JP3592186B2 - Data recording / reproducing device - Google Patents

Description

【００５９】
次に、データ記録再生装置の再生動作について説明する。
録再制御部１７では、記憶媒体１８から再生に必要なパケットが読み出され、再生バッファ１９に入力され、一時蓄積される。バッファコントロール部４３は、再生バッファ１９からの読み出しを制御する。読み出されたデータは、タイムスタンプパケットセレクト部２０でタイムスタンプパケットであるかどうかの識別が行われる。タイムスタンプパケットでなければ、データは出力部２２に入力され、出力部２２から再生データが出力される。もしタイムスタンプパケットであると識別された場合は、コントロール部４０のタイムスタンプ比較部４１でそのタイムスタンプの値が保持される。
【００６０】
再生カウンタ４２では、最初にきたタイムスタンプの値を初期値としてセットし、カウントをスタートする。再生カウンタ４２に初期値がセットされると、タイムスタンプ比較部４１からバッファコントロール部４３に読み出し要求が出される。その要求に対してバッファコントロール部４３から読み出し信号が再生バッファ１９へ出され、再生バッファ１９に蓄積されたデータがタイムスタンプパケットセレクト部２０を介して出力部２２に入力され、出力部２２から再生データが出力される。
【００６１】
次のタイムスタンプパケットが識別されると、同様に、そのタイムスタンプの値がタイムスタンプ比較部４１で保持される。タイムスタンプ比較部４１では、そのタイムスタンプの値（Ｔ）と再生カウンタ４２の値（Ｃ）を比較して、一致あるいはＴ＜Ｃであれば、バッファコントロール部４３に読み出し要求を出すとともに、再生カウンタ４２のカウント値をリセットする。バッファコントロール部４３では、再生バッファ１９へ読み出し要求を出し、再生バッファ１９から出力されたデータは、出力部２２から出力される。この装置の再生カウンタ４２は、２７ＭＨｚのクロックを使用する。
【００６２】
次に、本発明の第４の実施の形態を説明する。
第４の実施の形態では、パケットセレクト部１３でパケットをセレクトする際に、アダプテーションフィールドコントロールフラグとパケットのＰＣＲフラグによりＰＣＲパケットを識別するものである。
ＰＣＲの識別は、ＰＩＤからだけでなく、ＴＳパケットに存在するアダプテーションフィールドコントロールフラグとＰＣＲフラグを調べれば、ＰＣＲが存在するかどうかの識別が可能である。ＴＳの構造は、前記図１３に示されている。
【００６３】
本データ記録再生装置では、ＰＣＲパケットの識別をＰＩＤから行わず、アダプテーションフィールドコントロールフラグとＰＣＲフラグから行う。本データ記録再生装置のハード的構成は、第１乃至第３の実施の形態のデータ記録再生装置と同様である。
ＰＣＲの識別の手法は、パケットセレクト部１３でまず、ＴＳの中のアダプテーションフィールドコントロールフラグ（２ビット）の値が１１あるいは１０であるかを確認し、１１あるいは１０であれば、次にＰＣＲフラグ（１ビット）の確認を行う。もし１であれば、ＰＣＲを含むことを確認できる。上記以外であれば、ＰＣＲを含まないことを確認できる。
【００６４】
次に、本発明の第５の実施の形態を説明する。
第５の実施の形態に係るデータ記録再生装置の基本的な構成は、図１と同じであるためこの部分の説明を省略する。
第５の実施の形態では、パケット生成部１５が、一定時間が経過するとタイムスタンプパケットを生成し、コントロール部２１は、タイムスタンプセレクト部１３からタイムスタンプを取得し、再生カウンタ４２のカウント値と比較することでデータの送出タイミングを計るものである。
【００６５】
図１０は、本実施の形態のデータ記録再生装置のパケット生成部７０の構成を示すブロック図である。図４に示すパケット生成部３０と同一構成部分には同一符号を付している。
また、本実施の形態のデータ記録再生装置のコントロール部の構成は、図５に示すコントロール部４０と同一である。
図１０において、パケット生成部７０は、カウント値設定部７１、記録カウンタ３１、及びタイムスタンプパケット生成部３２を備えて構成される。
上記パケット生成部７０及びコントロール部４０（図５参照）は、それぞれ図３のパケット生成部１５及びコントロール部２１に置き換えて用いられる。
【００６６】
以下、上述のように構成されたデータ記録再生装置の動作を説明する。基本的な動作は第１の実施の形態のデータ記録再生装置と同様であるため説明を省略し、パケット生成部７０の動作について詳細に説明する。
まず、データ記録再生装置の記録動作について説明する。
第１の実施の形態のデータ記録再生装置と同様に、図３において、記録が開始されると、パケット生成部７０の記録カウンタ３１のカウント値がリセットされる。カウント値設定部７１には、予め決められたカウントがセットされている。
【００６７】
カウント値設定部７１では、記録カウンタ３１のカウント値が設定されたカウント値と一致しているか比較を行う。もし、カウント値が一致した場合は、パケット挿入部１６にトリガ信号を出力する。パケット挿入部１６にトリガ信号が入力されると、現在パケット挿入部１６から再録制御部１７に出力しているデータがパケットの切れ目であれば、記録カウンタ３１から現在出力されているカウント値を時刻情報とするタイムスタンプパケットを生成するようにカウント値設定部７１にトリガ信号を出す。
カウント値設定部７１では、上記トリガ信号により、記録カウンタ３１に現在のカウント値をタイムスタンプパケット生成部３２に出力するように指示を出す。その指示に従い、記録カウンタ３１は、タイムスタンプパケット生成部３２にカウント値を出力する。
【００６８】
タイムスタンプパケット生成部３２では、入力されたカウント値を情報とするタイムスタンプパケットが生成され、タイムスタンプパケットが生成されると、生成信号をパケット挿入部１６に入力する。パケット挿入部１６では、この生成信号をトリガとして、生成されたタイムスタンプパケットを再録制御部１７に転送し、そのタイムスタンプパケットを記録媒体１８に記録する。そして、再び記録バッファ１４に蓄積されているパケットを再録制御部１７に転送し、再録制御部１７は記録媒体１８にパケットを記録する。
【００６９】
次に、データ記録再生装置の再生動作について説明する。
録再制御部１７では、記録媒体１８から再生に必要なパケットが読み出され、再生バッファ１９に入力され、一時蓄積される。バッファコントロール部４３は、再生バッファ１９からの読み出しを制御する。読み出されたデータは、タイムスタンプパケットセレクト部２０によりタイムスタンプパケットであるかどうかの識別が行われる。タイムスタンプパケットでなければ、データは出力部２２に入力され、出力部２２から再生データが出力される。もしタイムスタンプパケットであると識別された場合は、タイムスタンプ比較部４１でそのタイムスタンプの値が保持される。
【００７０】
再生カウンタ４２では、最初のタイムスタンプパケットがきたとき、カウンタをリセットし、カウントをスタートする。再生カウンタがリセットされると、タイムスタンプ比較部４１からバッファコントロール部４３に読み出し要求が出される。その要求に対してバッファコントロール部４３から読み出し信号が再生バッファ１９に出力され、再生バッファ１９に蓄積されたデータがタイムスタンプパケットセレクト部２０を介して出力部２２に入力される。
【００７１】
次のタイムスタンプパケットが識別されると、そのタイムスタンプの値がタイムスタンプ比較部４１で保持される。タイムスタンプ比較部４１では、そのタイムスタンプの値（Ｔ）と再生カウンタ４２の値（Ｃ）を比較して、一致あるいはＴ＜Ｃであれば、バッファコントロール部４３に読み出し要求を出すとともに、再生カウンタ４２のカウント値をリセットする。バッファコントロール部４３では、再生バッファ１９へ読み出し要求を出し、再生バッファ１９から出力されたデータは、出力部２２から出力される。
【００７２】
次に、本発明の第６の実施の形態を説明する。
第６の実施の形態では、コントロール部２１において取得したタイムスタンプより再生カウンタ４２から出力されるカウント値が小さい場合、カウント値がタイムスタンプと等しくなるまでダミーデータを出力するようにコントロールを行うダミーデータ挿入手段を有するものである。
【００７３】
図１１は、本発明の第６の実施の形態のデータ記録再生装置の構成を示すブロック図である。本実施の形態の説明にあたり図３と同一構成部分には同一番号を付して重複部分の説明を省略する。
図１１において、データ記録再生装置８０は、タイムスタンプパケットセレクト部２０及びコントロール部２１と出力部２２との間に、ダミーデータ生成部８１及び出力切換部８２からなるダミーデータ挿入部８３（ダミーデータ挿入手段）を備えて構成される。
【００７４】
記録の方法については、第１乃至第５の実施の形態のデータ記録生装置と同様であるため説明を省略する。
再生の方法は、タイムスタンプ比較部４１でタイムスタンプを取得するところまでは第１乃至第５の実施の形態と同様である。
【００７５】
タイムスタンプ比較部４１では、取得したタイムスタンプ（Ｔ）と再生カウンタから出力されるカウント値（Ｃ）を比較し、一致あるいはＴ＜Ｃであれば、第２の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出す。また、第３又は第５の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出すとともに、再生カウンタ４２のカウント値をリセットする。もしＴ＞Ｃであれば、ダミーデータ生成部８１にダミーデータを生成するように指示を出すとともに、出力切換部８２にダミーデータ生成部８１で生成されたデータを出力するように指示を出す。出力切換部８２では、その指示に従いデータ出力し、出力部２２が再生データを出力する。タイムスタンプ比較部４１で、Ｔ＝ＣあるいはＴ＞Ｃとなったら、第２の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出す。また、第３又は第５の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出すとともに、再生カウンタ４２のカウント値をリセットする。また同時に、出力切換部８２に出力するデータをタイムスタンプセレクト部２０から出力されたデータに切り換えるように指示を出す。その指示に従い、出力切換部８２は、出力部２２に出力するデータを切り換える。
