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• 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 ?

  


• WebVTT Audio Descriptions for Elephants Dream

  10 mars 2015, par silvia

  When I set out to improve accessibility on the Web and we started developing WebSRT – later to be renamed to WebVTT – I needed an example video to demonstrate captions / subtitles, audio descriptions, transcripts, navigation markers and sign language.

  I needed a freely available video with spoken text that either already had such data available or that I could create it for. Naturally I chose “Elephants Dream” by the Orange Open Movie Project , because it was created under the Creative Commons Attribution 2.5 license.

  As it turned out, the Blender Foundation had already created a collection of SRT files that would represent the English original as well as the translated languages. I was able to reuse them by merely adding a WEBVTT header.

  Then there was a need for a textual audio description. I read up on the plot online and finally wrote up a time-alignd audio description. I’m hereby making that file available under the Create Commons Attribution 4.0 license. I’ve added a few lines to the medadata headers so it doesn’t confuse players. Feel free to reuse at will – I know there are others out there that have a similar need to demonstrate accessibility features.

• Convert chapters from xml to ffmetadata ?

  3 février 2021, par Soul Spark

  I wanted to add chapters to my encoded mkvs, but I get *.xml files when I download it from online. So is there any way to convert it to FFMETADATAFILE so that when I encode it using ffmpeg I can add chapters to my mkv ??

  



  Sample Input

  



  &lt;?xml version="1.0"?>&#xA;&#xA;&#xA;&#xA;-<chapters>&#xA;&#xA;&#xA;-<editionentry>&#xA;&#xA;<editionflagdefault>1</editionflagdefault>&#xA;&#xA;<editionflaghidden>0</editionflaghidden>&#xA;&#xA;&#xA;-<chapteratom>&#xA;&#xA;<chapteruid>95534594</chapteruid>&#xA;&#xA;<chaptertimestart>00:00:00.000000000</chaptertimestart>&#xA;&#xA;<chaptertimeend>00:01:30.000000000</chaptertimeend>&#xA;&#xA;<chapterflaghidden>0</chapterflaghidden>&#xA;&#xA;<chapterflagenabled>1</chapterflagenabled>&#xA;&#xA;&#xA;-<chapterdisplay>&#xA;&#xA;<chapterstring>Chapter 1</chapterstring>&#xA;&#xA;<chapterlanguage>und</chapterlanguage>&#xA;&#xA;</chapterdisplay>&#xA;&#xA;</chapteratom>&#xA;&#xA;&#xA;&#xA;</editionentry>&#xA;&#xA;</chapters>&#xA;

  



  Sample Output

  



  ;FFMETADATA1
title=bike\\shed
;this is a comment
artist=FFmpeg troll team

[CHAPTER]
TIMEBASE=1/1000
START=0
#chapter ends at 0:01:00
END=60000
title=chapter \#1
[STREAM]
title=multi\
line


  



  By the way I use ffmpeg in cli mode only.