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• How to convert animated webp to gif in android / java ?

  21 avril 2022, par UHS

  I want to convert the animated webp files to gif file and looking for solution since couple of days but did not get any easy straight solution yet.

  


  I tried ffmpeg but it could not do the job and after looking for solution I found that webp decoder is not implemented in ffmpeg yet.
https://trac.ffmpeg.org/ticket/4907

  


  I also checked libwebp library by google and they also says animated webp is not supported. https://developers.google.com/speed/webp/docs/dwebp

  


  I tried demo of aspose this library also fail to convert animated webp to gif.
https://products.aspose.com/imaging/java/conversion/webp-to-gif/

  


  I think ImageMagick can convert animated webp to gif but do not know how to implement that in my project.
How can I avoid dropouts when using (imagemagick) `mogrify` to convert webp files to animated gif ?

  


  So is there any easy way to convert webp to gif

  


• ffmpeg continuous live streaming of dynamic files from directory

  4 septembre 2022, par user72261

  So I have been using ffmpeg to create a live stream from files stored in a folder using concat list.

  


  This works perfectly for local, static content but I have a security system in my warehouse that uploads .mp4 files to my server in the office.

  


  This system doesn't have any live stream functionality so I would like to set up a live stream myself using ffmpeg to continually read the latest files from the folder.

  


  I tried setting up a script to read all files in the directory and sort them based on the file name that is a UNIX timestamp of the date/time the video was taken. Then had the script select the latest segments after that last used segment and create a new concat list such as below

  


  file '00000.mpd'
file '00001.mp4'
file '00002.mp4'
file '00003.mp4'
file '00004.mp4'


  


  After doing some reading I found out to make it loop that file you could reference its self in the list like so

  


  file '00000.mpd'
file '00001.mp4'
file '00002.mp4'
file '00003.mp4'
file '00004.mp4'
file 'concat.txt'


  


  This seemed to work ok until I started getting the error impossible to open concat.txt. This file doesn't exist, which I can only guess is because ffmpeg is trying to open the file as its being updated by the script.

  


  Has anyone come across this before or know another way to do it ?

  


• ffmpeg -ss then apply filter then concat producing timestamp errors

  6 août 2020, par Bob Ramsey

  Using ffmpeg, I have split a file into multiple parts using -ss. Then I apply a filter to some of the files, then concat the files back together. When I do that, I get : Non-monotonous DTS in output stream 0:0 ; previous : 341334, current : 340526 ; changing to 341335. This may result in incorrect timestamps in the output file. The output file plays, but there are noticeable skips where the files are joined.

  


  Here's how I am splitting the file :

  


  ffmpeg -i full_source.mp4 -ss 0 -to 14.264250 -c copy  01-plain.mp4
ffmpeg -i full_source.mp4 -ss 14.264250 -to 18.435083 -c copy  01-filtered.mp4

ffmpeg -i full_source.mp4 -ss 18.435083 -to 29.988292 -c copy  02-plain.mp4
ffmpeg -i full_source.mp4 -ss 29.988292 -to 31.865167 -c copy  02-filtered.mp4
...
ffmpeg -i full_source.mp4 -ss 0 -to 14.264250 -c copy  10-plain.mp4
ffmpeg -i full_source.mp4 -ss 234.484203 -to 300.000 -c copy  10-filtered.mp4


  


  Then I apply a different drawtext filter on each of the 10 filtered files and save them with a new name, like :

  


  ffmpeg -hide_banner -loglevel warning -y -i 01-filtered.mp4 -filter_complex "drawtext=fontfile=calibri.ttf:fontsize=24:fontcolor=white:x=300:y=500:text='hello world'" -crf 15 01-filtered-complete.mp4


  


  Finally, I join all of the plain and complete files back together like this :

  


  ffmpeg  -f concat -safe 0 -i mylist.txt -c:a copy -c:v copy  outfile.mp4


  


  And that's where the timing error comes in. I've tried adding -vsync drop in the concat command, but that didn't really work either. Same version of ffmpeg does the split, the filter, and the concat. I've tried different versions, everything from 20170519 to one from May 2020 with the same result. Always making sure that all three steps are done by the same version of ffmpeg.

  


  The only thing I can see is that ffprobe shows a duration of 14.27 for 01-plain.mp4 when it should be 14.264250. All of the other files show a similar rounding difference. The files are 23.98 fps. If I do all of my filters in really long command without splitting the file, I can use the more precise numbers with no problem. It just takes 10 times as long. This is all scripted, it happens a couple of hundred times a day and time is money, so I can't take 10 times as long to do each file.

  


  Any ideas ? Thanks in advance !