Recherche avancée

Sur d’autres sites (3137)

• FFmpeg amix + volume filters create saturated output ?

  1er septembre 2021, par Sonia Seddiki

  


  First of all, this is a question asked more out of curiosity than desperate need of fixing. I seem to have "fixed" it by upgrading from FFmpeg 3.4.6 to FFmpeg 4.3.1. Or so I think, at least the result is much better.

  


  


  I'm trying to mix 2 audio files (of the same length, so no scale variation here) using FFmpeg amix filter :

  


  

  • A music which starts pretty loud in the beginning and then is almost quiet until the end,

  


  • An audio that starts with silence (basically as long as the music is loud), then continues with a person speaking at an "average" volume

  


  


  Now, I learnt that the filter will divide each input volume by 1/nb_active_inputs (by 2 in my case then), so I added a volume filter on the output to multiply its volume by 2. My command basically looks like this :

  


  ffmpeg -i music.mp3 -i voice.mp3 -filter_complex amix=inputs=2:duration=first[mix];[mix]volume=2[out] -map [out] output.mp3


  


  After that complex filter, my final output is completely distorted. The voice sounds overall very loud and saturated.

  


  I'm not an expert with audio nor with FFmpeg so I assume I'm missing something. I'm trying to understand what is going on and why I am having this result since I use the same inputs, filters and filter options in both cases. Only the FFmpeg version differs.

  


  I've tried to read the code of af_amix.c for both versions but can't seem to find any explanation for that difference. I've seen that the 4.3.1 has a weights option for inputs but from what I understood, they default to 1.0 if not specified. Any clue would be much appreciated.

  


• ffmpeg for archval and convertability

  26 juillet 2021, par Satya

  I've got a couple hundred gigs of *.dv files. I'd like to convert them to H.264 or something else or even leave them alone. The purpose is archival, with an eye to maximum convertability especially to DVD. The content is family videos.

  


  Would this be fine ?

  


  ffmpeg -i input.dv \
    -c:v libx264 -preset slower \
    -crf 17 \
    -pix_fmt yuv420p \
    output.mp4


  


  I went with the slower preset because encoding time isn't an issue and I'd like a smaller file size. crf 17 is for least-lossy while being widely playable. I read somewhere that yuv420p is needed for some Quicktime players.

  


  Should I throw in -c:a aac for AAC audio ? The audio is voice only, no need for music-hall quality.

  


  I looked at https://trac.ffmpeg.org/wiki/Encode/H.264 for previous research and that's where I got those settings, but it is silent on the audio settings.

  


• No audio from discord bot. discord.py/ffmpeg

  22 juillet 2021, par Superior125

  I'm creating a simple music bot and I cant figure out why there is no audio from the bot. I've tried kicking and rejoining, changing code and more. I just cant figure this out. There is no errors from the command line and the bot has a little green circle around it as if there was audio from it. However it goes away if you rejoin the VC.

  


  Here is the code :

  


  import discord
from discord.utils import get
from discord.ext import commands
from discord import FFmpegPCMAudio
from discord.voice_client import VoiceClient

import youtube_dl
import os

TOKEN = "Token Here"
bot = commands.Bot(command_prefix='s')
intents = discord.Intents.default()
intents.members = True
client = commands.Bot(command_prefix=',', intents = intents)

@bot.event
async def on_ready():
    channel = discord.utils.get(bot.get_all_channels(), id=794444804607574026)
    await channel.connect()
    
    
@bot.command(name='play')
async def play(ctx, url):
    await message.content.startswith('play')
    player = await voice_client.create_ytdl_player(url)
    player = await voice.create_ytdl_player("https://youtu.be/K4DyBUG242c")
    player = await vc.create_ytdl_player()
    player.start()

bot.run(TOKEN) 


  


  If you want to, feel free to improve it. I got this code from a YouTube tutorial so I don't completely understand the audio part.