JP4616432B2 - Signal processing device - Google Patents

Description

但し、単位の（Ｂ）は（ＢＹＴＥ＝８ｂｉｔ）のことである。
【００２９】
撮像画面の画素数 Ｐｘ＝１２８０×１０２４ （画素）
輝度・色差データ Ｙｃ＝２×８ （ｂｉｔ）
フレームレート Ｆｘ＝３０ （ｆｒａｍｅ／秒）
画像データの圧縮率 Ｃｖ＝１
画像データの転送速度 Ｖｆ （Ｂ／秒）
また、音声データの転送速度Ｗｆは、サンプリングビット数をＡｘ＝１６（ｂｉｔ）、サンプリングレートをＳｘ＝４８（ｋＨｚ）、音声チャンネル数をＴｘ＝２（ｃｈ）、音声の圧縮率をＣｗ＝１とすると、以下の式（２）に示す値となる。
【００３０】
【数２】
Ｗｆ＝Ａｘ×Ｓｘ×Ｔｘ×Ｃｗ／８ （Ｂ／秒） …（２）
＝１６×４８０００×２×１／８
＝０．１９２ （ＭＢ／秒）
但し、サンプリングビット数 Ａｘ＝１６ （ｂｉｔ）
サンプリングレート Ｓｘ＝４８ （ｋＨｚ）
音声チャンネル数 Ｔｘ＝２ （ｃｈ）
音声の圧縮率 Ｃｗ＝１
音声データの転送速度 Ｗｆ
一般にパーソナルコンピュータ等で用いられているＵＳＢやＳＣＳＩに代表されるデータの転送手段を用いても、転送速度は１．５〜１０（ＭＢ／秒）程度であるので上記の連続した画像データを転送することはできない。従って、動画像を転送速度が遅い通信手段を用いて転送する場合には、圧縮・伸張処理部４０においてＭＰＥＧ等のデータ圧縮手法を用いてデータを圧縮制御して転送する手法が一般に採用されている。撮像信号処理部１６から読み出される画像データを例えば１／８に圧縮し、マルチプレクス３８から読み出される音声データを例えば１／２に圧縮したとすると、画像データと音声データとを合わせた合成データの転送速度ＶＷｆは以下に示す式（３）で表される。
【００３１】
【数３】

但し、画像データの転送速度 Ｖｆ （Ｂ／秒）
音声データの転送速度 Ｗｆ （Ｂ／秒）
合成データの転送速度 ＶＷｆ （Ｂ／秒）
上記のようにデータを圧縮することにより、１０（ＭＢ／秒）の転送速度を持つ通信手段で画像データと音声データの転送を行うことが可能となる。また、記録媒体４２に画像データと音声データを記録する場合には、記録媒体の転送速度に応じた転送速度となるようにデータの圧縮率を入力手段２６から入力して設定してもよい。このように圧縮された画像データのヘッダー部には、再生時に伸張するときのパラメータとなる圧縮率情報やＹＣまたはＲＧＢ等のデータの情報が記録されているので、伸張時には画像データと音声データが正しく展開される。
【００３２】
上記の説明のとおり、通信の転送速度や記録媒体４２に対するデータの転送速度が撮影時に生成されるデータの量よりも少ない場合には、何らかの手法を用いてデータの量を減少する必要がある。従来は予め定められた記録媒体の転送速度に対応したデータの生成量となる撮影しか許可されていなかったが、本発明によれば、データの転送速度に応じてデータの量を自動で変更することが可能であるので、限られたデータの転送速度の中で最大の画像データを記録または転送することが可能となる。
【００３３】
図２は、本発明に係る動画記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャートである。撮影データ量を変化させて記録の形態を変更する際には、撮影を開始する前に同図に示すプログラムルーチンに分岐してくる。
【００３４】
同図のステップＳ１００「開始」（以下Ｓ１００のように省略して説明する）に分岐してくると、次のＳ１０２「記録時間指定モード？」に進む。
【００３５】
Ｓ１０２では、画像データを転送する転送先の記録媒体の容量が撮影予定時間に対して少ない場合に於いて、記録時間をあらかじめ優先して設定するか否かの判断を行っている。記録時間を優先して設定する場合には、Ｓ１０４「記録時間指定」に分岐する。Ｓ１０４では制御手段２２の指令によって表示手段５６上に記録時間の設定モードであることを表示し、記録時間の設定を促す表示を行う。電子カメラ８の使用者は、入力手段２６に対して記録時間の入力を行う。入力された記録時間のデータは制御手段２２が読み取るとともに、使用者に確認してもらうために表示手段５６に入力した内容を表示する。
【００３６】
次のＳ１０６「デバイス通信速度判定」では、外部機器との通信の転送速度又は記録媒体４２に対する転送速度を判定する処理を行う。
【００３７】
通信速度を判定する場合には、通信可能状態に接続されているホスト機器（電子カメラ８）と、撮影した画像データや記録した音声データを転送する転送先である外部機器とを通信が可能な状態に設定しておき、転送速度を取り決めるとよい。転送速度の取り決め方法を図３に示す。
【００３８】
同図によれば、通信開始時の通信状態は、予め取り決めてある初期状態のプロトコルに従って行われる。初期状態の転送速度は何れの外部機器とも通信可能な一般的な９６００（ｂｐｓ）程度の転送速度にしておく。まず最初にホスト機器から「ＥＮＱ」（要求信号）送信する。外部機器が「ＥＮＱ」を受信したら通信が開始されたことを認識するとともに「ＡＣＫ」（応答信号）をホスト機器に返す。ホスト機器は「ＡＣＫ」を受信することによって外部機器が接続されており、且つ通信が正常に行われていることを知ることができる。
【００３９】
その後種々の取り決めを行う中で転送速度の取り決めを行う。例えばホスト機器から２３０４００（ｂｐｓ）の転送速度をサポートするか否かのコマンド「ＳＥＴ−ＣＭＤ」を送信する。外部機器は「ＳＥＴ−ＣＭＤ」を受信したことを示す「ＡＣＫ」をホスト機器に送信するとともに、転送速度２３０４００（ｂｐｓ）をサポートすることを示す回答信号「ＡＮＳ−ＣＭＤ」を送信する。
【００４０】
ホスト機器は「ＡＮＳ−ＣＭＤ」を受信したことを示す応答「ＡＣＫ」を外部機器に送信する。そして転送速度を変更することを示すコマンド「ＥＯＴ」を送信して、以降転送速度を切り換えて通信する。
【００４１】
転送速度を切り換えた後に、通信状態が正常であるか否かを確認するためにホスト機器は外部機器に対して「ＥＮＱ」を送信する。外部機器は「ＥＮＱ」を受信するとデータリンクが確立されたことを認識するとともにホスト機器に対して「ＡＣＫ」を送信する。ホスト機器もまた「ＡＣＫ」を受信することによってデータリンクが確立されたことを認識する。そして、以降は設定した新しいプロトコルでデータの送受信を行う。
【００４２】
図２に示すＳ１０６で記録媒体４２との転送速度を決定する方法は、記録媒体４２の固有の転送速度を設定する方法と、実際にデータを記録してみて実測する方法とがある。記録媒体４２がメモリーカードである場合にはメモリーカードの内部に記憶されているＣＩＳ（Ｃａｒｄ Ｉｎｆｏｒｍａｔｉｏｎ Ｓｔｒｕｃｔｕｒｅ）等のＩＤ情報を読み取り、記録可能な記録速度を判定する。また、ＥＥＰＲＯＭ等のような記録速度にばらつきがあるものについては、実際にデータを記録してみて実測するとよい。
【００４３】
このようにしてデバイス通信速度が判定されると次のＳ１０８「記録可能領域捜索」に進む。Ｓ１０８では記憶媒体４２等の記憶可能領域を検索して、Ｓ１１０「記録残容量判定」にて記録可能な容量を判定する。この記録残容量は後のステップでデータの圧縮率を決定する一つのパラメータとなる。
【００４４】
なお、Ｓ１０２の判断で記録時間指定モードでないと判断した場合にはＳ１１２「デバイス通信速度判定」に進む。ここでは前記Ｓ１０６でデバイスの通信速度を判定した方法と同様にして通信速度を判定する。
【００４５】
次のＳ１１４「スポーツモード？」では、画像のフレームレートを大きく設定するか否かの判断を行っている。被写体が高速で移動するスポーツのシーン等を撮影する場合には、フレームレートを高く設定すると自然な動きが再現される。また、被写体が高速で移動しない場合には、画像データの容量を減らすためにフレームレートを低く設定しておくとよい。
【００４６】
Ｓ１１４でスポーツモードを設定しなかった場合にはＳ１１６「フレームレート１５Ｈｚ」に分岐する。Ｓ１１６では、フレームレートを通常の半分の毎秒１５フレームにして画像データの量を減少させる。
【００４７】
次のＳ１１８「解像度重視？」では、記録する画像データの画素数を、解像度を重視する設定にするか否かの判断を行っている。ここで、解像度を重視する設定にした場合にはＳ１２０「記録画素数１２８０×９６０×２画素」に進み高解像度の設定にする。もし、Ｓ１１８で解像度を重視する設定にしない場合にはＳ１２２「記録画素数６４０×４８０×２画素」に分岐して、転送する画像データの容量を減少させる設定にする。
【００４８】
また、Ｓ１１４にてスポーツモードを選択した場合には次のＳ１２４「フレームレート３０Ｈｚ」に進み、Ｓ１２６「記録画素数６４０×４８０×２画素」にて記録画素数を少ない値に設定してＳ１２８「圧縮率計算」へ進む。
【００４９】
Ｓ１２８では、下記の式（４）に基づいて圧縮率の計算を行う。圧縮率の計算には、制限されているデバイス通信速度から算出する方法と、制限されている記録容量から算出する方法がある。
【００５０】
このときまでに撮像画面の画素数Ｐｘ＝１２８０×１０２４（画素）と、Ｙ−Ｃデータを４：２：２の方式で削減して画像データを輝度情報を８ｂｉｔにしたものと、色差データを８ｂｉｔのＹｃ＝２×８ｂｉｔと、フレームレートＦｘ＝１５（Ｈｚ）とはすでに決定しているので、音声のサンプリングビット数Ａｘ＝１６（ｂｉｔ）、サンプリングレートＳｘ＝４８（ｋＨｚ）、音声チャンネル数Ｔｘ＝２（ｃｈ）、音声圧縮率をＣｗ＝１／２と設定すると、映像データの圧縮率Ｃｖは以下の式（４）で表される。ここで、ＶＷｆを一般的なＥＥＰＲＯＭの転送速度の１（ＭＢ／秒）とすると、画像データの圧縮率Ｃｖは以下の結果となる。
【００５１】
【数４】

