Media Recognition: DV part 3

DVCAM (encoding)

Type:	Digital videotape cassette encoding
Introduced:	1996
Active:	Yes, but few new camcorders are being produced.
Cessation:	-
Capacity:	184 minutes (large), 40 minutes (MiniDV).
Compatibility:	DVCAM is an enhancement of the widely adopted DV format, and uses the same encoding. Cassettes recorded in DVCAM format can be played back in DVCAM VTRs (Video Tape Recorders), newer DV VTRs (made after the introduction of DVCAM), and DVCPRO VTRs, as long as the correct settings are specified (this resamples the signal to 4:1:1). DVCAM can also be played back in compatible HDV players.
Users:	Professional / Industrial.
File Systems:	-
Common Manufacturers:	Sony, Ikegami.

DVCAM is Sony’s enhancement of the DV format for the professional market. DVCAM uses the same encoding as DV, although it records ‘locked’ rather than ‘unlocked’ audio. It also differs from DV as it has a track width of 15 microns and a tape speed of 28.215 mm/sec to make it more robust. Any DV cassette can contain DVCAM format video, but some are sold with DVCAM branding on them.

Recognition

DVCAM labelled cassettes come in large (125.1 x 78 x 14.6 mm) or MiniDV (66 x 48 x 12.2mm) sizes. Tape width is ¼”. Large cassettes are used in editing and recording decks, while the smaller cassettes are used in camcorders. They are marked with the DVCAM logo, usually in the upper-right hand corner. 

HDV (encoding)

Type:	Digital videotape cassette encoding
Introduced:	2003
Active:	Yes, although industry experts do not expect many new HDV products.
Cessation:	-
Capacity:	1 hour (MiniDV), up to 4.5 hours (large)
Compatibility:	Video is recorded in the popular MPEG-2 video format. Files can be transferred to computers without loss of quality using an IEEE 1394 connection. There are two types of HDV, HDV 720p and HDV 1080, which are not cross-compatible. HDV can be played back in HDV VTRs. These are often able to support other formats such as DV and DVCAM.
Users:	Amateur/Professional
File Systems:	-
Common Manufacturers:	Format developed by JVC, Sony, Canon and Sharp.

Unlike the other DV enhancements, HDV uses MPEG-2 compression rather than DV encoding. Any DV cassette can contain HDV format video, but some are sold with HDV branding on them. 

There are two different types of HDV: HDV 720p (HD1, made by JVC) and HDV 1080 (HD2, made by Sony and Canon). HDV 1080 devices are not generally compatible with HDV 720p devices. The type of HDV used is not always identified on the cassette itself, as it depends on the camcorder used rather than the cassette.

Recognition 

HDV is a tape only format which can be recorded on normal DV cassettes. Some MiniDV cassettes with lower dropout rates are indicated as being for HDV, either with text or the HDV logo. These are not essential for recording HDV video. 

Media Recognition: DV part 2

DV (encoding)

Type:	Digital videotape cassette encoding
Introduced:	1995
Active:	Yes, but tapeless formats such as MPEG-1, MPEG-2 and MPEG-4 are becoming more popular.
Cessation:	-
Capacity:	MiniDV cassettes can hold up to 80/120 minutes SP/LP. Medium cassette size can hold up to 3.0/4.6 hrs SP/LP. Files sizes can be up to 1GB per 4 minutes of recording.
Compatibility:	DV format is widely adopted. Cassettes recorded in the DV format can be played back on DVCAM, DVCPRO and HDV replay devices. However, LP recordings cannot be played back in these machines.
Users:	DV is aimed at a consumer market – may also be used by ‘prosumer’ film makers.
File Systems:	-
Common Manufacturers:	A consortium of over 60 manufacturers including Sony, Panasonic, JVC, Canon, and Sharp.

DV has a track width of 10 microns and a tape speed of 18.81mm/sec. It can be found on any type of DV cassette, regardless of branding, although most commonly it is the format used on MiniDV cassettes. 

Recognition

DV cassettes are usually found in the small size, known as MiniDV. Medium size (97.5 × 64.5 × 14.6 mm) DV cassettes are also available, although these are not as popular as MiniDV. DV cassettes are labelled with the DV logo.

DVCPRO (encoding)

Type:	Digital videotape cassette encoding
Introduced:	1995 (DVCPRO), 1997 (DVCPRO 50), 2000 (DVCPRO HD)
Active:	Yes, but few new camcorders are being produced.
Cessation:	-
Capacity:	126 minutes (large), 66 minutes (medium).
Compatibility:	DVCPRO is an enhancement of the widely adopted DV format, and uses the same encoding. Cassettes recorded in DVCPRO format can be played back only in DVCPRO Video Tape Recorders (VTRs) and some DVCAM VTRs.
Users:	Professional / Industrial; designed for electronic news gathering
File Systems:	-
Common Manufacturers:	Panasonic, also Philips, Ikegami and Hitachi.

