AJA Video Capture
|From Release :||2016.1|
This page contains some notes specific to AJA Video capture.
We support capturing video, audio and timecode data.
Video capture is subject to the following :
- No 2160p (quad-SDI) video formats. Attempting to set such a format with capture mode will fail.
- No high frame rate (> 30 fps) 1080p video formats. Attempting to set such a format with capture mode will fail.
- No stereo (capture or layoff). Attempting to set stereo with capture mode will silently ignore desired stereo.
- Only 10-bit YUV422 and 10-bit RGB444 colour representations.
The RGB444 supports dual-link and 3G level B connectivity. Attempting to set any other colour representation with capture mode will fall back to a supported colour representation.
Audio can be captured from :
- Embedded SDI audio or
- AES/EBU inputs
- 2016.1 Timecodes for captured frames are read from SDI (not from the VTR via RS422).
- 2017.1 Timecodes for captured frames are read from the VTR via RS422.
AJA Video capture in 2016.1 therefore relies on the VTR device sending timecodes embedded in the SDI stream. This requirement no longer applies from 2017.1.
Connections and Modes
Single / Dual Link Modes
- Single Link - When only a single link is in use, input is taken from SDI input 1, which is port 1 on Kona 3G and Kona 4 cards.
- Dual-Link - When dual link is in use, channel 1 of the dual link must be passed to SDI input 1 (port 1) and channel 2 to SDI input2 (port 2).
Video, audio and time codes are usually passed through from the SDI input ports to the corresponding SDI output ports, permitting monitoring of the stream being captured. The pass-through output is configured exactly the same as the input (e.g. if the input is dual-link 10-bit RGB444, then so is the output). Video and audio should also be passed through to HDMI.
- 2016.1 Video outputs always pass through input video when capturing.
- 2017.1 Pass-through of input video when capturing is an option, chosen when the "Capture SDI Output" preference is set to "Direct Pass-through". For some users' SDI setups, this pass-through behaviour can cause SDI signal timing issues because the timing of the passed-through SDI video is not the same as the timing of SDI video actively output by the SDI card. In this case, the "Capture SDI Output" preference can be set to "Blank" to produce black output with the SDI card's normal output timing when capturing. This will resolve such timing issues but input video will not be passed through.
On AJA cards where the direction of the SDI ports is configurable, SDI ports 1 and 2 now remain configured as inputs when the card is used to output video.
This is only for formats that are not 2160p.
This enables video input to SDI port 1 to be used as a video synchronisation source for video output. The means the Input Video option is always available in the Output Sync preference.
When 2160p video formats are active, which need to use all 4 SDI ports as outputs, the card will fall back to using internal sync if set to use Input Video.