Methods and systems for constraining a video signal
AssigneeBroadcom Corporation
InventorsDarren Neuman, Patrick Law, Alek Movshovich, Chuck Monahan
Life of this patent
Estimating the term…
Abstract
Systems and methods for filtering to comply with copy-protection regulations set forth for HDTV signals by the Motion Picture Association of America (“MPAA”) are presented. A copy-protection filter constrains the resolution of the HDTV signal when copy-protection bits are present in a video signal. The copy-protection filter may be placed in an analog data stream before the video signal is converted from a digital to an analog signal. A second copy-protection filter is optionally placed in a digital data stream. The copy-protection filter may be combined with other filters in a video encoder, or with a scaler before the input video data stream enters a compositor.
Claims25
A device for constraining a video signal, comprising:
- a compositor configured to mix a video data stream and a graphics data stream to produce the video signal;
- and
- a video encoder coupled to the compositor,
- wherein the video encoder comprises at least one copy-protection filter configured to constrain, based on the presence of input copy-protection bits, the resolution of the video signal to comply with an output frame format, and
- wherein the at least one copy-protection filter includes a low pass cutoff frequency based on the output frame format.
A device for constraining a video signal, comprising:
- a scaler, for scaling a video data stream;
- a compositor configured to mix the video data stream and a graphics data stream to produce the video signal;
- and
- a video encoder coupled to the compositor,
- wherein the scaler includes at least one copy-protection filter configured to constrain, based on the presence of input copy-protection bits, the resolution of the video signal to comply with an output frame format, and
- wherein the at least one copy-protection filter includes a low pass cutoff frequency based on the output frame format.
A method of constraining a video signal, comprising:
- (a) searching for input copy-protection bits;
- (b) filtering, by a video encoder, pixels of the video signal, when input copy-protection bits are present, to decrease the resolution of the video signal to comply with an output frame format;
- (c) passing the video signal through a low pass filter with a cutoff frequency based on the output frame format;
- and
- (d) outputting the decreased-resolution video signal.
A method of constraining a video signal having an initial resolution, comprising:
- (a) inputting the video signal;
- (b) constraining, by a video encoder, the video signal to a fraction of the initial resolution when input copy-protection bits are present to comply with an output frame format, wherein said fraction is based on an initial frame format and the output frame format, and wherein the constraining includes passing the video signal through a low pass filter with a cutoff frequency based on the output frame format;
- and
- (c) outputting the constrained video signal.
A method of filtering a raster video signal, comprising:
- constraining a video data stream when input copy-protection bits are present to comply with an output frame format, wherein the constraining includes passing the video signal though a low pass filter with a cutoff frequency based on the output frame format;
- mixing the constrained video data stream and a graphics data stream to produce a constrained composite video signal;
- and
- encoding, by a video encoder, the constrained composite video signal.
A method of constraining a video signal having an initial resolution, said method comprising:
- (a) inputting the video signal;
- (b) inserting sync timing signals into timing portions of the video signal;
- (c) constraining, by a video encoder, data portions of the video signal when input copy-protection bits are present to a fraction of the initial resolution to comply with an output frame format, wherein the constraining includes passing the video signal through a low pass filter with a cutoff frequency based on the output frame format;
- and
- (d) outputting an output video signal,
- wherein the output video signal includes both constrained data portions and unconstrained timing portions.
Dependencies are inferred from the claim text.