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• Is it possible to fetch some key-frames of a video by using the HTTP Range header

  9 décembre 2020, par pvd

  I've read the SO problem , and it seems not applying to my specific case.

  


  Is it possible to fetch some key-frames of a video from web server by the HTTP Range header ? For example, for a 30 seconds duration video, we'd like to analysis the I-frame around 00:00:02, 00:00:15, 00:00:28.

  


  I need to analysis the videos from internal web server to detect if there's specific watermarks in it and some other analysis.

  


  Since the first I-frame might be invalid sometimes(Logo for example), we were planning to extract the I-frame from the 00:00:02, the middle I-frame, and the last 2nd second I-frame.

  


  For example, for a 30 seconds duration video, we'd like to analysis the I-frame around 00:00:02, 00:00:15, 00:00:28.

  


  We could make it works while download the whole video, since most of the data we downloaded from the server are not being used. I was wondering if maybe we could only use the HTTP Range header to download partial data and analysis it ?

  


• Trouble downloading files in Dropbox Python API v2

  16 août 2019, par jack

  I’m trying to download .mov files from Dropbox, manipulate them with ffmpeg, and upload back to Dropbox, but I’m getting an error when I use the files_download method.

  I’m able to read files from Dropbox without any problem using dbx.files_list_folder

  When trying to download files, I’ve used the following :

  import dropbox
  
  access_token = 'MY TOKEN'
  
  dbx = dropbox.Dropbox(access_token)
  
  metadata,file=dbx.files_download('path to .mov file')

  and I get the error

  SSLError: HTTPSConnectionPool(host='content.dropboxapi.com', port=443): Max retries exceeded with url: /2/files/download (Caused by SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])")))

  I don’t know if this is a cause, but I didn’t use the Dropbox app key or app secret in setting things up. In going through the API v2 setup, it looked like all you need is the API Access token, but I’m wondering if there’s a permissions error.

  I’ll only be using this app for myself—it’s not meant for production.

• Monitoring ffmpeg two-passes encoding

  31 décembre 2024, par Hodol

  I'm new in FFMPEG.

  


  According to the official guide, https://trac.ffmpeg.org/wiki/Encode/VP9 I use the following command to convert a large h.264 file :

  


  ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 0 -crf 30 -pass 1 -an -f null /dev/null
ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 0 -crf 30 -pass 2 -c:a libopus output.webm


  


  However, the pass-1 takes too long time and it does not log progress. With -report option I can see something is in progress but I don't know how long I should wait.

  


  Here's questions :

  


  

  1. Is there any way to see the progress of 1-pass ?

  


  2. Is there any way to speed up the process ?

  


  


  Thank you,