DVCPRO is Panasonic’s enhancement of the DV format, which is aimed at a professional market. DVCPRO uses the same encoding as DV, but it features ‘locked’ audio, and uses 4:1:1 sampling instead of 4:2:0. It has an 18 micron track width, and a tape speed of 33.82 mm/sec which makes it more robust. DVCPRO uses Metal Particle (MP) tape rather than Metal Evaporate( ME) to improve durability.

DVCPRO 50 and DVCPRO HD are further developments of DVCPRO, which use the equivalent of 2 or 4 DV codecs in parallel to increase the video data rate.

Any DV cassette can contain DVCPRO format video, but some are sold with DVCPRO branding on them.

Recognition
DVCPRO branded cassettes come in medium (97.5 × 64.5 × 14.6mm) or large (125 × 78 × 14.6mm) cassette sizes. The medium size is for use in camcorders, and the large size in editing and recording decks. DVCPRO 50 and DVCPRO HD branded cassettes are extra-large cassettes (172 x 102 x 14.6mm). Tape width is ¼”.

DVCPRO labelled cassettes have different coloured tape doors depending on their type; DVCPRO has a yellow tape door, DVCPRO50 has a blue tape door, and DVCPRO HD has a red tape door.

Images of DVCPRO cassettes are available at the Panasonic website.

Media Recognition: DV part 1

DV can be used to refer to both a digital tape format, and a codec for digital video. DV tape usually carries video encoded with the DV codec, although it can hold any type of data. The DV format was developed in the mid 1990s by a consortium of video manufacturers, including Sony, JVC and Panasonic, and quickly became the de facto standard for home video production after introduction in 1995. Videos are recorded in .dv or .dif formats, or wrapped in an AVI, QuickTime or MXF container. These can be easily transferred to a computer with no loss of data over an IEEE 1394 (Fire Wire) connection.

DV tape is ¼ inch (6.35mm) wide. DV cassettes come in four different sizes: Small, also known as MiniDV (66 x 48 x 12.2 mm), medium (97.5 × 64.5 × 14.6 mm), large (125.1 x 78 x 14.6 mm), and extra-large (172 x 102 x 14.6 mm). MiniDV is the most popular cassette size.

DV cassettes can be encoded with one of four formats; DV, DVCAM, DVCPRO, or HDV. DV is the original encoding, and is used in consumer devices. DVCPRO and DVCAM were developed by Panasonic and Sony respectively as an enhancement of DV, and are aimed at a professional market. The basic encoding algorithm is the same as with DV, but a higher track width (18 and 15 microns versus DV’s 10 micron track width) and faster tape speed means that these formats are more robust and better suited to professional users. HDV is a high-definition variant, aimed at professionals and consumers, which uses MPEG-2 compression rather than the DV format.

Depending on the recording device, any of the four DV encodings can be recorded on any size DV cassette. However, due to different recording speeds, the formats are not always backwards compatible. A cassette recorded in an enhanced format, such as HDV, DVCAM or DVCPRO, will not play back on a standard DV player. Also, as they are supported by different companies, there are some issues with playing back a DVCPRO cassette on DVCAM equipment, and vice versa.

Although all DV cassette sizes can record any format of DV, some are marketed specifically as being of a certain type; e.g. DVCAM. The guide below looks at some of the most common varieties of DV cassette that might be encountered, and the encodings that may be used with them. It is important to remember that any type of encoding may be found on any kind of cassette, depending on what system the video was recorded on.

MiniDV (cassette)

Type:	Digital videotape cassette
Introduced:	1995
Active:	Yes, but is being replaced in popularity by hard disk and flash memory recording. At the International Consumer Electronics Show 2011 no camcorders were presented which record on tape.
Cessation:	-
Capacity:	Up to 80 minutes SP / 120 minutes LP, depending on the tape used; 60/90 minutes SP/LP is standard. This can also depend on the encoding used (see further entries). Files sizes can be up to 1GB per 4 minutes of recording.
Compatibility:	DV file format is widely adopted. Requires Fire Wire (IEEE 1394) port for best transfer.
Users:	Consumer and ‘Prosumer’ film makers, some professionals.
File Systems:	-
Common Manufacturers:	A consortium of over 60 manufacturers including Sony, Panasonic, JVC, Canon, and Sharp

MiniDV refers to the size of the cassette; as noted above, it can come with any encoding. As a consumer format they generally use DV encoding. DVCAM and HDV cassettes also come in MiniDV size.

MiniDV is the most popular DV cassette, and is used for consumer and semi-professional (‘prosumer’) recordings due to its high quality.

