, if the addition result exceeds the target time, the random access processing unit 400 determines the moof time length C for the basic content time length A. ₁ , C ₂ , ... are sequentially added along the time series. When the addition result becomes equal to the target time, the random access processing unit 400 specifies the last sample corresponding to the last added moof time length as the target sample, and outputs target sample identification information indicating the target sample. To do.
[0190]
When the addition result exceeds the target time, the random access processing unit 400 adds the traf time length D to the addition result immediately before the target time is exceeded. ₁ , D ₂ , ... are sequentially added along the time series. When the addition result becomes equal to the target time, the random access processing unit 400 identifies the last sample corresponding to the last added traf time length as the target sample, and outputs target sample identification information indicating the sample. .
[0191]
Further, when the addition result exceeds the target time, the random access processing unit 400 adds the sample time length E to the addition result immediately before the target time is exceeded. ₁ , E ₂ , ... are sequentially added along the time series. Here, when the addition result becomes equal to the target time, the random access processing unit identifies the sample corresponding to the last added sample time length as the target sample, and outputs target sample identification information indicating the target sample. To do.
[0192]
FIG. 19 is a flowchart showing the operation of the random access processing unit 400.
First, the random access processing unit 400 adds the extended content time length B to the basic content time length A, and determines whether or not the addition result is equal to the target time X (step S400).
[0193]
As a result of the determination, when it is determined that they are equal (Y in step S400), the random access processing unit 400 determines that the target sample is a sample at the end of the MP4 file data (step S402).
[0194]
When it is determined that they are not equal (N in step S400), the random access processing unit 400 first sets the variable N to N = 1 (step S404), and then sets the basic content time length A and the moof time length C. _n Is used to calculate the time length a by the following formula (step S406).
[Expression 1]

[0195]
Here, the random access processing unit 400 determines whether or not the time length a is equal to the target time X (step S408). If it is determined that the time length is equal (Y in step S408), the target sample is the moof time length C. _N It is determined that it is the last sample corresponding to (step S410).
[0196]
When the random access processing unit 400 determines that the time length a is not equal to the target time X (N in step S408), the random access processing unit 400 further determines whether the time length a is larger than the target time X (step S408). S412).
[0197]
When it is determined that the time length a is not greater than the target time X (N in Step S412), the random access processing unit 400 sets N = N + 1 (Step S414) and repeats the operation from Step S406. Note that the above formulas are the basic content time length A and moof time length C. ₁ ~ C _N The random access processing unit 400 does not execute all the addition processing of the above formulas every time N increases, temporarily stores the addition processing result, and N increases by 1. C corresponding to N _N Is further added to the stored addition processing result to find the solution of the above formula.
[0198]
When it is determined that the time length a is larger than the target time X (Y in step S412), the random access processing unit 400 first sets the variable M to M = 1 (step S416), and sets the basic content time length A and moof. Time length C _n And traf time length D _m Is used to calculate the time length b by the following formula (step S417).
[Expression 2]

[0199]
Here, the random access processing unit 400 determines whether or not the time length b is equal to the target time X (step S418). When it is determined that they are equal (Y in step S418), the target sample is the traf time length D. _M It is determined that it is the last sample corresponding to (step S420).
[0200]
When the random access processing unit 400 determines that the time length b is not equal to the target time X (N in step S418), the random access processing unit 400 further determines whether the time length b is greater than the target time X (step S418). S422).
[0201]
When it is determined that the time length b is not greater than the target time X (N in Step S422), the random access processing unit 400 sets M = M + 1 (Step S424) and repeats the operations from Step S417. When it is determined that the time length b is greater than the target time X (Y in step S422), the random access processing unit 400 first sets the variable L to L = 1 (step S426), and sets the basic content time length A, moof. Time length C _n , Traf time length D _m , Sample time E _l Is used to calculate the time length c according to the following equation (step S428).
