I have installed it. It changes the version number I have to 12.0.96.1. So far, I have only experimented a little with its claimed ability to improve playback of AVCHD/H.264 video since that seems to be causing the most angst at the moment.
I have done 3 experiments so far: the first with AVCHD from a Panasonic S9; another with video from what I think is a Sony (though it might have been a JVC); and from the Canon website example of its new 24 Mbps AVCHD cameras. There is some good news and some bad.
First, the good news. It will be recalled from other threads that a major concern with edited AVCHD has been the very noticeable blips occurring mostly after inserted transitions in AVCHD. In all of my experiments, I took about 30 seconds of video from the various cameras (and in the case of the Canon 24 Mbps simply repeated the 10 second sample clip), and inserted randomly chosen F/X Transitions in several cuts made or where clips were joined. I then chose Share > Create Video File > Same as First clip (since I had an AVCHD, and no title or anything else at the beginning of the projects). In each case, it took about 2.5 times (and in the case of the S9 video, a little over 3x) real time to render a new AVCHD file.
In the case of the Sony (?) and Canon playback of the newly rendered video, I could detect NO blips at all, let alone associated with the transitions. I think this will be very good news if others find the same thing when they install the patch. I would stress here that I have previously used this same video in all three cases in the past, and had blips in rendered files in all 3 cases when I inserted transitions and rendered new files.
Unfortunately, part of the bad news is that there were still slight blips in the case of the Panasonic S9 footage following each transition.
The other bad news also affects the Panasonic. The Pansonic has been problematic in both VS11.5+ and X2 in even being able to play back the video in Clip Mode and particularly so in Project mode. With the patch, it certainly plays now absolutely smoothly on my Quad in Clip mode. Unfortunately. It is still very jerky and erratic in Project Mode. Worse, when the edited project was rendered, the resulting clip -- though it played smoothly in a way -- had not only the blips mentioned above, but various other artifacts and the occasional hang or jerk which had obviously been rendered into it rather than being a problem in playback.
More generally, I cannot say that I detected any improvement at all in playback in all three cases above in Project Mode. That remains very erratic. But as I say, the rendered new file plays absolutely smoothly with all edits and no transition blips in two of the three cases.
I hope others will now install the patch and report back here on their experiences. Hopefully, there will be good news at least for some...


