I'm trying to convert a video file exported from Blackmagic Fusion as DNxHR with Alpha checked to WebM or PNG. FFMPEG seems to ignore the alpha and the background is black. Is there something I need to do? This is what I'm currently using:
ffmpeg -ss 0.5 -i DNxHR444A.mov -vframes 1 test.png
or
ffmpeg -i DNxHR444A.mov -c:v libvpx-vp9 -crf 30 -b:v 0 test.webm
I can upload my test video if that helps. But it's quite large.
FFmpeg's DNXHD/R decoder does not support alpha. Either use another codec on export, or export alpha separately (it will be a grayscale picture). With the 2nd method, ffmpeg can combine the main image and the alpha for onward processing.
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I have a lot of created png images with transparency / alpha channel.
These need to be converted to a webm file with the VP9 codec to have a video with transparent areas.
The output framerate should be 60fps. But filter_complex (which i need to select the yuva420p format) apparently has an issue with that.
I found an answer how to fix that; tried to adapt it to my case but it did not work.
The 1055 source png files should create a video with 60fps and a duration of 17.6 sec. But the result is a file with 42.2 sec (1055 frames at 25fps); according to ffmpeg 2530 frames were used.
So the video file itself has 60fps but the source frames are "stretched" to 25fps. Kind of a slow-mo video.
What do i need to change?
Or would it be possible to put the pngs into a VP9 webm with 60fps without using filter_complex at all?
The command i'm using by adapting another found answer is:
ffmpeg -hide_banner -i srcImgMasked_%05d.png -filter_complex "nullsrc=size=1920x1080:rate=60 [base]; [0]format=yuva420p [bla]; [base] [bla] overlay=shortest=0" -c:v libvpx-vp9 -crf 20 -b:v 0 -threads 0 result.webm -y
I'm trying to extract alpha channel from ProRes (mov) in greyscale to a separate mp4 file (to emulate video with transperancy on the html page later).
ffmpeg -i in.mov -hide_banner -f mp4 -vcodec libx264 -vf alphaextract,format=yuv420p out.mp4
but I don't get a filled alpha channel but only a sort of border of it. Pretty sure that original file is ok (tried with different files) and encoding it to webm showed correct transperency.
What I get from ffmpeg
How original file looks like
It's a bug; patched in git master.
Workaround for older versions is
ffmpeg -i in.mov -vf format=yuva444p16le,alphaextract,format=yuv420p -c:v libx264 out.mp4
I have a video with a transparent background that is very large despite being only 6 seconds. I was hoping I could compress it with FFmpeg but everything I try seems to discard the alpha channel...
This code brings the file down from 33gb to 24mb:
ffmpeg -i "C:\Users\djcim\Desktop\Intro For Now\Video Intro.avi" -map 0 -c:v libx264 -preset slow ^
-crf 17 -acodec copy "C:\Users\djcim\Desktop\Intro For Now\Compressed.avi"
But as stated I lose the alpha channel, any ideas on how I could significantly compress my file while preserving the alpha channel?
There are various codecs that support alpha viz. qtrle, png, ffv1..etc
Try those 3 to check which yields the best size. All are lossless. The first two only support RGB pixels, whereas FFV1 supports both RGB and YUV but few applications support it. PNG is the most widely compatible.
e.g.
ffmpeg -i "Video Intro.avi" -map 0 -c:v png -c:a copy "Compressed.avi"
(Suggest using MOV container)
I'm trying to create an MP4 video with ffmpeg using JPEG2000 images as frames.
It works when the JPEG2000 is 8bpp, but I need it to work for at least 12 bits (ideally 12, but could be 16). The images are grayscale.
This is the command I'm using:
ffmpeg.exe -i imagen.jp2 video1.mp4
If I try to use -pix_fmt it says it's not supported by the encoder (it doesn't matter which format I use).
Some sample images can be found here:
http://ioingresodemanda.com/jp2.rar
I could also use any other tool, it doesn't need to be ffmpeg.
UPDATE: Adding ffmpeg output - http://pastebin.com/NyY3vgpz
Thanks in advance
If you are ok with mp4 file having a different video format the following will work
ffmpeg -strict -2 -i 12bit.jp2 -vcodec libx264 -an out.mp4
ffmpeg -strict -2 -i 12bit.jp2 -vcodec mpeg4 -an out.mp4
ffmpeg doesn't support 12-bit color. Most of the H264 profiles only support 8-bit color; a few support 10-bit, and only the super-obscure lossless Hi444PP profile supports 14-bit color. The x264 encoder does support some of the profiles with 10-bit color, but that's as far as it goes, and you have to explicitly enable it using the --bit-depth option:
http://git.videolan.org/?p=x264.git;a=commit;h=d058f37d9af8fc425fa0626695a190eb3aa032af
As noted in the commit, you may also want to keep in mind that "very few H.264 decoders support >8 bit depth currently".
I have some FLV videos with alpha channels, and I want to convert each of them to PNG images using ffmpeg but keep the transparency.
So far, I've tried this:
ffmpeg -i input.flv -an -y %d.png
But this outputs the PNG files with black background.
Is there any way to do this?
Alternate acceptable solution: If I can output the images and give the alpha channel a certain color of my choice. I can then remove it later via imagemagick and convert that color to transparency.
I know its quite late for an answer but I was searching for a similar solution and found this : ffmpeg -i video.flv -r 25 -vcodec png -pix_fmt rgb32 %d.png