Efficiency Estimation of Video Compression with a Bidirectional TV Images Resizing
Abstract
The possibility of using wavelet transformations for bidirectional resize (scaling) of TV images is considered in the article. It is preliminary twice reduction of image sizes before compression and restoration of their sizes after decoding. This approach makes it possible to reduce the image data before encoding by a factor of 4 and thereby increase the efficiency of video streams encoding of broadcast and industrial TV, especially in 4K and 8K formats. But since wavelet transforms do not reduce the volume of video data inside a frame, in the article. the possibility of zeroing the array of HF (high frequency) wavelet coefficients is investigated and its impact on the visual quality of test images of various structures and scenes is assessed. It was found that direct display of low frequency coefficients in the form of pixel values leads to the appearance of point color distortions, since they can have negative values. Therefore, ways to eliminate negative values in the array of low-frequency coefficients are considered. An assessment of the efficiency increasing of video compression by using the image scaler in a wavelet video codec Dirac are presented.