On Sat, 21 Oct 2023 at 22:34, pehache <pehach...@gmail.com> wrote: > Le 26/03/2021 à 00:55, Craig L. a écrit : > > Sorry. I don't think I responded to this correctly before. > > > > > > I think I tried exactly that based upon this stackoverflow question: > > > > > https://stackoverflow.com/questions/64981984/ffmpeg-transcode-uhd-h265-to-sdr-h264-without-color-loss > > > > > > The example in that post uses this command: > > > > |ffmpeg -i 4K.ts -vf > > > zscale=t=linear:npl=100,format=gbrpf32le,zscale=p=bt709,tonemap=tonemap=hable:desat=0,zscale=t=bt709:m=bt709:r=tv,format=yuv420p > > > -c:v h264 -crf 19 -preset ultrafast output.mp4 | > > > > Which I thought might be my solution but when I tried it, it ended up > > making the video too red. > > > > Same here, much too red output in the shadows. > > (I'm leaving the rest the rest of the discussion below, as it is an old > one) > > > > > > > > > On 3/25/21 4:09 PM, Pavel Koshevoy wrote: > >> On Thu, Mar 25, 2021 at 9:27 AM Craig L. <ffm...@trafficality.com> > wrote: > >> > >>> I recently started finding certain videos were washing out upon H.264 > >>> conversion. > >>> > >>> > >>> After doing some research I found that if I added -color_primaries > >>> bt2020 to the command, the color would come out correctly, but ONLY if > >>> the video was played in Quicktime. When played in Chrome, it would > look > >>> washed out. > >>> > >>> Here is a link to a screengrab showing the video in quicktime on the > >>> left and in Chrome on the right. Same video. > >>> > >>> > >>> *https://snipboard.io/N8nYv0.jpg* <https://snipboard.io/N8nYv0.jpg> > >>> > >>> > >>> > >>> > >>> After much research I can't figure out how to handle this? > >>> > >>> What is the correct way to convert these videos that I suppose are 10 > >>> bit HDR into H.264 so that they will play correctly in Chrome, etc. > >>> > >>> > >>> > >>> This is my current command: > >>> > >>> /usr/local/bin/ffmpeg -i "156237-Video2.mov" -filter_complex > >>> "scale=480:270" -color_trc smpte2084 -color_primaries bt2020 -c:v > >>> libx264 -profile:v high -pix_fmt yuv420p -level 5.1 -preset ultrafast > >>> -movflags faststart -vsync 2 -c:a aac -b:a 128k -y > >>> 156237-Video2.mov-16-9-1616621202.mp4 > >>> > >>> > >>> > >>> > >>> > >> For best possible player compatibility you really need to convert from > >> HDR10 to SDR (bt709). > >> > >> To do that you need to use either colorspace or zscale ffmpeg filter. > >> The > >> colorspace filter didn't support HLG the last time I checked, but that > >> wouldn't matter if your source is HDR10, not HLG. > >> Since you'd be converting from high dynamic range to standard dynamic > >> range > >> you would also need to use the tonemap filter. > >> > >> There is probably a LUT file somewhere that implements HDR10 -> BT709 > >> color > >> space conversion and tone mapping in one step, skipping > >> zscale/tonemap. If > >> you had such LUT you could use it with lut3d filter. > >> > >> Pavel. > > Hey there,
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