Recognition

These cassettes are the small cassette size, measuring 66 x 48 x 12.2mm. Tape width is ¼”. They carry the MiniDV logo, as seen below:

Media recognition - Floppy Disks part 3

3 inch Disks (Mitsumi 'Quick Disk')

Type:	Magnetic storage media
Introduced:	?1985
Active:	Unlikely.
Cessation:	Used in the 1980s.
Capacity:	?128KB - 256KB
Compatibility:	Requires a 3” drive appropriate to the manufacturer's specifications.
Users:	Likely to have been individual users and small organisations. Used for word-processing, music and gaming.
File Systems:	Unknown. May vary according to use. The disks were manufactured by Mitsumi and offered as OEM to resellers and used in a range of contexts including Nintendo (Famicom), various MIDI keyboards/samplers (Roland) and the Smith Corona Personal Word Processor (PWP).
Common Manufacturers:	Disks: Mitsumi appear to have made the magnetic disk (the innards), while other manufacturers made the cases. This resulted in different case shapes and labelling. For example Sharp Corona labelled the disks as DataDisk 2.8".  Drives: Mitsumi?

Recognition

The Smith Corona Personal Word Processor (PWP) variant of the disk is double sided with one side being labelled ‘A’ and the other ‘B’. Each side also had a dedicated write-protect hole, known as a 'breakout lug'.

2.8" Smith Corona 'Quick Disk'

3.5" floppy side-by-side with a 2.8" Smith Corona 'Quick Disk'

Nintendo Famicon disk
Some rights reserved by bochalla

High Level Formatting

Unknown. Possibly varied according to use.

3 Inch Disk Drives
Varied according to disk. The Smith Corona word processing disks are most likely to turn up in an archival collection. These were used in a Smith Corona PWP and possible models nos. include: 3,5,6, 6BL, 7, X15,X25, 40, 50LT, 55D, 60, 65D, 75D, 80, 85DLT, 100, 100C, 220, 230, 250, 270LT, 300, 350, 355, 960, 990, 2000, 2100, 3000, 3100, 5000, 5100, 7000LT, DeVille 3, DeVille 300, Mark X, Mark XXX, Mark XL LT. 

Lego mockup of a Nintendo Famicon drive

Some rights reserved by kelvin255

 

 

Useful links
http://www.cromwell-intl.com/technical/quickdisk-recovery.html
http://en.wikipedia.org/wiki/History_of_the_floppy_disk

Media Recognition Guide - Flash Media

Flash memory is the alternative to byte-programmable memory, which is used by hard, floppy and Zip disks. It is much less expensive, meaning large capacity devices are economically viable and has faster access times and much better shock resistance and durability. Altogether this makes it particularly suitable for use as a portable storage device. Flash memory does have a finite number of write-erase cycles, but manufacturers can guarantee at least 100,000 cycles, which is a much larger number than with byte-programmable memory.

USB Flash Drive

Type:	Flash memory data storage device with USB interface
Introduced:	2000, though the company that invented the device is a legal issue.
Active:	Yes
Cessation:	-
Capacity:	First drive had a capacity of 8 MB but the latest versions can have capacities as large as 256 GB
Compatibility:	Widely supported by modern operating systems including Windows, Mac OS, Linux and Unix systems.
Users:	Broad. Has replaced 3.5” floppy disks as the preferred device for individuals and small organisations for personal data storage, transfer and backup.
File Systems:	FAT, NTFS, HFS+, ext2, ext3
Common manufacturers:	Many manufacturers and brands including Sandisk, Integral, HP, Kingston Technology and Sony

Recognition

USB flash drives can come in a range of shapes and sizes, but as a general rule they measure somewhere in the region of 70mm x 20mm x 10mm and all have a male USB connector at one end. Capacity also varies widely, though the majority of manufacturers specify this either by printing the information on the casing or etching it onto the connector.

Using the word ‘drive’ is misleading as nothing moves mechanically in a USB flash drive. However, they are read and written to by computers in the same way they read and write to disk drives, therefore they are referred to by operating systems as ‘drives’.

The only visible component is the male USB connector, often with a protective cap. Inside the plastic casing is a USB mass storage controller, a NAND flash memory chip and a crystal oscillator to control data output. Some drives also include jumpers and LEDS and a few also have a write-protect switch.

High Level Formatting

USB drives use many of the same file systems as hard disk drives, though it is rare to find a drive that contains a version that pre-dates its creation. Therefore, USB drives most likely contain FAT32, rather than FAT16 or FAT12. FAT32 is the file system most commonly found on USB drives due to its broad compatibility with all major operating systems. NTFS can be used but it is not as reliable when used on operating systems other than Windows. If a drives is intended for a specific operating system, you can expect to find either HFS+ (for Macs) or ext2 or ext3 (for Linux).

