Digital Video - video captured to a PC from a digital camcorder, often through Firewire. There are two methods of storing DV video data, referred to in this article as type-1 and type-2. Both are stored usually in AVI files. You should be aware of two salient points regarding these respective types to keep in mind when designing multimedia devices and their respective software drivers and utilities:

Any DV stored as type-1 cannot be used with VfW-based editors.
Microsoft provides DV encoder and decoder filters for DirectShow only, and will not provide support for encoding or decoding DV video data for VfW.
It is important to understand the format used to store video and audio in an AVI file for VfW.

Although an AVI file can have n number of streams, the most common case is one video stream and one audio stream. The stream format headers define the format (including compression) of each stream. The existence of one video stream, one audio stream, or both in an AVI file is a de facto standard for VfW.

A native DV stream, on the other hand, interleaves the video and audio data into a single stream. As stated in the introduction, Microsoft is defining two methods (type-1 and type-2) that developers can use for storing DV data in AVI files. The method chosen by a developer will impact the ease with which the data can then be used with current and future video editing applications.

Type-1 Method

The native DV interleaved stream that is produced and consumed in I/O with a DV device contains DV compressed video and pulse code modulated (PCM) audio data. This single interleaved stream can be stored in an AVI file as "ivas" stream (for interleaved video/audio stream). Microsoft refers to this format as a type-1 DV AVI file.

Because the type-1 format stores data as a single AVI stream, type-1 DV AVI files are not compatible with VfW. DirectShow, however, easily handles type-1 data streams by routing the streams to a DV Splitter filter that produces a DV-encoded video stream and one or more PCM audio streams for playback or subsequent processing.

Type-2 Method

Interleaved DV data can also be split into a single video stream and one to four audio streams within an AVI file. Microsoft refers to this format of storing DV data as type-2. This format has the advantage of being backward compatible with VfW, because it contains a standard video stream and at least one standard audio stream.

The type-2 file format requires a small amount of additional processing to split and multiplex the DV stream during the functions of capture and transmit to IEEE 1394 DV devices. MS Info
Free Type 1 to Type 2 Converter from Ulead