但し、撮像画面の画素数 Ｐｘ＝１２８０×１０２４ （画素）
輝度・色差データ Ｙｃ＝２×８ （ｂｉｔ）
フレームレート Ｆｘ＝１５ （Ｈｚ）
音声サンプリングビット数 Ａｘ＝１６ （ｂｉｔ）
サンプリングレート Ｓｘ＝４８ （ｋＨｚ）
音声チャンネル数 Ｔｘ＝２ （ｃｈ）
音声圧縮率 Ｃｗ＝１／２
合成データの転送速度 ＶＷｆ＝１ （ＭＢ／秒）
映像データの圧縮率 Ｃｖ
また、撮影時間をＬｘ＝２０秒とし、記録媒体４２の記録残容量をＱｘ＝１６（ＭＢ）とすると、画像データの圧縮率Ｃｖは以下の式（５）にて示される。
【００５２】
【数５】
Ｑｘ≧ＶＷｆ×Ｌｘ （Ｂ）
≧（Ｖｆ＋Ｗｆ）×Ｌｘ
≧（Ｐｘ×Ｙｃ×Ｆｘ×Ｃｖ／８＋Ａｘ×Ｓｘ×Ｔｘ×Ｃｗ／８）×Ｌｘ
Ｃｖ≦（Ｑｘ×８／Ｌｘ−Ａｘ×Ｓｘ×Ｔｘ×Ｃｗ）／（Ｐｘ×Ｙｃ×Ｆｘ）…（５）
≦（１６００００００×８／２０−１６×４８０００×２×１／２）
／（１２８０×１０２４×２×８×１５）
≒０．０１７９ ≒１／５５．９
但し、撮影時間 Ｌｘ＝２０ （秒）
記録残容量 Ｑｘ＝１６ （ＭＢ）
画像データの圧縮率 Ｃｖ
上記の式（４）と、上記の式（５）で求めたそれぞれの圧縮率Ｃｖの小さい方の値を採用して画像データを圧縮する。このようにして、制御手段２２は、入力手段２６から指定される記録画素数、画質、フレームレートの中の優先順位を基に、これらのパラメータを決定する。電子カメラ８の使用者が動画の動きの画質を優先させる場合には、スポーツモードの指定を行いフレームレートは落とさずに、記録画素数やＹ−Ｃ変換する際の色差信号量を減少させるか、または圧縮率を小さくすることで調節する。また、使用者が画質を優先させる場合には、記録画素数、あるいは圧縮率を維持したままフレームレートを落とすことで調節する。記録画素数、あるいは圧縮率のいずれを重視するかは、画像解像度低下と、圧縮歪み増加のトレードオフで決定する。
【００５３】
なお、上記の計算方法では音声データの圧縮率を固定として計算したが、画像データの圧縮率とともに変化させてもよい。このようにして、記録媒体のデータ転送速度や記憶媒体の残容量に応じて、画像データと音声データの容量の縮小量が決定したら、次のＳ１３０「記録ボタンＯＮ？」に進む。
【００５４】
Ｓ１３０では、記録ボタンが押されるまで待つ処理を行っている。ここで、記録ボタンが押された場合には、次のＳ１３２「圧縮・記録」に進む。
【００５５】
Ｓ１３２では、制御手段２２がＳ１２８で算出した圧縮率に基づいてデータを圧縮する指令と、画像データと音声データとを圧縮・伸張処理部４０に伝送して圧縮処理を行い、圧縮されたデータは圧縮・伸張処理部４０から読み出して記録・再生処理部４４又は、通信信号処理部４６に出力される。
【００５６】
圧縮されたデータを記録・再生処理部４４に伝送すると、記録・再生処理部４４は記録媒体４２に対してデータを記録するための通信や、メモリのコントロールを開始する。また、圧縮されたデータを通信信号処理部４６に伝送した場合には、通信信号処理部４６は外部機器に対してデータを伝送するための通信処理を開始する。
【００５７】
データの伝送が開始されるとＳ１３４「記録ボタンＯＦＦ？」に進み、記録ボタンが押されているか否かの判断を行う。ここで、記録ボタンが押されている場合にはＳ１３２に分岐して撮影データの圧縮・記録を継続する。記録ボタンが押されていない場合には次のＳ１３６「終わり」に進み、本サブルーチンを終了して元のルーチンに戻る。
【００５８】
図４は、本発明に係る連写記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャートである。静止画像を連続して記録する連写記録の場合には、制御手段２２は撮像信号処理部１６における間引き回路の間引き率、または、圧縮・伸張処理部の圧縮率を転送速度に合致したデータ量となるように調節し、所望の画質、撮影間隔が得られるように制御する。
【００５９】
連写撮影するデータの記録の形態を変更する際には、撮影を開始する前に同図に示すプログラムルーチンに分岐してくる。
【００６０】
同図のステップＳ１５０「開始」に分岐してくると、次のＳ１５２「連写速度設定」に進む。
【００６１】
Ｓ１５２では、撮影画像の連写速度Ｅｘ（ｆｒａｍｅ／秒）を設定する。この連写速度は、動画撮影時のフレームレートＦｘ（ｆｒａｍｅ／秒）に相当する。Ｓ１５２では制御手段２２の指令によって表示手段５６上に連写速度の設定モードであることを示し、連写速度の設定を促す表示を行う。電子カメラ８の使用者は、入力手段２６に対して連写速度の入力を行う。入力された連写速度のデータは制御手段２２が読み取るとともに、表示手段５６に入力した内容を表示する。
【００６２】
次のＳ１５４「デバイス通信速度判定」では、外部機器との通信の転送速度又は記録媒体４２に対する転送速度を判定する処理を、Ｓ１０６の処理と同様に行う。
【００６３】
次のＳ１５６「記録画素数設定」では、記録する画像データの画素数を設定する。ここで、解像度を重視する設定にする場合には、より大きな値の転送速度が必要となる。
【００６４】
Ｓ１５８「圧縮率計算」では、前記の式（４）及び（５）に基づいて圧縮率の計算を行う。なお、フレームレートＦｘを連写速度Ｅｘに置き換えて計算する。また、一般に静止画の撮影では音声は記録しないのでＷｆ＝０（Ｂ／秒）と置いてもよい。なお、以下の条件にて式（４）から下式（６）を求めてみる。
【００６５】
【数６】

但し、音声データ転送速度 Ｗｆ＝０ （Ｂ／秒）
画像データ転送速度 Ｖｆ＝１ （ＭＢ／秒）
合成データ転送速度 ＶＷｆ＝Ｖｆ （Ｂ／秒）
連写速度 Ｅｘ＝５ （ｆｒａｍｅ／秒）
記録画素数 Ｐｘ＝１２８０×１０２４ （画素）
色差データ Ｙｃ＝２×８ （ｂｉｔ）
従って、約１／１３．１にデータを圧縮すれば記録可能となる。
【００６６】
また、連写速度Ｅｘ＝１０（ｆｒａｍｅ／秒）として記録画素数Ｐｘ＝６４０×４８０（画素）とする場合には、前記式（６）から下式（７）に示す圧縮率を求めることができる。
【００６７】
【数７】

但し、音声データ転送速度 Ｗｆ＝０ （Ｂ／秒）
画像データ転送速度 Ｖｆ＝１ （ＭＢ／秒）
合成データ転送速度 ＶＷｆ＝Ｖｆ （Ｂ／秒）
連写速度 Ｅｘ＝１０ （ｆｒａｍｅ／秒）
記録画素数 Ｐｘ＝６４０×４８０ （画素）
色差データ Ｙｃ＝２×８ （ｂｉｔ）
従って上記の設定の場合は、約１／６．１４にデータを圧縮すれば記録可能となる。
【００６８】
更に、連写速度Ｅｘ＝５（ｆｒａｍｅ／秒）で、圧縮率Ｃｖ＝１／８＝０．１２５が必須である場合には、上記式（５）から以下の式（８）に示す計算を行って、画像データの一時記憶用バッファメモリの領域を確保することによって記録可能とすることができる。
【００６９】
【数８】

