Why won`t my DVD play on a TV?
by Ray Williamson

[Click: How do I make DVDs that run every time? for Ray's recommendations.]

A DVD (and the same applies to CDs) created in a computer can have a number of different file systems. They are not all fully compatible with each other.

• The file system required for DVDs to play in a separate player is UDF 1.02 (UDF = Universal Disc Format).

• Windows Explorer (depending on version) can burn DVDs to UDF 1.50 , UDF 2.1 , and/or UDF 2.5 , all of which can read UDF 1.02 discs, but a UDF 1.02 player cannot read discs with a higher UDF.

In other words - as is usual with computer systems - they have backwards compatibility but not forwards compatibility.

This is the reason why your computer-made DVDs or CDs run perfectly on your computer, but may not work in a separate player, whether connected to a TV or to a projector.

With the exception of Windows Vista, which offers the option to burn to UDF 1.02 (Microsoft calls it a "mastered" burn) a separate program is required to copy files and burn DVDs. Such programs are generally supplied as part of video editing suites of software and their use is recommended.

Also noted in this article is the free program IsoBuster which will tell the user what file systems are on the disc; it will also copy files - even deleted files - from a disc and recover data, music, video, etc from corrupted files or otherwise unreadable files and damaged discs, both DVDs and CDs.

What`s the problem?

The usual scenario is that you finish editing your film, then render it and burn it to DVD. This original master DVD runs perfectly on any DVD player (viewed via TV or projector). You copy the files from this disc (or off your hard drive), and the copies run on your computer, but will not work on many DVD players. This is because the copy has an incompatible file system.

What is this UDF anyway?

UDF stands for "Universal Disc Format". At once we are in difficulties, because it is neither universal nor a format, in the sense that floppy disks and hard drives are formatted - formatting being the process in which disk sectors are numbered with an address mark so that the directory can find the location of files on the disk. Incidentally, magnetic disks are referred to as "disks", and optical discs, such as CDs and DVDs, as "discs", reflecting their respective continents and languages of origin.

UDF is a system for organising files on DVDs so that menus will work and files will play with a minimum of human intervention. CDs have a similar system based on ISO-9660, called CDFS while commercial audio CDs have a system called CD-DA/CD-ROM.

A simple system like UDF 1.02 was all well and good in the days when DVDs only came factory-made from a video shop. However, when it was decided to use CDs and DVDs for computer file storage, this was not enough.

Over the years, the UDF system has been developed so that files can be added (or deleted) easily at any time by computer, to allow files to be moved from one computer to another, and to allow the use of long filenames and similar enhancements. Each of these later types is described by Microsoft as a "live file system".

UDF 1.02, being an "older type", does not permit the later addition or deletion of files. Once files are recorded, "mastered", or "burned", onto the disc, that is it. However, as 1.02 is the only truly "universal" file system, this is the one we want most of all.

UDF version compatibility

Is it possible to change the file system on a particular disc to an earlier version?

Yes and no!

Using Windows Vista`s Windows Explorer, a file system can be changed to a different version without damage to the disc contents ... with one exception: you cannot change to 1.02 - the one we want - from a higher UDF! You can, however, copy the files and burn them onto a new disc as a "mastered" burn: that is in UDF 1.02 system. Windows 2000 and XP do not offer this facility without using a specialised utility which is usually part of editing software.

Mass-produced video DVDs all use the UDF 1.02 file system, with ISO-9660 and usually Joliet as well, and these are the ones we want for our DVDs.

Other file systems

UDF is not the end of the story. In many cases there are other file systems on the disc. These usually include two types of ISO-9660, referred to as ISO and Joliet. These are described as being in "bridge format" with UDF.

UDF, Joliet, and ISO-9660 point to the same files on the disc so that large video and audio files do not need to be duplicated on the same disc.

The purpose of ISO-9660 / Joliet is to enable discs to be read by computers made in the 1990s. Joliet is a version of ISO-9660 which copes with long filenames.

Although Vista provides UDF 1.02, it does not provide ISO-9660, which it ought to do to enable the DVD to run under some versions of Windows Media Player. Such DVDs will run in Cyberlink PowerDVD, which is often supplied with computers or editing software.

