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In the Forum: Didital Things
In the Thread: Windows Based Transport: A quiet and capable Source?
Post Subject: 65min Audio Data and 74 min Audio Data plus Other CodesPosted by Amir on: 8/15/2018
https://www.cdmediaworld.com/hardware/cdrom/cd_techinfo.shtml
https://en.wikipedia.org/wiki/CD-ROM
Facts:
  • One sector holds 2352 bytes of AUDIO.
  • The DATA Transfer-rate
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sampling rate * channels * audio bitsize
44100 * 2 (stereo) * 16 (16 bit) bits/second
1411200 bits/second
176400 bytes/second
Sector Transfer rate
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176400/2352 sectors/second
75 sectors/second
1 MByte AUDIO    
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1048576 bytes
1048576/2352 sectors
446 sectors
333000 sectors 
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333000/75 seconds
4440 seconds
4440/60 minutes
74 minutes
333000 sectors 
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333000/446 Mbytes AUDIO
747 Mbytes AUDIO

The reason why an AUDIO CD  holds more data/sector lays in the fact that it uses the complete 2352 bytes to store AUDIO in one sector. This means that an Audio-Byte is per default corrupt as there is no CRC checking. Due to hardware datacorrection these errors are not heard.

This method can not be used for a Data-Bytes as the data would be corrupt. To fix this problem a DATA sector contains both Data and CRC-CCITT Information.

CRC-CCITT is a 16 bit EDC (Error Detecting Code). For every byte of data a 16 bit CRC code is calculated, resulting in 128 CRCs, 16 bits each. These CRCs, therefore, take up 256 bytes of the 2352 bytes available. The remaining 48 bytes are reserved for future use. This leaves 2048 bytes available for actual Data.





It seems 65min of 74min is audio data (2048 bytes of 2352) . the only thing could convince me the ripped audio data is not equal to optical disk is that cd rom could not read correct data and cdplayer could do that.

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