On 4/10/16, Mark Hassman <[email protected]> wrote: > >> -----Original Message----- >> From: ffmpeg-user [mailto:[email protected]] On >> Behalf Of Paul B Mahol >> Sent: Sunday, April 03, 2016 11:42 AM >> To: FFmpeg user questions >> Subject: Re: [FFmpeg-user] videodetect filter? - equivalent >> to:https://ffmpeg.org/ffmpeg-filters.html#silencedetect >> >> On 4/3/16, Moritz Barsnick <[email protected]> wrote: >> > On Sat, Apr 02, 2016 at 17:02:19 -0400, Mark Hassman wrote: >> >> Any chance someone knows a set of filters to accomplish the same >> >> thing for video as: >> https://ffmpeg.org/ffmpeg-filters.html#silencedetect.. i.e. >> >> timestamps output for start/end of motion. >> > >> > While silence would be more like darkness in video ;-) I >> get what you >> > mean: >> > >> >> I've looked at: >> >> http://www.lavrsen.dk/foswiki/bin/view/Motion/WebHome, but already >> >> transcoding with ffmpeg - hoping to add a simple filter to >> accomplish the same. >> > >> > I too am looking for a filter which can at least imitate simple >> > features of the tool "motion", as motion only does >> real-time detection >> > from input devices. This would mean replicating "motion"'s >> algorithms >> > in a filter, or using existing filters. >> > >> > I once tried, and had come to the conclusion - from reading >> the docs - >> > that the decimate filter might be close to the right thing. >> While the >> > docs mention "regular intervals", which wouldn't be >> appropriate, they >> > also speak of "threshold for duplicate detection" and "detection of >> > [small] movements". I have never gotten the decimate filter to work >> > for anything I needed it for though, which went beyond >> motion detection. >> > >> > For anyone willing to help out, here are the main chaacteristics of >> > "motion"'s features, some of which may not be feasible >> within ffmpeg: >> > - Detection of motion by observing the number of changed pixels from >> > one frame to the next, and passing this detected frame on to the >> > output. (This could be a percentage or a mean square deviation >> > instead, but "motion" doesn't support that.) >> > - Retaining a configurable amount of images before and after the >> > detected event. >> > - Optionally visually marking the section of the video >> where the change >> > was detected. (This could be in frame metadata instead, >> but "motion" >> > doesn't support that.) >> > >> > At least the first point would be nice to have, but I'd rather not >> > implement such a filter which reinvents the wheel. >> > >> > In other words: I too would appreciate a hint as how to use >> ffmpeg's >> > filters to achieve this. >> >> See singnalstats filter. > > > Thanks for the advice! > > Using signalstats YDIF, I'm able to derive what I need. However, I'm unable > to get the data out of ffmpeg for parsing/eventing. > > The drawtext filter has access to all the set_meta values > (https://ffmpeg.org/pipermail/ffmpeg-cvslog/2014-June/078245.html) - > injecting the relevant data via graphical overlay works as expected, but I > can't find a way to push into stdout or ascii file. > > Unsuccessfully, i've been looking for another filter capable of accessing > ffmpeg's internal meta tags to accomplish this. The closest i've found is > showinfo, but i can't specify which meta tags to use. > > I've also tried the scene filter, but it modifies the video - i need only > reporting. > > Note: I'm using ffmpeg - not ffprobe as this is a live encode.. ffmpeg > doesn't support -show_entries/frame_tags. Is there any way to effectively > reproduce this with ffmpeg? >
ffprobe or with ffmpeg and metadata filter. > > Does anyone have ideas on this? > Thanks in advance! > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
