On 12/31/19, Mark Filipak <[email protected]> wrote: > Is your application real-time? > > On 12/30/2019 10:32 PM, Mick Finn wrote: >> You need some rule based / AI processing to determine ‘bad lighting >> sections’ - if you achieve would be viable commercial product. >> Does ffmpeg have histogram and histogram equalization features? >> Blindly doing histogram equalization on entire sequence might actually >> work depending on content. >> >> Sent from my iPhone >> >>> On Dec 31, 2019, at 6:58 AM, Oliver Dain <[email protected]> wrote: >>> >>> Hi Michael, >>> >>> Thanks for the suggestion. I'm not sure what your suggesting would work >>> for >>> us. Lets say we have a video that's 5 minutes long and there's a 5 second >>> segment somewhere in the middle that needs its levels adjusted. If we >>> used >>> your solution we'd adjust the entire video so the 5 seconds that was bad >>> would now look good but the rest of the video would look worse. We're >>> producing hundreds and hundreds of videos per day and the segments that >>> need adjusting are different for each video so manually finding the time >>> offsets where curves should be applied isn't possible (to say nothing of >>> finding the appropriate curve for each video). >>> >>> What we need is a solution that analyzes the video to detect when frames >>> are dark and then lightens only those frames. What I think we need is >>> something like the "pp=autolevels" filter but I haven't had much luck >>> with >>> that. >>> >>> Thanks, >>> Oliver >>> >>> On Mon, Dec 30, 2019 at 3:24 PM Michael Shaffer <[email protected]> >>> wrote: >>> >>>> Issues 1 and 2 would be pretty simple to fix. I would use Adobe >>>> Photoshop >>>> create a "curves" layer which can then be exported as a .crv file. The >>>> .crv >>>> file can be loaded by ffmpeg and applied to the image. Adobe Photoshop >>>> has >>>> an auto-adjust button which gets it close, then you can tweak the >>>> individual RGB values. That is how I eliminate atmospheric haze in real >>>> time on my live cam. Here's a view of how it looks: >>>> https://www.youtube.com/watch?v=_ixjB6dKsgk >>>> >>>> I'm not sure about how you would auto detect changes in the >>>> brightness/contrast. I know OpenCV can do that by calculating a >>>> histogram >>>> of the entire image. I'm not sure if ffmpeg can do that or not since >>>> I've >>>> never needed to do that. >>>> >>>> Michael >>>> >>>> >>>> >>>>> On Mon, Dec 30, 2019 at 4:52 PM Oliver Dain <[email protected]> wrote: >>>>> >>>>> Hi ffmpeg-users, >>>>> >>>>> My company, revl.com, has several videos that could be improved. We've >>>>> played around with ffmpeg filters and haven't had much success. We're >>>>> hoping to find a contractor who can help. This would be a paid contract >>>>> probably lasting about a week. >>>>> >>>>> Specifically we have 4 types of issues: >>>>> >>>>> 1. Sections of video that are too dark due to back-lighting >>>>> 2. Sections of video that are too dark due to general low-light levels >>>>> 3. Bits of video that are shaky >>>>> 4. Videos that generally look OK but could look even better with >>>> different >>>>> saturation or contrast settings. >>>>> >>>>> Ffmpeg provides a lot of filters and each filter can take a variety of >>>>> configuration options. What we're hoping to find is a set of filter >>>>> configurations (e.g. a string passed --filter-complex) that will >>>>> improve >>>>> our footage. These filters need to be configured to automatically >>>>> detect >>>>> frames that exhibit the issue; applying a filter at specific manually >>>>> determined time points is not sufficient. It is OK to tell ffmpeg which >>>>> parts of the video frame to use for determining proper light levels >>>>> however. >>>>> >>>>> If you're interested please reply directly to me and we can setup a >>>>> quick >>>>> video chat to discuss the project in detail. >>>>> >>>>> Thanks, >>>>> Oliver Dain >>>>> _______________________________________________ >>>>> ffmpeg-user mailing list >>>>> [email protected] >>>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user >>>>> >>>>> To unsubscribe, visit link above, or email >>>>> [email protected] with subject "unsubscribe". >>>> _______________________________________________ >>>> ffmpeg-user mailing list >>>> [email protected] >>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user >>>> >>>> To unsubscribe, visit link above, or email >>>> [email protected] with subject "unsubscribe". >>> _______________________________________________ >>> ffmpeg-user mailing list >>> [email protected] >>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user >>> >>> To unsubscribe, visit link above, or email >>> [email protected] with subject "unsubscribe". >> _______________________________________________ >> ffmpeg-user mailing list >> [email protected] >> https://ffmpeg.org/mailman/listinfo/ffmpeg-user >> >> To unsubscribe, visit link above, or email >> [email protected] with subject "unsubscribe". >> > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe".
There is normalize filter for RGB, and histeq filter for YUV. _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
