Priority selection apparatus as for a video signal processor

In a video signal encoder, apparatus for separating digital codewords CW of compressed video signal data into two data streams of codewords CW, respective codewords CW representing different types of compressed video data and which codewords are subject to being variable length encoded with codelengths of different numbers of bits, said apparatus comprising:

• video signal compression means for providing said codewords CW;
• a source of a parameter P representing the percent of data to be allocated between said two data streams;
• memory means, coupled to said compression means, for storing a predetermined group of codewords CW, which group is associated with a predetermined image area;
• means, responsive to said parameter P for generating an indicia which indicates particular codewords CWi in said group of codewords;
• means for reading said group of codewords from said memory means in sequences of codewords, said sequences arranged according to a predetermined hierarchy of codeword types, and responsive to said indicia, for applying codewords CW according to said hierarchy through the codeword CWi to a first data stream, and applying the remaining codewords CW to a second data stream.

Apparatus for parsing compressed video data into high and low priority data streams, said video data occurring as codewords of different types, which types are categorized in a predetermined hierarchy of priority, said apparatus comprising;

• means for providing a parameter P indicative of the percentage of data to be applied to each of said high and low priority data streams;
• means for grouping codewords associated with respective predetermined image areas, and responsive to said parameter P, for determining the types of codewords in each group, which, when their respective bits are summed according to said type hierarchy in descending order of priority, will substantially equal the P.sup.th percent of the total number of codeword bits in said group;
• and
• means for applying said determined types of codewords to said high priority data stream, and the remaining types of codewords to the low priority data stream.