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• ffmpeg encoder streaming issues

  8 août 2017, par bobsingh1

  I am trying to build ffmpeg encoder on linux. I started with a custom built server Dual 1366 2.6 Ghz Xeon CPUs (6 cores) with 16 GB RAM with Ubuntu 16.04 minimal install. Built ffmpeg with h264 and aac. I am taking live source OTA channels and encoding/streaming them with following parameters

  -vcodec libx264 -preset superfast -crf 25 -x264opts keyint=60:min-keyint=60:scenecut=-1 -bufsize 7000k -b:v 6000k -maxrate 6300k -muxrate 6000k -s 1920x1080 -format yuv420p -g 60 -sn -c:a aac -b:a 384k -ar 44100

  And I am able to successfully udp out using mpegts. My problem starts with 5th stream. The server can handle four streams and as soon as I introduce 5th stream I start seeing hiccups in output. Looking at my cpu usage using top I still see only 65% to 75% usage with occasional 80% hit. Memory usage is well within acceptable parameters. So I am wondering either top is not giving me accurate cpu usage or something is not right with ffmpeg. The server is isolated for udp in/out on a 1 Gbps network.

  I decided to up the cpu power and installed two 3.5 Ghz CPUs (6 cores) thinking it was perhaps the cpu clock. To my surprise the results were no different. So now I am wondering is there some built in limit I am hitting when I process at 1080p. If I change the resolution to 720p it is able to process 8 streams but 720 is not acceptable.
  My target is 10 1080p streams per server.
  So my questions are
  1. If I use a quad motherboard and up the cpu count to 4 (6 or 8 cores) will I get 10 1080p streams ? Is there any theoretical max I can go with ffmpeg per machine ?
  2. Do cores matter more or does clock matter more ?
  3. Any suggestions in improvement with my options. I have tried ultrafast preset but the output quality is unacceptable.

  Thanks in advance

• Combine many videos in list using FFMPEG

  2 septembre 2022, par anoor1234

  I have a bunch of videos that are MP4s with different FPS, resolution, aspect ratio, basically everything. I'm trying to see if its possible to use FFMPEG to combine them into a single 1080/720 video using a single command, or at least make them all similar format so that combining is easy. Speed and less CPU power would be preferred but I'm in no rush and

  


  I found this command on another stack overflow question :

  


  ffmpeg -i 1.mp4 -i 2.mp4 -i 3.mp4 -filter_complex \
"[0:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v0];
 [1:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v1];
 [2:v]scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1,setsar=1,fps=30,format=yuv420p[v2];
 [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1[v][a]" \
-map "[v]" -map "[a]" -c:v libx264 -c:a aac -movflags +faststart output.mp4


  


  The problem is that I have more that 3 videos to combine and I don't know how to work this command with more, I have an entire list of videos in a list.txt file structured as such :

  


  file './videos/video1.mp4'
file './videos/video2.mp4'
file './videos/video3.mp4'


  


  The code that somewhat worked for me was this

  


  ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4


  


  It combines the video well and fairly fast but I get weird glitches with the audio and the resolution is weird (I'm hoping for 1920x1080). I suspect this is due to the varying attributes of each video but I'm not sure. I'm familiar with Python but I have found no Python script that can do what I ask. If there any way to combine my list into one video (using FFMPEG or not) reliably ?

  


• Anomalie #4562 : Suite #4468 : Unification des CSS pour les boutons et les icônes

  6 octobre 2020

  Mais pour l’ajout là c’est bizarre on voit pas le fond, c’est un peu nul, en tout cas pour cette couleur.

  Oui : https://core.spip.net/issues/4562#note-25 et https://core.spip.net/issues/4562#note-5

  Peut-être l’inverse aussi, le retrait est plus gros que l’ajout : ça ne va pas.

  Oui c’est pas voulu, la capture a été faite à l’arrache dans l’inspecteur, devait rester un font-size planqué quelque part (il y en a pleins d’imbriqués en vrac de partout). Les 2 étaient censés être à la même taille.

  Mais bref, pour mettre le bouton d’ajout à la taille normale il y a pas trop la place pour l’instant : les .toggle_box_link sont positionnés en absolute, ça ferait déborder. Et s’il faut faire rentrer tout ça je sens que ça va amener modifier pleins de choses en cascade. On tire sur un fil et on finit par dérouler toute la pelote de laine :p

  On peut y aller par étapes aussi : laisser tout en .mini.link dans un 1er temps ça me semble acceptable, histoire de garder un truc proche de ce qu’il y avait avant, mais déjà un peu plus harmonisé. Et pis après on amélioera.