That's a great idea to use specified colours directly supported by ffmpeg and helps narrow down the issue a lot!
Would you count this as a bug? If this is a known legacy quirk, it seems one of the ugliest and most misleading quirks I have seen in a while, and I could imagine being responsible for wasting thousands of hours of thought based upon mis-diagnosed colour-profiling assumptions. I've spoken with two separate long-time video professionals so far, and they were both convinced this was a colour profile thing and that my source images were the problem, and not ffmpeg's behaviour, despite saying I checked both BMPs in a hex editor, and they were byte-identical (other than resolution/filesize). Are you using Windows per chance? To make things even more confusing, one of the aforementioned pros says he can't spot a difference on his non-Windows system (presuming Mac, could be Linux) between the two output mp4s' colours. I'm almost suspecting this is a problem only with the Windows version of ffmpeg, or at least with the OS's viewer (e.g: Chrome / Classic Media Player). Maybe Paul could confirm that. Dan On Wed, 14 Sep 2022 15:49:23 +0100, Michael Koch <astroelectro...@t-online.de> wrote:
Am 14.09.2022 um 11:21 schrieb Dan:Using the latest 5.1.1 "essentials build" by www.gyan.dev. Hi all, I'm a beginner to ffmpeg so I'm having a hard time believing that a utility so old and so widely used has such a fundamental bug, but the evidence is staring me in the face and leads me to no other conclusion. It's incredibly easy to replicate thankfully. I want to convert numerous frames to make an animation, but thankfully, I've simplified the problem to even using a single image to make a '1 frame video' for the purposes of debugging. Simply perform this command line: ffmpeg.exe -i original.png -crf 0 -vcodec libx264 output.mp4 ...With this "original.png" ("fC2Tj") image: https://i.stack.imgur.com/5jkct.png And this command line: ffmpeg.exe -i doubleHeight.png -crf 0 -vcodec libx264 output.mp4 ...On this "doubleHeight" ("RGIvA") image: https://i.stack.imgur.com/PLdsb.png The double height version is darker than it should be. I've checked the resulting video in both Media Player Classic and Chrome.The issue can be reproduced without input images as follows: ffmpeg -f lavfi -i color=0x19be0f:s=400x576 -crf 0 -vcodec libx264 -t 5 -y out1.mp4 ffmpeg -f lavfi -i color=0x19be0f:s=400x578 -crf 0 -vcodec libx264 -t 5 -y out2.mp4 The color seems to be brighter if the height is 576 or smaller, and darker if the height is 578 or larger. It's clearly visible if you play both videos side by side. I did test with VLC Player and FFplay. I don't see how zscale could fix this issue. 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".
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