【００７６】
次に、本発明の第７の実施の形態を説明する。
第７の実施の形態に係るデータ記録再生装置の基本的な構成は、第６の実施の形態の図１１と同じであるため、図１１を用いて説明する。
第７の実施の形態では、コントロール部２１は、取得したタイムスタンプより再生カウンタから出力されるカウント値が小さい場合、カウント値がタイムスタンプと等しくなるまでに、トランスポートストリームパケットを挿入可能な数を算出し、その数だけダミーデータパケットを生成し、出力をコントロールするダミーデータ挿入手段を有するものである。
記録の方法は、第６の実施の形態のデータ記録生装置と同様であるため省略する。
【００７７】
再生の方法は、タイムスタンプ比較部４１でタイムスタンプを取得するところまでは第１乃至第５の実施の形態と同様である。タイムスタンプ比較部４１では、取得したタイムスタンプ（Ｔ）と再生カウンタ４２から出力されるカウント値（Ｃ）を比較し、一致あるいはＴ＜Ｃであれば、第２の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出す。また、第３又は第５の実施の形態に適用する場合は、バッファコントロール部４３に読み出し要求を出すとともに、再生カウンタ４２のカウント値をリセットする。もしＴ＞Ｃであれば、その差を用いて次の再生データを出力するまでに、いくつＴＳパケットを挿入するか算出し、ダミーデータ生成部８１に生成するパケット数の指示を出すとともに、出力切換部８２に挿入するダミーデータパケットの数を指示する。
【００７８】
生成するダミーデータパケットの算出の一例について説明する。記録カウンタ３１、再生カウンタ４２で使用するクロックは、システムクロックを用いる。ここで、システムクロック＝再生のビットレートの３倍、Ｔ＝０ｘ２７８、Ｃ＝０ｘ４４であったとする。
【００７９】
タイムスタンプ比較部４１で、タイムスタンプ（Ｔ）と再生カウンタ４２から出力されるカウント値（Ｃ）の差（Ｔ−Ｃ）を求めると、その値が０ｘ２３４であることがわかる。これは、１０進数で表せば５６４である。この値を１８８で割ればシステムクロック上でのダミーパケット数が算出され、その値は５６４／１８８＝３となる。この値を再生ビットレートとシステムクロックの比率で割ることにより、再生ビットレートでのダミーパケット数となる。この値は、３／３＝１となり１パケット分のダミーデータを挿入すれば良いことになる。この操作をタイムスタンプパケットが到着するたびに行えば良い。
【００８０】
出力切換部８２では、ダミーデータ生成部８１からの指示に従い、指示されたパケット数データをダミーデータ生成部８１から入力し、そのデータを出力する。出力切換部８２で、指定されたパケット数データを出力すると、バッファコントロール部４３に読み出し要求を出す。また同時に、タイムスタンプ比較部４１に、指示されたパケット数出力したことを告知するトリガ信号を出力する。
【００８１】
タイムスタンプ比較部４１では、このトリガ信号により、第３又は第５の実施の形態に適用する場合は、再生カウンタのカウント値をリセットする。また同時に、出力切換部８２に出力するデータをタイムスタンプセレクト部２０から出力されたデータに切り換えるように指示を出す。その指示に従い、出力切換部８２は、出力部２２に出力するデータを切り換える。
【００８２】
なお、上記各実施の形態に係る表示装置を、上述したようなデジタル放送の電波を受信可能なデジタル放送受信機能を備えたテレビジョン受信機に適用することもできるが、記録装置の種類や記録方法等は限定されず、全ての装置に適用可能である。
また、上記各実施の形態では、番組としてデジタル放送番組を記録する例について説明したが、記録する番組は何でもよく、現行テレビ放送番組や、ラジオ放送番組等の音声番組であってもよい。
【００８３】
また、上記各実施の形態では、記録媒体は、データを記録できる記録媒体であればどのような装置でもよい。特に、データ転送速度やランダム・アクセス性能が高く、高速アクセスが可能なＨＤＤを記録媒体に用いれば、長時間記録した番組の中から所望の番組を瞬時に検索し、直ぐに利用することが可能になる。また、光磁気ディスク等ＨＤＤ以外の記録装置を用いてもよく、同様の効果を得ることができる。
【００８４】
また、上記各実施の形態では、ＭＰＥＧ２におけるトランスポートストリーム方式によって多重化されたＴＳデータから所望の番組データを受信して記録する場合を例に挙げたが、勿論これには限定されず、ＭＰＥＧストリームを用いるものであれば全ての装置（例えば、ＭＰＥＧ４，ＭＰＥＧ７レベルの規格に準拠する装置）に適用可能である。
【００８５】
また、上記各実施の形態では、本発明によるデータ記録再生装置をデータ記録機能とデータ再生機能を有するデータ記録再生装置に適用した場合を例に挙げたが、これに限らずデータ記録機能のみを有するデータ記録装置、データ再生機能のみを有するデータ再生装置にも適用することができる。
さらに、上記データ記録再生装置を構成する各回路部、例えば受信部、バッファ等の種類、数及び接続方法などは前述した各実施の形態に限られない。
【００８６】
【発明の効果】
以上、詳述したように、本発明によれば、ストリームのビットレートによらず、多重化データから任意のストリームを抽出し、共通の再生ストリーム送出速度を用いて、再生を行うことができる。具体的には、以下のような効果を得ることができる。
【００８７】
請求項１記載の発明によれば、再生時のデータ送出タイミングをストリームのビットレートによらず、タイムスタンプパケットの時刻に合わせるだけで良く、容易に送出タイミングを制御することができる。
請求項２記載の発明によれば、記録時にタイムスタンプパケットをＰＣＲパケットの直前に挿入し、再生時には、そのタイムスタンプの値を基に再生データの送出タイミングを調整しているため、ストリームのビットレートによらず、受信したタイミングでＰＣＲの送出が可能となり、多重化データから特定のデータを抜き出して記録しても、再生に支障をきたすことがなくなる効果を得ることができる。
【００８８】
請求項３記載の発明によれば、２つのＰＣＲの差分をタイムスタンプパケットの情報として用いるため、記録カウンタ５と再生カウンタ１３に必要なビット長が実際のＰＣＲより少なくて済む効果を得ることができる。
請求項４記載の発明によれば、特にＰＣＲのＰＩＤを指定することなくタイムスタンプパケットをＰＣＲパケットの直前に挿入することが可能であり、ＰＣＲのＰＩＤを知る必要がなくなる効果を得ることができる。
【００８９】
請求項５記載の発明によれば、ＰＣＲパケットによらず、一定時間間隔によりタイムスタンプパケットを挿入するため、データ放送などＰＣＲが存在しないストリームに関しても、送出間隔をコントロールすることができる。
請求項６又は７記載の発明によれば、再生時にデータを途切れさせることなく出力することができる。
【図面の簡単な説明】
【図１】本発明によるＰＣＲ値を用いた場合のパケット間隔復元方法の説明図である。
【図２】本発明によるシステムクロックを用いた場合のパケット間隔復元方法の説明図である。
【図３】本発明の第１実施の形態のデータ記録再生装置の構成を示すブロック図である。
【図４】本実施の形態のデータ記録再生装置のパケット生成部の構成を示すブロック図である。
【図５】本実施の形態のデータ記録再生装置のコントロール部の構成を示すブロック図である。
【図６】本実施の形態のデータ記録再生装置のタイムスタンプパケットの構成を示す図である。
【図７】本発明の第２実施の形態のデータ記録再生装置の受信データ、記録データ及び出力データを示す説明図である。
【図８】本発明の第３実施の形態のデータ記録再生装置のパケット生成部の構成を示すブロック図である。
【図９】本実施の形態のデータ記録再生装置のＰＣＲの構造を示す図である。
【図１０】本発明の第５実施の形態のデータ記録再生装置のパケット生成部の構成を示すブロック図である。
【図１１】本発明の第６の実施の形態のデータ記録再生装置の構成を示すブロック図である。
【図１２】ＭＰＥＧ２のトランスポートストリーム（ＴＳ）の構造を示す図である。
【図１３】従来のデータ記録再生装置の受信時と送信時のビットレートを一致させた場合の受信データ、記録データ及び送信データを示す説明図である。
【図１４】従来のデータ記録再生装置の受信時と送信時のビットレートを変化させた場合の受信データ、記録データ及び送信データを示す説明図である。
【符号の説明】
１０，８０ データ記録再生装置
１１ 受信部（受信手段）
１２ 同期検出部（同期検出手段）
１３ パケットセレクト部（パケット抽出手段）
１４ 記録バッファ
１５，３０，５０，７０ パケット生成部（パケット生成手段）
１６ パケット挿入部（パケット挿入手段）
１７ 録再制御部（録再制御手段）
１８ 記録媒体
１９ 再生バッファ
２０ タイムスタンプパケットセレクト部（タイムスタンプパケット抽出手段）
２１，４０ コントロール部（制御手段）
２２ 出力部（出力手段）
３０ とから構成される。
３１ 記録カウンタ
３２ タイムスタンプパケット生成部
４１ タイムスタンプ比較部
４２ 再生カウンタ
４３ バッファコントロール部
５１ ＰＣＲ取得部（ＰＣＲ取得手段）
５２ 前ＰＣＲ保持部（前ＰＣＲ保持手段）
５３ ＰＣＲ差分算出部（ＰＣＲ差分算出手段）
６１ ＰＣＲ＿ｂａｓｅ領域
６２ ＰＣＲ＿ｅｘｔｅｎｔｉｏｎ領域
６３ Ｓｔｕｆｆｉｎｇ領域
７１ カウント値設定部
８１ ダミーデータ生成部
８２ 出力切換部
８３ ダミーデータ挿入部（ダミーデータ挿入手段）
１００ タイムスタンプパケット[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data recording / reproducing apparatus for extracting and recording / reproducing one data from multiplexed data obtained by time-division multiplexing a plurality of data.
