[FFmpeg-user] ffmpeg : images to mp4 -> exact framerate required

[Lars Michaelis]

Hi,

I'm creating a mp4 file from several images by following ffmpeg call.

     ffmpeg.exe -y -framerate 25 -i img_%08d.png -vcodec libx264 -pix_fmt 
yuv420p -preset veryslow -crf 25 out.mp4

Each image displays a timestamp in milliseconds(for output framerate = 
25 fps).

img_00000000.png => 0
img_00000001.png => 40
img_00000002.png => 80
img_00000003.png => 120
img_00000004.png => 160
img_00000000.png => 240
img_00000000.png => 320
img_00000000.png => 360

and so on.

The problem is, I need an exact framerate of 25 fps, this means every 
40ms the image shall change.

But when I am playing the created video and pause inbetween, I can see a 
time difference of up to 200ms between the playtime and the time 
dispalyed in the video itself. Allowed is only gap of 40ms. I checked 
with different players, so the problem is in the video itself.

I tried several different options, but could not solve this.

Is there any parameter available, which ensures, that each picture is 
shown exactly 40 ms.

Thanks