[Equation 3]

[0202]
Here, the random access processing unit 400 determines whether or not the time length c is equal to the target time X (step S430). When it is determined that the time length c is equal (Y in step S430), the target sample is the sample time length E. _L It is determined that the sample corresponds to (step S432).
[0203]
When the random access processing unit 400 determines that the time length c is not equal to the target time X (N in step S430), the random access processing unit 400 further determines whether the time length c is larger than the target time X (step S430). S434).
[0204]
When it is determined that the time length c is not greater than the target time X (N in Step S434), the random access processing unit 400 sets L = L + 1 (Step S436) and repeats the operations from Step S428. When it is determined that the time length c is larger than the target time X (Y in step S), the random access processing unit 400 determines that an error has occurred (step S438).
[0205]
Then, after the target sample is identified in step S402, step S410, step S420, or step S432, the random access processing unit 400 outputs target sample identification information indicating the target sample (step S440).
[0206]
As described above, in the present modification, the mof time length field 131d for storing the moof time length information is provided in the mfhd 131 of the moof 130 ′ of the extension area, and the traf time length field 135 for storing the traf time length information is further provided in the tfhd 133. In addition, when searching for a target sample from the target time during random access, first, the extended content time length is used, then the moof time length shorter than the extended content time length is used, and then the moof time length is shorter. Since the traf time length is used and, finally, a sample time length shorter than the traf time length is used, the amount of calculation is reduced compared with the operation of the conventional random access processing unit 812 shown in FIG. Can find out.
[0207]
Then, the random access processing unit 400 outputs the MP4 file data 100 ′ and the target sample identification information to the decoding unit 213, and reproduces the content from the target sample indicated by the target sample identification information. This is executed by the unit 214.
[0208]
FIG. 20 is a display diagram illustrating the syntax of tfhd133.
As shown in FIG. 20, for example, 32 bits are assigned to the traf time length field 135 of the traf 132.
[0209]
The main control unit 410 of the random access processing unit 400 determines the output status of the moof time length information from the moof time length processing unit 420 and the validity of the moof time length indicated by the moof time length information. When trying to use the moof time length, if the moof time length information is not output, or if it is determined that the moof time length is not valid, all the time stored in the trof time length processing unit 430 in the moof 130 ′ It is also possible to output the traf time length information and use the sum of these traf time lengths instead of the moof time length. Further, the main control unit 410 of the random access processing unit 400 determines the output status of the traf time length information from the traf time length processing unit 430 and the validity of the traf time length indicated by the traf time length information. When trying to use the traf time length, when the traf time length information is not output or when it is determined that the traf time length is not valid, all the samples stored in the traf 132 in the sample time length processing unit 440 Time length information may be output, and the sum of these sample time lengths may be used instead of the traf time length.
[0210]
In the above modification, each sample includes a flag indicating whether or not seek is possible. However, one flag is included for a plurality of samples corresponding to moof130, or a plurality of samples corresponding to traf132 is included. One flag may be included. Thereby, the process of checking the flag for each sample can be omitted.
[0211]
【The invention's effect】
As is clear from the above description, according to the demultiplexing apparatus according to the present invention, since the multiplexed data is demultiplexed for each set by the processing means, the content is obtained from the multiplexed data distributed as a stream. Can be downloaded and reproduced, and the total time length is specified by the total time length specifying means based on the total time length information included in the front end of the multiplexed data, and the total time length is displayed by the display means. Thus, the user can be notified of the total length of time even during download reproduction, and the convenience during content download reproduction can be improved. The demultiplexer according to the present invention is suitable for use in a personal computer or mobile phone that downloads and plays back MP4 file data, and the multiplexer according to the present invention is a multimedia data such as an image or sound. Is suitable for use in a digital video camera, a mobile phone with a recording function, or the like that creates and records MP4 file data.
[Brief description of the drawings]
FIG. 1 is a data configuration diagram showing a file format of MP4 file data handled by a demultiplexer and a multiplexer in an embodiment.
