Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Corporation of America

Ren Egawa

Edwin Robert Meyer

Hee-Yong Kim

Saiprasad V Naimpally

Richard Sita

Larry Phillips

Michael Iaquinto

A video decoder compliant with the Advanced Television Systems Standard (ATSC) includes circuitry which decodes an ATSC encoded image and employs a downconversion process to produce a standard definition video signal. The video decoder includes a frequency-domain filter to reduce the resolution of the ATSC encoded signal. The video decoder downconversion system also includes a formatting section having vertical and horizontal filters, as well as resampling processing, to format the decoded and downconverted video image for a particular display and aspect ratio. The decoder senses the display format of the encoded video signal and changes the processing provided by the decoder to produce a standard definition output signal regardless of the display format of the encoded input signal. The system also includes a format converter which may be programmed to use a plurality of methods to convert the aspect ratio of the input signal for display on a display device having a different aspect ratio. In one mode, the system sequences through the possible methods to allow the user to select one method.

HDTV downconversion system

A video down conversion system compliant with the Advanced Television Systems Standard (ATSC) includes a decoder which decodes a Main Profile, High Level (MP&commat;HL) image and employs a downconversion processor to produce a standard definition video signal. The system stores a subsampled image in order to reduce memory requirements and employs an upsampling filter to generate reference image data from the stored. subsampled image. The reference image data spatially correspond to the image data produced by the video decoder before it is subsampled. The upsampling filter uses different filter coefficients based on the subsampling phase of the stored image and the half-pixel indicator in the motion vector which is used to locate the downsampled reference image data in the stored subsampled image.

Upsampling filter and half-pixel generator for an HDTV downconversion system

A discrete cosine transform domain (DCT) filter for lowpass filtering a high resolution encoded video image represented as frequency-domain coefficient values, such as macroblocks, before decimation of the video image in the spatial domain. The DCT filter masks or weights the DCT coefficients of the video image macroblocks before processing by an inverse DCT. The filter may be implemented as a block mirror filter in the frequency domain, and the filter values may be combined with the IDCT coefficient values. Original motion vectors of the high resolution encoded video image are translated because low resolution reference images used by the decoder are not equivalent to the original high resolution images. Therefore, motion vectors are scaled to retrieve low resolution prediction blocks which are up-sampled to generate the original pixel and half-pixel values in the spatial domain. The up-sampled prediction block is added to the DCT filtered inverse-DCT transformed pixel values if the current macroblock is part of a non-intraframe encoded image. After motion compensation processing of the original macroblock, the reconstructed macroblock in the lower resolution is decimated accordingly.

Frequency domain filtering for down conversion of a DCT encoded picture

An apparatus and method, applicable to variable bit rate video and constant bit rate video, is disclosed for replacing 'stuffing bytes' with private data. The invention takes advantage of the otherwise wasted resources dedicated to 'stuffing' in a data stream in order to insert private data. This is accomplished by inserting useful private data in a Transport Stream instead of the stuffing bits. That is, effectively, a re-multiplexing operation occurs where, based on the existence of certain conditions in a Transport Packet (e.g., stuffing bytes exist), the information necessary to replace stuffing bytes with private data yet still comply with established standards is accomplished. This data generally is referred to as privatestuff data in order to distinguish it from typical private data which may otherwise be encoded into a Transport Stream. The stuffing bytes removed from the Transport Packet may come from an adaptation field in the Transport Header or directly from the Transport Payload or both.

Method and apparatus for sending private data instead of stuffing bits

A method of splicing two compressed video signals which have been encoded according to the standard adopted by the Moving Picture Experts Group (MPEG) determines an amount of null information that is to be inserted between the two video signals in order to ensure that an input buffer of an MPEG decoder does not overflow after receiving the spliced video signals. The method allows a splice to occur after any access unit (picture) in the first compressed video signal. The amount of null information is determined from the data rates of the first and second compressed video signals and the amount of new data which is provided to the buffer before the data is retrieved from the buffer for both the first and second video signals. The video signals are spliced by inserting the null information, as sequence stuffing bits into a buffer immediately after the selected picture in the first video signal. The second video signal is transmitted to the buffer immediately after these stuffing bits.

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Princeton, NJ, United States of America

Ren Egawa