Patent ID: 7143432
Filing Date: 2006-11-28
Classification: H04N

Abstract:
1. A circuit at a network device and which is configured to form an output video stream, the circuit comprising: a cropper block to receive a plurality of video frames from a frame buffer and to extract at least a portion of each video frame; a resolution modification circuit configured to receive the plurality of video frames from the cropper block, and configured to modify resolution of the plurality of video frames, if a desired resolution for the output video stream is different than a resolution of an input video stream, the plurality of frames being derived from the input video stream; a frame reduction circuit coupled to the resolution modification circuit configured to reduce a number of video frames in the plurality of video frames from the resolution modification circuit, if a desired frame rate for the output video stream is different than a frame rate of the input video stream; a depth reduction circuit coupled to the frame reduction circuit configured to reduce bit depth of the plurality of video frames from the frame reducing circuit, if a desired bit depth for the output video stream is different than a bit depth of the input video stream; a rate reduction circuit coupled to the depth reduction circuit, configured to scale the plurality of video frames from the depth reduction circuit, in response to a desired bit rate for the output video stream, which is a different bit rate than other output video streams from the network device; an encoder coupled to the rate reduction circuit, configured to encode the plurality of video frames from the rate reduction circuit into the output video stream, wherein the cropper block, resolution modification circuit, frame reduction circuit, depth reduction circuit, rate reduction circuit, and encoder can share data with each other and form part of a transcoder block at the network device that receives a single input video stream having the plurality of video frames, the transcoder block having a plurality of encoders, each of the plurality of encoders at the network device being capable to generate an output video stream that is different than other output video streams simultaneously generated by other encoders at the network device, in a manner that the network device can select and send multiple different simultaneous output video streams having different bit rates corresponding to respective multiple different client device characteristics and channel conditions, at least some of the simultaneous output video streams having a bit rate that exceeds a bit rate capability of a least-capable client device; and an encryptor block to encrypt at least one of the output video streams, wherein a horizontal resolution of a frame from at least one of the output video streams is a fractional multiple of a horizontal resolution of a video frame from the plurality of video frames derived from the input video stream, wherein at least some of the output video streams can have same encoding formats but differences in frame rates, bit rate, color depth, color format, or resolution, wherein if the input video stream includes compressed digital data, the transcoder block is configured to de-compress the compressed digital data into decompressed data and to re-compress the decompressed data so that some of the multiple simultaneous output video streams have different compression formats, and wherein the resolution modification circuit, frame reduction circuit, depth reduction circuit, rate reduction circuit can perform at least one of upsample, increase number of frames, increase color depth, and increase bit rate, respectively, of the simultaneous output video streams during transmission if the client device characteristics or channel conditions permit such increases, and wherein the resolution modification circuit, frame reduction circuit, depth reduction circuit, rate reduction circuit can perform at least one of subsample, decrease number of frames, decrease color depth, and decrease bit rate, respectively, of the simultaneous output video streams during transmission if desired characteristics for the output video streams require a reduction from those of the input video stream.