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• How do I run ffmpeg v360 filter on a stream with limited memory ?

  21 février 2024, par Dmitry Filippov

  I am currently using ffmpeg python in a microservice for changing a projection of a VR video in S3 bucker. Ideally I would like to use as little memory as possible, reading a video file from s3 as a stream, transcoding it and uploading back into a separate file all in-memory.

  


  However, when I run this code with large videos (above 10GB), the ffmpeg process gets terminated with no exception and boto3 uploads a 0B "file" to s3. When I run this with a small (100MB) video or on my local machine with 16GB RAM, the upload finishes up fine.

  


  Code :

  


    with (
    ffmpeg
    .input(input_url)
    .filter("v360", inputProjection, outputProjection, in_stereo=inputStereo, out_stereo=outputStereo)
    .output('pipe:', format=outputFormat)
    .run_async(pipe_stdout=True)
  ).stdout as dataStream:
     client.upload_fileobj(dataStream, aws_s3_bucket, outputFile)


  


  I expect the ffmpeg to apply the filter to a video as a stream only holding a small section in memory at a time, but instead it seems to try to download the entire video into the local memory before applying the filter (when the script fails, stdout contains either no data or only the metadata of the video)

  


  I cannot support the full download as I am planning to use the script on 100GB+ videos and it needs to run as a microservice in a kubernetes cluster.

  


• How do I apply filter to only one input source ?

  3 septembre 2014, par Rangi Lin

  I want to add a watermark image to a video, and also want to make watermark fade out later.

  Here is the option I use :

  ffmpeg -i video.mpg -filter_complex "overlay=0:0, fade=out:0:60" -i watermark.png animation_watermark.mpg

  However, it fade out entire video instead of just the watermark, how do I tell ffmpeg apply filter to specified input ?

• Why does the remainder of the video not appear in this FFMPEG complex filter graph ?

  10 janvier 2019, par Jonathan Gilbert

  I have a filter graph where I am trying to shift the first 18 seconds of a long video up by 60 pixels in each frame (the frame size is 1920x1040) without affecting the rest of the video. The graph definition looks like this :

  -filter_complex "[0:v] trim=start=0:duration=18 [pretitle];\
  
                   [0:v] trim=start=18,setpts=PTS-STARTPTS [remainder];\
  
                   color=color=black:size=1920x1040 [blank];\
  
                   [blank][pretitle] overlay=0:-60 [pretitle_shifted];\
  
                   [pretitle_shifted][remainder] concat [t];\
  
                   [t] ass=Subtitles.ass,fade=t=out:st=2608.6:d=2 [output]"
  
  -map [output] -map 0:1

  This filter graph runs without errors, but after the first 18 seconds, the video is just the subtitles on a black background. I can’t figure out why. :-(