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• how to compile FFMPEG and merge it to one android ".so" file

  5 avril 2016, par user965347

  i am intereseted to compile the ffmpeg source to android to be invoked with jni as one ".so" last time i tried 0.8 versions but failed it always shows that something is undeclared, i tried all of google examples but it seems doesnt work for me,
  i tried this one

  Link One

  but it seems that the ffmpeg.c is not included with compile , but when i compile it always error, it says that something undeclared, and i cant build this project as one android ".so" file

  i also tried this one,
  Link Two

  but it seems i cant understand.

  i have tried everything , but none of them work ,none of them merge all ".o" , ".so" , ".a" into one ".so" files

  is there any good example in google or somewhere to compile ffmpeg as one ".so" file and have a good downloadable source i can compile ?

• Output a video with "slide up" transition using more than 100 images in FFMPEG ?

  9 juillet 2021, par Joseph Ladera Fugata

  I have more than a hundred images of the same size and format that my company wants to display at the big 9:16 (rotated 16:9) screen outside the front gate. It's supposed to be easy but they required me to have it slide from top to bottom, meaning that it should look like a smooth auto scroll effects. I searched here and there but no luck.

  


  I have tried xfade like this :

  


  ffmpeg -loop 1 -i input.txt -filter_complex
"xfade=transition=slideup:duration=10:offset=0,format=yuv420p" output.mp4


  


  It didn't do anything just a bunch of error referring to the inputs. Which is supposed to be just 2 images in the first place.

  


  The next thing I tried was using Concat from someone named @Gyan at his reply HERE and here's my version of the code :

  


  ffmpeg -y -f concat -safe 0 -i input.txt
-vf tile=1x%img_count%,loop=%_my_loop_count_var%:1:0,
crop=iw:ih/%img_count%:0:clip((t-%_start_time%)/%sec_per_img%*ih/%img_count%\,0\,ih*%img_count_minus_one%/%img_count%)
-r 25 -c:v libx264 -preset ultrafast output.mp4


  


  When I played with it, it gives a different output even do the image are all the same dimensions.

  


  I found someone on youtube used this but it is using bash and I am on windows. Unless someone here can convert it to a batch script would be great. I look into it and it seems like he's just V-stacking them kinda like what I did but there's more. I know I could have gone through win bash but I doubt the script will run on a non-Unix environment just by having bash, and I'm not yet familiar with Cygwin either.

  


  I also did tried other options posted by others here, I just forgot to bookmark them, but non of them works on more than a hundred images.

  


  I love to hear a response if anyone can help.

  


• Decode h264 video

  29 août 2011, par john bowring

  I am looking for a way to decode h264 (or indeed any video format) using c#. The ultimate goal is to be able to decode the images and very strictly control the playback in real time. The project I am working on is a non-linear video art piece where the HD footage is required to loop and edit itself on the fly, playing back certain frame ranges and then jumping to the next randomly selected frame range seamlessly.

  I have created an app which reads image files (jpegs) in from the disk and plays them on screen in order, I have total control over which frame is loaded and when it is displayed but at full HD res it takes slightly longer than I want to load the images from hard drive (which are about 500k each), I am thinking that using a compressed video format would be smaller and therefore faster to read and decode into a particular frame however I cannot find any readily available way to do this.

  Are there any libraries which can do this ? i.e. extract an arbitrary frame from a video file and serve it to my app in less time than it takes to show the frame (running at 25fps), I have looked into the vlc libraries and wrappers for ffmpeg but I don't know which would be better or if there would be another even better option. Also I don't know which codec would be the best choice as some are key frame based making arbitrary frame extraction probably very difficult.

  Any advice welcome, thanks