FIG. 2 is a configuration diagram showing a configuration of a demultiplexing device that performs playback based on MP4 file data as described above.
FIG. 3 is a block diagram showing an internal configuration of a content time length specifying unit of the time processing unit same as above.
FIG. 4 is a block diagram showing an internal configuration of a track time length specifying unit of the time processing unit same as above.
FIG. 5 is a flowchart showing a characteristic operation of a content time length specifying unit of the demultiplexing apparatus according to the above.
FIG. 6 is an image display diagram showing an image displayed by the reproduction unit of the demultiplexing device.
FIG. 7 is an image display diagram showing another image displayed by the reproduction unit of the demultiplexing device same as above.
FIG. 8 is a configuration diagram showing the configuration of the multiplexing device of the above.
FIG. 9 is a flowchart showing the operation of the multiplexing device of the above.
FIG. 10 is a display diagram showing the trex syntax of the above.
FIG. 11 is a block diagram showing an internal configuration of a content time length specifying unit that handles MP4 file data including mehd.
FIG. 12 is a flowchart showing the characteristic operation of the content time length specifying unit.
FIG. 13 is a display diagram showing the syntax of mehd.
FIG. 14 is a data configuration diagram showing a moof file format of MP4 file data handled by the demultiplexing apparatus according to the modified example;
FIG. 15 is a block diagram showing an internal configuration of a random access processing unit of a demultiplexer according to a modification of the above.
FIG. 16 is a block diagram showing an internal configuration of a moof time length processing unit according to a modification example;
FIG. 17 is a block diagram showing an internal configuration of a traf time length processing unit according to a modification example;
FIG. 18 is an explanatory diagram for explaining a schematic operation of a random access processing unit according to the modification example;
FIG. 19 is a flowchart showing an operation of a random access processing unit according to the modification.
FIG. 20 is a display diagram showing the syntax of tfhd according to the modified example.
FIG. 21 is a data configuration diagram showing a basic file format of MP4 file data in a conventional example.
FIG. 22 is a data configuration diagram showing a detailed configuration of moov.
FIG. 23 is a data configuration diagram showing a detailed configuration of a moof.
FIG. 24 is a block diagram showing a configuration of a conventional multiplexing apparatus that generates MP4 file data according to the above.
FIG. 25 is a flowchart showing an operation related to generation of moov data and moof data in the multiplexing apparatus of the above.
FIG. 26 is a configuration diagram showing a configuration of a conventional demultiplexer that performs playback based on MP4 file data.
FIG. 27 is a block diagram showing the internal configuration of the time length specifying unit.
FIG. 28 is a block diagram showing the configuration of the random access processing unit of the above.
FIG. 29 is a block diagram showing the internal configuration of the track control unit of the above.
FIG. 30 is an explanatory diagram for explaining a schematic operation of the random access processing unit same as above.
FIG. 31 is an explanatory diagram for explaining a problem in the conventional demultiplexing apparatus same as above.
