for the sake of discussion, i'll also use "ghost frames" to refer to the process i use to invoke these frames. ( nick extracrispy tells me he can do something similar in quicktime, for example.) my process involves a bug in certain versions of avidemux, though there are likely other ways you could do something similar. Specifically, i use avidemux version 2.5.4. the process is likely to work in other 2.5 and earlier versions, though i haven't tested them. it definitely does not work in the current version, 2.6.
AVIDEMUX 2.5 MAC
Avidemux 2.5.4 mac mac#Īlso, during the workshop, some mac users reported that they couldn't get avidemux to install. for os x lion/mtn lion, check these instructions for installing avidemux. I initially discovered ghost frames thanks to another glitchy behavior in avidemux.
AVIDEMUX 2.5 WINDOWS 7
my desktop computer runs windows 7 and has a video capture card for recording tv signals off a coax connection. The default tv capture program in windows 7 is called windows media center, which records programs in a format called WTV. WTV is proprietary (closed) format, but it's close enough to MPEG that when i try to open a WTV file in avidemux 2.5.4, it asks me "This looks like an MPEG. Occasionally you'll get weirder, unpredictable glitches like this: Do you want to index it?"Īnswering yes to this question and no to any follow-up questions results in a video that is recognizable but thoroughly mangled. I'd been playing around with this wtv transcoding glitch for months before i saw my first ghost frame, which i discovered by accident. to invoke ghost frames in avidemux, scroll through a damaged video backwards. if your file is damaged in the "right" way (say, via WTV transcoding), then you'll start to see frames that aren't really there: just skip to the end (or any point in the middle, if you prefer), and use your left arrow key to reverse through the file. What seems to be happening here is that avidemux is getting confused and applying incremental changes in the wrong direction.
AVIDEMUX 2.5 FULL
To save space, MPEG files only occasionally send full frames (keyframes or i-frames) and fill the rest of the video with p- and b- frames that only describe which pixels have changed since the previous frame. You can even do something i call dancing between the keyframes, inching back and forth through a glitchy area of the file as the artifacts become increasingly pronounced: (and i love the fact that you do this by going in reverse it really makes it seem like some magic ritual.) reversing through the file seems to trick avidemux into applying these changes wrong, thus revealing glitched frames that aren't actually in the file. Of course, it's one thing to see a ghost, and something else altogether to capture a ghost. ghost frames disappear just as suddenly as they appear. Skip so much as one frame too far and those ghostly glitches you've been cultivating could vanish. You can't just hold down the left arrow key and storm through the place: you have to inch along. So that's how you summon ghost frames from WTV files.
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