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• ffmpeg : How to replace a series of frames with a series of image files ?

  14 septembre 2020, par Arnon Weinberg

  Given a video file, start and end timestamps, there is a known number of frames between those timestamps in the video file, and I have an equal number of .png files in a directory to replace them with. The .png files are sorted as 001.png ... NNN.png. How would I go about updating the video file with the replacement frames using ffmpeg ?

  


  This is a followup to using ffmpeg to replace a single frame based on timestamp, but I'm asking about replacing multiple sequential frames based on 2 timestamps.

  


  Presumably something like :

  


  ffmpeg -i input.mp4 -i %3d.png -filter_complex "something including the timestamps 4.40,5.20" -c:a copy output.mp4


  


  I would also be okay with using frame numbers instead of timestamps if that makes things easier, and it's reasonable if start and end frames must be keyframes.

  


  Background :

  


  Many machine learning algorithms for video processing use ffmpeg to extract specific scenes from videos based on start and end timestamps, dump them into a sequence of .png files, process them in some way (denoise, deblur, colorize, annotate, inpainting, etc), and output the results into an equal number of .png files. The output frames are usually assembled into a new video file, but I would like instead to update the source video file so as to preserve audio, unedited video, and other video properties (fps, keyframes, etc).

  


  This approach will not work as-is for some categories of video processing algorithms. For example, interpolation results in more frames than were originally extracted, and upscaling results in higher-resolution images. As such, I would appreciate an explanation of any solution so that I can adapt it for such cases (or I will ask separate questions for those).

  


• How to create a video from a series of images with varying image durations ?

  6 octobre 2020, par user1354557

  I'd like to programmatically create a video file that is composed of a series of images. However, I'd also like to be able to specify a duration for each image. I often see ffmpeg examples suggested for similar tasks, but they always assume the same duration for each image. Is there an efficient way to accomplish this ? (An inefficient solution might be setting the frame rate to something high and repeatedly copying each image until it matches the intended duration)

  



  I will be dynamically generating each of the images as well, so if there is way to encode the image data into video frames without writing each image to disk, that's even better. This, however, is not a requirement.

  



  Edit : To be clear, I don't necessarily need to use ffmpeg. Other free command-line tools are fine, as are video-processing libraries. I'm just looking for a good solution.

  


• Create a video from a series of images using commandline [duplicate]

  19 novembre 2020, par Aedam

  I have a few thousand images, each are jpg, and the filename is unix timestamp in milliseconds, which means each file name has gaps to the next filename, but all are sequential.

  


  Does anyone know how to merge this into a video with a certain duration and/or frame rate ? I was looking into FFMPEG, and ExifTool, but I don't think those do sequential merges that have gaps in the filename

  


  I have tried the following threads :

  


  


  • ffmpeg from pngs... Error with subset of PNGS ?

    


  


  • Using ffmpeg with not consecutive numbered files

    


  


  • ffmpeg img to video = Could find no file with path

    


  


  


  I am using Windows so -pattern_type glob in ffmpeg is not an option.