Need a easy filter sample. e.g. Create a thumbnail image every X seconds of the video #338

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1. jb-alvarado commented on Sep 3, 2018

   

   jb-alvarado

   on Sep 3, 2018

   Last edited by jb-alvarado

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   I think you can do it more simple:

   import av
   
   count = 0
   container = av.open('test_clips/test.mp4', 'r')
   
   for packet in container.demux():
       if packet.stream.type == 'video':
           for frame in packet.decode():
               if count % 25 == 0:
                   frame.to_image().save('%04d.png' % count)
               count += 1
2. nishant-ever commented on May 9, 2019

   

   nishant-ever

   on May 9, 2019

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   @jb-alvarado unless I'm misreading the code, it seems to select every frame divisible by 25 yielding frames 0, 25, 50, .... But it doesn't give a frame rate of 1 fps. Do you know if we can achieve this using the fps filter especially when the input video can have any frame rate? Thanks!
3. jb-alvarado commented on May 10, 2019

   

   jb-alvarado

   on May 10, 2019

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   When you want to have images as output you can use two methods:

   1. before you use the modulo operator you read the fps from input file and use this as a modulo.
   2. you use the fps filter, this one drops all other frames

   When you want a video output the second method is better, but you have to look here in the issues and examples for a proper way to use filters in PyAV. My knowledge about PyAV is not so deep.

   Here I have try one time to change the fps, but as I remember there was some issues, and of course the queue and pipe to ffplay is not necessary.
4. nishant-ever commented on May 10, 2019

   

   nishant-ever

   on May 10, 2019

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   Thanks @jb-alvarado for a quick response. Unfortunately there are no examples for using filters. I've also asked a question in the Gitter channel for the project. Your solution here does give me some ideas but my problem is a little more complicated since I'm doing filtering on a video stream as opposed to a file on the disk. I'll see if I can come up with something. Thanks again!
5. PyAV-Org

   locked and limited conversation to collaborators on Mar 25, 2022
6. jlaine

   converted this issue into a discussion #934 on Mar 25, 2022