Futatabi (after the Japanese word *futatabi*, 再び, meaning “again” or
“for the second time”) is a system for instant replay. Even though Futatabi
is meant to be used with Nageru, shares some code with it and is built from
-the same source distribution (with matching version numbers), it is a separate
+the same source distribution, it is a separate
application. Futatabi is meant for slow motion for e.g. sports broadcasts, but
can also be used as a more generic multitrack recorder for later editing.
Futatabi currently uses a GPU reimplementation of
`Fast Optical Flow using Dense Inverse Search (DIS) <https://github.com/tikroeger/OF_DIS>`_
-by Kroeger et al, although this may change in the future.
+by Kroeger et al, together with about half of the algorithm from
+`Occlusion Reasoning for Temporal Interpolation Using Optical Flow <https://www.microsoft.com/en-us/research/publication/occlusion-reasoning-for-temporal-interpolation-using-optical-flow/>`_
+(to do the actual interpolation based on the estimated
+optical flow), although this may change in the future.
+
+Since Futatabi is part of the Nageru source distribution, its version number
+mirrors Nageru. Thus, the first version of Futatabi is version 1.8.0,
+which is the Nageru version when it was first introduced.
System requirements
quality, or just wish to test, you can use a faster preset, or turn off
interpolation entirely. Futatabi requires OpenGL 4.5 or newer.
-For other required libraries, see :doc:`compile`; when you build Nageru,
-you also compile Futatabi.
+For other required libraries, see :ref:`compile`; when you build Nageru,
+you also build Futatabi.
Getting started
Sample multicamera data
'''''''''''''''''''''''
+Good multicamera sample video is hard to come by, so it can be hard to
+test or train before an actual event. To alleviate this, I've uploaded some
+real-world video from the very first event where an early version of Futatabi
+was tested. (There are some issues with the JPEG quality, but it should
+largely be unproblematic.) You are free to use these for training or
+demonstration purposes. Do note that they will not be displayed entirely
+correctly in most video players (see :ref:`futatabiformat`), although
+they will certainly be watchable.
+
+There are two files:
+
+ * `Trøndisk 2018, finals only (MJPEG, 77 GB) <https://storage.sesse.net/trondisk2018-finals-multicam-mjpeg.mkv>`_:
+ The final match, in MJPEG format (roughly 52 minutes). This can be downloaded
+ and then fed directly to Nageru as if it were a real camera stream
+ (remember the --slow-down-input option).
+ * `Trøndisk 2018, entire tournament (H.264, 74 GB) <https://storage.sesse.net/trondisk2018-multicam-h264.mp4>`_: The entire tournament,
+ with no cuts (roughly 12 hours). However, due to space and bandwidth
+ constraints, it has been transcoded to H.264 (with some associated
+ quality loss), and needs to be transcoded to MJPEG before Nageru can use it.
+
+Both files are mixed-resolution, with some cameras at 1080p59.94 and some
+at 720p59.94 (one even switches between matches, as the camera was replaced).
+They contain four different camera angles (overview camera on crane, detail camera
+in tripod, two fixed endzone overhead cameras) with differing quality depending
+on the camera operators. In short, they should be realistic input material
+to practice with.
+
+Please download these files only once, instead of streaming them directly over
+HTTP each time you want to test.
+
+
Transferring data to and from Nageru
------------------------------------
+.. _futatabiformat:
+
Video format specification
''''''''''''''''''''''''''
projects / nageru-docs / blobdiff