[FFmpeg-user] ~50% performance difference overlaying static image with png series using -vf/-filter_complex

[Paul B Mahol]

On 8/22/13, d-fens <d-fens at 00010111.de> wrote:
> hi,
>
> i have a background png and a sequence of pngs with transparency which
> should overlay the background.
>
> when i use
>
> ./ffmpeg -i %04d.png -vf "movie=bg.png [bg]; [in] format=rgb32, split
> [T1], fifo, [bg] overlay=0:0, [T2] overlay=0:0 [out]; [T1] fifo [T2]"
> out.mp4
>
> (taken from
> http://stackoverflow.com/questions/10438713/overlay-animated-images-with-transparency-over-a-static-background-image-using-f)
> i get arround 13fps for fullHD images, but using
>
> ./ffmpeg -loop 1 -i bg.png -i %04d.png -filter_complex
> overlay=shortest=1 out.mp4

Try removing loop and shortest.

>
> i get around 7fps for the same images.
> I guess the background image gets re-read here but thats just a guess;
> as the second, newer version looks much more clean and simple i wonder
> whats the way to get best performance in this scenario?
>
> greets!
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