| 摘要 |
<p>Device for coding (100) and decoding (300) an extended definition video (EDTV) signal. The EDTV signal is composed of a first series of picture lines with a compatible video signal (Y, UV) and at least one second series of picture lines with a helper signal (H). An example is the PALplus signal which comprises 430 picture lines with a compatible PAL signal and two bars of 72 picture lines with a helper signal. If these 574 picture lines are subjected to conventional transform coding, at least one row of 8*8 picture blocks comprises both picture lines of the PAL signal and picture lines of the helper signal. This causes visible artefacts in the centre of a PALplus picture. In accordance with the invention, the device (100) comprises means (105-110) for adding extra picture lines (36, 37; 56, 57) to the first and/or second series of picture lines in order to bring the number of picture lines in each series to an integral multiple of 8. The extra picture lines may be constituted by a constant luminance signal (DC), the reference signal of PALplus picture line 623, or a duplicate of the most adjacent picture line from the PALplus signal.</p> |
