On Sun, Nov 22, 2020 at 11:35 AM Michael Koch <astroelectro...@t-online.de> wrote:
> Am 08.11.2020 um 18:12 schrieb ZEITFELD: > > > > > > Hello nice girls ans guys! > > > > I have a highspeed camera that records raw data to DNG files. Now I try > > to have the fastest possible preview video of what is recorded. I > > succeeded using the GPU via FFMPEG, which is absolutely the fastest way > > I found until now. > > > > This is the command line I use: > > > > FFMPEG -R 25 -F IMAGE2 -I FRAME_%06D.DNG -VCODEC LIBX264 -CRF 25 > > -PIX_FMT YUV420P PREVIEW.MP4 > > > > This gives me a MP4, but the colors are broken, the image is too dark > > and green and the quality is very bad, with a lot of banding and > > artifacts. > > > > Does anyone know how to make ffmpeg apply reasonably balanced settings > > when reading the DNGs? > > did you (or anybody else) find a solution for this problem? > There is a solution, but I gave up teaching unteachable. > > Paul did already give a few hints: > -- swscale is old and ignores color_trc metadata that is required for > correct display > -- use zscale for converting pixel formats > -- set output trc > -- make sure to set right pixel format prior to calling zscale as it > does not support bayer formats > > Open questions: > -- How can zscale be used for converting the pixel format, if it doesn't > support the "bayer_rggb16le" format that the input images have? zscale > doesn't have any options for pixel formats. > -- Is "output trc" a synonym for "transfer characteristic"? Is that the > "transfer" option in zscale? To which value must it be set? > -- How can the pixel format be set prior to calling zscale? With > "-pix_fmt" before the input? Or after the input? Or with > "-pixel_format"? Or with "format=" at the beginning of the filter chain? > -- The input color space is "sRGB". How can this be set? > > I did already spend about 20 hours of try-and-error on this problem > before I gave up. > Part of the problem is the missing documentation for the zscale filter. > That's only a list of options and possible values. No explanations what > the options mean, and no examples. > > Michael > > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".