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MITES DVD FAQsBelow is a list of Questions and Answers to assist you with any enquiries you may have:
How do I best prepare my tapes for DVD transfer?
How much material can I fit onto a DVD? How do I make a disc that will play in the US? How long will my DVD-R last? Dyes and relevance? Which system is best for authoring discs? How can I put a Quicktime movie onto DVD? What is a surround sound track? Can MITES reproduce my disc in large quantities? Can I make a seamless loop from my film? What qualities / advantages does DVD have over other formats? What are the possibilities for interactivity? What other technology will work with DVD-R discs? I want to make a DVD-R with subtitles that I can switch on and off - what is the best approach? Why will a DVD-R disc not play in all DVD players? Are there other common problems encountered in an exhibition environment? How do I best prepare my tapes for DVD transfer? It is important to prepare a tape correctly for DVD transfer, otherwise the material may have to be dubbed onto another source, possibly losing video information in the process. When outputting to tape, you should ensure the following: The tape has output colour bars from source at 75% for a minimum of 20 seconds at the beginning of the tape. This is useful for checking deterioration on the tape and for calibrating the signal output between the source machine and the DVD production machine there is an audio tone (if the video has audio) peaking at -10dB (this should indicate the peak audio for the video as well) and recorded at 48 kHz (this also applies to video audio) There should be black of a minimum of 20 seconds before the film starts All titles and credits must be placed for the correct duration and in the correct place After the film is finished, a minimum of 20 seconds further black is required All timecode on the tape must be continuous MITES do not recommend sending master tapes without ensuring that a further back up master is retained Back to index
How much material can I fit onto a DVD?
For the maximum quality, about one hour of video with audio. Most commercial feature film DVDs are encoded at a bitrate of 4.5 - 6 Megabits per second. MITES optimum encoding is 9.8 Megabits per second. To calculate the bitrate of your movie, divide the total duration in seconds into 36,096. If the figure is 9 or above then the maximum bitrate will be used for standard DVD-R production. More material can be fitted onto discs if going through a duplication plant. Back to index
How do I make a disc that will play in the US?
DVDs, like videos, need to conform to national television standards. As these standards are different in Europe and the US, a separate DVD will need to be made for each location. The standards (PAL for UK, NTSC for USA) are different from the region codes that limit the market in which a DVD can be sold. DVDs made at MITES are all-region discs that are normally authored to play in PAL DVD players. The MITES system can produce NTSC DVDs, but these need to be authored from NTSC videotapes. These are more expensive as additional NTSC players are required to play the tape into the system. The situation is further complicated by the fact that many PAL DVD players can play NTSC discs but few NTSC players can play PAL discs. Many artists exhibiting in the US have opted to take a PAL player with them rather than re-authoring the disc. Back to index
How long will my DVD-R last?
Among the manufacturers that have done testing, there is consensus that, under recommended storage conditions, DVD-R discs should have a life expectancy of 100 to 200 years or more; DVD-RW, DVD+RW, and DVD-RAM discs should have a life expectancy of 25 years or more. However, independent testing results are few and far between, and one of them yielded a life expectancy of 30 years for DVD-R authoring discs if stored at 25 C (77 F) and 50% relative humidity (an accelerated aging study at National Institute of Standards and Technology [NIST], based in the USA) so more work needs to be done. MITES recommend retaining and storing a non-exhibition copy of DVD-R discs for future duplication when possible, in the conditions as described above, and recommend duplication from such a disc every 15 years. It is worth bearing in mind that the DVD format uses an aggressive compression tool to fit material onto DVD discs (1 hour of uncompressed video takes up about 80 Gigabytes of space and has to be compressed down to about 4.2 Gigabytes to fill a disc). This compression is likely to make it unattractive to archivists who may prefer archived work to be as true to the original as possible. MITES have a separate digiBeta archiving and image processing facility available which is also dedicated to the clean-up and preservation of tape formats. Back to index
Dyes and relevance?
According to our investigations, Verbatim and TDK discs for Authoring use a metal-azo dye for information storage which is stable at temperatures up to 250 C and has the highest compatibility level between different manufactures of read-only devices (DVD players and Drives). Most DVD players have an optimum operating temperature of 4 - 45 C (storage - 30 - 60 C) with a maximum of 70 C, so both types are stable under properly controlled operating conditions. Back to index
Which system is best for authoring discs?
When a piece of video is encoded to MPEG-2 for use on a DVD disc, it uses a very high ratio compression system to enable the very large amount of information to fit onto DVD discs. The quality of the final image is dependent upon how well this stage is managed. Much of this management is done invisibly within the software that the system uses and is assisted by dedicated hardware. As the issue of image quality is probably the most important factor for MITES DVD users, the system we use is rated the highest for both intra-frame and inter-frame compression quality. So while newer and lower cost systems are available, it is yet to be seen whether they can achieve this standard of image quality. Back to index
How can I put a Quicktime movie onto DVD?
