As part of various broadcasters requests media provided for broadcasting environment must be PSE (Photosensitive Epilepsy) free. There should be not frames sequences that could trigger that symptoms.
I would like to know if there exists some free software for quality check media in mov, mp4 and mxf with dnxhd, h264 and prores codecs and if ffmpeg can do it showing the possible harmful patterns and passages.
Thanks!
Unfortunately, I don't know of any free software that checks for PSE. As of 2013, the test for PSE was only available closed source. However, all of the major commercial QC tools can check for it. (You would need to check with each vendor if it is supported for all of the codecs you need to QC.)
I wrote an ffmpeg filter which attempts to do this. It's not perfect, but it does seem to work well with a good part of the test samples I was working with.
It has now been included into ffmpeg, and should be available in the next release.
With mpv, you can enable it with:
mpv video.mp4 --vf=photosensitivity
The filter can be made more or less strict by changing its parameters, e.g.:
mpv video.mp4 --vf=photosensitivity:threshold=0.5 # lower is stricter
To check how bad a video is from the command line, you can run the filter in bypass mode, and look at the verbose output:
ffmpeg -i video.mp4 -vf photosensitivity=bypass=1 -v verbose -f null /dev/null
The output would have lines such as:
[photosensitivity @ 000000000929aa80] badness: 69183 -> 70173 / 15360 (456% - EXCEEDED)
For programmatic use, the filter also produces some frame metadata. You can ask ffmpeg to export it to a text file as follows:
ffmpeg -i video.mp4 -vf photosensitivity=bypass=1,metadata=print:file=photosensitivity-analysis.txt -f null /dev/null
The created photosensitivity-analysis.txt file will have one block of lines such as these per frame:
frame:300 pts:300 pts_time:10
lavfi.photosensitivity.badness=4.269336
lavfi.photosensitivity.fixed-badness=4.269336
lavfi.photosensitivity.frame-badness=0.459766
lavfi.photosensitivity.factor=1.000000
When badness is greater than one, the badness threshold has been exceeded.
Some Broadcasters require a Harding Test which is patented and proprietary, it creates a Certificate; thus getting someone to accept liability isn't going to be free.
You can find a number of places online that will test a video file (or Game, Poster, Art, etc.) but those aren't free, the Harding website has authenticated tests and support.
Free software claiming to perform the same checks (so when you submit your work, it won't be rejected) is available from the University of Maryland in the form of PEAT, their Photosensitive Epilepsy Analysis Tool.
Note: Restrictions on use
The Photosensitive Epilepsy Analysis Tool (PEAT) was developed to provide a free resource for Web designers and computer software developers. Use of PEAT to assess material commercially produced for television broadcast, film, home entertainment, or gaming industries is prohibited. For broadcast, film, home entertainment, and gaming applications, the Harding FPA software should be employed.
To get the real thing, a Certificate, you'll need to pay. To get software that claims to do the same thing without accepting liability or providing the authentic Certificate is possible, I found that source with less than 10 min. of searching.