但し、音声データ転送速度 Ｗｆ＝０ （Ｂ／秒）
画像データ転送速度 Ｖｆ＝１ （ＭＢ／秒）
合成データ転送速度 ＶＷｆ＝Ｖｆ （Ｂ／秒）
記録画素数 Ｐｘ＝６４０×４８０ （画素）
色差データ Ｙｃ＝２×８ （ｂｉｔ）
記録残容量 Ｑｘ （Ｂ）
連写速度 Ｅｘ＝５ （ｆｒａｍｅ／秒）
撮影時間 Ｌｘ＝２ （秒）
連続連写枚数 Ｅｘ×Ｌｘ （ｆｒａｍｅ）
データ圧縮率 Ｃｖ＝０．１２５
従って上記の設定の場合には、０．７６８（ＭＢ）の一時記憶用バッファメモリを準備すれば記録可能となる。
【００７０】
次のＳ１６０「圧縮率≧１／１６？」では圧縮率が１／１６以上であるか否かの判断を行っている。もしＳ１５８で圧縮率の計算を行った結果、圧縮率が１／１６以上でない場合には圧縮しすぎであるのでＳ１６２「記録画素数６４０×４８０×２画素」に分岐して画素数を落とす設定を行ったのちにＳ１５８に再び戻る。もしＳ１５８で圧縮率の計算を行った結果、圧縮率が１／１６以上である場合には次のステップＳ１６４「記録ボタンＯＮ？」に進む。
【００７１】
Ｓ１６４では、記録ボタンが押されるまで待つ処理を行っている。ここで、記録ボタンが押された場合には、次のＳ１６６「連写圧縮・記録」に進む。
【００７２】
Ｓ１６６では、制御手段２２がＳ１５８で算出した圧縮率に基づいてデータを圧縮する指令を出力するとともに、画像データと音声データとを圧縮・伸張処理部４０に伝送して圧縮処理を行い、圧縮されたデータは圧縮・伸張処理部４０から読み出して記録・再生処理部４４又は、通信信号処理部４６に出力する。
【００７３】
圧縮されたデータを記録・再生処理部４４に伝送すると、記録・再生処理部４４は記録媒体４２に対してデータを記録するための通信や、メモリのコントロールを開始する。また、圧縮されたデータを通信信号処理部４６に伝送した場合には、通信信号処理部４６は外部機器に対してデータを伝送するための通信処理を開始する。
【００７４】
データの伝送が開始されるとＳ１６８「記録ボタンＯＦＦ？」に進み、記録ボタンが押されているか否かの判断を行う。ここで、記録ボタンが押されている場合にはＳ１６６に分岐して撮影データの連写圧縮・記録を継続する。記録ボタンが押されていない場合には次のＳ１７０「戻り」に進み、本サブルーチンを終了して元のルーチンに戻る。
【００７５】
図５は、本発明に係る連写記録のモードにおけるバッファメモリ２０使用時の記録の形態を決定するフローチャートである。バッファメモリ２０使用時には、連写速度と、記録画素数と、圧縮率と、連写枚数との設定を以下に示すように行う。バッファメモリ２０に対するデータの転送速度はたいへん高いので、撮影又は記録したデータは一時的にバッファメモリ２０に取り込んでおいて後に記録媒体又は外部機器に転送する。
【００７６】
連写撮影で且つバッファメモリ２０を使用する場合には、撮影を開始する前に同図に示すプログラムルーチンに分岐してくる。
【００７７】
同図のステップＳ１８０「開始」に分岐してくると、次のＳ１８２「連写速度設定」に進む。
【００７８】
Ｓ１８２では、撮影画像の連写速度Ｅｘ（ｆｒａｍｅ／秒）を設定する。Ｓ１８２では制御手段２２の指令によって表示手段５６上に連写速度の設定モードであることを示し、電子カメラ８の使用者は、入力手段２６に対して連写速度の入力を行う。入力された連写速度のデータは制御手段２２が読み取るとともに、表示手段５６に入力した内容を表示する。
【００７９】
次のＳ１８４「記録画素数設定」では、記録する画像データの画素数を設定し次のＳ１８６「圧縮率設定」では、記録するときの圧縮率の設定を行う。
【００８０】
Ｓ１８８「連写枚数設定」では、連写速度Ｅｘ（ｆｒａｍｅ／秒）と、撮影時間Ｌｘ（秒）との積である連続連写枚数Ｅｘ×Ｌｘ（ｆｒａｍｅ）の設定を行う。
【００８１】
ここで、連写速度Ｅｘ＝５（ｆｒａｍｅ／秒）で、圧縮率Ｃｖ＝１／８＝０．１２５が必須である場合には、上記式（５）から以下の式（９）に示す計算を行って、画像データの一時記憶用バッファメモリ２０の領域を確保する。
【００８２】
【数９】

但し、音声データ転送速度 Ｗｆ＝０ （Ｂ／秒）
画像データ転送速度 Ｖｆ＝１ （ＭＢ／秒）
合成データ転送速度 ＶＷｆ＝Ｖｆ （Ｂ／秒）
記録画素数 Ｐｘ＝６４０×４８０ （画素）
色差データ Ｙｃ＝２×８ （ｂｉｔ）
記録残容量 Ｑｘ （Ｂ）
連写速度 Ｅｘ＝５ （ｆｒａｍｅ／秒）
撮影時間 Ｌｘ＝２ （秒）
連続連写枚数 Ｅｘ×Ｌｘ （ｆｒａｍｅ）
データ圧縮率 Ｃｖ＝０．１２５
従って、０．７６８（ＭＢ）の一時記憶用バッファメモリを準備すれば記録可能となる。
【００８３】
次のステップＳ１９０「記録ボタンＯＮ？」では、記録ボタンが押されるまで待つ処理を行っている。ここで、記録ボタンが押された場合には、次のＳ１９２「連写圧縮・記録」に進む。
【００８４】
Ｓ１９２では、制御手段２２がＳ１８６で設定した圧縮率に基づいてデータを圧縮する指令を出力する。更に画像データと音声データとを圧縮・伸張処理部４０に伝送して圧縮処理を行い、圧縮されたデータは圧縮・伸張処理部４０から読み出して記録・再生処理部４４又は、通信信号処理部４６に出力する。
【００８５】
圧縮されたデータを記録・再生処理部４４に伝送すると、記録・再生処理部４４は記録媒体４２に対してデータを記録するための通信や、メモリのコントロールを開始する。また、圧縮されたデータを通信信号処理部４６に伝送した場合には、通信信号処理部４６は外部機器に対してデータを伝送するための通信処理を開始する。
【００８６】
データの伝送が開始されるとＳ１９４「記録ボタンＯＦＦ？」に進み、記録ボタンが押されているか否かの判断を行う。ここで、記録ボタンが押されている場合にはＳ１９６「記録枚数≧設定枚数」に分岐して記録枚数が設定枚数以上であるか否かの判断を行う。記録枚数が設定枚数以上である場合にはＳ１９８「戻り」へ進み、記録枚数が設定枚数以上でない場合にはＳ１９２に戻り、撮影データの連写圧縮・記録を継続する。
【００８７】
また、Ｓ１９４で記録ボタンが押されていない場合には、次のＳ１７０「戻り」に進み、本サブルーチンを終了して元のルーチンに戻る。
【００８８】
図６は、本発明に係る音声記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャートである。音声記録の場合には制御手段２２は撮像信号処理部１６における間引き回路の間引き率、または、圧縮・伸張処理部の圧縮率を記録媒体転送速度や通信の転送速度に合致した記録速度に調節し、所望の画質、撮影間隔が得られるように制御する。
【００８９】
音声記録するデータの記録の形態を変更する際には、撮影を開始する前に同図に示すプログラムルーチンに分岐してくる。
【００９０】
同図のステップＳ２００「開始」に分岐してくると、次のＳ２０２「音声サンプリングレート、音声サンプリングビット数、音声チャンネル数、音声圧縮率、設定」に進み、各定数の設定を行う。
【００９１】
次のＳ２０４「デバイス通信速度判定」では、外部機器との通信の転送速度又は記録媒体４２に対する転送速度を判定する処理をＳ１０６の処理と同様に行う。
【００９２】
Ｓ２０６「圧縮率計算」では、前記の式（４）及び（５）に基づいて圧縮率の計算を行う。なお、画像の記録を行わない場合には、Ｖｆ＝０（Ｂ／秒）と置いて計算する。以下の式（１０）に、Ｖｆ＝０（Ｂ／秒）に於ける圧縮率Ｃｗの計算例を示す。
【００９３】
【数１０】
音声データ転送速度 Ｗｆ＝１ （ＭＢ／秒）
画像データ転送速度 Ｖｆ＝０ （ＭＢ／秒）
音声のサンプリングビット数 Ａｘ＝１６（ｂｉｔ）
サンプリングレート Ｓｘ＝４８（ｋＨｚ）
音声チャンネル数 Ｔｘ＝２（ｃｈ）