[0002]
[Prior art]
MPEG2 (international standard ISO / IEC13818-1) proposed by MPEG (Moving Picture Expert Group) is an encoding method for compressing digital video signals and digital audio signals.
MPEG2 employs a time division multiplexing method using packets. For example, when a video signal and an audio signal are multiplexed using this method, the video signal and the audio signal are divided into streams of appropriate length called packets, and the video signal packet and the audio signal packet are appropriately divided. Switch to time division transmission.
[0003]
Further, MPEG2 employs a multiplexing / demultiplexing method compatible with multiprogramming in order to realize transmission of a plurality of program data. For example, if this method is used, not only video signals and audio signals constituting one program data can be transmitted in a time-division manner, but also video signals and audio signals constituting a plurality of programs can be transmitted in a time-division manner.
[0004]
As one of such multiplexing / demultiplexing methods compatible with multiprogramming, there is a method called a transport stream. In this transport stream system, a PES packet (Packetized Elementary Stream Packet) is further divided into a plurality of packets, and a plurality of program data is transmitted in a time-division manner. Each packet is of fixed length and its length is relatively short, specifically 188 bytes. FIG. 12 is a diagram showing the structure of an MPEG2 transport stream (TS).
[0005]
Further, in order to receive and reproduce program data transmitted in a time-division manner using the transport stream (TS) method, an encoder provided in the transmitting device and a decoding device provided in the receiving device (reproducing device) are used. It is necessary to synchronize with the device. In the transport stream method, in order to synchronize between an encoder and a decoder, information for setting and calibrating a time reference called a PCR (Program Clock Reference) is transmitted. Synchronize between the encoder and the decoder based on the PCR.
[0006]
In order to synchronize the encoder and the decoder using the PCR, it is necessary to accurately manage the value of the PCR and the time at which the PCR arrives at the decoder. Specifically, the PCR is 6-byte data, and the decoder needs to set the value of the PCR in the decoder at the time when the last byte of the PCR arrives. Then, using the arrival time of the PCR and the value of the PCR, the decoder sets or calibrates an STC (System Time Clock: system synchronization signal) which is a reference of the decoding process and the reproduction process in the decoder.
[0007]
More specifically, the decoder has a PLL circuit (Phase Locked Loop circuit) in which a counter for outputting the STC is incorporated. The PLL circuit calculates the difference between the PCR value and the STC value each time the PCR arrives, converts the result into a control signal, and performs feedback control based on the control signal. Thereby, an STC that completely matches the arrival cycle of the PCR can be created, and synchronization between the encoder provided in the transmitting device and the decoder provided in the receiving device can be established with high accuracy. .
[0008]
By the way, there has been developed a technique for receiving multiplexed data transmitted using the multiplexing / demultiplexing method of the multiprogramming method as described above and recording the received multiplexed data. If such a technology is established, for example, a broadcasting station that provides digital satellite broadcasting services multiplexes a plurality of movies recorded by digital signals and transmits the multiplexed movies to each home. The recorded movie can be recorded as a digital signal.
Here, two methods have been proposed as a method of recording multiplexed data transmitted using the multiplexing / demultiplexing method of the multiprogramming method.
[0009]
A first method is to record all transmitted multiplexed data. In this method, since all of the multiplexed data is recorded, there is a problem that the data amount becomes large. In addition, even if unnecessary program data is included in a plurality of multiplexed program data, there is a problem that the unnecessary program data cannot be excluded.
[0010]
The second method is a method of extracting and recording one program data from the transmitted multiplexed data. If this method is adopted, only necessary program data can be recorded, and the data amount can be reduced. However, when the second method is adopted, there is a problem that when reproducing the recorded program data, the synchronization by the PCR is hindered.
[0011]
That is, even when the program data once recorded is reproduced, the STC of the reproducing device is set based on the reproduction time of the PCR and the value of the PCR, as in the case of receiving and reproducing the multiplexed data transmitted from the transmitting device. Or it needs to be calibrated. However, if one program data is extracted from the time-division multiplexed signal and recorded, the relationship between the PCR playback time and the PCR value is broken, and the STC of the playback device is set or set based on the PCR. There is a problem that calibration cannot be performed.
In order to solve these problems, the data recording method described in Japanese Patent Application Laid-Open No. 11-275524 discloses a method of recording and reproducing packet number data indicating the number of packets between extracted packets in extracting program data from multiplexed data. Is trying to solve the problem by referring to the numerical value and restoring the packet interval.
[0012]
[Problems to be solved by the invention]
However, in such a conventional data recording method, since the bit rate of the input data is not taken into consideration, there occurs a problem that data having different bit rates cannot be reproduced by a common reproducing apparatus.
This problem will be described with reference to FIGS.
[0013]
FIG. 13 is an explanatory diagram showing reception data, recording data, and transmission data when the bit rates at the time of reception and transmission are matched, and FIG. FIG. 4 is an explanatory diagram showing data, recording data, and transmission data.
Here, it is assumed that data having different bit rates are 27 Mbps (FIGS. 13 and 14) and 9 Mbps (FIG. 14). The 27 Mbps data is a stream in which one TS packet arrives approximately every 0.055 ms, and the 9 Mbps data is a stream in which one TS packet arrives approximately every 0.167 ms.
FIG. 13 shows an example in which only the program A is recorded from a TS stream having a bit rate of 27 Mbps in which three programs are multiplexed and transmitted at a bit rate of 27 Mbps using the conventional method.
[0014]
P in the figure represents one TS packet (188 bytes). The PCR value inside the packet P is the PCR value attached to the TS packet, and needs to match the STC value when the packet arrives at the multifunction peripheral. In the figure, a 27 Mbps clock represents a clock used in PCR or STC, and its interval is constant regardless of the bit rate of received data or transmitted data. The reception bit rate is the bit rate of the input stream. The program A is extracted from this multiplexed stream, and the number of packets between packets (in FIG. 13, the number of packets = 2) is counted and recorded to be recorded data. In the transmission data, the transmission interval of the stream is restored by inserting empty packets by the number of packets counted in the recording data.
[0015]
FIG. 14 shows an example in which only a program A is recorded from a TS stream having a bit rate of 9 Mbps in which three programs are multiplexed and transmitted at a bit rate of 27 Mbps using the conventional method. As in the case of FIG. 13, the program A is extracted from the stream, the number of packets between packets (the number of packets = 2 in FIG. 14) is counted and recorded, and the recorded data is the recorded data. By inserting empty packets for the number of packets counted therein, the transmission interval of the stream is restored. However, the transmission data in this case is not at the interval indicated by the PCR value.
[0016]
This is because the number of packets depends on the bit rate at the time of reception, and if the bit rate of the stream to be transmitted differs from that at the time of reception, the stream cannot be transmitted at the correct interval. As described above, one packet is about 0.167 ms for 9 Mbps data, and about 0.055 ms for 27 Mbps data. Since the interval between inserted packets differs depending on the bit rate at the time of reception, the time interval between packets cannot be restored from the number of inserted packets.
