Owner manual

PIX 270i User Guide and Technical Information
27
Recording
** Not supported over HDMI
Progressive Segmented Frames (PsF)
Some cameras output video signal in progressive segmented frames (PsF). PsF is a method for
transmitting progressive video in an interlaced stream. A device generates PsF signal by splitting
each frame into two segments. PsF segments are the same as interlaced fields in that one segment
represents the even lines of a frame and the other segment represents the odd lines of a frame. PsF
segments differ from interlaced fields in that there is no motion between each segment in a pair.
The PIX 270i will automatically sense PsF signal from most cameras that output PsF over SDI. This
is accomplished through the use of a flag inserted into the SDI signal by the camera. If a camera does
not insert this flag into the SDI stream or if it outputs PsF signal over HDMI, then the Setup Menu
option [Video - Input PsF Detect] can be set to Interpret 1080i as PsF. This will force the PIX 270i to
treat all 1080i signal as if it were PsF and deinterlace it accordingly.
Selecting a Video Codec
Setup Menu option: [Video - Codec].
The PIX 270i has two families of intra-frame, DCT-based codecs available: Apple ProRes and Avid
DNxHD, with five levels of compression for ProRes and four levels of data compression available for
DNxHD. Both codecs are intermediate codecs that assist the editing process by eliminating the need
to transcode video before importing into Final Cut (ProRes) or Avid (ProRes or DNxHD).
ProRes is a variable data rate codec and DNxHD is a fixed data rate codec. PIX 270i supports all
compression levels and bit rates of ProRes and DNxHD and automatically records the correct bit rate
dependent upon the video input resolutions and frame rate. The data rates indicated in the Setup
Menu item [Video - Codec] indicate the maximum data rate at 1080p30.
DNxHD 36 Mb/s only supports 1080p signal. Standard definition recording is only available for ProRes
422 HQ, ProRes 422, and ProRes 422 Proxy.
Interruption of Signal During Recording
In video mode, in the event that video signal is lost (an unplugged HDMI or SDI cable, for example)
during recording, the PIX 270i will pause the recording and wait for video signal to be re-initialized.
If video signal is re-initialized recording will begin again to a new file of the same name with an
“A” appended to the end. Further interruptions of signal during that take will cause an alphabetic
filename progression (“B”, “C”, etc).
In Audio Mode, loss of video signal will have no affect on the transport state unless the video signal is the
sync reference source.
Alignment of Audio and Video
An advantage to recording audio on the PIX 270i along with the video is the elimination of audio/
video sync problems in post. The PIX 270i has many options regarding audio sources along with the
two options for video inputs, HDMI and SDI. Given this flexibility, care must still be taken to ensure
good audio/video sync.