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• Understanding ffmpeg -benchmark results

  6 septembre 2022, par Ivy Growing

  Adding -benchmark flag to ffmpeg command resutls with addition of following 2 lines in the shell output :

  


  bench: utime=10.125s stime=4.234s rtime=5.606s
bench: maxrss=110080kB


  


  The maxrss serves to indicate the maximum RAM used during the ffmpeg execution. The utime, stime, rtime indicate accordingly :

  


  

  • user time ;

  


  • system time ;

  


  • real time.

  


  


  I tried to understand the meaning of these times from the source code and failed. Please, help.

  


  

  1. Which of these times indicate how much time was human waiting while the ffpmeg was processing the video ?

  


  2. Can this time be seen directly or it's a combination/calculation of these 3 parameters ?

  


  3. How it can be for certain videos utime > rtime and for others utime < rtime ?

  


  


• FFmpeg error while converting from MP4 to MP3 in Python

  4 février 2024, par Jack142

  When I try to convert videos from a YouTube playlist, it gives me an error :

  


  


  File "C :\Users\fonti\AppData\Local\Programs\Python\Python310\lib\site-packages\ffmpy.py", line 106, in run
raise FFRuntimeError(self.cmd, self.process.returncode, out[0], out[1])
ffmpy.FFRuntimeError : C:/ffmpeg/bin/ffmpeg.exe -i "Nightcore - To Be Human // lyrics.mp4" "Nightcore - To Be Human // lyrics.mp3" exited with status 1

  


  


  The code I'm using :

  


  from pytube import Playlist
import ffmpy
from ffmpy import FFmpeg

playlistLink = input("Introduz o link da Playlist: ")
playlist = Playlist(playlistLink)   

diretório = 'E'
while diretório != 'M' and diretório != 'V':
    diretório = input("Vais baixar música ou vídeos? (M/V)")
    if diretório == 'M':
        downloadDirectory = "C:/Users/fonti/Documents/Projetos Python/Youtube/Músicas"
    elif diretório == 'V':
        downloadDirectory = "C:/Users/fonti/Documents/Projetos Python/Youtube/Vídeos"

print("Número total de vídeos a baixar: ", len(playlist.video_urls))    

print("\n\n Links dos vídeos:\n")

for url in playlist.video_urls:
    print(url) 

def MP3():
    for video in playlist.videos:

        audio = video.streams.get_audio_only()
    
        audio.download(downloadDirectory)

        videoTitle = video.title
    
        new_filename = videoTitle + '.mp3'
        default_filename = videoTitle + '.mp4'
    
        print(default_filename+'\n\n'+new_filename)

        ff = ffmpy.FFmpeg(
            executable = 'C:/ffmpeg/bin/ffmpeg.exe',
            inputs={default_filename : None},
            outputs={new_filename : None}
        )
        ff.run()


def MP4():
    for video in playlist.videos:
        print('Downloading : {} with url : {}'.format(video.title, video.watch_url))
        video.streams.\
            filter(type='video', progressive=True, file_extension='mp4').\
            order_by('resolution').\
            desc().\
            first().\
            download(downloadDirectory)

escolha = 'E'
while escolha != 'V' and escolha != 'A':
    escolha = input("Queres formato de vídeo ou áudio (V/A)? ")
    if escolha == 'V':
        MP4()
    elif escolha == 'A':
        MP3()
    else:
        print("Escolha inválida")


  


  If I try to download the videos from the playlist, it works fine. But when I try to download the audios, it gives me the error.

  


• Why does FFmpeg encode by default ?

  2 décembre 2022, par Hashim Aziz

  By default the following unpresuming FFmpeg command :

  


  ffmpeg -i "input.mp4" "output.mkv"


  


  ...will lossily encode a file unless it has the -c copy flag added, which will then pass the video through without any encoding. I remember not realising this as a beginner to FFmpeg years ago and being surprised when I found out, and ever since then it's something I've wondered about but not got around to asking.

  


  The main justification for this behaviour that comes to mind for me is that encoding is a much more common operation, and it might be annoying to have to pass an extra -encode flag for most uses.

  


  Was this ever one of the reasons cited for this design decision ? Has the issue ever even been discussed in the FFmpeg mailing lists, or has it remained unquestioned since being written during the days of Fabrice Bellard ?