On 9/10/17, Richard Ling <dive...@rling.com> wrote: > I'm thinking of adding a temporal filter (one that relies on context from > previous frames), and I've realised I'm a bit confused about how they > should work. > > Say I open a file with ffplay and let it play up to frame 100. Then I open > the same file with another instance of ffplay and seek directly to frame > 100. It seems to me that frame 100 should look the same in both cases. > Put another way, a specific set of filters, applied to a specific file, > should completely define what every frame of that file looks like. Seeking > around in the file should not change that. Is that right (in principle)? > > So, looking at some of the existing temporal filters (eg. deflicker), I > don't think that is what happens. They filter based on the frames > previously passed to the filter, and if the user seeks over a bunch of > frames, the filter will see frames as consecutive that are not actually > consecutive in the file, so it will give a different result. Also, looking > at the API, I can't see a way to get the behaviour I expect. I can't see a > way for a filter to ask its inputs for a frame from a different (specific) > time. Is that right? > > If my understanding is wrong, please let me know! > > If my undersanding is correct, then I guess my questions are: > (1) is this behaviour a known issue (or a deliberate design choice)?
Both. There is no seeking in lavfi (yet). > (2) is it OK for new temporal filters to keep the same behaviour as > existing ones -- that is, they will give different results when seeking > happens, compared to sequential processing? If so I'll just do the same > thing for my filter. Yes, its OK. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