上記の式（１０）に示すとおり、１（ＭＢ／秒）の転送速度があれば、音声データのみの場合は圧縮しなくても十分転送可能となる。また、音声チャンネルを４（ｃｈ）とした場合であってもＣｗ≒２．６４２となり、圧縮しなくても転送可能である。
【００９４】
次のＳ２０８「音声圧縮率≧音声基準？」では圧縮率が音声基準以上であるか否かの判断を行っている。もしＳ２０６で圧縮率の計算を行った結果、圧縮率が音声基準以上でない場合には圧縮しすぎであるのでＳ２１０「音声サンプリングレート１／２」に分岐して音声のサンプリングレートを現在の１／２に減じる演算を行った後にＳ２０６に再び戻る。もしＳ２０８で圧縮率の計算を行った結果、圧縮率が音声基準以上である場合には次のステップＳ２１２「記録ボタンＯＮ？」に進む。
【００９５】
Ｓ２１２では、記録ボタンが押されるまで待つ処理を行っている。ここで、記録ボタンが押された場合には、次のＳ２１４「音声圧縮・記録」に進む。
【００９６】
Ｓ２１４では、制御手段２２がＳ１２８で算出した圧縮率に基づいてデータを圧縮する指令と画像データと音声データとを圧縮・伸張処理部４０に伝送して圧縮処理を行い、圧縮されたデータは圧縮・伸張処理部４０から読み出して記録・再生処理部４４又は、通信信号処理部４６に出力する。
【００９７】
圧縮されたデータを記録・再生処理部４４に伝送した場合には、記録・再生処理部４４は記録媒体４２に対してデータを記録するための通信やメモリのコントロールを開始する。また、圧縮されたデータを通信信号処理部４６に伝送した場合には、通信信号処理部４６は外部機器に対してデータを伝送するための通信処理を開始する。
【００９８】
データの伝送が開始されるとＳ２１６「記録ボタンＯＦＦ？」に進み、記録ボタンが押されているか否かの判断を行う。ここで、記録ボタンが押されている場合にはＳ２１４に分岐して音声データの圧縮・記録を継続する。記録ボタンが押されていない場合には次のＳ２１８「戻り」に進み、本サブルーチンを終了して元のルーチンに戻る。
【００９９】
【発明の効果】
以上説明したように本発明に係る信号処理装置によれば、画像データや音声データを記録媒体又は外部機器に転送する際に、制御手段は記録媒体又は外部機器とのデータの転送速度又は、記録容量に応じて前記画像データや前記音声データのデータ量を制御するようにしたので、優先する記録条件を指示するだけでデータの転送速度を有効に使用した撮影データの転送や記録を行うことが可能となる。
【図面の簡単な説明】
【図１】本発明に係る画像記録方法が適用された電子カメラの実施の形態を示すブロック図
【図２】本発明に係る動画記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャート
【図３】転送速度の取り決め方法を示す図
【図４】本発明に係る連写記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャート
【図５】本発明に係る連写記録のモードにおけるバッファメモリ使用時の記録の形態を決定するフローチャート
【図６】本発明に係る音声記録のモードにおける画像データ量を減少させる記録の形態を決定するフローチャート
【符号の説明】
８…電子カメラ、１０…撮影レンズ、１４…ＣＣＤ（固体撮像素子）、１６…撮像信号処理部、１８…撮像タイミング制御手段、２０…バッファメモリ、２２…制御手段、２８…マイクロフォン、３２…サンプリングレート発生器、３４…Ａ／Ｄ変換器、４２…記録媒体、４４…記録・再生処理部、４６…通信信号処理部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image or audio signal processing apparatus, and more particularly to a signal processing apparatus that changes the amount of image or audio data in accordance with the data transfer rate.
[0002]
[Prior art]
In a digital camera that records still images and moving images on a medium, a method of compressing and recording the data in order to record more image data and audio data on the medium is known. Japanese Laid-Open Patent Publication No. 6-315107 discloses a moving image recording digital camera that records on a medium by switching the compression rate when compressing data between a still image and a moving image. Japanese Patent Application Laid-Open No. 7-264530 discloses a digital camera having each mode of continuous shooting, pseudo moving image, still image, and shooting with sound.
[0003]
[Problems to be solved by the invention]
Conventionally, however, the relationship between the transfer speed of image data to a recording medium and the amount of image data to be transferred has been unclear, so that it has not been possible to effectively record the transfer speed.
[0004]
The present invention has been made in view of such circumstances, and provides a signal processing apparatus capable of transferring and recording photographing data that effectively uses the data transfer speed only by instructing a preferential recording condition. The purpose is to do.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, a first signal processing apparatus of the present invention includes an imaging unit that captures a moving image of a subject to obtain image data, a compression unit that compresses the image data, and the compressed image data. Buffer memory for temporary recording, recording means for sequentially recording image data temporarily recorded in the buffer memory, and transfer speed for sequentially transferring and recording image data temporarily recorded in the buffer memory to the recording means A transfer rate detecting means for detecting a recording remaining capacity that can be recorded in the recording means, and the transfer ratedetectionCalculating the first compression rate of the image data based on the transfer speed detected by the means, and calculating the second compression rate of the image data based on the remaining recording capacity of the recording means; Control means for selecting a higher compression ratio from among the second compression ratios before the start of moving image capturing, and controlling the data amount of the image data using the selected compression ratio. It is characterized by.
  The second signal processing apparatus of the present invention further comprises frame rate setting means for setting a frame rate of the image data in the first aspect, wherein the control means is configured to set the frame rate high. The amount of the image data is controlled while maintaining the frame rate of the image data as set.
[0006]
According to a third signal processing device of the present invention, in the second aspect, when the frame rate is set high, the control unit decreases the number of recorded pixels, and the image signal acquired by the imaging unit The image data amount is controlled by at least one of means for reducing the color difference signal amount during Y-C conversion or controlling the compression rate.
According to a fourth signal processing apparatus of the present invention, in any of the first to third aspects, the signal processing device further includes resolution emphasis setting means for setting emphasis on the resolution of the image data, and the control means emphasizes the resolution. When the setting is performed, the data amount of the image data is controlled while maintaining the number of recording pixels or the compression rate of the image data.
[0007]
  In the fourth signal processing apparatus according to the fourth aspect of the present invention, in the fourth aspect, when the setting that places importance on the resolution is performed, the control unit reduces the frame rate of the image data to reduce the data of the image data. It is characterized by controlling the amount.
  According to a sixth signal processing device of the present invention, in the first to fifth aspects, the sixth signal processing device further includes a sound collecting unit that collects sound and acquires sound data when capturing the moving image, and the compression unit includes the image Data and audio data are compressed, the buffer memory temporarily records the compressed image data and audio data, and the recording means sequentially records the image data and audio data temporarily recorded in the buffer memory. The transfer speed detecting means detects a transfer speed when the image data and the audio data temporarily recorded in the buffer memory are sequentially transferred to the recording means for recording, and the control means is configured to detect the transfer speed.detectionCalculating a first compression rate combination of the image data and the audio data based on the transfer speed detected by the means, and a second combination of the image data and the audio data based on a recording remaining capacity of the recording means. A combination of compression ratios is calculated, and a data amount of the image data and the audio data is controlled using a higher compression of the first and second compression ratio combinations.
[0008]
  The seventh signal processing apparatus of the present invention includes an imaging unit that continuously captures images of a subject to obtain image data, a compression unit that compresses the image data, a buffer memory that temporarily records the image data, and the buffer memory Recording means for recording the image data temporarily recorded on the recording medium; transfer speed detecting means for detecting a transfer speed when the image data temporarily recorded in the buffer memory is sequentially transferred to the recording means for recording; and the transfer speeddetectionThe compression rate of the image data is calculated based on the transfer speed detected by the means, and when the calculated compression rate is high compression equal to or less than a predetermined value, the number of recorded pixels is reduced and the compression rate is recalculated to calculate the compression rate. And control means for controlling the data amount of the image data.
  An eighth signal processing apparatus according to the present invention includes an imaging unit that continuously captures images of a subject to obtain image data, a compression unit that compresses the image data, a buffer memory that temporarily records the image data, and the buffer memory Recording means for recording the temporarily recorded image data, recording pixel number setting means for setting the number of recording pixels of the image data, compression rate setting means for setting the compression rate of the image data in the compression means, and Continuous shooting number setting means for setting the number of continuous shooting at the time of continuous shooting, and necessary for temporarily recording the image data captured by the continuous shooting based on the recording pixel number, the continuous shooting number, and the compression ratio A recording capacity is calculated, the calculated recording capacity is ensured on the buffer memory, and the image data obtained by continuous shooting is temporarily recorded in the buffer memory and then transferred to the recording means. Characterized in that it comprises a means.
  A ninth signal processing apparatus of the present invention includes a sound collection unit that continuously collects sound to obtain sound data, a compression unit that compresses the sound data, and a buffer memory that temporarily records the compressed sound data; A recording means for sequentially recording the audio data temporarily recorded in the buffer memory; and a transfer speed detection for detecting a transfer speed when sequentially recording the audio data temporarily recorded in the buffer memory to the recording means. Means and said transfer ratedetectionCalculating the compression rate of the audio data based on the transfer speed detected by the means, and if the compression rate is less than the audio reference, reducing the sampling rate of the audio data and recalculating the compression rate to calculate the audio data And a control means for controlling the amount of data.
  In a tenth signal processing apparatus of the present invention, in the first to seventh or ninth aspects, the data temporarily recorded in the buffer memory by the recording means is transferred to an external device and recorded, and the transfer speed is The detecting means acquires the transfer rate from the external device.
  In an eleventh signal processing apparatus of the present invention, in the first to seventh or ninth aspects, the data temporarily recorded in the buffer memory by the recording means is transferred to and recorded on a recording medium, and the transfer speed is The detecting means acquires information on the recording medium and determines a transfer speed to the recording medium.
  In a twelfth signal processing apparatus of the present invention, in the first to seventh or ninth aspects, the data temporarily recorded in the buffer memory by the recording means is transferred to a recording medium for recording, and the transfer speed The detecting means detects the transfer speed by actually transferring data in advance.
  In a thirteenth signal processing device of the present invention, in the first to eighth aspects, the control means changes at least one of a thinning rate, a compression rate, a frame rate, and the number of pixels of image data. It is characterized by controlling the amount of image data.
  In a fourteenth signal processing apparatus of the present invention, in the sixth or ninth aspect, the control means changes at least one of the compression rate, the number of sampling bits, the sampling rate, and the number of channels to change the audio data. It is characterized by controlling the amount of data.
[0009]
According to the present invention, when transferring image data or audio data to a recording medium or an external device, the control means controls the image data or audio data according to the data transfer speed or recording capacity with the recording medium or external device. Therefore, it is possible to transfer and record image data using the data transfer speed effectively only by instructing the priority recording condition.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a signal processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0011]
FIG. 1 is a block diagram showing an embodiment of an electronic camera to which an image recording method according to the present invention is applied.
[0012]
The optical system of the electronic camera 8 includes a photographing lens 10 that can adjust the focus, a diaphragm 12 that adjusts the amount of light, and a solid-state imaging device (CCD) 14 that converts an image into an electrical signal. An imaging signal obtained by the CCD 14 is obtained as digital R, G, B signals via an analog processing circuit and an A / D converter provided in the imaging signal processing unit 16.
[0013]
The CCD 14 and the imaging signal processing unit 16 are driven in synchronization with a timing signal output from the imaging timing control means 18. Since the timing signal output from the imaging timing control means 18 can be changed by a command from the control means 22, the pixel data thinning rate, frame rate, and number of pixels can be freely controlled. Is possible. In addition, the imaging signal processing unit 16 can perform processing such as image size change, sharpness correction, gamma correction, contrast correction, and white balance correction.
[0014]
The R, G, and B signals output from the imaging signal processing unit 16 are temporarily stored in the buffer memory 20 sequentially via the bus line 24.
[0015]
The control means 22 extracts the luminance component in the image from the obtained digital signal value of the image, integrates it for a predetermined area, etc. to obtain the luminance level of the subject, and obtains the subject's luminance level obtained here. A TTLAE function for obtaining an exposure power (photographing aperture and shutter speed) necessary for photographing from the luminance level can be installed.
[0016]
Further, inside the control means 22 are provided a RAM (not shown) which is a readable / writable storage means, and a ROM for storing programs and constants for controlling the operation of the control means 22.
[0017]
The input means 26 of the electronic camera 8 is provided with a recording button, a function switch, a cursor key, a confirmation switch, etc. (not shown), and each operation information is sent to the control means 22.
[0018]
The sound collection unit, which is an audio recording system, includes microphones 28 and 28 that convert audio signals into electric signals, microphone amplifiers 30 and 30 that amplify weak audio signals output from the microphones 28 and 28, and control means 22. A sampling rate generator 32 that generates and generates a sampling rate specified by a command from A, and A / D converters 34 and 34 that sample audio signals in accordance with the sampling rate and convert them into digital data, Data compression units 36 and 36 that reduce the amount of digital data, and a multiplex 38 that synthesizes the right channel and the left channel of audio data and transmits them to the bus line 24 are provided.
[0019]
The bus line 24 includes a compression / decompression processing unit 40 that performs compression control of image data and audio data using a technique typified by MJPEG and MPEG, and performs processing for expanding and controlling compressed data, and image data and audio data. A recording / playback processing unit 44 is provided for converting data in order to record or read data on the recording medium 42. The recording medium 42 may be a removable recording medium represented by a memory card or MO. Further, a communication signal processing unit 46 used when image data and audio data are transmitted to an external device by communication, and a communication timing control means 48 for controlling the communication speed are provided.
[0020]
In order to reproduce the image data recorded on the recording medium 42, the data read by the recording / reproduction processing unit 44 is decompressed by the compression / decompression processing unit 40 as necessary, and reproduced by the reproduction signal processing unit 52. Based on the timing signal output from the timing control means 54, the signal is converted into a signal that can be displayed and a signal that can be output to the outside. The converted signal is transmitted to the display means 56 to display the captured image.
[0021]
Further, in order to reproduce the audio data recorded on the recording medium 42, the data read out by the recording / reproduction processing unit 44 is decompressed by the compression / decompression processing unit 40 as necessary, and the demultiplex 58 The audio signal is separated into each channel and transmitted to the data decompression units 60 and 60. The audio data expanded by the data expansion units 60 and 60 is transmitted to the D / A converters 62 and 62 and converted into analog audio signals according to the sampling rate information emitted from the sampling rate generator 64. Then, after the quantization distortion is attenuated by the low-pass filters 66 and 66, it is output from the output terminals 68 and 68 to the outside of the electronic camera 8.
[0022]
A photographing process of the electronic camera 8 configured as described above will be described.
[0023]
An image to be photographed is formed on a light receiving surface of a solid-state imaging device (CCD) 14 through a photographing lens 10 and a diaphragm 12. This subject image is photoelectrically converted into a charge signal in an amount corresponding to the amount of incident light by each sensor in the CCD. A timing signal is output from the imaging timing control means 18, whereby the charge signal accumulated in the CCD 14 is sequentially output, and the imaging signal processing unit 16 amplifies the R, G, and B signals of the image data and reduces noise. A process of converting into digital data is performed.
[0024]
The control means 22 temporarily stores the image data converted into the digital data in the buffer memory 20. The image data stored in the buffer memory 20 is extracted as necessary, and is sequentially transmitted to the reproduction signal processing unit 52 and displayed on the display means 56.
[0025]
In the audio recording system, the weak audio signals output from the microphones 28 and 28 are amplified by the microphone amplifiers 30 and 30, the audio signals are sampled at a predetermined sampling rate, and the digital data is output by the A / D converters 34 and 34. Is converted to The capacity of the digital data is compressed by the data compression units 36 and 36, and then the right channel and the left channel of the audio data are synthesized by the multiplex 38 and transmitted to the bus line 24.
[0026]
When a recording button provided on the input means 26 is pressed, a mode for photographing a subject is entered. Then, the control means 22 performs processing for sequentially recording the image data stored in the temporary buffer memory 20 and the audio data obtained from the multiplex 38 on the recording medium.
[0027]
At this time, the number of pixels of the imaging screen is Px = 1280 × 1024 (pixels), Y-C data is reduced by the 4: 2: 2 method, the image data is 8 (bit) in luminance information, and the color difference data is 8 (in color). bit) Yc = 2 × 8 (bit), the frame rate is Fx = 30 (frame / second), and the compression rate of the image data is Cv = 1, the transfer rate Vf of the image data is expressed by the following equation (1 )
[0028]
[Expression 1]

