A method for reducing the memory required for decompression by storing compressed information using DCT base technology and a decoder for implementing the method

摘要

Disclosed are a method for reducing the memory required for decompressing a compressed frame by storing the frame in a compressed format using DCT base technology, and a decoder for implementing the method. The decoder includes a decoder module having a parser, a block decoder module and a motion compensation engine. The decoder module is connected to a DCT encoder module whose output is connected to the memory. The decoder also includes a stored DCT decoder module, which has an input connected to a memory, a first output connected to a motion compensation module, and a second output serving as the output of the decoder.;In operation, any predictive frame needed for motion compensation decompression of the compressed frame is decompressed in the stored DCT decoder module. The compressed frame is compressed in the DCT encoder module to obtain a recompressed frame. The decompressed frame is compressed in the DCT encoder module to obtain a recompressed frame. The recompressed frame is then stored in memory. In a DCT-enabled decoder this is only done for frames with inter-picture prediction errors, such as P and S frames. Frames that do not have inter-picture prediction errors, such as I frames, can bypass most decoder modules and all DCT encoder modules. Compressed frames can be stored in memory without being decompressed and recompressed. When any frame is to be displayed they are decompressed in the memorized DCT decoder module. The digital representation of a compressed frame encoded using DCT technology is much smaller than the digital representation of a decompressed frame and requires less room in memory than the decompressed frame. The decoder needs less memory because the frames used or decoded for decoding other frames are stored in a compressed format. Due to the reduction of the memory required, the memory can be made smaller and embedded in the decoder.;In another embodiment of the present invention, the DCT decoder module stored when the decoder decodes a frame using the DCT base technology can be deleted, and the DCT decoder module included in the decoder module satisfies the following two functions. When running fast enough to perform, it can be used to decompress the compressed frame and to decompress the frames required by the motion compensation engine.