Apple Final Cut Express HD - Manual (Page 216)

216 Part IV Capturing and Importing
Video Compression
HDV uses MPEG-2 compression with a constant bit rate (CBR). I-, P-, and B-frames are
used, creating a long-GOP (group of pictures) pattern.
MPEG-2 video and audio are composed of a hierarchy of data streams:
 Elementary stream: This can be a video, audio, subtitle, or other basic media stream.
Formats like HDV contain both video and audio elementary streams.
 Transport stream: A transport stream encapsulates elementary streams for real-time
distribution, such as television or Internet broadcast.
 Program stream: A program stream also encapsulates elementary streams for stored
media such as DVD or computer media files.
HDV devices store and transmit elementary video and audio streams in an MPEG-2
transport stream. When you capture HDV video, Final Cut Express HD automatically
extracts the elementary video and audio streams from the transport stream and stores
the data in tracks in a QuickTime media file.
Audio
HDV uses two audio tracks with a sample rate of 48 kHz and 16-bit resolution per sample.
The audio is encoded using the MPEG-1 Layer 2 format with a data rate of 384 kbps.
Timecode
The timecode format of an HDV camcorder matches the frame rate of the video format.
For example, 1080i50 footage uses 25 fps timecode.
Important: Some HDV camcorders do not record timecode, so you won’t be able to
precisely recapture any clips if you delete the corresponding media files.