[0017]
As described above, when recording the number of packets between the extracted packets, it is necessary to control the bit rate of the transmission stream according to the bit rate of the reception stream. It is difficult to perform this on a device, and for example, it becomes impossible to reproduce data obtained by recording a CS broadcast or a BS digital broadcast using a common device. In addition, when encoding an analog broadcast and recording it digitally, in response to requests to change the bit rate and extend the recording time, the transmission bit rate of the playback stream must be changed for each bit rate. Must.
[0018]
The present invention has been made in view of such a problem, and it is an object of the present invention to extract an arbitrary stream from multiplexed data regardless of the bit rate of the stream and perform playback using a common playback stream transmission speed. It is an object of the present invention to provide a data recording / reproducing apparatus capable of performing the above.
[0019]
[Means for Solving the Problems]
The data recording / reproducing apparatus of the present invention includes: a receiving unit that receives desired program data from a plurality of program data; a synchronization detecting unit that detects a synchronization of a transport stream in the received MPEG; and a packet ID of the transport stream. Packet extracting means for identifying and extracting a specific packet, a recording buffer for storing the packet identified by the packet extracting means, and packet generating means for generating a time stamp packet using the arrival time of the specific packet as information Packet insertion means for inserting the time stamp packet generated by the packet generation means into the transport stream, a recording medium for recording the transport stream after the time stamp packet is inserted, and recording and reproduction of the recording medium Control the recording and playback control A stage, a reproduction buffer for storing reproduction data, a time stamp packet extracting means for identifying the time stamp packet from output data of the reproduction buffer, and obtaining a time stamp from the time stamp packet extracted by the time stamp extracting means. And control means for controlling reading of data from the reproduction buffer based on the time information of the time stamp, and output means for outputting data read from the reproduction buffer.
[0020]
Further, the packet insertion unit may insert the time stamp packet generated by the packet generation unit immediately before the specific packet. The specific packet extracted by the packet extracting means is a PCR packet, and the packet generating means counts a time stamp using a PCR identification signal output when the PCR packet is identified as a trigger. Having a counter, generating a packet using the count value from the reproduction counter as information, the control means acquires a time stamp from the time stamp extraction means, and compares the time stamp with the count value of the reproduction counter. By controlling the transmission timing of the PCR, at the time of reproduction, the transmission timing of the reproduction data is adjusted based on the value of the time stamp. Transmission is possible.
[0021]
The specific packet extracted by the packet extracting means is a PCR packet, and the packet generating means obtains the PCR when the PCR packet is extracted by the packet extracting means; A pre-PCR holding unit that holds a PCR packet that has arrived immediately before the packet, and a PCR that calculates a difference between a PCR value obtained by the PCR obtaining unit and a PCR value held by the pre-PCR holding unit. A packet having a difference calculated by the PCR difference calculating means as time information, the control means acquiring a time stamp from the time stamp extracting means, and counting the reproduction counter. By controlling the transmission timing of the PCR by comparing the For use the difference R as the information of the time stamp packet can be less than the bit length of the actual PCR required for recording counter and playback counter.
[0022]
Further, when the packet is extracted by the packet extracting means, a PCR packet is identified by an adaptation field control flag and a PCR flag of the packet, so that the time stamp packet can be extracted without specifying the PID of the PCR. It becomes possible to insert immediately before, and it is not necessary to know the PID of the PCR.
[0023]
Further, the packet generation means generates a time stamp packet after a predetermined time has elapsed, irrespective of the arrival time of the specific packet, and the control means obtains a time stamp from the time stamp extraction means and reproduces the time stamp packet. Since the data transmission timing is controlled by comparing with the count value of the counter, a time stamp packet is inserted at a fixed time interval regardless of the PCR packet. , The transmission interval can be controlled.
[0024]
Further, the packet generation means has a reproduction counter that counts a time stamp triggered by a PCR identification signal output when a PCR packet is identified, and generates a packet using the count value from the reproduction counter as information. Further, when the count value output from the reproduction counter is smaller than the acquired time stamp, the reproduction device includes dummy data insertion means for outputting dummy data until the count value becomes equal to the time stamp. Data can be output without interruption.
[0025]
Further, when the count value output from the reproduction counter is smaller than the acquired time stamp, the dummy data insertion means calculates the number of transport stream packets that can be inserted before the count value becomes equal to the time stamp. Since the dummy data packets are generated and output by the number thereof, the data can be output without interruption during reproduction.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a data recording / reproducing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
As an embodiment of the present invention, a data recording / reproducing apparatus according to the present invention extracts and records desired program data from multiplexed data in which a plurality of program data are time-division multiplexed by a transport stream system in MPEG2, The case where the recorded program data is reproduced will be described as an example.
[0027]
First, the basic concept of the present invention will be described.
The present invention makes it possible to extract an arbitrary stream from multiplexed data regardless of the bit rate of the stream by inserting a special packet (time stamp packet) for storing a PCR value. The PCR value indicates an absolute time at which a packet including the PCR value arrives at the decoder. Therefore, the packet interval can be restored regardless of the bit rate.
[0028]
FIG. 1 is an explanatory diagram of a packet interval restoring method using a PCR value according to the present invention. FIG. 1A shows reception data, recording data, and transmission data when transmitting at 27 MHz. b) shows transmission data when transmitted at 18 MHz.
In FIG. 1A, as in the case of FIG. 14, the received data is a TS stream having a reception bit rate of 9 Mbps in which three programs (program A, program B, and program C) are multiplexed. It is assumed that only the program A is extracted and recorded from among them, and transmitted at a common transmission bit rate (27 MHz in FIG. 1A) independent of the stream.
[0029]
When extracting program A from the received multiplexed stream, the PCR value added to program A (PCR value = 10 in FIG. 1) or the PCR difference value (PCR difference value = 10-1 in FIG. 1) The time stamp packet 100 holding 9) is inserted and recorded immediately before the packet including the PCR value.
When reproducing the recorded data, the PCR packet interval is restored with reference to the value in the time stamp packet 100. At this time, a clock counter similar to the STC of the decoder is referred to (27 MHz counter in FIG. 1), and the counter value is the PCR value in the time stamp packet 100 (PCR value = 10 in FIG. 1) or the PCR difference value. By transmitting the dummy data until the value matches (in FIG. 1, the PCR difference value = 10-1 = 9), the transmission interval of the stream can be restored.
[0030]
FIG. 1B shows an example in which the stream recorded in FIG. 1A is transmitted at a bit rate of 18 Mbps. Also in this case, the interval between the packet having the PCR value = 1 and the packet having the PCR value = 10 is constant.
Also, the PCR value may not be used as the value held in the time stamp packet 100, and the packet interval of the transmission data can be restored by using a clock that does not depend on the bit rate of the stream. This method will be described with reference to FIG.
[0031]
FIG. 2 is an explanatory diagram of a packet interval restoring method using a system clock according to the present invention.
As in the case of FIG. 1, the received data is a TS stream having a reception bit rate of 9 Mbps in which three programs (program A, program B, and program C) are multiplexed. It is assumed that only the program A is extracted and recorded from among them, and is transmitted at a common transmission bit rate (27 MHz in FIG. 2) independent of the stream. To maintain and restore the packet interval, a common system clock counter is used when receiving and transmitting the stream. This clock counter is a counter that changes at fixed intervals regardless of the bit rate.
[0032]
When the program A is extracted from the received multiplexed stream, the system clock value of the corresponding TS packet (system clock value = 14 in FIG. 2) or the system clock value of the TS packet including the PCR that appeared last time (FIG. 2). Then, the system clock value = 14-1 = 13) is inserted as a time stamp packet 100 immediately before the corresponding TS packet.
When reproducing the recorded data, the PCR packet interval is restored by referring to the value in the time stamp packet 100 and the clock counter. By sending the dummy data until the counter value matches the value in the time stamp packet 100 at the time of sending, the sending interval of the stream can be restored.
[0033]
FIG. 3 is a block diagram showing a configuration of the data recording / reproducing apparatus according to the first embodiment of the present invention. The data recording / reproducing apparatus according to the present embodiment can be applied to a television receiver having a digital broadcast receiving function capable of receiving digital broadcast radio waves.
[0034]
In FIG. 3, a data recording / reproducing apparatus 10 includes a receiving unit 11 (receiving means) for digitally receiving broadcast data, a synchronization detecting unit 12 (synchronous detecting means) for detecting synchronization of a received MPEG-2 transport stream, and an MPEG2 A packet selecting unit 13 (packet extracting means) for identifying a packet ID of the transport stream and selecting a specific packet; a recording buffer 14 for storing the packet identified by the packet selecting unit 13; A packet generating unit 15 (packet generating means) for generating a time stamp packet having the information as a packet, a packet inserting unit 16 (packet inserting means) for inserting the time stamp packet generated by the packet generating unit 15 into the MPEG2 transport stream. , MPEG after packet insertion A recording medium 18 for recording the transport stream, a recording / reproduction control unit 17 (recording / reproduction control means) for controlling recording / reproduction of the recording medium 18, a reproduction buffer 19 for storing reproduction data, A time stamp packet selecting unit 20 (time stamp packet extracting means) for identifying a time stamp packet, and a time stamp are obtained from the time stamp packet selected by the time stamp selecting unit 20, and reproduced based on the time information of the time stamp. It comprises a control unit 21 (control means) for controlling the reading of data from the buffer 19, and an output unit 22 (output means) for outputting the data read from the reproduction buffer 19.
