When submitting video evidence in DVD format there are a number of issues which affect the adjudicator’s ability to view this on our existing equipment. We produce below some useful advice for both local authorities and appellants who are considering the submission of evidence in this way.
Writeable DVD’s come in a number of different formats. At the simplest level they all store data, but there are small differences between them in how they do this.
- DVD-R – supported by Panasonic, Toshiba, Apple, Hitachi, NEC, Pioneer, Samsung and Sharp.
- DVD+R – supported by Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others.
These formats support a single write only. Once a user has filled the disc with data, it cannot be overwritten and replaced with other data.
- DVD-RW – the re-writeable equivalent of DVD-R
- DVD+RW – the re-writeable equivalent of DVD+R
These formats support multiple writes. Discs can be overwritten and replaced with other data.
Most DVD recorders now support both writeable and re-writeable media of both types. For most operations all types work exactly the same.
Both standards work correctly on all drives most of the time, but there are certain issues which cause problems in specific cases.
One of these differences is when creating DVDs to store video for DVD players. The standard for commercial DVDs is for two folders to be located on the DVD, VIDEO_TS (for video files) and AUDIO_TS (for audio files, but rarely used).
Certain manufacturers of DVD recorders also create a VIDEO_RM folder. In theory, this folder is supposed to be ignored by other DVD players; however, the problem with the discs produced by these recorders is that they do not fully conform to DVD standards. This can cause the disc to play incorrectly within certain applications. The most common manufacturers of recorders to create this folder are Philips and Sony. nIt is a known issue that DVDs with the VIDEO_RM folder may not play correctly in Windows Media Player and Windows Media Center. Other PC based DVD playing solutions may also be affected.
Fortunately, there are a number of ways that this can be resolved.
If the DVD is being created by a recorder manufactured by a company that creates the VIDEO_RM folder, it will only be added to the DVD if the user uses DVD+R or DVD+RW media. As long as the recorder supports the use of DVD-R or DVD-RW media, it will generate the DVD correctly when used in conjunction with these media types.
It is therefore recommended that only DVD-R or DVD-RW media is used in the creation of DVD’s for use on home DVD players as well as computers, irrespective of the manufacturer of the recorder.
If you are in any doubt about how to prepare a DVD which can be viewed on a standard PC or a normal DVD player, you should consult the manual which accompanied the DVD recorder and/or authoring software you are using.