<3/5> CD Builder Script Grammar Supplementary Explanation

★ PROGRAMMER'S GUIDE ★ CD builder script grammar supplementary explanation

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CD Builder Script Grammar Supplementary Explanation

3. 3. About the relationship between sector rate and bit rate

This chapter describes the relationship between sector rate and bit rate.
Any integer value can be defined for the sector rate, but there are two typical values, 75 sectors / second and 150 sectors / second, and the bit rate (CD rate) that can be described in each case is.

CD rate (75) = 75 x 2324 x 8 = 1,394,400 (bps)
CD rate (150) = 150 x 2324 x 8 = 2,788,800 (bps)

It will be.

This means the maximum value of the sum of the bit rates that can be described in <File> ‥‥‥ <EndFile>, and if the sum of the bit rates exceeds this maximum value, the stream cannot be multiplexed.
When the disc format conforms to CD-ROM XA, the data length per sector that can be used in the MPEG multiplex differs depending on the data type, and is as follows.

MPEG video: 2296 bytes
MPEG audio: 2279
Data (FORM1): 2048
Data (FORM2): 2324

Therefore, the following conversion is required between the bit rate defined by the <BitRate> keyword and the CD rate.

Now, the bit rate of MPEG video is BR (MV), the bit rate of MPEG audio is BR (MA), the bit rate of data (FORM1) is BR (F1), and the bit rate of data (FORM2) is BR (F2). Suppose you want to do multiplex

BR (MV) x 2324 BR (MA) x 2324 BR (F1) x 2324 BR (F2) x 2324 CD rate ≧ ─────── ＋ ─────── ＋ ─────── ＋ ─────── 2296 2279 2048 2324 BR (MV) BR (MA) BR (F1) = (──── ＋ ──── ＋ ────) × 2324 ＋ BR (F2) 2296 2279 2048

It becomes the relationship of.
This relationship must always hold during multiplex, is checked at run time, and an error occurs if it violates.

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★ PROGRAMMER'S GUIDE ★ CD builder script grammar supplementary explanation