[0035]
The receiving unit 11 selects a signal received at the input terminal and receives a broadcast program of a desired channel.
Upon receiving the recording command, the recording / reproduction control unit 17 controls the recording medium 18 to be in a recording state and records the program received by the receiving unit 11.
The recording medium 18 is for recording a signal selected by the recording / reproducing control unit 17, and is a disk such as a VTR (Video Tape Recorder), a hard disk drive (HDD), a VDP (Video Disc Player), and an MO (Magneto Optical). Device.
[0036]
Hereinafter, the operation of the data recording / reproducing apparatus configured as described above will be described.
First, the recording operation of the data recording / reproducing device 10 will be described.
The data recording / reproducing device 10 receives a broadcast television program such as a terrestrial wave, cable, BS, or CS. The broadcast television broadcast program is received by the receiving unit 11 as a signal including the received broadcast program. The receiving unit 1 receives digital broadcast data transferred from a broadcast station or the like. Here, the data received by the receiving unit 1 is an MPEG2 transport stream (hereinafter, referred to as TS). The TS has a configuration in which packets including data related to video and audio are multiplexed, and one packet is 188 bytes. Each packet is provided with an ID (hereinafter, referred to as a PID) for identifying data included in each packet.
[0037]
The PID is provided with a unique PID for each packet constituting each program. For example, PID = 0x11 for audio, PID = 0x31 for video, PID = 0x79 for additional data, PID = 0x20 for PCR, etc. . By identifying the PID, the viewer can select a desired program. The receiving unit 11 may be a device that receives an analog broadcast and encodes the received broadcast into an MPEG2 stream.
The received TS is synchronized by the synchronization detector 12 and input to the packet selector 13. The packet selecting unit 13 selects a packet having a PID constituting a program desired by the viewer.
[0038]
The packet selected by the packet selector 13 is input to the recording buffer 14 and is temporarily stored. The packet insertion unit 16 reads the packets stored in the recording buffer 14, and the read packets are recorded on the recording medium 18 by the recording / reproduction control unit 17. At this time, data read from the packet insertion unit 16 is performed in packet units. The packet generation unit 15 generates a packet using the data transmission time at the time of reproduction as information. When a generation signal is input from the packet generation unit 15, reading from the recording buffer 14 is temporarily stopped, and the generated time stamp packet is output to the recording / reproduction control unit 17. When the output of the time stamp packet is completed, the packet is read from the recording buffer 14 again. Then, the data is recorded on the recording medium 18 by the recording / reproduction control unit 17.
[0039]
Next, the reproducing operation of the data recording / reproducing device 10 will be described.
In the recording / reproducing control unit 17, packets necessary for reproduction are read from the recording medium 18 and temporarily stored in the reproduction buffer 19. The time stamp selecting unit 20 reads out the packet from the reproduction buffer 19 and, when identifying the time stamp packet, causes the controller unit 21 to hold the value of the time stamp. If the time of the clock in the control unit 21 matches the time of the time stamp, the packet is read from the reproduction buffer 19.
The read packet is output by the output unit 22. If the packet is not a time stamp packet, the packet is continuously read from the reproduction buffer 19 and output until the time stamp packet is identified.
[0040]
As described above, the data recording / reproducing apparatus 10 of the first embodiment identifies the packet ID of the MPEG2 transport stream and selects the PCR packet, and the recording buffer for storing the identified packet. 14, a packet generation unit 15 that generates a time stamp packet using the arrival time of a specific packet as information, a packet insertion unit 16 that inserts a time stamp packet into a transport stream, and records the transport stream after packet insertion. A recording medium 18 to be recorded, a recording / reproducing control unit 17 for controlling recording and reproduction of the recording medium 18, a time stamp packet selecting unit 20 for identifying a time stamp packet from output data of a reproduction buffer 19 for storing reproduction data, and Based on the time information of the time stamp A control unit 21 for controlling the reading of data from the raw buffer 19 and an output unit 22 for outputting the data read from the reproduction buffer 19 are provided. Streams can be extracted and playback can be performed using a common playback stream delivery rate.
[0041]
That is, in the conventional example, the number of packets between extracted packets in the multiplexed stream is stored, and dummy data corresponding to the number of packets is inserted during reproduction. Therefore, in order to restore the packet interval, the data must be output at a bit rate (clock) equal to the bit rate of the input data, and each stream needs to have a different output clock. On the other hand, in the present embodiment, a time stamp packet having the arrival time of the PCR packet as information is generated, inserted and recorded immediately before the PCR packet, and at the time of reproduction, based on the information of the time stamp packet. , And the transmission timing of the PCR. Since the time stamp is a numerical value that does not depend on the input / output bit rate, it is possible to restore the packet interval even at a bit rate different from the data bit rate of the input data. Of these, by setting the highest one as the transmission bit rate, it is possible to reproduce with a reproducing apparatus having a common output clock.
[0042]
Next, a second embodiment of the present invention will be described.
The basic configuration of the data recording / reproducing apparatus according to the second embodiment is the same as that shown in FIG. 1, and a description thereof will be omitted.
In the second embodiment, the packet generation unit 15 generates a packet whose count value is information by using a PCR identification signal output when the PCR selection unit 13 identifies a PCR packet as a trigger, and the control unit 21 The time stamp is obtained from the time stamp selecting unit 20 and is compared with the count value of the reproduction counter to measure the transmission timing of the PCR.
[0043]
FIG. 4 is a block diagram showing a configuration of the packet generation unit 30 of the data recording / reproducing apparatus of the present embodiment, and FIG. 5 is a block diagram showing a configuration of the control unit 40.
In FIG. 4, the packet generation unit 30 includes a recording counter 31 and a time stamp packet generation unit 32. 5, the control unit 40 includes a time stamp comparison unit 41, a reproduction counter 42, and a buffer control unit 43.
The packet generation unit 30 and the control unit 40 are used in place of the packet generation unit 15 and the control unit 21 of FIG. 3, respectively.
[0044]
Hereinafter, the operation of the data recording / reproducing apparatus configured as described above will be described. A description of parts that perform the same operations as those of the data recording / reproducing apparatus according to the first embodiment will be omitted, and only different operations will be described.
First, the recording operation of the data recording / reproducing device will be described.
As in the data recording / reproducing apparatus of the first embodiment, in FIG. 3, the packet selecting unit 13 selects the TS packets received by the receiving unit 11 and temporarily stores them in the recording buffer 14. At the same time, when a PCR packet (a packet with a PID of 0x20 in this embodiment) is identified, a PCR packet identification signal is output to the recording counter 31. The recording counter 31 starts counting from the start of recording and outputs a count value when the PCR packet identification signal is input. The time stamp packet generation unit 32 generates a time stamp packet using the count value as information. If a packet can be generated, a generation signal is output to the packet insertion unit 16. This information is used to measure data transfer timing during reproduction. The description of the reproduction method will be described later.
[0045]
The packet insertion unit 16 reads the packets stored in the recording buffer 14, and the read packets are recorded on the recording medium 18 by the recording / reproduction control unit 17. Data read from the packet insertion unit 16 is performed in packet units. When a generation signal is input from the time stamp packet generation unit 32, reading from the recording buffer 14 is temporarily suspended, and the generated time stamp packet is output to the recording / reproduction control unit 17, and when the output of the time stamp packet ends. The packet is read from the recording buffer again. At this time, the packet read from the packet insertion unit 16 is a PCR packet. That is, the time stamp packet is inserted immediately before the PCR packet. Then, the data is recorded on the recording medium 18 by the recording / reproduction control unit 17.
[0046]
Next, the reproducing operation of the data recording / reproducing apparatus will be described.
In the recording / reproducing control unit 17, packets necessary for reproduction are read from the recording medium 18, input to the reproduction buffer 19, and temporarily stored. The buffer control unit 43 controls reading from the reproduction buffer 19. The read data is identified by the time stamp packet selector 20 as to whether it is a time stamp packet. If the packet is not a time stamp packet, the data is input to the output unit 22 and the output unit 22 outputs reproduced data. If the packet is identified as a time stamp packet, the time stamp comparison unit 41 of the control unit 40 holds the value of the time stamp. The reproduction counter 42 sets the first time stamp value as an initial value and starts counting.
[0047]
When the initial value is set in the reproduction counter 42, a read request is issued from the time stamp comparing unit 41 to the buffer control unit 43. In response to the request, a read signal is output from the buffer control unit 43 to the reproduction buffer 19, and the data stored in the reproduction buffer 19 is input to the output unit 22 via the time stamp packet selection unit 20, and is reproduced from the output unit 22. Data is output.
