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• cliping a webm file using moviepy and ffmpeg parameters

  19 février 2015, par headdetective

  Using moviepy, I am trying to trim a section of a webm file like this :

  my_file.write_videofile(name, codec = 'libvpx')

  Of course, I have already defined the beginning and end of the clip, etc. The code is returning the segment I want, however, I am noticed a decrease in the quality of the file.
  I am not resizing or constraiing the file size anywhere, so I don’t understand why the clip has an inferior quality compared to the original.

  There are some parameters that I could play with, which I suspect are set as defaults in moviepy to speed of video manipulation, but the documentation of moviepy does not say anything about them :

  ffmpeg_params :

  Any additional ffmpeg parameters you would like to pass, as a list of
  terms, like [‘-option1’, ‘value1’, ‘-option2’, ‘value2’]

  Anybody outhere is familiar with the right parameters to keep the quality of the original file ? As an alternative, is anybody is familiar with any other library to trim webm files ?

  Below are two pics showing the difference in quality. The first one is a frame of the trimmed file, the second one is approximately the same frame, for the original file.

  

  

  Thank you

• Reduce ffmpeg CPU usage with h265 [closed]

  23 septembre 2024, par Neskelogth

  I have a video file to convert using ffmpeg on Ubuntu 22.04. The input uses the codec h264 and I want to convert it to h265 (mainly for storage capacity reasons). The output of ffmpeg -version is

  


  ffmpeg version N-113725-g37702e2066 Copyright (c) 2000-2024 the FFmpeg developers
built with gcc 11 (Ubuntu 11.4.0-1ubuntu1~22.04)
configuration: --enable-nonfree --enable-cuda-nvcc --enable-libnpp --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib64 --disable-static --enable-shared --enable-libx265 --enable-gpl
libavutil      58. 39.100 / 58. 39.100
libavcodec     60. 39.101 / 60. 39.101
libavformat    60. 21.101 / 60. 21.101
libavdevice    60.  4.100 / 60.  4.100
libavfilter     9. 17.100 /  9. 17.100
libswscale      7.  6.100 /  7.  6.100
libswresample   4. 13.100 /  4. 13.100
libpostproc    57.  4.100 / 57.  4.100


  


  I saw online that one of the options of ffmpeg is -threads, but apparently it does not work, since using ffmpeg -i input.mp4 -c:v libx265 -c:a copy output.mp4 and ffmpeg -i input.mp4 -c:v libx265 -c:a copy -threads 2 output.mp4 seem to be exactly the same in terms of CPU usage as shown by htop. Is there something wrong in my usage of -threads ?

  


• Efficient RTMP Video Stream Processing in Go : Replacing ffmpeg and OpenCV with WebSockets or WebRTC ?

  17 juillet 2023, par dumbQuestions

  I currently have a Go program that retrieves and processes a video stream from an RTMP server by using OpenCV, and then forwards the processed stream to another RTMP server with FFmpeg. While this solution works, I am wondering if there are more efficient approaches leveraging Go modules like WebSockets or WebRTC.

  


  My current implementation involves the following steps :

  


  

  1. Use OpenCV to connect to the source RTMP server and capture the video stream.

  


  2. Process the images with OpenCV.

  


  3. Use FFmpeg to forward the processed video stream to the destination RTMP server.

  


  


  Although it gets the job done, I have concerns about the overall efficiency and latency of this setup, especially when dealing with high-resolution video streams.

  


  I've heard about WebSockets and WebRTC as alternatives for real-time video streaming and processing, but I'm not sure how to implement them in Go. Are they more efficient than my current approach ? What are the potential benefits and drawbacks of using WebSockets or WebRTC in terms of video stream handling and processing in a Go program ?

  


  I'd greatly appreciate any insights, or tips on how to improve the efficiency and real-time performance. Thank you !