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I am using IMAPIv2 to burn CD/DVDs in my C# project. I realized that the interface burns in XA-format (Mode 2). I believe XA-format is mainly used for ISOs. A lot of examples about IMAPIv2 on the web uses the following method to demonstrate total disc space and free space:

discFormatData.Recorder = discRecorder;
IMAPI_MEDIA_PHYSICAL_TYPE mediaType = discFormatData.CurrentPhysicalMediaType;
this.MediaType = GetMediaTypeString(mediaType);
fileSystemImage = new MsftFileSystemImage();
fileSystemImage.ChooseImageDefaultsForMediaType(mediaType);
MediaStateString = GetMediaStatus(discFormatData.CurrentMediaStatus);
if (discFormatData.MediaHeuristicallyBlank) MediaStateString = "Blank";

Int64 freeMediaBlocks = discFormatData.FreeSectorsOnMedia;
this.TotalDiscCapacity = 2048 * freeMediaBlocks;
Int64 userMediaBlocks = discFormatData.TotalSectorsOnMedia - discFormatData.FreeSectorsOnMedia;
this.TotalUsedDiscSpace = 2048 * userMediaBlocks;

Unfortunately, if I multiply 2048 * with TotalSectorsOnMedia as described above I will not get a correct Total Disc Capacity. When I burn a 800 MB capacity disc with IMAPIv2 then the above code will show that my disc capacity is somewhat around 650 MB. When I check the disc with other software burners, i see that the mode is set XA. Is it possible to set this mode before burning? Also, how would I solve the issue of determining disc free space if there are sessions written in mode 1? Is it possible to learn in which mode the disc is written?

Thanks.

Shimrod
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Mert Sevinc
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1 Answers1

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In order to get the total disk capacity you need to multiply the number of sectors by the length of the user data field on each sector(which on CD-ROM/XA (eXtended Architecture) Mode 2 would be 2336 bytes instead of 2048)

A sector on a CD-ROM holds 2048 bytes of user data, leaving 304 bytes for other purposes. Every data sector begins with a 16-byte header:

  • 12-byte sync field (00 ff ff ff ff ff ff ff ff ff ff 00)
  • 3 byte address (minute, second, fraction (1/75th) of a second)
  • 1 byte mode

The mode byte determines what the remaining 2336 bytes in the sector looks like:

  • Mode 0: null data; serves no practical purpose for CD recording
  • Mode 1: the typical CD-ROM layout 2048 bytes of user data 4 bytes of EDC (Error Detection Code, a 32-bit CRC) 8 bytes of reserved space, set to zeros 172 bytes of "P" parity 104 bytes of "Q" parity
  • Mode 2: 2336 bytes of user data, usually used for CD-ROM/XA

In order to retrieve the type of data provided for the sectors in one track you can use the method get_SectorType from IRawCDImageTrackInfo interface.

The possible sector types are defined by the IMAPI_CD_SECTOR_TYPE enumeration:

typedef enum  { 
 IMAPI_CD_SECTOR_AUDIO          = 0x00,
 IMAPI_CD_SECTOR_MODE_ZERO      = 0x01,
 IMAPI_CD_SECTOR_MODE1          = 0x02,
 IMAPI_CD_SECTOR_MODE2FORM0     = 0x03,
 IMAPI_CD_SECTOR_MODE2FORM1     = 0x04,
 IMAPI_CD_SECTOR_MODE2FORM2     = 0x05,
 IMAPI_CD_SECTOR_MODE1RAW       = 0x06,
 IMAPI_CD_SECTOR_MODE2FORM0RAW  = 0x07,
 IMAPI_CD_SECTOR_MODE2FORM1RAW  = 0x08,
 IMAPI_CD_SECTOR_MODE2FORM2RAW  = 0x09
} IMAPI_CD_SECTOR_TYPE;
  • IMAPI_CD_SECTOR_AUDIO With this sector type, Audio data has 2352 bytes per sector/frame. This can be broken down into 588 contiguous samples, each sample being four bytes. The layout of a single sample matches the 16-bit stereo 44.1KHz WAV file data. This type of sector has no additional error correcting codes.
  • IMAPI_CD_SECTOR_MODE_ZERO With this sector type, user data has 2336 bytes per sector/frame. This seldom-used sector type contains all zero data, and is almost never seen in media today.
  • IMAPI_CD_SECTOR_MODE1 With this sector type, user data has 2048 bytes per sector/frame. Mode1 data is the most common data form for pressed CD-ROM media. This data type also provides the greatest level of ECC/EDC among the standard sector types.
  • IMAPI_CD_SECTOR_MODE2FORM0 With this sector type, user data has 2336 bytes per sector/frame. All Mode 2 sector types are also known as "CD-ROM XA" modes, which allows mixing of audio and data tracks on a single disc. This sector type is also known as Mode 2 "Formless", is considered deprecated, and is very seldom used.
  • IMAPI_CD_SECTOR_MODE2FORM1 With this sector type, user data has 2048 bytes per sector/frame. All Mode 2 sector types are also known as "CD-ROM XA" modes, which allows mixing of audio and data tracks on a single disc.
  • IMAPI_CD_SECTOR_MODE2FORM2 With this sector type, user data has 2336 bytes per sector/frame, of which the final four bytes are an optional CRC code (zero if not used). All Mode 2 sector types are also known as "CD-ROM XA" modes, which allows mixing of audio and data tracks on a single disc. This sector type is most often used when writing VideoCD discs.
  • IMAPI_CD_SECTOR_MODE1RAW With this sector type, user data has 2352 bytes per sector/frame. This is pre-processed Mode1Cooked data sectors, with sector header, ECC/EDC, and scrambling already added to the data stream.
  • IMAPI_CD_SECTOR_MODE2FORM0RAW With this sector type, user data has 2352 bytes per sector/frame. This is pre-processed Mode2Form0 data sectors, with sector header, ECC/EDC, and scrambling already added to the data stream.
  • IMAPI_CD_SECTOR_MODE2FORM1RAW With this sector type, user data has 2352 bytes per sector/frame. This is pre-processed Mode2Form1 data sectors, with sector header, ECC/EDC, and scrambling already added to the data stream.
  • IMAPI_CD_SECTOR_MODE2FORM2RAW With this sector type, user data has 2352 bytes per sector/frame. This is pre-processed Mode2Form2 data sectors, with sector header, ECC/EDC, and scrambling already added to the data stream.

Remarks: Some sector types are not compatible with other sector types within a single image. The following are typical examples of this condition: If the first track is audio, then all tracks must be audio. If the first track is Mode1, then all tracks must be Mode1. Only the three Mode2 (XA) sectors (Mode 2 Form 0, Mode 2 Form 1, and Mode 2 Form 2) may be mixed within a single disc image, and even then, only with other Mode 2 (XA) sector types.

rmp
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