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• dowload video with csv file using youtube-dl and ffmpeg but ffmpeg not working

  30 juin 2020, par Rupendra Singh Rathore

  def start(self, newfile=None, part=None):
    ydl_opts = {}
    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        while True:
            videos = self.get_videos()
            print('{} videos to go'.format(len(videos)))  # print no. of video remaining
            video = get_first_item(videos)  # get next video for downloading
            print(video)
            if video is None:  # check if video is there or not
                break

            c = f'ffmpeg $(youtube - dl - g {ydl.download([video])} | sed "s/.*/-ss 00:05 -i &/") - t 1: 00 - c copy out.mkv'

            videos.remove(video)  # remove video from list
            self.save_file(videos)  # save updated list to file

            print('All downloaded')


  


  c = f'ffmpeg $(youtube - dl - g ydl.download([video]) | sed "s/.*/-ss 00:05 -i &/") - t 1 : 00 - c copy out.mkv

  


  how to download video with duration. i using youtube_dl and ffmpeg in python funtion.please check my script and suggest me.. thank you

  


• ffmpeg : How does one designate what parts of an overlay video stream let the underlay video stream show through ?

  21 février 2023, par Walt Howard

  Stream 0 is a rotating planet created using povray. (https://www.povray.org/)

  


  Stream 1 is just a static jpeg of stars.

  


  I'm using overlay like this :

  


  nice ffmpeg -i protoplanet.mp4 -i stars.jpg \
         -filter_complex "[0:v]scale=1024:768[scaled];[1:v][scaled]overlay=0:0" \
         -movflags faststart -pix_fmt yuv420p -r 10 planet.mp4


  


  I had it working when I used the output from povray directly. I didn't have to know why that worked, because it just did. However, after adding some post processing to the planet video, the entire video has no alpha channel (educated guess) so the background stream (Stream 1) cannot show through.

  


  The post processing I did was this (which works great) : https://www.reddit.com/r/ffmpeg/comments/im2mkp/creating_a_retro_glow_effect_with_ffmpeg/

  


  But that made the video unable to have an overlay background possibly due to it destroying the alpha channel and turning many of the blacks to dark grey.

  


  I can merge the pure POVRAY output and the background and then add the glow effect, but it adds the effect to the background stars and captions also which ruins the effect to some degree. I want to glo-ify the planet first, then stick it on a pure starfield background.

  


  In thinking this over I may have to recreate the alpha channel after adding the glow effect, using a nearest match to black and dark grey to alpha.

  


  Hmmm. It might be a codec issue as I didn't specify any -c:v in any of my commands....

  


• Is there any way to trim YouTube video without downloading it to local machine ?

  12 août 2020, par Sonu Bamniya

  I am creating an app to trim video where a user either can upload the video file or can paste YouTube URL.
I am able to make the trimmer work for upload video using FFmpeg, but for YouTube URL, firstly I need to download the video to the local machine and then trim it using FFmpeg.

  



  I am using youtube-dl NodeJS library to save the video file to locally, but the issue is as I am allowing the user to download only 15Sec video no more than that, and I have applied validation of 60m long video, yet when I get 1080p video there are two issues.

  



  1. There is no audio in the 1080p video.


  



  and

  



  2. The video is taking too long to download locally and the process is taking almost 7-8mins to complete.


  



  For the first one, I can get the audio and video separately and then merge both of them in the video, but the second one is where I am stacked.

  



  I have added a time log I can see the trimming is taking only about 3-4 seconds, but the downloading is taking too long.

  



  Is there any way to make it work faster ? Or, Is there any way I can download only that part of the video, not the full video, in any technology.

  



  I am open to using any technology until it is working faster than my current implementation.

  



  If this is something related to server configuration, please suggest which one would work better.