I reproduced the issue in VLC v2.1.0 on Windows (8.0) and v2.0.9 (EDIT: and v2.1.1) on Mac (10.9 Maverics).
I am referring to the filter/output module called "Scene filter" that outputs frames from a video as images to a specified folder/directory.
When I use it on a .mov file (720p @ 30fps, recorded on my iPhone) and I want to extract the frames with a recording ratio of 1 (I want to output every single frame), I only get about 15 or so good ones, then the output png files seem to be sporadically empty (0 bytes). I've tested this on fairly fast PCs.
Is there a way to let it know to forget about frame rate and take as much time as it needs to do it reliably? Even with dummy video output selected (nothing gets displayed) the problem persists. If anyone with some expertise knows it to be an unlikely thing to reasonably be achievable, then please let me know. I am considering some other software tools but I like the simplicity of being able to use VLC.
I'm using the GUI to configure the output with Tools->Preferences (VLC->Preferences... on Mac), then selecting Show Settings: All and then configuring it under Video/Filters/Scene filter and switching on this filter under Video/Filters. I've also tried with the following two options under Video unchecked: "Drop late frames" and "Skip frames" but still I get a significant percentage of empty images in the output.
Also, during display when outputting the video sometimes gets a bit garbled on certain sections (looks like typical mpeg errors) and the garbledness is also reflected in some of the non-zero size frames - the ones that actually wrote a picture to disk.
Any help would be appreciated