| 摘要 |
<p>A method and apparatus are provided for detecting scene changes between successive fields in a digital television signal. I-frames, which start new GOPs, are aligned with scene changes. In a preprocessing stage (205, 210), the change in the sum of pixel differences between consecutive odd fields, or consecutive even fields, is calculated for every consecutive input field. A scene change is detected when a large positive value in the change of sum is followed by a large negative value therein. A decision of which picture type to use is not made until a final encoding stage (225, 235). I-frames can be inhibited when an encoder buffer level is too high. A counter resets the scene change indication to avoid a perpetual scene change state for transitions from still to motion. In film mode, the MPEG-recommended frame-based encoding is deactivated when a scene change occurred on a field boundary (e.g., when there is no redundant field in the picture).</p> |
