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• FFMPEG color range cropped to 15-235 in RGB

  20 décembre 2017, par Some1Else

  I have a series of BMPs (or PNG) images that I want to convert to XVID and MP5 movie formats.

  Encoding works but the resulting movie has a washed out color look to it and the blacks are somehow moved to RGB 16 and the brightest 255 values are moved down to 235. I want the output movie to use the same 0 to 255 colors as the source frames.

  Now there are all sorts of conflicting doco out there for FFMPEG so I am hopinbg someone has an example command line that does what I need. I have tried all sorts of pix_fmt flags but none of them get the output movie in the full color range.

  For XVID

  ffmpeg.exe -framerate 60 -i "D:\SRC%05d.BMP"  -c:v mpeg4 -vtag xvid -qscale 1 -y "D:\OUTPUT.AVI""

  For H265

  ffmpeg.exe -framerate 60 -i "D:\SRC%05d.BMP" -c:v libx265 -x265-params lossless=1 -s 3840x2160 -pix_fmt yuvj420p -an -y "D:\OUTPUT.MP4""

  The yuvj420p is supposed to give the full color range but ffmpeg complains "Incompatible pixel format ’yuvj420p’ for codec ’libx265’, auto-selecting format ’yuv420p’"

  So, are there any FFMPEG gurus out there that can give me the magic switches to get my output movies with black blacks and colors that maintain the original frame files 0-255 RGB values.

• How to apply 'simple 'opacity to combined(layered) mp4s in FFMPEG

  27 mai 2021, par Cam

  I am not getting the final image results I need when layering together multiple mp4s of the same length and format into a single output MP4. I am using ffmpeg to create a pseudo 'motion blur' effect on animation, and need to layer mp4s together with identical opacities to produce the final video.

  


  I am using a base 'black' MP4 as the first layer for a background, and then adding a series of source mp4s with equal opacity over the top in each pass. Here I am showing a photoshop mockup using their 'normal' blending mode which is exactly the blending effect I am trying to replicate with ffmpeg. I understand that the final composite is less "bright" but that's fine (unless you have any ideas).


  


  Instead of looking like the result above, I am getting output where the colors are either all pink, garbled, super dark or generally hugely overbright etc based on trying different blend modes.

  


  Here are the commands I am using :

  


  To create the original (uncompressed ?) 'black' MP4 from a sequence of black pngs :

  


  ffmpeg -start_number 0 -r 24 -f image2 -s 1920x1080 -i black_seq.%04d.png -vcodec libx264 -crf 0 -pix_fmt yuv420p   black_seq.mp4 -y


  


  I then take that "black_seq.mp4" and blend a set of n number of source mp4s over the top with an opacity value. This runs in a loop and the output.mp4 of each pass becomes the input.mp4 of the next pass until it completes. In this example a total of 10 source mp4s assigns their opacity to 0.1 for each pass, and this is a single pass (below). The source mp4s are all very similar in their appearance and color, essentially just the same sequence of animation but offset in time by fractions of a single frame and have been generated from color pngs, using the same code that produced the first black layer (above).

  


  ffmpeg i input.mp4 -i n_layer.mp4 -vcodec libx264 -crf 0 -pix_fmt yuv420p   -filter_complex "blend=all_mode='overlay':all_opacity=0.1" output.mp4 -y


  


  Then finally add some compression to the result as the final "blur.mp4"

  


  ffmpeg -i "output.mp4" -vcodec libx264 -crf 25 -pix_fmt yuv420p "blur.mp4" -y


  


  And yes, this is certainly highly inefficient as an approach, but I am learning. The main issue I am trying to solve is, despite the final blur.mp4 being less "bright", it has colors that are not matching the original animation and instead looks like the animation has been hue shifted somehow.

  


  This image shows a cropped output for comparison (the processed blur is set to zero for clarity)


  


  I would love some insight.

  


• Looking function in wrong DLL

  23 avril 2021, par Samuel

  I link avcodec.lib, .... avxxx.lib (ffmpeg library) to my vs2008 project, but show the error message box "procedure entry point could not be located in the dynamic link library" while double click it.

  


  I check my program with DLL dependencies tool, it shows the program try to find DXVA2CreateDirect3DDeviceManager9 in avcodec.dll. It is impossible to find that function definitely.

  


  I also saw someone has the same problem with me.
The procedure entry point could not be located in the dynamic link library - looking in wrong DLL

  


  This post solve me problem, but why ?