There are many other file systems, but I will not go into them here, as they are explained in IsoBuster's Help files. There are so many that it is no wonder we run into trouble!

ISO / Joliet compatibility

• Mac OS 8.1+, Windows 98, and Windows 2000 read UDF filenames
• Windows NT 4.0 and Windows 98 read Joliet filenames
• MS-DOS and Windows 95 and earlier read ISO-9660 filenames
• Mac OS 8.0 and earlier read HFS or ISO-9660 filenames.

Why do my DVDs work on some players and not others?

Because DVD players are not all equal!

Many of the modern types will play UDF 1.50 and UDF 2.1 without any trouble, but others will not.

How can you tell?

The specification published or supplied with DVD players is not always informative on this point, nor are sales staff! If it says the DVD will play "DVD-R, DVD+R, Photo CD and other types", this is a good sign. For maximum compatibility it is often best to avoid economy supermarket brands! However, the German brands from Aldi and Lidl seem to be good - I say "seem to" because, of course, types and specifications can change.

UDF 2.5 is relatively new, so it is unreasonable to expect players to handle it just yet.

How can I tell what file systems are on my disc?

There is a free program called IsoBuster which you can download from the internet from this link: www.isobuster.com The download is 2.34 MB, which takes about 15 minutes on a dialup connection. This is a useful utility as it can also recover corrupted and erased files, in many cases from badly-damaged discs. In severe cases it can pick off fragments of damaged files and join them together for you to sort out. As well as the free version, a commercial version is available, but you are unlikely to need it. IsoBuster works with DVDs, CDs, HD-DVDs, and Blu-Ray discs.

• A word of warning: files which have been deleted can be recovered with IsoBuster, so bear this in mind if the disc contains confidential material.

How do I use IsoBuster to discover which versions of file systems are on my disc?

• Start IsoBuster. It should detect your DVD/CD drive automatically. If not, or after inserting a fresh disc, click the Refresh icon.
• Right-click the name given to your disc alongside a small coloured icon (or on UNNAMED, or sometimes the date of burning, if you have not given it a name.)
• At the bottom of the menu that appears, click Properties.
• Click the Advanced tab.
• The version number appears at the top of the list.
• Repeat this process for the other occurrences of the disc name.

Can I use IsoBuster to run a file that will not work in my computer?

Yes! Use IsoBuster to extract files to your hard drive (make sure there is enough space!) and run them from there. Note that IsoBuster itself will not copy files to a fresh disc but you can use your video editing software to copy them ... or even Windows Explorer if the full set of file systems is not needed. This works the same for all video, audio, data files, documents, etc on your disc.

Does IsoBuster work with Vista?

Yes, but ... starting with Windows Vista, the Windows Help program WinHlp32.exe is no longer included with Windows operating systems. Therefore, IsoBuster`s Help files may not work, as Vista uses a new version of Windows Help. If this is the case, download the old-style Windows Help from the Microsoft support site: http://support.microsoft.com/kb/917607 You will find two files, only one of which you will need, but they do not tell you which one! My guess (it is just a guess) is that the file with the higher number is for 32 bit Vista, and the other is for 64 bit Vista systems.

This is the interface for IsoBuster:

Note that in this example the disc title to right-click to check each file system is "INCD" and "2.60 incd".

Your own DVD will probably not look as complex as this example.

Want to know more?

Try these highly informative sites: http://diskinternals.com/glossary/udf.html and http://www.dvddemystified.com/dvdfaq.html

Also look in IsoBuster`s Help files. Look up "File Systems" if you want a comprehensive list.

[Click: How do I make DVDs that run every time? for Ray's recommendations.]

21st November 2007

Ray Williamson is also a member of
Creative View Productions www.creativeviewproductions.org
and the the Baird Film & TV Initiative www.bairdfilmandtv.com
The Electric Palace Cinema, High Street, Hastings, holds a free screening and networking evening for filmmakers four times a year. For details see www.electricpalacecinema.com . Contact info@electricpalacecinema.com or telephone 01424 720393 to be placed on the mailing list.

Page updated on 21 March 2008

Authors' views are not necessarily those of The Institute of Amateur Cinematographers

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