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4. File placement on disk

The total number of streams that can be prefetched is up to the CD buffer capacity (up to 200 sectors). Therefore, a stream that exceeds its capacity and cannot be prefetched cannot be branched without delay.

(1) Non-interleaved branch candidates

If the branch candidates for A are B and C and the file layout on the disk is as shown in Figure 4.1, only B can be prefetched.
だ け There is no problem as long as only the pre-read portion of A seeks and branches to B and C in time. However, if it is necessary to prefetch both B and C in order to delay the branch selection timing, this example can branch to C without delay.


Figure 4.1: Non-interleaved branch candidates (C cannot be prefetched)

(2) Overall interleaving of branch candidates

After playback of A, to branch to B and C without delay, there is a method of interleaving B and C after A as shown in Figure 4.2.


Figure 4.2: Overall interleaving of branch candidates (all B and C)

(3) Partial interleaving of branch candidates

As shown in Figure 4.3, there is a method of dividing B into B1 and B2, C into C1 and C2, and interleaving only B1 and C1. In this case, only a part of B and C (B1, C1) needs to be interleaved, and seeking to B2 and C2 is possible and independence is high. However, file division is required.

Figure 4.3 Partial interleaving of branch candidates (parts of B and C)

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