Wide-band multi-format audio/video production system with frame-rate conversion
A multi-format digital video production system enables a user to process an input video program to produce an output version of the program in a final format which may have a different frame rate, pixel dimensions, or both. An internal production format of 24 fps is preferably chosen to provide the greatest compatibility with existing and planned formats associated with HDTV standard 4:3 or widescreen 16:9 high-definition television, and film. Images are re-sized horizontally and vertically by pixel interpolation, thereby producing larger or smaller image dimensions so as to fill the particular needs of individual applications. Frame rates are adapted by inter-frame interpolation or by traditional schemes, including “3:2 pull-down” for 24-to-30 fps conversions. Simple speed-up (for 24-to-25 conversions) or slow-down (for 25-to-24 conversions) for playback, or by manipulating the frame rate itself using a program storage facility with asynchronous reading and writing capabilities. The step of converting the signal to a HDTV format is preferably performed using a modified upconversion process for wideband signals (utilizing a higher sampling clock frequency) and a resizing to HDTV format frame dimensions in pixels.
1. A method of producing an audio/video recording, comprising the steps of:
receiving an input video image at a portable audio/video recording device;
converting the input video image into a digital production format by sampling the input program at a sampling frequency in excess of 18 megahertz;
providing a high-capacity digital video storage equipped with an asynchronous program recording and reproducing capability performing a frame-rate conversion; and
processing the recorded video program in the production format using the high-capacity video storage on a selective basis outputting a version of the video program having a desired frame rate and image dimensions in pixels.
2. The method of claim 1 , wherein the portable audio/video recording device is a camcorder.
3. The method of claim 1 , wherein the portable audio/video recording device is a portable communication device.
4. A portable audio/video recording device, comprising:
an image sensor, having pixel dimensions of at least 1024×576;
a graphics processor converting the input video image into a digital production format by sampling the input program at a sampling frequency in excess of 18 megahertz;
a high-capacity digital video storage equipped with an asynchronous program recording and reproducing capability and performing a frame-rate conversion; and
output circuitry processing the recorded video program in the production format using the high-capacity video storage on a selective basis to output a version of the video program having a desired frame rate and image dimensions in pixels.
5. The device of claim 4 , wherein the portable audio/video recording device is a camcorder.
6. The device of claim 4 , wherein the portable audio/video recording device is a portable communication device.