Recherche avancée

Sur d’autres sites (9016)

• Batch file to sort TIFF stacks into folders

  14 septembre 2018, par Julie K

  I am working on a project that involves analyzing videos filmed on a GoPro in ImageJ ; unfortunately, this means I have to convert all my videos ( 400) to TIFF stacks. Therefore, I would like to create a batch file that will take a folder of MP4 videos, convert them to AVI files at 10fps with the first 4:20 removed, then convert those AVI files to TIFF stacks and have the resulting TIFFs sorted into folders based on their names. I have tried going straight from MP4 to TIFF and have always gotten an error message, hence the MP4 to AVI to TIFF conversions.

  I have been going at this in a step wise manner by finding other batch codes people have developed on here, and I have gotten to the point where the batch file will convert the videos to TIFF files with sequential numbers at the end of the file names for the TIFF stacks, but I am struggling to get the sorting into folders part correct.

  The file naming convention I have been using is just the standard GoPro naming convention but with the addition of sequential numbers (i.e., GOPR0210_0001.tiff, GOPR0210_0002.tiff, etc.) so that the TIFF stack is in the correct order.

  Right now what I have is :

  @echo off
  
  
  
  for %%f in (*.MP4) do ffmpeg -y -ss 00:04:20 -i "%%f" -r 10 -qscale 0 "%%~nf_10fps.avi"
  
  
  
  for %%f in (*.AVI) do ffmpeg -i "%%f" -pix_fmt rgba -compression_algo deflate %%~nf_%%05d.tiff
  
  
  
  for %%a in (*.tiff) do (
  
  set f=%%a
  
  set g=!f:~0,10!
  
  md "!g!" 2>nul
  
  move "%%a" "!g!"
  
  )
  
  
  
  pause

  I got the listed code for moving the files from .bat file sorting files into folders
  but I just end up with all my TIFF files sorted into a folder called " !g !"

  I have also looked at/tried :

  • Batch File to Move Files with Same Beginning String to a Folder with That String Name
  • Batch create folders based on part of file name and move files into that folder
  • Batch Create a Folder Based on Filename, and Move Multiple Related Files to The Created Folder
  • Batch File to Move Files with Same Beginning String to a Folder with That String Name
  • .BAT file to move files into folders and subfolders by filename... can’t get subfolders to work

  Any tips, comments, or helpful hints would be greatly appreciated ! This is my first time trying to make a batch file. Thanks !

• How to flatten a VR video to display in normal screen ? [closed]

  14 mai 2023, par d-b

  I am not sure about the terminology here, but I have a VR-video that is intended to be shown using a headset with separate screens for each eye. It is not 3D in the sense that when you turn your head you will see something different, it is just "2,5D" so you get a sense of depth when looking at it. There are two video channels that are more or less identical, they are just recorded with slightly different angle, similar to how human eyes see the world. I hope this makes it clear what type of video I have, otherwise please ask for clarification in a comment (and if there is a special terminology for this type of video, please let me know).

  


  More details : the original video is 4320x2160, basically 2 square channels at 2160 x 2160.

  


  I want to show this video undistorted on a regular screen.

  


  I have read the following questions here on SO :

  


  


  1. How to reproject and join these two clips with ffmpeg ?

     


  


  2. Flatten 360 fisheye video

     


  


  3. How to de-warp 180 degree or 360 degree fisheye video with ffmpeg ?

     


  


  4. Flatten 360 fisheye video

     


  


  5. Unwarping 180 VR Footage with FFmpeg v360 Filter

     


  


  


  (and problably a few more).

  


  I think I want to extract the two video channels (note that they are in the same video stream, not like in a movie where you can have several separate audio streams for different languages) into separate files and then "undistort" them.

  


  (3) gave me a command to splitting the video into two files :

  


  ffmpeg -i -myclip.mp4 -filter_complex "[0]crop=iw/2:ih:0:0[left];[0]crop=iw/2:ih:ow:0[right]" -map "[left]" -map 0:a /tmp/left.mp4 -map "[right]" -map 0:a /tmp/right.mp4


  


  That seemed to have worked as expected but then I also need to "undistort" the content because it was filmed with some fisheye lens or something like that (straight lines not in the absolute centre of the image are more or less circular).

  


  (5) suggested this command :

  


  ffmpeg -i left.mp4 -vf "v360=input=hequirect:output=flat:h_fov=100:v_fov=67.5:w=1280:h=720" leftfixed.mp4


  


  but that produced an output that was 4320x2160 (obviously only from one channel, since input was just one channel) but just the centre of the original image, I estimate the content to be the 500x250 px (upscaled to 4320x2160, so very blocky) of the midpoint of the original image.

  


  How can I "undistort" this video so it looks good on a 2D-screen while the size is preserved ?

  


• FFMPEG -codec copy creates incorrect duration when edit atoms are in input

  6 juin 2019, par Jesse Michael

  When using FFMPEG to -codec copy an input with Edit Atoms before transcoding, the resulting output contains incorrect durations.

  mp4dump reveals a list of edit atoms for this example mp4 on the audio track.

  ...
  
      [edts] size=8+52
  
        [elst] size=12+40
  
          entry count = 3
  
          entry/segment duration = 111968
  
          entry/media time = 0
  
          entry/media rate = 1
  
          entry/segment duration = 111968
  
          entry/media time = 322560
  
          entry/media rate = 1
  
          entry/segment duration = 111968
  
          entry/media time = 645120
  
          entry/media rate = 1
  
  ...

  using ffmpeg version 4.1.3 and running

  ffmpeg -i example.mp4 -codec copy example-copy.ts

  and then running

  ffmpeg -i example-copy.ts example-out.mp4

  produces an output with a different duration than the input introducing A/V sync issues

  input audio stream duration=21.868776

  output audio stream duration=23.821769

  The issue does not occur when skipping the -codec copy step and going straight to the transcode step (but this step is currently an important part of our workflow).

  The issue also doesn’t occur (for this example) when -codec copying to a different video container, like .nut, but in other examples (specifically ones with a single edit atom entry with > 0 media_time) changing the video container doesn’t solve the issue.

  Is FFMPEG ignoring/dropping the edit list when using the codec copy operation ?

  Is this the expected behavior or is there and issue with FFMPEG ?