I have a series of png's that have an alpha channel as a background. Each file is named like file_name.0001.png and so on, in subsequent order. I'd like to join these png's into a video with ffmpeg and maintain the transparency.
I've tried a couple of things but I suspect I'm running into a codec issue. When I run ffmpeg, the video is created but the background is black.
If it makes a difference, I'm wanting to use the video in Microsoft Powerpoint. Thanks!
Edit
The suggested duplicate is very close to what I was looking for, thank you! The only reason it's not a complete solution is none of the options presented in the other thread work well with Microsoft Powerpoint. None of the codecs used in the suggested solution play well with Powerpoint. This is not the fault of ffmpeg, but of Powerpoint.
Though ffmpeg doesn't seem to be able to do what I need, I found that imagemagick did the trick. I was able to create a gif from the images and the alpha channel was preserved. I used the following:
convert -dispose 3 -coalesce images.*.png gif_file_name.gif
The -dispose 3 is critical as it tells imagemagick to clear the image prior to overlay, otherwise, you can see each image overlaid on each other (since they have the transparent background).
I couldn't get ffmpeg to create a video that preserved the alpha channel and was Powerpoint friendly (not the fault of ffmpeg). Though ffmpeg doesn't seem to be able to do what I need, I found that imagemagick did the trick. I was able to create a gif from the images and the alpha channel was preserved. I used the following:
convert -dispose 3 -coalesce images.*.png gif_file_name.gif
The -dispose 3 is critical as it tells imagemagick to clear the image prior to overlay, otherwise, you can see each image overlaid on each other (since they have the transparent background).
Related
I have use ffmpeg and mp4parser to add image watermark on video.
both works when video size is small like less than 5MB to 7Mb but
when it comes to large video size(anything above than 7MB or so..)
it fails and it doesn't not work.
what are the resources that helps to adding watermark on video quickly. if you have any useful resources that please let me know?
It depends on what exactly you need.
If the watermark is just needed when the video is viewed on the android device, the easiest and quickest way is to overlay the image with a transparent background over the video view. You will need to think about fullscreen vs inline and portrait vs landscape to ensure it lines up as you want.
If you want to watermark the video itself, so that the watermark is included if the video is copied or sent elsewhere, then ffmpeg is likely as fast as other solutions on the device itself. If you are able to send the video to a server and have the watermark applied there you will have the ability to use much more powerful compute resource.
I have transferred some film to video files from 16mm (native 4:3). The image looks great.
When I scanned them, I scanned to a native 16:9. As I overscanned them, I got the entire height of the frame, which is what I want. But it also got the soundtrack and perforation. But I want to go just to the frame line on the sides as well.
I can CROP the image down with FFMPEG to remove the information outside of the framing I want [-vf crop=1330:1080:00:00].
I know this will result in a non-standard aspect ratio.
This plays fine on a computer (vlc just adapts to the non-standard).
But for standardized delivery, I would love to keep the native 1920x1080 pixels, but just make everything outside of the centered 1330:1080 black.
Is there a way to specifically select where the pillar bars are?
I really want to re-encode the video as little as possible.
In that vein, does anyone have a better tool than -vf crop as well?
thank you very very much.
Use crop then pad:
ffmpeg -i input -vf "crop=1330:ih,pad=1920:ih:-1:-1" output
I'd like to create a wipe in/out from left to right effect with ffmpeg and/or ImageMagick that is common to most video editors. (e.g. Adobe Premiere, Final Cut Pro and even OpenShot) Some might call this a slide in/out transition effect.
I found that ffmpeg has a lot of filters (including fades), but none seem to be the correct choice for this.
There are also ImageMagick transitions that achieve a wipe in effect. Like in the following example (that is derived from here):
convert overlay.png -crop 10x1080 miff:- | convert - out.gif
But I found it hard to control the actual speed/duration of the transition. I'd like it to last only 2.5 seconds. But I can't make it that fast, because the -delay 1x30 option doesn't seem to let me decrease the delay that low. There is also a library with ImageMagick transitions here that unfortuantely isn't compatible with batch.
I suppose there is a solution for ffmpeg that I couldn't think of, yet. I'd really appreciate your advice!
I have been looking for a way to convert a sequence of PNGs to a video. There are ways to do that using the CONCAT function within FFmpeg and using a script.
The problem is that I want to show certain images longer than others. And I need it to be accurate. I can set a duration (in seconds) in the script file. But I need it to be frame-accurate. So far I have not been successful.
This is what I want to make:
Quicktime video with transparancy (Prores4444 or other codec that supports transparancy + alpha channel)
25fps
This is what I have: [ TimecodeIn - TimecodeOut in destination video ]
img001.png [0:00:05:10 - 0:00:07:24]
img002.png [0:00:09:02 - 0:00:12:11]
img003.png [0:00:15:00 - 0:00:17:20]
...
img120.png [0:17:03:11 - 0:17:07:01]
Of course this is not the format of the script file. Just an idea about what kind of data I am dealing with. The PNG-imagefiles are subtitles I generate elsewhere in my application. I would like to be able to export the subtitles as a transparent movie that I can easily import in my video editing software.
I also have been thinking of using blank transparent images I will use as spacers, between the actual subtitle images.
After looking around I think this might help:
On the FFMPEG site they explain about making a timed slideshow
In the Concat demuxer section they talk about making a slideshow, based on a text file, with references to the image files and the duration of the image.
So, I create all the PNG images I need. These images have the subtitle text. Each image holds one subtitle page.
For the moments I want to hide the subtitle, I use a blank PNG.
I generate a text file as explained on the FFMPEG website.
This text file will reference to all the PNGs. For the duration I just calculate the outcue - incue. Easy... I think...
I am looking for a way to "find" animated GIFs so I can remove them from a folder.
This must work on Windows 7 or Windows XP.
Edit: I am looking to distinguish between animated and regular GIFs. If I could select all GIFs that might be ok as then I could sort by size, but some GIFs are saved with the extension .jpg! That is why I think I probably need a special Image viewer program.
You can use ImageMagick to get the number of frames in a GIF like this:
identify -format "%[scene]\n" YourImage.gif[-1]
identify -format "%[scene]\n" YourImage.jpeg[-1]
It actually gets the frame number of the last frame, so if the image has 37 frames, it will tell you that frame 36 (starting at zero) is the last. So, an animated GIF will give an output of 1 or more since it has multiple frames.
This also works, if the image is mis-named by using a different name suffix. ImageMagick isn't fooled by this, it will still discover that in reality it is a GIF. If it is a standard JPEG, or a GIF with only 1 frame it will return 0.
ImageMagick is free and available for OSX, Linux and Windows - here.