[FFmpeg-user] Creating screencap mosaic sheet issues

[Mitch Crane]

Through some trial and error I got what appears to be a reasonable
output using the following command line:

ffmpeg -i D:\movies\input.avi -vf
"fps=fps=1/5,select='isnan(prev_selected_t)+gte(t-prev_selected_t\,5)',scale=160:90,tile=5x5"
-qscale:v 3 -y %03d_sheet.jpg

My input file was a 23.98 fps, which I rounded up to 24. I added
"fps=fps=1/5" to what you already had in your options. I arrived at
1/5 frames per second by multiplying the frame rate of the input by
the interval at which I wanted thumbnails to be captured and then
dividing that number by the number of thumbnails in each output file.
This was just a guess and I'm not sure if my logic is correct or I
just got lucky. I only verified my results by eyeballing it and seeing
that the number of thumbnails was in the ballpark of the length of the
movie in seconds divided by 5.

On Tue, Oct 7, 2014 at 11:32 AM, kosta vlotis
<kosta.vlotis.manwin at gmail.com> wrote:
> I'm trying to create a screencap mosaic sheet similar to what is shown in
> https://trac.ffmpeg.org/wiki/How%20to%20take%20multiple%20screenshots%20to%20an%20image%20%28tile%2C%20mosaic%29
> .
>
> I'm running into a few issues:
>
>    - Firstly, I can't seem to figure out how to set the screencap interval.
>    I need to set the interval to 5 seconds.
>    - Secondly, I've played with some variations of the command and what
>    seems to be happening is the same sheet gets duplicating 5 times before
>    moving on to the next.
>
>
> Screencap mosaic jpg images with the following specs need to be created:
>
>    - 5x5 tiles
>    - images must have a resolution of 160x90 @ 16:9
>    - the screencap interval must be 5 seconds.
>    - These must be created for the duration of the video.
>
>
> Here is my command line (running the latest zeranoe windows build):
> ffmpeg -i video.mpeg -vf
> "select='isnan(prev_selected_t)+gte(t-prev_selected_t\,5)',scale=160:90,tile=5x5"
> -qscale:v 3 -y %02d_sheet.jpg
>
> Can anyone help?
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