Either by sending it to MITES as a .mov file* or by making it into a uncompressed Quicktime file using an Avid or Media 100 suite (or any one of the transcoder software/boards/applications that support Quicktime on the market - including Final Cut Pro). * This may incur an extra cost for processing the .mov file. Back to index
What is a surround sound track?
An audio track composed of up to six separate channels that can be split between six separate speakers. DVD supports surround sound. Most DVD players support surround sound, but in order to hear the surround sound you will need either a decoder amplifier (which takes the single surround sound track from the DVD player and splits it into the separate channels) or a DVD player with built-in decoder (it will have six phono connectors on the back). MITES can composite 5.1 Surround from 6 mono .aiff sources (see above). Back to index
Can MITES reproduce my disc in large quantities?
Yes, but is worth bearing in mind that for duplication past a certain number it is more economical to go through a commercial duplication plant using the DLT facility available through MITES. This process involves Glass Mastering, a process that at present only takes place in duplication houses that have been set up with the proper conditions necessary for "Pressing" DVD discs. Generally the duplication houses would not consider pressing projects of less than 250 discs. The Glass Master is not in fact made of glass, but is a digital file designed to work with the pressing equipment. DVD disc information is pressed into the blank media whereas DVD-R disc information is recorded by changing a dye set within the layers of the blank media. Back to index
Can I make a seamless loop from my film?
It is not physically possible at present to make genuine seamless loops with DVD. This is because when the laser inside the DVD player reading the disc reaches the end, it will hold the playback on the last frame of the movie for a few frames. If the last frame is at the end of a moving sequence, some players will interlace between the last two frames, creating a juddering effect. In this case, it is generally recommended to put a few frames of black instead. If the last two image frames is relatively still, it is possible to get the players to hold this frame and create the illusion of a seamless loop. For this to work effectively MITES recommend finishing a movie sequence with three identical frames. Back to index
What qualities / advantages does DVD have over other formats?
A DVD is a high quality reproduction format that does not wear down through repeated use (like most tape formats). DVD discs have a very short search time, unlike tapes that have to be rewound or fast-forwarded to locate a specific point. DVD discs and players are cheap, light and easily transported. MITES DVD discs can be digitally duplicated for back-up whenever necessary. DVD discs offer levels of choice and interaction unprecedented by any other portable formats. Back to index
What are the possibilities for interactivity?
There are many ways in which DVD can be interactive. There can be seamless crossover between up to 32 text subtitles streams (including pictographs), 8 audio streams (including 5.1 Surround) and 9 video streams (provided they are identical durations including black). This allows a fluid transition between these elements accessed through a remote control device. There can be many more different video, audio and subtitle streams accessed within a navigable structure using menus. You can have hidden and/or moving menus, menus within a video clip to take you to another part of the disc, and so on. If you have a query, contact MITES to discuss your particular requirements. Back to index
What other technology will work with DVD-R discs?
DVD-R discs made at MITES will play on Mac DVD-Rom drives and most PCs or laptops that have DVD-Rom drives. However, because of the demanding bitrates utilised by MITES in the production of discs, CPUs with less than 1G processors may struggle with the demands of the disc. MITES' DVD players can also be synchronized together with synchronization units (available from MITES) that will enable up to ten DVD players to work simultaneously. There are several different synchronisation units available, each offering different levels of accuracy and reliability and each requiring specific DVD authoring (see below). It is also possible to use DVD in conjunction with a large number of interactive hardware in an installation environment using functions such as MIDI timecode, Dataton Trax and DMX lighting. For more information on bespoke solutions to installation enquiries, contact MITES. SYNCHRONISATION UNITS Below is a brief overview of the functionality of the most popular synchronisation units for working with DVD players: CAMBRIDGE MEDIA - Up to 9 players synching, frame accurate within 3 frames, exclusively for use with Philips Pro 175/170 DATATON - Up to 8 players synching at present, Frame accurate, works with other hardware, exclusively for use with Pioneer 7300 DVD players DAVE JONES - Up to 10 discs synching at present, frame accurate exclusively for use with Pioneer 7300 DVD players Back to index
I want to make a DVD-R with subtitles that I can switch on and off - what is the best approach?