[0048]
When the next time stamp packet is identified, the time stamp value is held in the time stamp comparing unit 41 in the same manner. The time stamp comparing unit 41 compares the value (T) of the time stamp with the value (C) of the reproduction counter 42, and if they match or T <C, issues a read request to the buffer control unit 43 and Data is output from the output unit 19, and reproduction data is output from the output unit 22.
[0049]
In this data recording / reproducing apparatus, it is necessary that the frequency of the clock for counting the recording counter 31 and the frequency of the reproduction counter 42 be equal. The clock to be used may be a 27 MHz clock used for the PCR of MPEG2, or another clock.
FIG. 6 shows an example of a packet generated by the time stamp packet generation unit 32.
[0050]
FIG. 6 is a diagram showing the structure of a time stamp packet, in which a flag is set in the most significant bit of the synchronization byte in order to distinguish a TS packet to be recorded from a time stamp packet.
The normal synchronization byte is 1 byte and is 0x47, but the synchronization byte attached to the time stamp packet is 0xC7. The time information output by the recording counter 31 from the byte next to the synchronization byte is stored. In FIG. 6, the time stamp is stored as 6-byte data as in the case of the PCR, but the time information may be within 187 bytes, and the data length may be determined so that the designer can easily design. Although FIG. 6 shows an example in which the most significant bit is flagged as the synchronization byte of the time stamp packet, various methods such as changing the PID or changing the header itself are conceivable. Although the packet is 188 bytes, the packet may not be of fixed length but may be of variable length as long as it can be confirmed that the packet is a time stamp packet.
[0051]
FIG. 7 is an explanatory diagram showing received data, recorded data, and output data of the data recording / reproducing apparatus, and shows a data receiving interval at the time of reception, a configuration of recorded data, and a data transfer interval at the time of reproduction.
When the user issues a recording instruction for program A, as shown in FIG. 7, only the TS packets constituting program A are recorded, and the TS packets of other programs are discarded. Then, at the time of reproduction, data is continuously output until the time stamp packet is identified. When the time stamp packet is identified, the output of the data is temporarily stopped. When the time stamp value and the counter value match, the next packet, that is, the PCR packet is transmitted. As is clear from FIG. 7, in the present data recording / reproducing apparatus, the output of the PCR packet can be performed at the same timing as the received data, so that the program reproduction is not hindered.
[0052]
Next, a third embodiment of the present invention will be described.
The basic configuration of the data recording / reproducing apparatus according to the third embodiment is the same as that of FIG.
In the third embodiment, when the PCR is selected by the packet selector 13, the packet generator 15 obtains the PCR, and holds the PCR that has arrived immediately before the PCR. The control unit 21 obtains a time stamp from the time stamp selecting unit 13 and compares it with the count value of the reproduction counter 42 to generate a packet using the difference between the two PCR values as time information. Is to be measured.
[0053]
FIG. 8 is a block diagram illustrating a configuration of the packet generation unit 50 of the data recording / reproducing device according to the present embodiment. The same components as those of the packet generation unit 30 shown in FIG.
The configuration of the control unit of the data recording / reproducing apparatus of the present embodiment is the same as the control unit 40 shown in FIG.
8, a packet generation unit 50 includes a PCR acquisition unit 51 (PCR acquisition unit), a pre-PCR holding unit 52 (pre-PCR holding unit), a PCR difference calculation unit 53 (PCR difference calculation unit), and a time stamp packet generation unit. 32.
The packet generation unit 50 and the control unit 40 (see FIG. 5) are used in place of the packet generation unit 15 and the control unit 21 in FIG. 3, respectively.
[0054]
Hereinafter, the operation of the data recording / reproducing apparatus configured as described above will be described. A description of parts that perform the same operations as those of the data recording / reproducing apparatus according to the first embodiment will be omitted, and only different operations will be described.
First, the recording operation of the data recording / reproducing device will be described.
As in the digital data recording / reproducing apparatus according to the first embodiment, in FIG. 3, the packet selecting unit 13 selects the TS packets received by the receiving unit 11, inputs the TS packets to the recording buffer 14, and temporarily stores them. . When the first PCR packet is identified by the packet selection unit 13, the PCR value is held by the PCR acquisition unit 51 of the packet generation unit 50.
[0055]
FIG. 9 is a diagram showing the structure of the PCR. As shown in this figure, the PCR is a 48-bit area in the option field of the TS, a 33-bit PCR_base area 61, a 9-bit PCR_extension area 62, and a 6-bit Stuffing area between the two areas. 63. The data in the PCR_base area 63 increases by 90 KHz, and the data in the PCR_extension area 61 increases by 1 in 27 MHz. The count up of the PCR value increases from 0 to 299 in units of 27 MHz in the PCR_extension area 61, and then the PCR_extension area 61 increases to 0 and the PCR_base area 63 increases by 1 at the same time.
[0056]
Returning to FIGS. 3 and 8, when PCR is acquired by the PCR acquisition unit 51, 0 is output from the PCR difference calculation unit 53 and is input to the time stamp packet generation unit 32. The time stamp packet generation unit 32 generates a new packet using the input data as information. The generated packet is inserted immediately before the PCR packet by the packet insertion unit 16 and recorded on the recording medium 18 by the recording / reproduction control unit 17. At the time of identifying the second and subsequent PCR packets, the previous PCR value (OP) held by the PCR acquisition unit 51 is held by the previous PCR holding unit 52, and the new PCR value (NP) is It is held by the acquisition unit 51.
[0057]
The PCR difference calculator 53 calculates the difference between the two PCRs. That is, the previous PCR value (OP) is subtracted from the new PCR value (NP) (NP-OP). The calculation result is input to the time stamp packet generation unit 32.
The time stamp packet generation unit 32 generates a time stamp packet using the input data as information, and inputs a packet generation signal to the packet insertion unit 16. When the generation signal is input, the packet insertion unit 16 inserts the generated packet immediately before the PCR packet, and transfers this packet to the recording / reproduction control unit 17. The recording / reproduction control unit 17 records the packet on the recording medium 18.
Here, the difference (NP-OP) calculated by the PCR difference calculation unit 53 is obtained by the following equation (1).
[0058]

[0059]
Next, the reproducing operation of the data recording / reproducing apparatus will be described.
In the recording / reproducing control unit 17, packets required for reproduction are read from the storage medium 18, input to the reproduction buffer 19, and temporarily stored. The buffer control unit 43 controls reading from the reproduction buffer 19. The read data is identified by the time stamp packet selector 20 as to whether it is a time stamp packet. If the packet is not a time stamp packet, the data is input to the output unit 22, and the output unit 22 outputs reproduced data. If the packet is identified as a time stamp packet, the time stamp comparison unit 41 of the control unit 40 holds the value of the time stamp.
[0060]
The reproduction counter 42 sets the first time stamp value as an initial value and starts counting. When the initial value is set in the reproduction counter 42, a read request is issued from the time stamp comparing unit 41 to the buffer control unit 43. In response to the request, a read signal is output from the buffer control unit 43 to the reproduction buffer 19, and the data stored in the reproduction buffer 19 is input to the output unit 22 via the time stamp packet selection unit 20, and is reproduced from the output unit 22. Data is output.
[0061]
When the next time stamp packet is identified, the time stamp value is held in the time stamp comparing unit 41 in the same manner. The time stamp comparing unit 41 compares the value (T) of the time stamp with the value (C) of the reproduction counter 42, and if they match or T <C, issues a read request to the buffer control unit 43 and performs reproduction. The count value of the counter 42 is reset. The buffer control unit 43 issues a read request to the reproduction buffer 19, and the data output from the reproduction buffer 19 is output from the output unit 22. The reproduction counter 42 of this device uses a clock of 27 MHz.
[0062]
Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, when a packet is selected by the packet selecting unit 13, a PCR packet is identified by an adaptation field control flag and a PCR flag of the packet.
The PCR can be identified not only by the PID but also by checking the adaptation field control flag and the PCR flag present in the TS packet to determine whether the PCR exists. The structure of the TS is shown in FIG.
[0063]
In the present data recording / reproducing apparatus, the identification of the PCR packet is not performed from the PID, but from the adaptation field control flag and the PCR flag. The hardware configuration of the data recording / reproducing apparatus is the same as that of the data recording / reproducing apparatuses of the first to third embodiments.
In the method of identifying the PCR, the packet selecting unit 13 first checks whether the value of the adaptation field control flag (2 bits) in the TS is 11 or 10, and if it is 11 or 10, then the PCR flag (1 bit) is confirmed. If 1, it can be confirmed that PCR is included. Otherwise, it can be confirmed that PCR is not included.
[0064]
Next, a fifth embodiment of the present invention will be described.
The basic configuration of the data recording / reproducing apparatus according to the fifth embodiment is the same as that of FIG.
