[FFmpeg-user] Output video size depending on frame rate while creating video from image list

[Stéphane Saffré]

Hi again,

Sorry for that, the email was accidentally sent...

I am creating a video from a list of images and as the video frame rate is
not important in my use case, I have experimented with different frame
rates and noticed that the ouput video size changes a lot depending on the
chosen frame rate to reach a minimum size limit.

Here is the command I ran for different frame rates:

ffmpeg -framerate 60 -start_number 1 -i %d.jpg -c:v libx264 -r 60 -pix_fmt
> yuvj420p  out-60fps.mp4


Here is some info on different output videos with different frame rate:

fps     video size    bit rate      bit/frame
> 30      47368102      16841991      561399.7
> 60      37289465      26516952      441949.2
> 100     30917271      36642691      366426.91
> 1000    30917271      366426915     366426.915


The bit rate increase as expected with the frame rate but the number of
bits per frame decrease slowly to reach a certain limit (note that the
video size is the same for 100 and 1000 fps).

I did notice a small decrease in image quality between lower and higher
frame rates but I don't have a rational explanation to this. Do you have
any idea ?

Thank you for your help.

--
*Stéphane SAFFRÉ*

2016-05-09 22:47 GMT+02:00 Stéphane Saffré <stephane.saffre at gmail.com>:

> Hello,
>
> I am creating a video from a list of images and
>
> --
> *Stéphane SAFFRÉ*
>