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I have two problems with FFmpeg, when I use it to join DNG files sequence into mp4 video file. I also need to downgrade the resolution of the video from 6016x3200 to 2030x1080. First of all I got almost black screen in the resulting video. Had to play with gamma and brightness options. But it was not enough!

New problems:

  1. something strange happens with aspect ratio in resulting video file: in the first frame aspect is normal, just like in the original picture, but all the rest frames are getting squeezed. can't figure out why this happen!? (see picture attached).

  2. colors are desaturated. despite the fact that I set "saturation" option to the maximum value. and also, the first frame of the video is different from the rest (while DNG files are all similar, first is no exception)

I tried prores codec as well, with the same result.

command I use is simple:

ffmpeg.exe -start_number 1 -i "K:\video\copter_R%5d.dng" -c:v libx264 -vf "fps=25,format=yuv420p, eq=gamma=3.2:brightness=0.2:contrast=1.6:saturation=3, scale=w=2030:h=1080" e:\output.mp4

I tried to use different variants of scale parameter: "scale=-1:1080" as well.

Illustration:

illustration of the problem ffmpeg dng sequence convert

UPDATE: ffmpeg log report for operation:

https://drive.google.com/file/d/1H6bdpU0Eo4WfR3h-SRtgf7WBNYVFRwz2/view?usp=sharing

AnnoyedByAds
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  • Size warning: each frame is about 15MB size. During my tests, I made conversion of 1 second video fragment, thats why I uploaded 25 frames in a folder, frames can be downloaded separetely. [link to google folder](https://drive.google.com/drive/folders/1u5m7aVAFPpEsL4YtDVsfSpfcve9PFG4m) – AnnoyedByAds Aug 16 '20 at 00:05
  • Consider making a [bug report](https://trac.ffmpeg.org/). Only 1 frame is needed. In report use `ffmpeg -i sample_r00000.dng output.png` and show the complete console output from the command. Make sure to use a recent ffmpeg version from the current git master branch for the report. This version is downloadable already compiled. See [download page](https://ffmpeg.org/download.html) for links for your OS. – llogan Aug 16 '20 at 19:09
  • llogan, thanks for reply! are you sure about only 1 frame? because the main problem with aspect ratio is seen in the rest frames, but does not present in the first... (and this is the most strange thing: I won't be surprised if all frames were squeezed). Convertion to TGA results it proper aspect ratio, the only problem is that image is way too dark, almost black screen (I wrote about it in original post). But I am more puzzled with aspect issue, and DNG to TGA doesn't reveal it... – AnnoyedByAds Aug 16 '20 at 20:30
  • You can provide a link to all 25 inputs if you prefer when you make the bug report. – llogan Aug 21 '20 at 18:18
  • Posted: https://trac.ffmpeg.org/ticket/9197 – Eugene Pankov Apr 21 '21 at 13:35

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