In the fifth embodiment, the packet generation unit 15 generates a time stamp packet after a lapse of a predetermined time, the control unit 21 obtains a time stamp from the time stamp selection unit 13, The comparison is used to measure the data transmission timing.
[0065]
FIG. 10 is a block diagram illustrating a configuration of the packet generation unit 70 of the data recording / reproducing apparatus according to the present embodiment. The same components as those of the packet generation unit 30 shown in FIG.
The configuration of the control unit of the data recording / reproducing apparatus of the present embodiment is the same as the control unit 40 shown in FIG.
In FIG. 10, the packet generation unit 70 includes a count value setting unit 71, a recording counter 31, and a time stamp packet generation unit 32.
The packet generation unit 70 and the control unit 40 (see FIG. 5) are used in place of the packet generation unit 15 and the control unit 21 in FIG. 3, respectively.
[0066]
Hereinafter, the operation of the data recording / reproducing apparatus configured as described above will be described. Since the basic operation is the same as that of the data recording / reproducing apparatus of the first embodiment, the description is omitted, and the operation of the packet generation unit 70 will be described in detail.
First, the recording operation of the data recording / reproducing device will be described.
As in the data recording / reproducing apparatus according to the first embodiment, in FIG. 3, when recording is started, the count value of the recording counter 31 of the packet generation unit 70 is reset. A predetermined count is set in the count value setting section 71.
[0067]
The count value setting unit 71 compares the count value of the recording counter 31 with the set count value. If the count values match, a trigger signal is output to the packet insertion unit 16. When the trigger signal is input to the packet insertion unit 16, if the data currently output from the packet insertion unit 16 to the re-recording control unit 17 is a packet break, the count value currently output from the recording counter 31 is used. A trigger signal is issued to the count value setting unit 71 so as to generate a time stamp packet as time information.
In response to the trigger signal, the count value setting unit 71 instructs the recording counter 31 to output the current count value to the time stamp packet generation unit 32. According to the instruction, the recording counter 31 outputs the count value to the time stamp packet generation unit 32.
[0068]
The time stamp packet generation unit 32 generates a time stamp packet using the input count value as information, and when the time stamp packet is generated, inputs a generated signal to the packet insertion unit 16. The packet insertion unit 16 transfers the generated time stamp packet to the re-recording control unit 17 using the generated signal as a trigger, and records the time stamp packet on the recording medium 18. Then, the packets stored in the recording buffer 14 are transferred to the re-recording control unit 17 again, and the re-recording control unit 17 records the packets on the recording medium 18.
[0069]
Next, the reproducing operation of the data recording / reproducing apparatus will be described.
In the recording / reproducing control unit 17, packets necessary for reproduction are read from the recording medium 18, input to the reproduction buffer 19, and temporarily stored. The buffer control unit 43 controls reading from the reproduction buffer 19. The read data is identified by the time stamp packet selection unit 20 as to whether it is a time stamp packet. If the packet is not a time stamp packet, the data is input to the output unit 22, and the output unit 22 outputs reproduced data. If the packet is identified as a time stamp packet, the time stamp comparing unit 41 holds the value of the time stamp.
[0070]
When the first time stamp packet comes, the reproduction counter 42 resets the counter and starts counting. When the reproduction counter is reset, a read request is issued from the time stamp comparing unit 41 to the buffer control unit 43. In response to the request, a read signal is output from the buffer control unit 43 to the reproduction buffer 19, and the data stored in the reproduction buffer 19 is input to the output unit 22 via the time stamp packet selection unit 20.
[0071]
When the next time stamp packet is identified, the time stamp value is held in the time stamp comparing unit 41. The time stamp comparing unit 41 compares the value (T) of the time stamp with the value (C) of the reproduction counter 42, and if they match or T <C, issues a read request to the buffer control unit 43 and performs reproduction. The count value of the counter 42 is reset. The buffer control unit 43 issues a read request to the reproduction buffer 19, and the data output from the reproduction buffer 19 is output from the output unit 22.
[0072]
Next, a sixth embodiment of the present invention will be described.
In the sixth embodiment, when the count value output from the reproduction counter 42 is smaller than the time stamp obtained by the control unit 21, a dummy control that outputs dummy data until the count value becomes equal to the time stamp is performed. It has data insertion means.
[0073]
FIG. 11 is a block diagram showing a configuration of a data recording / reproducing apparatus according to the sixth embodiment of the present invention. In the description of the present embodiment, the same components as those in FIG. 3 are denoted by the same reference numerals, and the description of the overlapping portions will be omitted.
11, a data recording / reproducing device 80 includes a dummy data insertion unit 83 (dummy data) including a dummy data generation unit 81 and an output switching unit 82 between the time stamp packet selection unit 20 and the control unit 21 and the output unit 22. Insertion means).
[0074]
The recording method is the same as that of the data recording apparatus according to the first to fifth embodiments, and the description is omitted.
The reproduction method is the same as in the first to fifth embodiments up to the point where the time stamp is acquired by the time stamp comparison unit 41.
[0075]
The time stamp comparing unit 41 compares the obtained time stamp (T) with the count value (C) output from the reproduction counter, and if they match or T <C, the time stamp (T) is applied to the second embodiment. Sends a read request to the buffer controller 43. When applied to the third or fifth embodiment, a read request is issued to the buffer control unit 43 and the count value of the reproduction counter 42 is reset. If T> C, it instructs the dummy data generation unit 81 to generate dummy data, and instructs the output switching unit 82 to output the data generated by the dummy data generation unit 81. The output switching section 82 outputs data according to the instruction, and the output section 22 outputs reproduced data. When T = C or T> C is satisfied by the time stamp comparing unit 41, a read request is issued to the buffer control unit 43 when applying to the second embodiment. When applied to the third or fifth embodiment, a read request is issued to the buffer control unit 43 and the count value of the reproduction counter 42 is reset. At the same time, an instruction is issued to switch data output to the output switching unit 82 to data output from the time stamp selection unit 20. According to the instruction, the output switching unit 82 switches the data to be output to the output unit 22.
[0076]
Next, a seventh embodiment of the present invention will be described.
The basic configuration of the data recording / reproducing apparatus according to the seventh embodiment is the same as that of the sixth embodiment shown in FIG. 11, and will be described with reference to FIG.
In the seventh embodiment, when the count value output from the reproduction counter is smaller than the acquired time stamp, the control unit 21 determines the number of transport stream packets that can be inserted until the count value becomes equal to the time stamp. Is calculated, dummy data packets are generated by that number, and dummy data insertion means for controlling output is provided.
The recording method is the same as that of the data recording apparatus according to the sixth embodiment, and a description thereof will be omitted.
[0077]
The reproduction method is the same as in the first to fifth embodiments up to the point where the time stamp is acquired by the time stamp comparison unit 41. The time stamp comparing unit 41 compares the obtained time stamp (T) with the count value (C) output from the reproduction counter 42, and if they match or if T <C, the time stamp (T) is applied to the second embodiment. Sends a read request to the buffer control unit 43. When applied to the third or fifth embodiment, a read request is issued to the buffer control unit 43 and the count value of the reproduction counter 42 is reset. If T> C, the difference is used to calculate how many TS packets are to be inserted before outputting the next reproduced data. The number of dummy data packets to be inserted into the switching unit 82 is indicated.
[0078]
An example of calculation of a dummy data packet to be generated will be described. A clock used by the recording counter 31 and the reproduction counter 42 uses a system clock. Here, it is assumed that the system clock is three times the reproduction bit rate, T = 0x278, and C = 0x44.
[0079]
When the difference (TC) between the time stamp (T) and the count value (C) output from the reproduction counter 42 is obtained by the time stamp comparing unit 41, it is found that the value is 0x234. This is 564 in decimal notation. If this value is divided by 188, the number of dummy packets on the system clock is calculated, and the value is 564/188 = 3. By dividing this value by the ratio between the reproduction bit rate and the system clock, the number of dummy packets at the reproduction bit rate is obtained. This value becomes 3/3 = 1, which means that dummy data for one packet should be inserted. This operation may be performed each time a time stamp packet arrives.
[0080]
In accordance with the instruction from the dummy data generation unit 81, the output switching unit 82 inputs the instructed packet number data from the dummy data generation unit 81 and outputs the data. When the output switching unit 82 outputs the designated number-of-packets data, a read request is issued to the buffer control unit 43. At the same time, it outputs to the time stamp comparing section 41 a trigger signal notifying that the designated number of packets have been output.
[0081]
The time stamp comparing unit 41 resets the count value of the reproduction counter in response to the trigger signal when applied to the third or fifth embodiment. At the same time, an instruction is issued to switch data output to the output switching unit 82 to data output from the time stamp selection unit 20. According to the instruction, the output switching unit 82 switches the data to be output to the output unit 22.
[0082]
Note that the display device according to each of the above embodiments can be applied to a television receiver having a digital broadcast receiving function capable of receiving digital broadcast radio waves as described above. The method and the like are not limited, and can be applied to all devices.
