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Bug de détection d’ogg
22 mars 2013, par
Mis à jour : Avril 2013
Langue : français
Type : Video
Autres articles (61)
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Des sites réalisés avec MediaSPIP
2 mai 2011, parCette page présente quelques-uns des sites fonctionnant sous MediaSPIP.
Vous pouvez bien entendu ajouter le votre grâce au formulaire en bas de page. -
La file d’attente de SPIPmotion
28 novembre 2010, parUne file d’attente stockée dans la base de donnée
Lors de son installation, SPIPmotion crée une nouvelle table dans la base de donnée intitulée spip_spipmotion_attentes.
Cette nouvelle table est constituée des champs suivants : id_spipmotion_attente, l’identifiant numérique unique de la tâche à traiter ; id_document, l’identifiant numérique du document original à encoder ; id_objet l’identifiant unique de l’objet auquel le document encodé devra être attaché automatiquement ; objet, le type d’objet auquel (...) -
MediaSPIP version 0.1 Beta
16 avril 2011, parMediaSPIP 0.1 beta est la première version de MediaSPIP décrétée comme "utilisable".
Le fichier zip ici présent contient uniquement les sources de MediaSPIP en version standalone.
Pour avoir une installation fonctionnelle, il est nécessaire d’installer manuellement l’ensemble des dépendances logicielles sur le serveur.
Si vous souhaitez utiliser cette archive pour une installation en mode ferme, il vous faudra également procéder à d’autres modifications (...)
Sur d’autres sites (13299)
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How can I simply replace the colors using the color masks on this image and then save it ? With RGBA channels as example
31 août 2020, par karl-policeSo I got this GIF here :




As you can see, it has Red, Green and Blue in it. And it also has a full transparency in it. This was composed together with FFMPEG out of images that looked exactly like that.




Then, with FFMPEG I "decomposed" the RGB and Alpha channels using the filter "extractplanes".


The gallery of that, in correct order starting from up to down, can be found here :




I am not sure if this actually helps me or if I'm supposed to decompose them. Because apperantly now, after decomposing them, I'm supposed to modify them, but I'm not really sure how. It's like how do I modify the red channel that only has black and white, so all at the end, will match to the specified HEX color that I want it to be to.




Now, my question is. How do I exactly make the color changing happen ? Can I do this simply with JavaScript ? Is it possible to do with FFMPEG, if possible without ImageMagicks ? Maybe a programming language where not much installation is needed to do that ?


What I understood is that. These channels basically contain values from 0 to 255 with black and white. I think the "brightness" is that what 0 and 255. So something inbetween, would be like grey.


So basically, like we do (255,0,0) for red. In these channels, if I want red somewhere I need to put one fully white pixel on the red channel and on all the other channels, there has to be a fully black pixel.


That's the concept. Now is the question, how can I do this ?




At the end I want to make it look like the colors this one has, as example :




This is from a game. So basically that's how it looks like in the game. And the game files only use these RGBA template sprites.




I asked a similar question here : How to change colors of an image using RGBA and more channels independently of their color


But somehow, I might didn't seem to explain it that well.




I made a thing here to test around with things. I guess that's nearly close, but the lines are kinda weird. jsfiddle.net/qsgazubk


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How to use the function expr in drawtext ffmpeg to add a text to video ?
18 décembre 2013, par nhanptI'm try to add a text to my video using FFmpeg.
Sources : http://www.ffmpeg.org/ffmpeg-all.html#drawtext-1ffmpeg -i 1385363109.avi -vf "drawtext=fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf : text = %{localtime}: \x=(w-tw)/2: y=h-(2*lh): fontcolor=white: box=1: boxcolor=0x00000000@1" -an -y out11.avi
I am trying to figure out how to add a timestamp in a formatable manner (specifically, I'd like to show mm:ss). I think this should be possible using a command like
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ffmpeg -i input.avi -vf "drawtext=fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf:expansion=normal:text='%expr=floor(t/60)~:%expr=floor(t)' : fontcolor=white " output.aviBut I just get a lot of
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[Parsed_drawtext_0 @ 0x1a68a80] %expr=floor(t/60) is not knownand no text is displayed.
If I try
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ffmpeg -i input.avi -vf "drawtext=fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf:expansion=normal:text='%expr' : fontcolor=white " output.aviI get instead
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[Parsed_drawtext_0 @ 0x2d22be0] %expr requires at least 1 argumentsso the version of drawtext I have definitely recognizes the expr function, but I can't figure out the syntax for giving it an argument. Does anyone know what the synatax is for the expr (or e) function ?
Alternately, if there is another way to display the timecode as mm:ss that would be great too. I know that using the 'timecode' argument of drawtext you can get hh:mm:ss:ff, or using text='%pts' gives me decimal seconds to the microsecond, but I am sure that my advisor (who is very picky) will not accept either of these. Thanks in advance for any assistance !
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FFMPEG Determine average color of an area of a video
12 novembre 2019, par Naved KhanI have a use case where I’d want to insert one of two watermarks - one designed for a dark-ish background, the other for a light background into a video. Let’s say that I’d want to do this on the top right corner of the video.
How do I determine the average color of the top right section of the video ? Post this, how do I determine which watermark to use by looking at the average color ?
I have a solution right now where I am taking equally spaced screenshots and then measuring the average color, but it’s excruciatingly slow, especially for longer videos.
# Calculate average color
black_distances = []
white_distances = []
movie = FFMPEG::Movie.new(video_file)
(0..movie.duration / 10).each do |second|
# extract a frame
filename = "tmp/watermark/#{SecureRandom.uuid}.jpg"
movie.screenshot filename.to_s, seek_time: second
# analyse frame for color distance
frame = MiniMagick::Image.open(filename)
frame.crop('20%x20%+80%+0')
frame.resize('1x1')
pixel = frame.get_pixels.flatten
distance_from_black = Math.sqrt(((black[0] - pixel[0])**2 + (black[1] - pixel[1])**2 + (black[2] - pixel[2])**2))
distance_from_white = Math.sqrt(((white[0] - pixel[0])**2 + (white[1] - pixel[1])**2 + (white[2] - pixel[2])**2))
black_distances.push distance_from_black
white_distances.push distance_from_white
File.delete(filename) if File.exist?(filename)
end
average_black_distance = black_distances.reduce(:+).to_f / black_distances.size
average_white_distance = white_distances.reduce(:+).to_f / white_distances.sizeI am also confused about how to use the resulting
average_black_distance
andaverage_white_distance
to determine which watermark to use.