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• ffmpeg-X264 encode —BGRA to AVFrame(ffmpeg) and viceversa ? for IOS

  6 avril 2012, par Asta ni enohpi

  Am working Video Processing in IOS(iphone/ipod/ipad) Using Objective c. i am using AVFoundation Framework to Capture Video . i want to Encode/decode those video frame using ffmpeg-libx264. i have compiled ffmpeg-x264 lib for ios. i got kCVPixelFormatType_32BGRA from AVFoundation.

  my problem is
  1.How to convert kCVPixelFormatType_32BGRA to AVFrame for enode using avcodec_encode_video ?

  2.How to convert AVFrame to kCVPixelFormatType_32BGRA @ decode side from avcodec_decode_video2 ?

  Please help me to start above process or give path for working tutorial .Thanks in advance.

• How to use ffmpeg to encode isolated motion vectors (using codecview)

  22 juillet 2021, par Temmeh

  I have been successfully using this command to superimpose MPEG motion vectors onto a video :

  


  ffmpeg -v error -flags2 +export_mvs -i input.mp4 -vf codecview=mv=pf+bf+bb -y output.mp4

  


  Now I would like to be able to export an h264 mp4 of just the motion vector arrows, like in this example, without the original video layered underneath. I checked the codecview documentation and and did not find a flag or option to do this.

  


  Any help is appreciated !

  


• Python script and equivalent command do not run the same

  19 août 2021, par user32882

  I would like to use youtubedl to download the audio from a YouTube video into an mp3 file. I came up with the following command to do so :

  


  youtube-dl -x --audio-format mp3 https://www.youtube.com/watch?v=SF8DGbfOFig&ab_channel=derang

  


  When I run the above command through my command line, it seems that I successfully manage to download the file in mp3 format :

  


  [youtube] SF8DGbfOFig: Downloading webpage
[download] Destination: Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k]-SF8DGbfOFig.webm
[download] 100% of 5.57MiB in 00:03
[ffmpeg] Destination: Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k]-SF8DGbfOFig.mp3
Deleting original file Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k]-SF8DGbfOFig.webm (pass -k to keep)


  


  I then tried to convert the above command to an equivalent python script as follows :

  


  import youtube_dl
links = ["https://www.youtube.com/watch?v=SF8DGbfOFig&ab_channel=derang"]
ydl_args = {
        'audioformat': 'mp3',
        'outtmpl': '%(title)s.%(ext)s',
        'extractaudio': True
    }
with youtube_dl.YoutubeDL(ydl_args) as ydl:
    results = ydl.download(links)


  


  However, this does not succeed in generating an mp3 file of the audio. These are the logs I am getting :

  


  WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[download] Destination: Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k].f135.mp4
[download] 100% of 4.42MiB in 00:02
[download] Destination: Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k].f251.webm
[download] 100% of 5.57MiB in 00:03
[ffmpeg] Merging formats into "Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k].mkv"
Deleting original file Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k].f135.mp4 (pass -k to keep)
Deleting original file Total Science & S.P.Y - Piano Funk (Ft. Riya & DāM FunK) [320k].f251.webm (pass -k to keep)


  


  What am I doing wrong here ? Aren't my command and python script equivalent ?