Type-1 vs. Type-2 DV Files

DV cameras produce interleaved audio-video; each frame of video also contains the audio information. If you save DV data to an AVI file, you have a choice:

• Include the native interleaved data as one stream in the AVI file, with type ivas. This is known as a type-1 file.
• Split the DV data into separate audio and video streams, with types auds and vids. This is known as a type-2 file.

For video capture, where maximum throughput is crucial, it is better to save the data as type-1. This is because type-2 files carry redundant data: the video stream still contains audio data, which is hidden by labeling the stream as video. Also, writing a type-2 file requires some additional processor time to split the interleaved stream.

On the other hand, type-1 format can present problems for real-time editing. The application must extract the audio from the interleaved stream, make the edits, and interleave the data again. Also, the type-1 format is not compatible with Microsoft® Video for Windows® (VFW). DirectShow can handle both types of files.

For more information, about type-1 and type-2 DV files, see DV Data in the AVI File Format