Further, in each of the above-described embodiments, an example in which a digital broadcast program is recorded as a program has been described. However, the program to be recorded may be anything, and may be an existing TV broadcast program or an audio program such as a radio broadcast program.
[0083]
In each of the above embodiments, the recording medium may be any device as long as it can record data. In particular, if an HDD that has high data transfer speed and random access performance and allows high-speed access is used as a recording medium, it is possible to instantly search for a desired program from programs recorded for a long time and use it immediately. Become. Further, a recording device other than the HDD, such as a magneto-optical disk, may be used, and the same effect can be obtained.
[0084]
Further, in each of the above embodiments, the case where desired program data is received and recorded from TS data multiplexed by the transport stream method in MPEG2 has been described as an example, but it is needless to say that the present invention is not limited to this. The present invention can be applied to all devices using a stream (for example, devices conforming to the MPEG4 and MPEG7 level standards).
[0085]
Further, in each of the above embodiments, the case where the data recording / reproducing apparatus according to the present invention is applied to a data recording / reproducing apparatus having a data recording function and a data reproducing function has been described as an example. The present invention can also be applied to a data recording device having the data reproducing device having only the data reproducing function.
Further, the types, numbers, connection methods, and the like of the circuit units constituting the data recording / reproducing apparatus, for example, the receiving unit, the buffer, and the like are not limited to the above-described embodiments.
[0086]
【The invention's effect】
As described in detail above, according to the present invention, an arbitrary stream can be extracted from multiplexed data regardless of the bit rate of the stream, and can be reproduced using a common reproduction stream transmission speed. Specifically, the following effects can be obtained.
[0087]
According to the first aspect of the present invention, the data transmission timing at the time of reproduction need only be adjusted to the time of the time stamp packet regardless of the bit rate of the stream, and the transmission timing can be easily controlled.
According to the second aspect of the present invention, the time stamp packet is inserted immediately before the PCR packet at the time of recording, and at the time of reproduction, the transmission timing of the reproduction data is adjusted based on the time stamp value. Regardless of the rate, it becomes possible to transmit the PCR at the timing of reception, and even if specific data is extracted from the multiplexed data and recorded, it is possible to obtain an effect of not hindering reproduction.
[0088]
According to the third aspect of the invention, since the difference between the two PCRs is used as the information of the time stamp packet, the effect that the bit length required for the recording counter 5 and the reproduction counter 13 can be smaller than the actual PCR can be obtained. it can.
According to the fourth aspect of the invention, it is possible to insert the time stamp packet immediately before the PCR packet without specifying the PID of the PCR, and it is possible to obtain the effect of not having to know the PID of the PCR. .
[0089]
According to the fifth aspect of the present invention, since the time stamp packet is inserted at a fixed time interval regardless of the PCR packet, it is possible to control the transmission interval even for a stream such as a data broadcast where no PCR exists.
According to the invention of claim 6 or 7, data can be output without interruption during reproduction.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a packet interval restoring method using a PCR value according to the present invention.
FIG. 2 is an explanatory diagram of a packet interval restoring method when a system clock is used according to the present invention.
FIG. 3 is a block diagram illustrating a configuration of a data recording / reproducing device according to the first embodiment of the present invention.
FIG. 4 is a block diagram illustrating a configuration of a packet generation unit of the data recording / reproducing device of the present embodiment.
FIG. 5 is a block diagram showing a configuration of a control unit of the data recording / reproducing device of the present embodiment.
FIG. 6 is a diagram showing a configuration of a time stamp packet of the data recording / reproducing device of the present embodiment.
FIG. 7 is an explanatory diagram showing received data, recorded data, and output data of a data recording / reproducing device according to a second embodiment of the present invention.
FIG. 8 is a block diagram illustrating a configuration of a packet generator of a data recording / reproducing device according to a third embodiment of the present invention.
FIG. 9 is a diagram showing a structure of a PCR of the data recording / reproducing device of the present embodiment.
FIG. 10 is a block diagram illustrating a configuration of a packet generation unit of a data recording / reproducing device according to a fifth embodiment of the present invention.
FIG. 11 is a block diagram illustrating a configuration of a data recording / reproducing device according to a sixth embodiment of the present invention.
FIG. 12 is a diagram showing the structure of a transport stream (TS) of MPEG2.
FIG. 13 is an explanatory diagram showing reception data, recording data, and transmission data when the bit rates at the time of reception and the time of transmission of the conventional data recording / reproducing apparatus are matched.
FIG. 14 is an explanatory diagram showing reception data, recording data, and transmission data when the bit rate at the time of reception and the bit rate at the time of transmission of the conventional data recording / reproducing apparatus are changed.
[Explanation of symbols]
10,80 data recording / reproducing device
11 Receiving unit (receiving means)
12. Synchronization detection unit (synchronization detection means)
13. Packet Selector (Packet Extractor)
14 Recording buffer
15, 30, 50, 70 packet generator (packet generator)
16 packet insertion unit (packet insertion means)
17 Recording / playback control unit (recording / playback control means)
18 Recording media
19 Playback buffer
20 Time Stamp Packet Selector (Time Stamp Packet Extraction Unit)
21, 40 control unit (control means)
22 Output part (output means)
30.
31 Recording counter
32 Timestamp packet generator
41 Timestamp comparison section
42 Playback counter
43 Buffer control section
51 PCR Acquisition Unit (PCR Acquisition Means)
52 Pre-PCR holding section (Pre-PCR holding means)
53 PCR difference calculation unit (PCR difference calculation means)
61 PCR_base area
62 PCR_extension area
63 Stuffing area
71 Count value setting section
81 Dummy data generator
82 Output switching unit
83 Dummy Data Insertion Unit (Dummy Data Insertion Means)
100 time stamp packet

Claims (7)

Receiving means for receiving desired program data from a plurality of program data;
Synchronization detection means for detecting the synchronization of the received transport stream in MPEG;
Packet extraction means for identifying a packet ID of the transport stream and extracting a specific packet;
A recording buffer for storing a packet identified by the packet extracting means;
Packet generation means for generating a time stamp packet having the arrival time of the specific packet as information,
Packet insertion means for inserting the time stamp packet generated by the packet generation means into the transport stream;
A recording medium for recording the transport stream after inserting the time stamp packet,
Recording / reproducing control means for controlling recording and reproduction of the recording medium;
A playback buffer for storing playback data;
Time stamp packet extracting means for identifying the time stamp packet from output data of the reproduction buffer;
A control unit that obtains a time stamp from the time stamp packet extracted by the time stamp extraction unit, and controls reading of data from the reproduction buffer based on time information of the time stamp;
An output unit for outputting data read from the reproduction buffer. The specific packet extracted by the packet extracting means is a PCR (Program Clock Reference) packet,
The packet generation means has a reproduction counter that counts a time stamp by using a PCR identification signal output when the PCR packet is identified as a trigger, and generates a packet using the count value from the reproduction counter as information. ,
2. The data recording / reproducing apparatus according to claim 1, wherein the control unit controls the transmission timing of the PCR by acquiring a time stamp from the time stamp extracting unit and comparing the time stamp with a count value of the reproduction counter. . The specific packet extracted by the packet extracting means is a PCR packet,
The packet generation means, a PCR acquisition means for acquiring the PCR when a PCR packet is extracted by the packet extraction means,
Pre-PCR holding means for holding a PCR packet that has arrived immediately before the PCR packet;
A PCR difference calculating unit that calculates a difference between the PCR value obtained by the PCR obtaining unit and the PCR value held in the pre-PCR holding unit,
Generating a packet using the difference calculated by the PCR difference calculating means as time information;
The data according to claim 1, wherein the control unit obtains a time stamp from the time stamp extraction unit, and controls the transmission timing of the PCR by comparing the time stamp with a count value of the reproduction counter. 4. Recording and playback device. 4. The data recording / reproducing apparatus according to claim 1, wherein a packet is identified by an adaptation field control flag and a PCR flag of the packet when the packet extracting unit extracts the packet. The packet generating means generates a time stamp packet after a predetermined time has elapsed, irrespective of the arrival time of the specific packet,
2. The data recording / reproducing apparatus according to claim 1, wherein the control unit controls a data transmission timing by acquiring a time stamp from the time stamp extracting unit and comparing the time stamp with a count value of a reproduction counter. The packet generation means has a playback counter that counts a time stamp triggered by a PCR identification signal output when a PCR packet is identified, and generates a packet that uses the count value from the playback counter as information,
2. The apparatus according to claim 1, further comprising a dummy data inserting unit that outputs dummy data until the count value becomes equal to the time stamp when the count value output from the reproduction counter is smaller than the acquired time stamp. Data recording and playback device. When the count value output from the reproduction counter is smaller than the obtained time stamp, the dummy data insertion unit calculates the number of transport stream packets that can be inserted before the count value becomes equal to the time stamp. 7. The data recording / reproducing apparatus according to claim 6, wherein a number of dummy data packets are generated and output.

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