Sound Devices PIX 220i - Manual (Page 34)

Video Scaling and Frame Rate Conversion
PIX recorders feature powerful, hardware-based video scaling, frame rate conversion, and de-inter-
lacing. This allows for converting the resolution and frame rate of video input to the recorded file
and to the HDMI and SDI outputs in real-time.
Video scaling and/or de-interlacing is active whenever the Setup Menu option
Video  File Resolution/Rate is set to something other than Same as Video Input. Any input
signal can be converted to any resolution. When set to record progressive frames, the PIX recorders
will convert incoming interlaced video to progressive frame video via its built-in, powerful, hard-
ware-based de-interlacer. The PIX recorders will also convert progressive segmented frame (PsF)
video to progressive video automatically if a progressive file (for instance 1080p30) is selected in
Video  File Resolution/Rate (If an interlaced file is selected, the PIX recorder will record PsF signal
unaltered, but the file will be stamped as interlaced).
Frame rate conversion occurs whenever the frame rate of Video
 File Resolution/Rate differs
from the frame rate of the input video signal. Frame rate conversion is achieved by appropri-
ately duplicating or dropping frames. The PIX recorder will auto-sense between integer and non-
integer frame rates (for instance 30 frames vs. 29.97 frames). The PIX will not frame rate convert
between integer and non-integer values. For example, if the incoming video signal is 1080i59.94,
it can be converted to 1080p29.97 or 720p59.94 but not 1080p30 or 720p60. The Setup Menu option
Video  File Resolution/Rate contains entries with a combination of integer and non-integer frame
rates (such as 1080p30/29.97). When any of these options are selected, the PIX recorder will record in
the indicated integer frame rate if the input video is an integer frame or record in the indicated non-
integer frame rate if the input video is a non-integer frame rate.
Not all frame rate conversions are visually desirable. When the OSD Item
File Resolution/Rate is red, the conversion of the frame rate of the input video to the frame set by
Video  File Resolution/Rate will contain a finite amount of motion judder. For example, if the
incoming video is 720p60 and Video  File Resolution/Rate is set to 720p50, the cadence of dropped
frames may be noticeable depending on the content. Conversions which are simply 1:2 or 2:1 (such
as 1080i59.94 to 1080p29.97) introduce no motion judder. For these conversions, the OSD Item
File Resolution/Rate stays white.
When the input video signal is 720p24 or 720p23.976, up-, down-, and cross-conversion is not available.
3:2 Pulldown Removal
Many cameras which shoot with a shutter speed of 24/23.976 frames per second will output signal on
the HDMI or SDI output at 60i/59.94i. To achieve this, the camera performs a “3:2 pulldown” pro-
cess. The 3:2 pulldown process splits each frame into 2 fields and duplicates a field periodically. The
PIX recorders are capable of removing 3:2 pulldown from a 60i/59.94i signal and converting it back
to 24/23.976 progressive frames per second in real-time. The PIX 3:2 removal process actively views
video fields looking for duplicates. When these duplicates are sensed, then this cadence is locked in
and the appropriate extra fields are removed. The process depends on motion in the incoming video.
The OSD File Resolution/Rate changes from orange to white when this cadence is detected:
PIX 220i and PIX 240i Video Recorder User Guide
32
v. 3.52 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
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