However, the unit (B) is (BYTE = 8 bits).
[0029]
Number of pixels on the imaging screen Px = 1280 × 1024 (pixels)
Luminance / color difference data Yc = 2 × 8 (bit)
Frame rate Fx = 30 (frame / second)
Compression rate of image data Cv = 1
Image data transfer speed Vf (B / sec)
The audio data transfer speed Wf is such that the number of sampling bits is Ax = 16 (bit), the sampling rate is Sx = 48 (kHz), the number of audio channels is Tx = 2 (ch), and the audio compression rate is Cw = 1. Then, the value shown in the following formula (2) is obtained.
[0030]
[Expression 2]
  Wf = Ax × Sx × Tx × Cw / 8 (B / second) (2)
      = 16 × 48000 × 2 × 1/8
      = 0.192 (MB / sec)
  However, the number of sampling bits Ax = 16 (bit)
        Sampling rate Sx = 48 (kHz)
        Number of audio channels Tx = 2 (ch)
        Audio compression rate Cw = 1
        Audio data transfer speed Wf
  Even if data transfer means represented by USB or SCSI, which is generally used in personal computers, is used, the above-mentioned continuous image data is transferred because the transfer speed is about 1.5 to 10 (MB / second). I can't do it. Therefore, when transferring a moving image using a communication means having a low transfer speed, a method is generally adopted in which the compression / decompression processing unit 40 controls and transfers data using a data compression method such as MPEG. Yes. The image data read from the imaging signal processing unit 16 is compressed to 1/8, for example, and read from the multiplex 38.voiceIf the data is compressed to, for example, ½, the combined data transfer speed VWf of the image data and the audio data is expressed by the following equation (3).
[0031]
[Equation 3]