Where possible when dealing with subtitles a professional subtitling company should be used to prepare the text. MITES can either work with or put people in touch with a third party for this. However it also is possible for MITES to import subtitles directly into its DVD production software for significantly cheaper results (£2 per minute as oppose to £16 per minute as an average commercial rate). If this is required it is important to prepare subtitles in the following way: The texts should be prepared in Simpletext or Notepad (i.e. it should be a simple text format without any of the additional information put in by software such as Word) and adhere to the follow format - Number of subtitle; tab; timecode in point; tab; timecode outpoint; return for new line i.e. 001 01:05:10:00 01:05:19:00 The cat sat on the mat 002 01:05:19:01 01:05:21:01 and ate a big rat The maximum number of characters per line is 43 (this includes spacing). If a line exceeds this, you must wrap it to the next line (again using return and then the tab key) For general purposes the maximum number of lines is 2. It is advisable to stick to San Serif fonts for clarity of display and to supply a few test files for compatibility checking. MITES cannot be held responsible for grammatical errors, and it is important if you are using unusual fonts (or type with non-English symbols), pictographic fonts (Japanese/Chinese etc.) or images, that you inform MITES at the earliest possible stage as these may require a different authoring approach. Back to index
Why will a DVD-R disc not play in all DVD players?
All DVD-R discs (like those at MITES) are made differently from those made in the pressing or duplication plants (where all commercial discs are made). In a duplication plant discs are pressed rather than burnt onto the blank media (DVD-R discs are burnt into the blank media) and most commercially available players are produced only with the specifications of commercially available discs in mind (which makes the players cheaper to produce). Consequently, there can be compatibility problems playing DVD-R discs with some players. MITES have found the most reliable to be the Philips 170/175 (a semi-professional machine which MITES can supply for exhibition purposes), and Pioneer 7300 players. It is always recommended that you try your disc in a player before buying. Back to index
Are there other common problems encountered in an exhibition environment?
There are many variables within the process of DVD production and installation that can affect the smooth running of discs. The most important factor for DVDs made at MITES is to ensure optimum quality for exhibition purposes, and as such the highest possible bitrate (speed of information off the disc) is used. This high bitrate can sometimes affect playback in non-professional player (see above for recommendations). Although the operating temperatures limits in DVD players are quite wide (see Dyes and Relevance? above), it has been noted that certain players have a tendency to trip up during playback. This may be down to a number of reasons: THE AMBIENT TEMPERATURE/HUMIDITY IS TOO HIGH - despite what the manufactures say, in practiced some players (even professional ones) have a tendency to overheat when left looping discs all day long in enclosed conditions. There are several ways to avoid this: 1. Avoid stacking DVD players on top of each other, otherwise ensure a minimum of 30cm between players. 2. Keep the area well ventilated with a fan if necessary, you want to avoid raising the temperature above 20 C and 50% relative humidity 3. Keep the area dust free as DVD players tend not to have fans and fine dust, particularly from MDF, can lodge on the boards and heat up the player. 4. Keep players well away from any other heat source, especially radiators, projectors and amplifiers. THE DISC IS DAMAGED - DVD players have a built in error-correction but if the discs damage exceeds the capabilities of this device then the discs will start to skip and/or stall. Scratches on the disc surface or grease and dirt will all effect play performance. THE PLAYER IS NOT POWERFUL ENOUGH - DVD-R discs require a lot of processing power to get the information stored off the disc and onto screen and if a player cannot achieve or does not have the processing speed necessary to play the highest rates then the disc may start to skip or even stop altogether. Always check with the manufacturer as to the BITRATE capabilities of the player to be used, or allow time to run the disc for one complete day in the installation situation and enough time to either source a more capable player or have the discs re-authored at a lower Bitrate if necessary. MITES recommend using professional level DVD players such as the Pioneer DVD-V7300 or the Philips Pro 175. THE DISC IS NOT A DVD-R DISC OR THE DVD PLAYER DOES NOT ACCEPT THE DISC TYPE YOU HAVE - all DVD players and disc types are not the same, ensure that the player you have can play the disc type that you have. MITES can produce DVD-R discs for Authoring and General Purpose Media at either 3.95G or 4.7Gcapacity. MITES can also offer a duplication service for multiple DVD discs (upwards of 250) for larger files which are identical to a commercially available disc, through a third party. Please contact MITES for costs of this process. LABELS THICKNESS MAY AFFECT PLAYBACK ON SOME PLAYERS - There has been some suggestion that the labelling of discs can have some effect on playback. In extensive tests involving gradually increasing the thickness and creasing on MITES labels there appears to be no evidence to support this claim when tested using Pioneer 7300 and Philips Pro175 professional standard machines (the machines on which all of MITES DVD discs are tested on before dispatch). Back to index
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DVD & DIGITAL MASTERING
Digital Mastering Noise Reduction Surround Sound 5.1 Compositing Duplication/Archiving Costs Image Processing Costs DVD Production Costs DVD FAQs
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