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Data storage capacity of a CD

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Data storage Abstract
You can fit on a S/VCD without overburning:
– approx. 735 MB of MPEG data onto a 74min/650MB disc
– approx. 795 MB of MPEG data onto an 80min/700MB disc

You can fit on a CD-ROM without overburning:
– approx. 650 MB of data onto a 74min/650MB disc
– approx. 703 MB of data onto an 80min/700MB disc

The total data capacity of user data of 1 sector on a CD
CD audio uses uncompressed PCM stereo audio, 16-bit resolution sampled at 44.1 kHz.

Thus 1 second of audio contains:
16 bits/channel * 2 channels * 44100 samples/second * 1 second
= 1411200 bits
= 176400 bytes

Since there are 75 sectors per second
1 sector
= 176400 bytes / 75
= 2352 bytes

One sector on a CD contains 2352 bytes max.

Thus:
– 74 min CD = 333,000 sectors
– 80 min CD = 360,000 sectors

Data capacity in Mb for an audio-CD
74 min
= 333,000 sectors * 2352 bytes / sector
= 783216000 bytes
= 746.9 Mb

80 min
= 360,000 sectors * 2352 bytes / sector
= 846720000 bytes
= 807.5 Mb

Data capacity in Mb for a CD-ROM
74 min
= 333,000 sectors * 2048 bytes / sector
= 681984000 bytes
= 650.4 Mb

80 min
= 360,000 sectors * 2048 bytes / sector
= 737280000 bytes
= 703.1 Mb

Data capacity in Mb for a S/VCD
74 min
= 333,000 sectors * 2324 bytes / sector
= 773892000 bytes
= 738.0 Mb

80 min
= 360,000 sectors * 2324 bytes / sector
= 836640000 bytes
= 797.9 Mb

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Conclusions
As you can see, the often quoted capacities of 650MB and 700MB refer to CD-ROM capacities.

Due to the fact that S/VCDs use a different burning mode where MORE of each sector is available as user data, the relatively capacities are HIGHER.

Now, since S/VCDs are not composed of PURELY video tracks and have some unavoidable overheads, the actually total capacity left for video tracks is a few Mb less for each disc (about 735 Mb for 74min discs and 795 Mb for 80min discs). This is where the often quoted capacities of 740MB and 800MB come from. They are quite accurate.

All these capacities are available BEFORE overburning. Overburning is where you burn MORE sectors than the disc is rated for. If you overburn, you can typically achieve about 1-2 minutes of additional capacity (depending on your drive and media).

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