However, image data transfer speed Vf (B / sec)
Audio data transfer speed Wf (B / sec)
Composite data transfer speed VWf (B / sec)
By compressing the data as described above, it is possible to transfer image data and audio data by communication means having a transfer rate of 10 (MB / second). When image data and audio data are recorded on the recording medium 42, the data compression rate may be input and set from the input means 26 so that the transfer speed is in accordance with the transfer speed of the recording medium. In the header portion of the image data compressed in this way, compression rate information and data information such as YC or RGB, which are parameters when decompressing at the time of reproduction, are recorded. Correctly deployed.
[0032]
As described above, when the communication transfer rate or the data transfer rate with respect to the recording medium 42 is smaller than the amount of data generated at the time of shooting, it is necessary to reduce the amount of data using some method. Conventionally, only photographing with a data generation amount corresponding to a predetermined transfer speed of a recording medium is permitted. However, according to the present invention, the amount of data is automatically changed according to the data transfer speed. Therefore, the maximum image data can be recorded or transferred within a limited data transfer speed.
[0033]
FIG. 2 is a flowchart for determining a recording mode for reducing the amount of image data in the moving image recording mode according to the present invention. When changing the recording mode by changing the amount of image data, the program branches to the program routine shown in FIG.
[0034]
When the process branches to step S100 “Start” (hereinafter abbreviated as S100), the process proceeds to the next S102 “Recording time designation mode?”.
[0035]
In S102, when the capacity of the transfer destination recording medium to which the image data is transferred is smaller than the scheduled shooting time, it is determined whether or not the recording time is preferentially set. If the recording time is set with priority, the process branches to S104 “Recording time designation”. In step S104, the display unit 56 displays a recording time setting mode according to a command from the control unit 22, and displays a prompt to set the recording time. A user of the electronic camera 8 inputs a recording time to the input unit 26. The input recording time data is read by the control means 22 and the input contents are displayed on the display means 56 for confirmation by the user.
[0036]
In the next S106 “determination of device communication speed”, processing for determining the transfer speed of communication with an external device or the transfer speed for the recording medium 42 is performed.
[0037]
When determining the communication speed, it is possible to communicate between a host device (electronic camera 8) connected in a communicable state and an external device that is a transfer destination for transferring captured image data or recorded audio data. It is good to set the status and negotiate the transfer speed. A method for determining the transfer rate is shown in FIG.
[0038]
According to the figure, the communication state at the start of communication is performed according to the protocol of the initial state decided in advance. The transfer rate in the initial state is set to a transfer rate of about 9600 (bps) which can be communicated with any external device. First, “ENQ” (request signal) is transmitted from the host device. When the external device receives “ENQ”, it recognizes that communication has started and returns “ACK” (response signal) to the host device. By receiving “ACK”, the host device can know that the external device is connected and the communication is normally performed.
[0039]
After that, the transfer rate is negotiated in various arrangements. For example, a command “SET-CMD” indicating whether to support a transfer rate of 230400 (bps) is transmitted from the host device. The external device transmits “ACK” indicating that “SET-CMD” has been received to the host device, and transmits an answer signal “ANS-CMD” indicating that the transfer rate 230400 (bps) is supported.
[0040]
The host device transmits a response “ACK” indicating that “ANS-CMD” has been received to the external device. Then, a command “EOT” indicating that the transfer rate is to be changed is transmitted, and thereafter, the transfer rate is switched to perform communication.
[0041]
After switching the transfer rate, the host device transmits “ENQ” to the external device in order to confirm whether or not the communication state is normal. When the external device receives "ENQ", it recognizes that the data link has been established and transmits "ACK" to the host device. The host device also recognizes that the data link has been established by receiving “ACK”. Thereafter, data is transmitted and received using the set new protocol.
[0042]
  Figure2The method of determining the transfer rate with the recording medium 42 in S106 shown in FIG. 2 includes a method of setting a specific transfer rate of the recording medium 42 and a method of actually measuring data by actually recording it. When the recording medium 42 is a memory card, ID information such as CIS (Card Information Structure) stored in the memory card is read to determine a recordable recording speed. Further, with respect to the recording speed variation such as an EEPROM, it is preferable to actually record data and actually measure it.
[0043]
When the device communication speed is determined in this way, the process proceeds to the next S108 “search for recordable area”. In S108, a storable area such as the storage medium 42 is searched, and the recordable capacity is determined in S110 “remaining recording capacity determination”. This remaining recording capacity is one parameter that determines the data compression rate in a later step.
[0044]
If it is determined in S102 that the recording time designation mode is not set, the process proceeds to S112 “device communication speed determination”. Here, the communication speed is determined in the same manner as the method of determining the communication speed of the device in S106.
[0045]
In the next S114 “sport mode?”, It is determined whether or not the frame rate of the image is to be set large. When shooting a sports scene or the like in which a subject moves at high speed, natural motion is reproduced by setting a high frame rate. If the subject does not move at high speed, the frame rate may be set low in order to reduce the amount of image data.
[0046]
If the sport mode is not set in S114, the process branches to S116 “frame rate 15 Hz”. In S116, the amount of image data is reduced by setting the frame rate to 15 frames per second, which is half the normal rate.
[0047]
In the next S118 “Resolution Emphasis?”, It is determined whether or not the number of pixels of the image data to be recorded is set to emphasize the resolution. Here, if the setting is focused on the resolution, the process proceeds to S120 “number of recording pixels 1280 × 960 × 2 pixels” to set the high resolution. If the setting for emphasizing the resolution is not made in S118, the process branches to S122 “recording pixel number 640 × 480 × 2 pixels” to reduce the volume of image data to be transferred.
[0048]
If the sports mode is selected in S114, the process proceeds to the next S124 “frame rate 30 Hz”, and the number of recording pixels is set to a smaller value in S126 “recording pixel number 640 × 480 × 2 pixels”. Proceed to “Calculation of compression ratio”.
[0049]
In S128, the compression rate is calculated based on the following equation (4). There are two methods for calculating the compression rate: a method of calculating from a restricted device communication speed and a method of calculating from a restricted recording capacity.
[0050]
Up to this point, the number of pixels Px = 1280 × 1024 (pixels) on the imaging screen, the YC data is reduced by the 4: 2: 2 method, the image data has 8 bits of luminance information, and the color difference data Since 8-bit Yc = 2 × 8 bits and frame rate Fx = 15 (Hz) have already been determined, the number of audio sampling bits Ax = 16 (bit), the sampling rate Sx = 48 (kHz), the number of audio channels When Tx = 2 (ch) and the audio compression rate is set to Cw = 1/2, the compression rate Cv of the video data is expressed by the following equation (4). Here, assuming that VWf is 1 (MB / second) of a general EEPROM transfer rate, the compression rate Cv of the image data is as follows.
[0051]
[Expression 4]

However, the number of pixels on the imaging screen Px = 1280 × 1024 (pixels)
Luminance / color difference data Yc = 2 × 8 (bit)
Frame rate Fx = 15 (Hz)
Number of audio sampling bits Ax = 16 (bit)
Sampling rate Sx = 48 (kHz)
Number of audio channels Tx = 2 (ch)
Audio compression rate Cw = 1/2
Composite data transfer rate VWf = 1 (MB / sec)
Video data compression rate Cv
Further, assuming that the shooting time is Lx = 20 seconds and the remaining recording capacity of the recording medium 42 is Qx = 16 (MB), the compression rate Cv of the image data is expressed by the following equation (5).
[0052]
[Equation 5]
  Qx ≧ VWf × Lx (B)
      ≧ (Vf + Wf) × Lx
      ≧ (Px × Yc × Fx × Cv / 8 + Ax × Sx × Tx × Cw / 8) × Lx
  Cv ≦ (Qx × 8 / Lx−Ax × Sx × Tx × Cw) / (Px × Yc × Fx) (5)
      ≦ (16000000 × 8 / 20-16 × 48000 × 2 × 1/2)
        / (1280 × 1024 × 2 × 8 × 15)
      ≒ 0.0179 ≒ 1 / 55.9
  However, shooting time Lx = 20 (seconds)
        Remaining recording capacity Qx = 16 (MB)
        Image data compression rate Cv
  The image data is compressed by adopting the smaller one of the compression ratios Cv obtained by the above equation (4) and the above equation (5). In this way, the control unit 22 determines these parameters based on the priority order among the number of recording pixels, the image quality, and the frame rate specified from the input unit 26. When the user of the electronic camera 8 gives priority to the motion image quality of the moving image, is the sport mode designated and does not reduce the frame rate, but reduces the number of recorded pixels and the color difference signal amount during YC conversion? Adjust by reducing the compression rate. Also userIs a pictureWhen giving priority to quality, adjustment is performed by reducing the frame rate while maintaining the number of recorded pixels or the compression rate. Whether the number of recording pixels or the compression rate is important is determined by a trade-off between a reduction in image resolution and an increase in compression distortion.
[0053]
In the above calculation method, calculation is performed with the compression rate of audio data fixed, but it may be changed together with the compression rate of image data. In this way, when the reduction amount of the capacity of the image data and the sound data is determined according to the data transfer speed of the recording medium and the remaining capacity of the storage medium, the process proceeds to the next S130 “Record button ON?”.
[0054]
In S130, a process of waiting until the recording button is pressed is performed. If the recording button is pressed, the process proceeds to the next S132 “compression / recording”.
[0055]
In S132, the control unit 22 transmits a command for compressing the data based on the compression rate calculated in S128, and the image data and the audio data to the compression / decompression processing unit 40 to perform the compression process. The data is read from the compression / decompression processing unit 40 and output to the recording / reproduction processing unit 44 or the communication signal processing unit 46.
[0056]
When the compressed data is transmitted to the recording / playback processing unit 44, the recording / playback processing unit 44 starts communication for recording data on the recording medium 42 and control of the memory. When the compressed data is transmitted to the communication signal processing unit 46, the communication signal processing unit 46 starts communication processing for transmitting data to the external device.
[0057]
When data transmission is started, the process proceeds to S134 “Record button OFF?” To determine whether or not the record button is pressed. If the record button has been pressed, the process branches to S132 and continues to compress and record the photographic data. If the record button has not been pressed, the process proceeds to the next S136 “END” to end the present subroutine and return to the original routine.
[0058]
FIG. 4 is a flowchart for determining a recording mode for reducing the amount of image data in the continuous recording mode according to the present invention. In the case of continuous shooting recording in which still images are continuously recorded, the control means 22 has a data amount that matches the thinning rate of the thinning circuit in the imaging signal processing unit 16 or the compression rate of the compression / decompression processing unit with the transfer rate. And so that a desired image quality and shooting interval can be obtained.
[0059]
When changing the recording mode of data for continuous shooting, the program branches to the program routine shown in FIG.
[0060]
When the process branches to Step S150 “Start” in FIG. 10, the process proceeds to the next S152 “Continuous shooting speed setting”.
[0061]
In S152, the continuous shooting speed Ex (frame / second) of the captured image is set. This continuous shooting speed corresponds to the frame rate Fx (frame / second) at the time of moving image shooting. In S152, the control unit 22 instructs the display unit 56 to indicate the continuous shooting speed setting mode, and performs a display prompting the user to set the continuous shooting speed. A user of the electronic camera 8 inputs a continuous shooting speed to the input unit 26. The control unit 22 reads the input continuous shooting speed data and displays the input content on the display unit 56.
[0062]
In the next S154 “device communication speed determination”, the process of determining the transfer speed of communication with the external device or the transfer speed for the recording medium 42 is performed in the same manner as the process of S106.
[0063]
In the next S156 “setting the number of recorded pixels”, the number of pixels of image data to be recorded is set. Here, in the case of setting with an emphasis on resolution, a higher transfer rate is required.
[0064]
In S158 “compression rate calculation”, the compression rate is calculated based on the equations (4) and (5). The calculation is performed by replacing the frame rate Fx with the continuous shooting speed Ex. In general, audio is not recorded in still image shooting, so Wf = 0 (B / second) may be set. The following equation (6) is obtained from equation (4) under the following conditions.
[0065]
[Formula 6]

