ffmpeg -- How do I overlay a PNG over another PNG?

Question

I have PNG A with alpha layer, which I want to overlay on top of another PNG B. How do I do that with ffmpeg?

I tried ffmpeg -i A.png -i B -filter_complex "[0:v][1:v] overlay=0:0" out.png, but I only see B.

Here is the command output.

> frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
> speed=0.0883x video:2169kB audio:0kB subtitle:0kB other streams:0kB
> global headers:0kB muxing overhead: unknown ffmpeg version
> N-83044-g2a293ec Copyright (c) 2000-2017 the FFmpeg developers   built
> with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)   configuration:
> --prefix=/data/local/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/data/local/ffmpeg_build/include
> --extra-ldflags=-L/data/local/ffmpeg_build/lib --bindir=/data/local/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree   libavutil      55. 43.100 / 55. 43.100   libavcodec     57. 72.100 / 57. 72.100   libavformat    57. 62.100 / 57. 62.100   libavdevice    57.  2.100 / 57.  2.100   libavfilter     6. 68.100 / 
> 6. 68.100   libswscale      4.  3.101 /  4.  3.101   libswresample   2.  4.100 /  2.  4.100   libpostproc    54.  2.100 / 54.  2.100 Input #0, png_pipe, from '/data/output/067_90.png':
> Duration: N/A, bitrate: N/A
>     Stream #0:0: Video: png, rgba(pc), 2560x1440, 25 tbr, 25 tbn, 25 tbc Output #0, image2, to
> '/data/output/067_90_down2.png':
> Metadata:
>     encoder         : Lavf57.62.100
>     Stream #0:0: Video: png, rgba, 1280x720, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
>     Metadata:
>       encoder         : Lavc57.72.100 png Stream mapping:   Stream #0:0 -> #0:0 (png (native) -> png (native)) Press [q] to stop, [?] for help frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
> speed=0.163x video:134kB audio:0kB subtitle:0kB other streams:0kB
> global headers:0kB muxing overhead: unknown

Solution 1

If you want to overlay A on top of B, you need to switch either the file input order or the overlay ingest order.

ffmpeg -i B.png -i A.png -filter_complex "[1]scale=iw/2:-1[b];[0:v][b] overlay" out.png

Solution 2

thia answer is not using ffmpeg yet... (i try to achieve the same but with a huge amount of images and oputput to a video file) but...

using the convert and composite command from imagemagick could help, the result is an animated gif, mpeg or either a single image.

this creates an animated gif with "overlay":

convert -delay 100 -loop 0 *.png test.gif

this will result in an mpeg file:

convert *.png test.mpeg

(anyway, for the mpeg file convert also runs ffmpeg :)

to just write an overlayed image file from multiple input files, you could use composite command from imagemagick:

composite -gravity center a.png b.png out.png

this overlays b.png (e.g. background) with a.png (e.g. foreground) preserving transparency. the output is written to out.png

or use more input images, the last one is the output image:

composite -gravity center a.png b.png c.png out.png

http://www.imagemagick.org/Usage/compose/

Comments

[Sibbs Gambling]

Thanks, but I added the two options, but it's still not working.

[Sibbs Gambling]

Thanks, but I just tried, still to no avail. :-(

[Gyan]

Can you add -report and run my command? Link to the report generated.

[Sibbs Gambling]

There you go -- s000.tinyupload.com/index.php?file_id=71172992522639780031. Thanks again for your help!

[Gyan]

You want 065_0 to be on top of 065?

[Sibbs Gambling]

That's right! :-)

[Gyan]

Assuming the alpha layer isn't all black, use the edited cmd.

[Sibbs Gambling]

It works now! Thanks a lot! Could you kindly also explain [1]...[b] and overlay? Can I in general combine many commands into one?

[Gyan]

Your overlay image is twice the size of the base image, so I inserted a scale filter to downsize it. [1] is short for 'pick the best matching stream' ([1:v] is short for pick the best matching video stream - same thing in this case) and [b] is the label for the scale output which is then fed to the overlay.