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Autres articles (92)
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Ajouter des informations spécifiques aux utilisateurs et autres modifications de comportement liées aux auteurs
12 avril 2011, parLa manière la plus simple d’ajouter des informations aux auteurs est d’installer le plugin Inscription3. Il permet également de modifier certains comportements liés aux utilisateurs (référez-vous à sa documentation pour plus d’informations).
Il est également possible d’ajouter des champs aux auteurs en installant les plugins champs extras 2 et Interface pour champs extras. -
Récupération d’informations sur le site maître à l’installation d’une instance
26 novembre 2010, parUtilité
Sur le site principal, une instance de mutualisation est définie par plusieurs choses : Les données dans la table spip_mutus ; Son logo ; Son auteur principal (id_admin dans la table spip_mutus correspondant à un id_auteur de la table spip_auteurs)qui sera le seul à pouvoir créer définitivement l’instance de mutualisation ;
Il peut donc être tout à fait judicieux de vouloir récupérer certaines de ces informations afin de compléter l’installation d’une instance pour, par exemple : récupérer le (...) -
Use, discuss, criticize
13 avril 2011, parTalk to people directly involved in MediaSPIP’s development, or to people around you who could use MediaSPIP to share, enhance or develop their creative projects.
The bigger the community, the more MediaSPIP’s potential will be explored and the faster the software will evolve.
A discussion list is available for all exchanges between users.
Sur d’autres sites (7568)
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Is it possible to change volume with no reencode with ffmpeg ?
30 juin 2023, par John SmithI just had this question because I used the following command with ffmpeg :



ffmpeg -i input.wav -filter:a "volume=0.2" output.wav




Following the documentation here : https://trac.ffmpeg.org/wiki/AudioVolume



However, when I created the new file, the output was half the size of the input and the bitrate of the audio track was reduced as well.



So my questions are :



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- Is the bitrate supposed to decrease with decreasing and increasing volume like so ?
- Is it possible to change volume without reencoding with ffmpeg ?






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Create a looped video with countdown
13 décembre 2016, par Enrico DeleoSomething maybe challenging here :
I want to stream (via rtmp) a video with a fixed image and a countdown applied on it. I know I can create a slideshow with even audio background with ffmtp (http://trac.ffmpeg.org/wiki/Create%20a%20video%20slideshow%20from%20images) but I’m wondering if I can loop it AND apply an overlay with the countdown to a given date.Any ideas ?
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encode YUV420 frame to VP9
21 novembre 2018, par User800222As title,
I’m pulling frames from a IP camera. I converted the input raw data to YUV420 format, and would like to encode YUV420 to VP9, and save frames as .webm format. Would I be able to do that ? Or should I input a BGR444 format for encoding ?
BTW, to set up the parameters for encoding vp9. Is the
av_dict_set()
the right function for setting parameters ?Ex : (http://wiki.webmproject.org/ffmpeg/vp9-encoding-guide)
av_dict_set(&opt, "crf" , "23", 0);
av_dict_set(&opt, "speed" , "4" , 0);
av_dict_set(&opt, "threads", "8" , 0);
av_dict_set(&opt, "pass" , "1" , 0);
av_dict_set(&opt, "b:v", "1400k", 0);Edit : The wiki uses 2 pass for setting parameters, would I be able to do in with 1 pass ?
Edit2 : Blow code seems to be working, wonder how can I bring the size of the videos (vp9) down ? Currently, I have similar size as using h264 encoder.
av_dict_set(&opt, "crf" , "45", 0);
av_dict_set(&opt, "speed" , "8" , 0);
av_dict_set(&opt, "quality", "realtime", 0);
av_dict_set(&opt, "threads", "8" , 0);
av_dict_set(&opt, "tile-columns", "3", 0);
av_dict_set(&opt, "frame-parallel", "1", 0);
av_dict_set(&opt, "row-mt", "1", 0);Update1 :
YUV420P can be encoded as VP9 !