However, audio data transfer speed Wf = 0 (B / sec)
Image data transfer speed Vf = 1 (MB / sec)
Composite data transfer speed VWf = Vf (B / sec)
Continuous shooting speed Ex = 5 (frame / second)
Number of recording pixels Px = 1280 × 1024 (pixels)
Color difference data Yc = 2 × 8 (bit)
Therefore, recording is possible if the data is compressed to about 1 / 13.1.
[0066]
When the continuous shooting speed Ex = 10 (frame / second) and the number of recorded pixels Px = 640 × 480 (pixels), the compression rate shown in the following expression (7) can be obtained from the above expression (6). it can.
[0067]
[Expression 7]

However, audio data transfer speed Wf = 0 (B / sec)
Image data transfer speed Vf = 1 (MB / sec)
Composite data transfer speed VWf = Vf (B / sec)
Continuous shooting speed Ex = 10 (frame / second)
Number of recording pixels Px = 640 × 480 (pixels)
Color difference data Yc = 2 × 8 (bit)
Therefore, in the case of the above setting, recording is possible if the data is compressed to about 1 / 6.14.
[0068]
Further, when the continuous shooting speed Ex = 5 (frame / second) and the compression ratio Cv = 1/8 = 0.125 is essential, the calculation shown in the following expression (8) from the above expression (5) is performed. The image data can be recorded by securing an area of the buffer memory for temporarily storing the image data.
[0069]
[Equation 8]

However, audio data transfer speed Wf = 0 (B / sec)
Image data transfer speed Vf = 1 (MB / sec)
Composite data transfer speed VWf = Vf (B / sec)
Number of recording pixels Px = 640 × 480 (pixels)
Color difference data Yc = 2 × 8 (bit)
Remaining recording capacity Qx (B)
Continuous shooting speed Ex = 5 (frame / second)
Shooting time Lx = 2 (seconds)
Continuous continuous shooting number Ex x Lx (frame)
Data compression rate Cv = 0.125
Therefore, in the case of the above setting, recording becomes possible if a buffer memory for temporary storage of 0.768 (MB) is prepared.
[0070]
In the next S160 “compression rate ≧ 1/16?”, It is determined whether or not the compression rate is 1/16 or more. If the compression ratio is not 1/16 or more as a result of the calculation of the compression ratio in S158, the compression is too much, so that the setting is made to branch to S162 “recording pixel number 640 × 480 × 2 pixels” to reduce the number of pixels. After returning to S158 again. If the compression rate is 1/16 or more as a result of the calculation of the compression rate in S158, the process proceeds to the next step S164 “Record button ON?”.
[0071]
In S164, a process of waiting until the recording button is pressed is performed. If the recording button is pressed, the process proceeds to the next S166 “Continuous Shot Compression / Recording”.
[0072]
In S166, the control means 22 outputs a command to compress the data based on the compression ratio calculated in S158, and the image data and the audio data are transmitted to the compression / decompression processing unit 40 to perform the compression process, and the compressed data is compressed. The data is read from the compression / decompression processing unit 40 and output to the recording / reproduction processing unit 44 or the communication signal processing unit 46.
[0073]
When the compressed data is transmitted to the recording / playback processing unit 44, the recording / playback processing unit 44 starts communication for recording data on the recording medium 42 and control of the memory. When the compressed data is transmitted to the communication signal processing unit 46, the communication signal processing unit 46 starts communication processing for transmitting data to the external device.
[0074]
When data transmission is started, the process proceeds to S168 “Record button OFF?” To determine whether or not the record button is pressed. Here, if the record button is pressed, the process branches to S166 and continuous shooting compression / recording of the shooting data is continued. If the record button has not been pressed, the process proceeds to the next S170 “Return” to end this subroutine and return to the original routine.
[0075]
FIG. 5 is a flowchart for determining the recording mode when the buffer memory 20 is used in the continuous recording mode according to the present invention. When the buffer memory 20 is used, the continuous shooting speed, the number of recorded pixels, the compression rate, and the number of continuous shots are set as follows. Since the data transfer rate to the buffer memory 20 is very high, the captured or recorded data is temporarily taken into the buffer memory 20 and then transferred to a recording medium or an external device.
[0076]
In the case of continuous shooting and using the buffer memory 20, the program branches to the program routine shown in FIG.
[0077]
When the process branches to “start” in step S180 in the same figure, the process proceeds to next S182 “continuous shooting speed setting”.
[0078]
In S182, the continuous shooting speed Ex (frame / second) of the captured image is set. In S <b> 182, the control unit 22 indicates that the continuous shooting speed setting mode is displayed on the display unit 56, and the user of the electronic camera 8 inputs the continuous shooting speed to the input unit 26. The control unit 22 reads the input continuous shooting speed data and displays the input content on the display unit 56.
[0079]
In the next S184 “recording pixel number setting”, the number of pixels of the image data to be recorded is set, and in the next S186 “compression ratio setting”, the compression rate for recording is set.
[0080]
In S188 “continuous shooting number setting”, the continuous continuous shooting number Ex × Lx (frame), which is the product of the continuous shooting speed Ex (frame / second) and the shooting time Lx (second), is set.
[0081]
Here, when the continuous shooting speed Ex = 5 (frame / second) and the compression rate Cv = 1/8 = 0.125 is essential, the calculation shown in the following equation (9) from the above equation (5). To secure an area of the buffer memory 20 for temporary storage of image data.
[0082]
[Equation 9]

However, audio data transfer speed Wf = 0 (B / sec)
Image data transfer speed Vf = 1 (MB / sec)
Composite data transfer speed VWf = Vf (B / sec)
Number of recording pixels Px = 640 × 480 (pixels)
Color difference data Yc = 2 × 8 (bit)
Remaining recording capacity Qx (B)
Continuous shooting speed Ex = 5 (frame / second)
Shooting time Lx = 2 (seconds)
Continuous continuous shooting number Ex x Lx (frame)
Data compression rate Cv = 0.125
Therefore, recording is possible if a buffer memory for temporary storage of 0.768 (MB) is prepared.
[0083]
In the next step S190 “Record button ON?”, A process of waiting until the record button is pressed is performed. If the recording button is pressed, the process proceeds to the next S192 “Continuous Shot Compression / Recording”.
[0084]
  In S192, the control means 22 is S186soSettingA command for compressing data based on the compression ratio is output. Further, the image data and the audio data are transmitted to the compression / expansion processing unit 40 to perform compression processing, and the compressed data is read from the compression / expansion processing unit 40 to be recorded / reproduced by the processing unit 44 or the communication signal processing unit 46. Output to.
[0085]
When the compressed data is transmitted to the recording / playback processing unit 44, the recording / playback processing unit 44 starts communication for recording data on the recording medium 42 and control of the memory. When the compressed data is transmitted to the communication signal processing unit 46, the communication signal processing unit 46 starts communication processing for transmitting data to the external device.
[0086]
When data transmission is started, the process proceeds to S194 “Record button OFF?” To determine whether or not the record button is pressed. If the record button is pressed, the process branches to S196 “number of recorded sheets ≧ set number of sheets” to determine whether the number of recorded sheets is equal to or greater than the set number. If the number of recordings is equal to or greater than the set number, the process proceeds to S198 “Return”. If the number of recordings is not equal to or greater than the set number, the process returns to S192, and continuous shooting compression / recording of the photographic data is continued.
[0087]
If the record button is not pressed in S194, the process proceeds to the next S170 “Return” to end this subroutine and return to the original routine.
[0088]
FIG. 6 is a flowchart for determining a recording mode for reducing the amount of image data in the audio recording mode according to the present invention. In the case of audio recording, the control means 22 adjusts the thinning rate of the thinning circuit in the imaging signal processing unit 16 or the compression rate of the compression / decompression processing unit to a recording rate that matches the recording medium transfer rate and the communication transfer rate. Control to obtain desired image quality and shooting interval.
[0089]
When changing the recording mode of data to be recorded by voice, the program branches to the program routine shown in FIG.
[0090]
When the process branches to step S200 “Start” in the figure, the process proceeds to the next S202 “Audio sampling rate, number of audio sampling bits, number of audio channels, audio compression rate, setting”, and each constant is set.
[0091]
In the next S204 “device communication speed determination”, the process for determining the transfer speed of communication with the external device or the transfer speed for the recording medium 42 is performed in the same manner as the process of S106.
[0092]
In S206 “compression rate calculation”, the compression rate is calculated based on the equations (4) and (5). When no image recording is performed, calculation is performed with Vf = 0 (B / second). The following formula (10) shows a calculation example of the compression rate Cw at Vf = 0 (B / sec).
[0093]
[Expression 10]
Audio data transfer speed Wf = 1 (MB / sec)
Image data transfer speed Vf = 0 (MB / sec)
Number of audio sampling bits Ax = 16 (bit)
Sampling rate Sx = 48 (kHz)
Number of audio channels Tx = 2 (ch)

