I have an alpha.mp4 (alpha matte video) and a color.mp4 (color video). How do I use ffmpeg to make a transparent HVEC (.mov) video?
I can combine with ffmpeg to make a .webm file following the instruction here:
https://www.unscreen.com/api under "Convert unpacked Pro Bundle to WEBM video with transparency"
I have a newer mac and should be able to use HVEC_videotoolbox from either these 2 videos or the .webm file created.
The closest I found was this which seems to generate a corrupt video that cannot be viewed in safari. Use FFmpeg to generate a movie with alpha channel from separate video and fill movies? but
Related
I'm using ffmpeg to convert some old videos. Some have VobSub subtitles, so I am hardcoding them in. Is there a way to add a semi transparent box behind the subtitles for easier reading?
I have a set of transparent images, where each one represents a frame of a video. I know that I can overlay them on top of another video using -i %d.png. What I want to be able to do is turn them into a transparent video ahead of time, and then later be able to overlay that transparent video onto another video. I've tried just doing -i %d.png trans.mov and then overlaying trans.mov on top of another video, but it doesn't seem like trans.mov is actually transparent.
You have to use an encoder that supports transparency/alpha channel. You can view a list of encoders with ffmpeg -h encoders and get further details with ffmpeg -h encoder=<encoder name>, such as ffmpeg -h encoder=qtrle. Then refer to the Supported pixel formats line: if has as "a" in the supported pixel format name, such as rgba, then it supports alpha. See a general list of pixel formats with ffmpeg -pix_fmts.
The simplest solution is to mux the PNG files into MOV:
ffmpeg -framerate 25 -i %d.png -c copy output.mov
I have a bunch of png images made from a python script. When I convert the images to a mp4 format using ffmpeg, the video looks good. But the moment I make them into gifs it starts creating random yellow patches as shown below.
The syntax I use to convert png to gif is ffmpeg -i img%04d.png animation.gif
Thanks.
As title says i stucked with video transparent. I have videos with no background on After Effects. I m trying to export in .mov format my video with all codecs that are inside my AE but videos dont play. Any suggestions?
So I thought to embed the image as part of video content while converting the m4a to mp4. The output file has the image as video content and it plays as expected in VLC but when the same was streamed from my CDN using JW player, I do not see the image as video content, still it is black and audio is heard. Not sure what is the issue with embeding. I used the FFMPEG to embed image as video content.
On the other hand is there any posibility with JW player to overlay an image as video content while audio can be heard in back end?
You need
to loop
the image
ffmpeg -loop 1 -r 1 -i img.png -i audio.m4a -shortest -filter:v \
'crop=trunc(iw/2)*2:trunc(ih/2)*2' out.mp4
repeat image over and over
once per second
stop video when audio stops
cut image to even dimensions if necessary