Formatting a disk is done in the same way as formatting a floppy disk. If being done on a Windows operating system for example the only difference is you will right click on the USB drive icon, rather than the floppy drive.

FireWire Flash Drive

Type:	Flash memory data storage device with firewire interface
Introduced:	2004
Active:	Yes
Cessation:	-
Capacity:	Either 4, 8 or 16 GB
Compatibility:	Compatible with any computer with a firewire connector
Users:	Limited. Never achieved the same popularity as USB flash drives. They come in smaller sizes and have slower memory
File Systems:	FAT, NTFS, HFS+, ext2, ext3
Common manufacturers:	Kanguru

Recognition

FireWire flash drives look similar and are similar in construction to USB drives, the one difference being that they use a FireWire connector, rather than a USB one. Due to this they have different data transfer rates and capacities than USB drives. Depending on which version of FireWire the drive has been manufactured with it has a transfer rate of either 49.13, 98.25 or 393 MB/s. With the exception of 40.13 MB/s, these rates exceed that of the latest USB version, however they have a much smaller capacity. Furthermore they are heavier and more expensive and fewer computers have the appropriate FireWire connectors compared to those with USB ports. Thus, FireWire flash drives have never dominated the market and are fairly rare.

High Level Formatting

FireWire drives only differ from USB drives in their type of connector, therefore they will contain the same file systems and can be formatted in the same way.

Media Recognition Guide - Iomega Zip Disks

Type:	Removable disk storage
Introduced:	1994
Active:	Yes, but used by minority
Cessation:	-
Capacity:	Either 100, 250 or 750MB
Compatibility:	Zip drive needs to be of a matching or higher capacity than the Zip disk. Supports Windows OS, IBM OS/2, Mac OS 7.6 to 9.2, MAC OS X and some Linux OS.
Users:	Small businesses and personal users to backup files
File Systems:	NTFS, FAT, ext2, HFS/+, ADFS
Common manufacturers:	Iomega

Recognition

The Zip disk was introduced by Iomega in 1994 as a medium capacity removable storage device to rival 3.5” floppy disks. There are three versions with capacities of 100, 250 and 750 MB, which is considerably more than a 3.5” floppy disk, and Zip disks have a quicker data transfer rate: 1 MB/s compared with a HD 3.5” floppy disk’s rate of 15.6 KB/s. However, Zip disks never reached the same popularity as floppy disks and could not compete with other forms of removable storage, such as CDs which offer much larger capacities. Therefore sales declined and use is limited at the time of writing [2010], though zip drives and disks are still available for purchase from online retailers.

Zip disks are physically similar to floppy disks, except they are larger and not quite rectangular. Their dimensions are 97 x 98 x 6mm compared to 3.5” floppy disk dimensions of 90 x 94 x 3mm.

Zip drives are more compact than floppy drives. Dimensions vary, but are around 170 x 110 x 25mm, although drives with a SCSI interface are larger, measuring 193 x 139 x 44mm. Drives are external and attached to a computer via an interface, either PATA, SCSI, USB or FireWire. Very early drives had an IDE interface (the forerunner to PATA), but these are not common. Not every interface can be found on each type of Zip drive. Below is a table setting out which interface is compatible with each drive:

Drive	Interface
	PATA	SCSI	USB	FireWire
Zip 100	Yes	Yes	Yes	No
Zip 250	Yes	Yes	Yes	Yes
Zip 750	Yes	No	Yes	Yes

High Level Formatting

Zip disks use the same file systems as floppy disks, with the most common being FAT for use with Windows, HFS or HFS+ for use with Mac OS and ext2 for use with Linux. Many disks come preformatted, but can still be reformatted by the user to suit their operating system.

Formatting with Windows

This is done in the same way as formatting floppy disks: with the disk inserted in the drive open ‘My Computer’, right click over the Zip disk drive icon and select ‘Format’. There are two options; either ‘Short Format’ or ‘Long Format’ and you can change the file system used with either option by selecting either Mac or PC. Click ‘Start’ and the disk will be formatted.

Formatting with Mac OS

Insert the disk into the zip drive. Open the IomegaWare folder then open the ‘Tools’ folder and double click on the Tools icon, which will open up the window. From here click on the appropriate icon for the disk you wish to format. There are two options, either ‘Short Erase’ or ‘Long Erase’. Long Erase should be used for disks containing errors. Select ‘Erase’ to begin formatting the disk. All content will be erased and the disk will be formatted to a file system appropriate for Mac OS (HFS/+).

Formatting with Linux

Formatting a zip disk using Linux is done in the same way as formatting floppy disks, the difference being you type man zip instead of man floppy. For more details see: http://linux.die.net/man/8/floppy