As shown in the above equation (10), if there is a transfer rate of 1 (MB / second), only audio data can be transferred without compression. Further, even when the audio channel is 4 (ch), Cw≈2.642, and transfer is possible without compression.
[0094]
In the next S208 “sound compression rate ≧ sound standard?”, It is determined whether or not the compression rate is equal to or higher than the sound standard. If the result of calculation of the compression rate in S206 is that the compression rate is not equal to or higher than the audio standard, the compression is too much, so that the flow branches to S210 “Audio sampling rate 1/2” and the audio sampling rate is set to the current 1 / After performing the calculation to reduce to 2, the process returns to S206 again. If it is determined in step S208 that the compression ratio is greater than or equal to the audio standard, the process proceeds to the next step S212 "Record button ON?"
[0095]
In S212, a process of waiting until the recording button is pressed is performed. If the record button is pressed, the process proceeds to the next step S214 “Audio compression / recording”.
[0096]
In S214, the control unit 22 transmits a command for compressing data based on the compression ratio calculated in S128, image data, and audio data to the compression / decompression processing unit 40 to perform compression processing, and the compressed data is compressed. Read out from the expansion processing unit 40 and output to the recording / reproduction processing unit 44 or the communication signal processing unit 46.
[0097]
When the compressed data is transmitted to the recording / reproduction processing unit 44, the recording / reproduction processing unit 44 starts communication for recording data on the recording medium 42 and control of the memory. When the compressed data is transmitted to the communication signal processing unit 46, the communication signal processing unit 46 starts communication processing for transmitting data to the external device.
[0098]
When data transmission is started, the process proceeds to S216 “Record button OFF?” To determine whether or not the record button is pressed. If the record button is pressed, the process branches to S214 to continue the compression / recording of the audio data. If the record button is not pressed, the process proceeds to the next step S218 “Return” to end this subroutine and return to the original routine.
[0099]
【The invention's effect】
As described above, according to the signal processing device according to the present invention, when transferring image data or audio data to a recording medium or an external device, the control means can transfer the data to or from the recording medium or the external device. Since the amount of the image data and the audio data is controlled according to the capacity, it is possible to transfer and record the shooting data effectively using the data transfer speed only by instructing the priority recording condition. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an electronic camera to which an image recording method according to the present invention is applied.
FIG. 2 is a flowchart for determining a recording mode for reducing the amount of image data in the moving image recording mode according to the present invention.
FIG. 3 is a diagram showing a method for determining a transfer rate.
FIG. 4 is a flowchart for determining a recording mode for reducing the amount of image data in the continuous recording mode according to the present invention.
FIG. 5 is a flowchart for determining a recording mode when using a buffer memory in the continuous recording mode according to the present invention.
FIG. 6 is a flowchart for determining a recording mode for reducing the amount of image data in the audio recording mode according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 8 ... Electronic camera, 10 ... Shooting lens, 14 ... CCD (solid-state image sensor), 16 ... Imaging signal processing part, 18 ... Imaging timing control means, 20 ... Buffer memory, 22 ... Control means, 28 ... Microphone, 32 ... Sampling Rate generator, 34 ... A / D converter, 42 ... recording medium, 44 ... recording / reproducing processor, 46 ... communication signal processor

Claims (14)

An imaging unit that captures a moving image of a subject and obtains image data;
Compression means for compressing the image data;
A buffer memory for temporarily recording the compressed image data;
Recording means for sequentially recording image data temporarily recorded in the buffer memory;
Transfer speed detecting means for detecting a transfer speed when image data temporarily recorded in the buffer memory is sequentially transferred to the recording means and recorded;
A recording remaining capacity detecting means for detecting a recording remaining capacity recordable in the recording means;
Calculating a first compression ratio of the image data based on the transfer speed detected by the transfer speed detection means, and calculating a second compression ratio of the image data based on a recording remaining capacity of the recording means; Control means for selecting the higher compression ratio of the first and second compression ratios before starting the moving image capturing and controlling the data amount of the image data using the selected compression ratio. When,
A signal processing apparatus comprising: A frame rate setting means for setting a frame rate of the image data;
2. The signal processing according to claim 1, wherein, when the frame rate is set high, the control means controls the data amount of the image data by maintaining the frame rate of the image data as set. apparatus.   The control means reduces the number of recorded pixels when the frame rate is set high, reduces the color difference signal amount when YC conversion of the image signal acquired by the imaging unit, or compression rate 3. The signal processing apparatus according to claim 2, wherein the amount of the image data is controlled by at least one of means for controlling the image data. Further comprising a resolution emphasis setting means for setting emphasis on the resolution of the image data;
The control unit controls the data amount of the image data while maintaining the number of recording pixels or the compression rate of the image data when the setting is made to place importance on the resolution. 4. The signal processing device according to any one of items 3.   5. The signal processing apparatus according to claim 4, wherein the control means controls the data amount of the image data by lowering a frame rate of the image data when the setting that attaches importance to the resolution is performed. A sound collection unit for collecting sound and acquiring sound data when capturing the moving image;
The compression means compresses the image data and the audio data,
The buffer memory temporarily records the compressed image data and audio data,
The recording means sequentially records image data and audio data temporarily recorded in the buffer memory,
The transfer speed detecting means detects a transfer speed when the image data and audio data temporarily recorded in the buffer memory are sequentially transferred to the recording means and recorded;
The control means calculates a first compression rate combination of the image data and the audio data based on the transfer speed detected by the transfer speed detection means, and the image based on the remaining recording capacity of the recording means. A data amount of the image data and the audio data is calculated by calculating a combination of the second compression rate of the data and the audio data, and using a combination of the first compression rate and the second compression rate that results in higher compression. The signal processing apparatus according to claim 1, wherein the signal processing apparatus is controlled. An imaging unit that continuously captures an image of a subject and obtains image data;
Compression means for compressing the image data;
A buffer memory for temporarily recording the image data;
Recording means for recording image data temporarily recorded in the buffer memory;
Transfer speed detecting means for detecting a transfer speed when image data temporarily recorded in the buffer memory is sequentially transferred to the recording means and recorded;
A compression rate of the image data is calculated based on the transfer rate detected by the transfer rate detecting means, and when the calculated compression rate is high compression equal to or less than a predetermined value, the number of recording pixels is reduced and the compression rate is restarted. Control means for calculating and controlling the data amount of the image data;
A signal processing apparatus comprising: An imaging unit that continuously captures an image of a subject and obtains image data;
Compression means for compressing the image data;
A buffer memory for temporarily recording the image data;
Recording means for recording image data temporarily recorded in the buffer memory;
Recording pixel number setting means for setting the recording pixel number of the image data;
Compression rate setting means for setting a compression rate of image data in the compression means;
Continuous shooting number setting means for setting the number of continuous shooting at the time of continuous shooting;
Based on the number of recording pixels, the number of continuous shots, and the compression ratio, a recording capacity necessary to temporarily record the image data captured by the continuous shooting is calculated, and the calculated recording capacity is secured on the buffer memory. Control means for transferring the image data captured by the continuous shooting to the recording means after temporarily recording the image data in the buffer memory;
A signal processing apparatus comprising: A sound collection unit that continuously collects sound to obtain sound data;
Compression means for compressing the audio data;
A buffer memory for temporarily recording the compressed audio data;
Recording means for sequentially recording the audio data temporarily recorded in the buffer memory;
Transfer speed detecting means for detecting a transfer speed when the audio data temporarily recorded in the buffer memory is sequentially transferred to the recording means and recorded;
The compression rate of the audio data is calculated based on the transfer rate detected by the transfer rate detection means, and when the compression rate is less than the audio reference, the sampling rate of the audio data is reduced and the compression rate is recalculated. Control means for controlling the data amount of the audio data;
A signal processing apparatus comprising: The recording means transfers and records the data temporarily recorded in the buffer memory to an external device,
The signal processing apparatus according to claim 1, wherein the transfer rate detection unit acquires the transfer rate from the external device. The recording means transfers the data temporarily recorded in the buffer memory to a recording medium for recording;
The signal processing apparatus according to claim 1, wherein the transfer speed detection unit acquires information on the recording medium and determines a transfer speed to the recording medium. The recording means transfers the data temporarily recorded in the buffer memory to a recording medium for recording;
The signal processing apparatus according to claim 1, wherein the transfer rate detection unit detects the transfer rate by actually transferring data in advance.   The control means controls the data amount of the image data by changing at least one of a thinning rate, a compression rate, a frame rate, and the number of pixels of the image data. A signal processing apparatus according to claim 1.   10. The signal processing according to claim 6, wherein the control means controls the data amount of the audio data by changing at least one of a compression rate, a sampling bit number, a sampling rate, and a channel number. apparatus.

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