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• How to use argument with dash in name in ffmpeg-python ?

  8 mai 2023, par orderlyfashion

  Following is a simple ffmpeg command line for encoding an input video into a AV1 output with CRF 30 :

  


  ffmpeg -i input.mkv -c:v libsvtav1 -crf 30 output.mkv


  


  Converting that command line into the syntax of ffmpeg-python is pretty straight-forward :

  


  (
    ffmpeg
    .input('input.mkv')
    .output('output.mkv', vcodec='libsvtav1', crf=30)
    .run()
)


  


  However, what happens if we want to specify the fast-decode option ? In ffmpeg that would mean extending our command line to include -svtav1-params fast-decode=1, i.e. :

  


  ffmpeg -i input.mkv -c:v libsvtav1 -crf 30 -svtav1-params fast-decode=1 output.mkv


  


  How do we specify the same thing in ffmpeg-python ? Adding svtav1-params='fast-decode=1' into the output arguments results in invalid Python code since variables are not allowed to have dash in the name :

  


  (
    ffmpeg
    .input('input.mkv')
    .output('output.mkv', vcodec='libsvtav1', crf=30, svtav1-params='fast-decode=1')
    .run()
)
# Error: Expected parameter name


  


  Replacing the dash with an underscore in the name makes ffmpeg-python read it literally which doesn't translate into a valid ffmpeg command line.

  


  How is it possible to specify fast-decode and other svtav1-params specific arguments in ffmpeg-python ?

  


• Correcting color cast with ffmpeg

  16 mai 2018, par Henry H

  I have two videos that have a pretty significant blue cast to them. I took some stills at the same time and I’m happy enough with the colors on those and I’d like to re-encode the videos, adjusting the colors to something similar to the stills.

  • A frame from the original video can be seen here : http://www.dotrose.com/temp/img_20180513_153484_original.png
  • An attempt at correcting the color, which would be acceptable : http://www.dotrose.com/temp/img_20180513_153484_corrected.png
  • A still image taken at the same time (but with some help from a flash) : http://www.dotrose.com/temp/img_20180513_153476.jpg

  I understand I could either create a large collection of jpg images from the video and color correct them before reassembling them into a new video or I could use ffmpeg’s color level’s filter to do it directly. What I don’t know is how to get the numbers to pass to the filter. I’m assuming I want to do something like this :

  ffmpeg -i video.mov -vf "colorlevels=rimin=##/255:gimin=##/255:bimin=#/255:rimax=###/255:gimax=###/255:bimax=###/255, eq=gamma=#.##" -y out.mov

  How do I get the values to use for each of the r, g, and b min and max settings and gamma to use in place of the ###s ? Assuming this is the right approach, of course.

  Update : Perhaps this question would be better asked in a forum for gimp or photoshop. But I know how to adjust the color in those. What I need to know is how I translate those changes to what ffmpeg is expecting.

• Interval option when downloading HLS format videos published on Internet sites using ffmpeg

  28 septembre 2021, par atsu8492

  I'm trying to download HLS format video as mp4 using ffmpeg.

  


  I don't want to bother the server side due to excessive requests, so I want to create an interval for ts file acquisition.

  


  When I actually run ffmpeg, I sometimes get an HTTP 429 error as shown below.

  


  In addition, it looked like there are no good options in ffmpeg.

  


  [https @ 000001bfef570100] Opening 'https://～/ts/9.ts' for reading
[https @ 000001bfeef31140] HTTP error 429 Too Many Requests
[hls @ 000001bfee6be200] keepalive request failed for 'https://～/ts/9.ts' with error: 'Server returned 4XX Client Error, but not one of 40{0,1,3,4}' when opening url, retrying with new connection
[https @ 000001bfef570100] Opening 'https://～/ts/9.ts' for reading
[https @ 000001bfef570100] Opening 'https://～/ts/10.ts' for reading
[https @ 000001bfef570100] Opening 'https://～/ts/11.ts' for reading
[https @ 000001bfef570100] Opening 'https://～/ts/12.ts' for reading
[https @ 000001bfef570100] Opening 'https://～/ts/13.ts' for reading
[https @ 000001bfeef31140] HTTP error 429 Too Many Requests
[hls @ 000001bfee6be200] keepalive request failed for 'https://～/ts/13.ts' with error: 'Server returned 4XX Client Error, but not one of 40{0,1,3,4}' when opening url, retrying with new connection
[https @ 000001bfef570100] Opening 'https://～/ts/13.ts' for reading
…


  


  Can you come up with any good way ?

  


  I'm not good at English, so I may not be able to respond well. sorry.
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