[Explanation of symbols]
100 MP4 file data
100a Basic area
100b Extended area
110 moov
113a mhex
113b Movie duration field
120 mdat
130 moof
140 mdat
200 Demultiplexer
210 Data acquisition unit
211 Time processing section
211a Content time length specifying part
211b Track time length specifying part
211c Playback time specifying part
212 Random access processor
213 Decryption unit
214 Playback unit

Claims (7)

A demultiplexer that demultiplexes the multiplexed data obtained by multiplexing the content that is a digital work from its head,
The multiplexed data includes a plurality of sets of a content storage box that stores a part of the multiplexed content and a related information storage box that stores related information related to the part of the content. The total time length information for specifying the total time length required for playback of the video is configured to be included in the head portion, and the multiplexed data includes the first area according to the content included therein. Or composed of first and second regions each having the set,
When the multiplexed data is composed of a first area, the total time length information indicates a time length required for reproduction of content included in the first area,
When the multiplexed data is composed of the first and second areas, the total time length information includes first time length information having a content indicating a time length required for reproducing the content included in the first area. And a time length required for reproduction of all contents included in the first area and the second area, or second time length information indicating that the time length is unknown. And
The demultiplexer is:
Obtaining means for obtaining the multiplexed data;
Processing means for demultiplexing the multiplexed data acquired by the acquiring means for each set;
Total time length specifying means for specifying the total time length based on total time length information included in the head of the multiplexed data acquired by the acquisition means;
Display means for displaying the total time length specified by the total time length specifying means,
The total time length specifying means is:
Determining whether the multiplexed data acquired by the acquisition means is composed of a first area or a first area and a second area;
When it is determined that the first area is configured, the time length indicated by the total time length information is specified as the total time length,
When it is determined that the content is composed of the first and second regions, the reproduction of all the contents included in the first region and the second region is further performed based on the second time length information. Determine if the length of time it takes is unknown,
When it is determined that it is not unknown,
Identifying a time length indicated by said second time length information as the total time length,
When it is determined that it is unknown,
It is determined that the total time length cannot be specified,
The display means includes
When the total time length is determined not to be specified by the total time length specifying means, it is notified that the total time length is unknown. In the head portion of the multiplexed data, area specifying information indicating whether or not the multiplexed data is composed of first and second areas is included,
The total time length specifying unit is configured such that the multiplexed data acquired by the acquiring unit is configured from a first region or from first and second regions based on the region specifying information. The demultiplexing apparatus according to claim 1, further comprising:   The multiplexed data includes the multiplexed content divided into a plurality of components, element time length information indicating the element time length required for reproduction of each component, and a plurality of components Unit time length information indicating the unit time length required for playback of the constituent unit consisting of:
  The demultiplexer further comprises:
  When the target time information indicating a predetermined target time is acquired, the acquisition unit uses the unit time length indicated by the unit time length information in preference to the element time length indicated by the element time length information. Random access processing means for identifying a component corresponding to the target time indicated by the target time information from the acquired multiplexed data;
  Playback means for playing back content from the component specified by the random access processing means;
  The demultiplexing apparatus according to claim 1, further comprising:   The random access processing means includes:
  By first adding the unit time length of each structural unit, the structural element corresponding to the target time is searched,
  If there is no component corresponding to the target time, the component time corresponding to the target time is specified by further adding the element time length of each component to the addition result closest to the target time. Do
  The demultiplexer according to claim 3.   The random access processing means includes:
  Determining whether or not the content indicated by the unit time length information is a valid unit time length;
  When it is determined that the unit time length is not valid, the constituent element corresponding to the target time is specified using the element time length indicated by the element time length information.
  5. The demultiplexer according to claim 4, wherein A multiplexing device that multiplexes content that is a digital work and generates multiplexed data,
Obtaining means for obtaining the content;
Multiplexing means for multiplexing the content;
Time length information generating means for generating total time length information for specifying the total time length required for reproduction of the content based on the content acquired by the acquiring means;
The time further so that a plurality of sets of a content storage box for storing a part of the content multiplexed by the multiplexing means and a related information storage box for storing related information related to the part of content are connected. Data generation means for generating the multiplexed data so that the total time length information generated by the length information generation means is included in the head part,
The data generation means includes
According to the content included in the multiplexed data, the multiplexed data is composed of a first area or a first area and a second area respectively having the set,
The time length information generating means includes
When the multiplexed data is composed of a first area, the total time length information is generated as content indicating a time length required for reproduction of content included in the first area,
When the multiplexed data is composed of first and second areas, the total time length information includes first time length information that indicates the length of time required to reproduce the content included in the first area. And a time length required to reproduce all contents included in the first area and the second area, or second time length information indicating that the time length is unknown. A multiplexing device characterized by the above. The data generation means includes
7. The multiplexing apparatus according to claim 6, wherein the multiplexed data is generated by including area specifying information indicating whether or not the multiplexed data is composed of first and second areas at the head. .

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