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Autres articles (103)
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MediaSPIP 0.1 Beta version
25 avril 2011, parMediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
The zip file provided here only contains the sources of MediaSPIP in its standalone version.
To get a working installation, you must manually install all-software dependencies on the server.
If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...) -
ANNEXE : Les plugins utilisés spécifiquement pour la ferme
5 mars 2010, parLe site central/maître de la ferme a besoin d’utiliser plusieurs plugins supplémentaires vis à vis des canaux pour son bon fonctionnement. le plugin Gestion de la mutualisation ; le plugin inscription3 pour gérer les inscriptions et les demandes de création d’instance de mutualisation dès l’inscription des utilisateurs ; le plugin verifier qui fournit une API de vérification des champs (utilisé par inscription3) ; le plugin champs extras v2 nécessité par inscription3 (...)
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Support audio et vidéo HTML5
10 avril 2011MediaSPIP utilise les balises HTML5 video et audio pour la lecture de documents multimedia en profitant des dernières innovations du W3C supportées par les navigateurs modernes.
Pour les navigateurs plus anciens, le lecteur flash Flowplayer est utilisé.
Le lecteur HTML5 utilisé a été spécifiquement créé pour MediaSPIP : il est complètement modifiable graphiquement pour correspondre à un thème choisi.
Ces technologies permettent de distribuer vidéo et son à la fois sur des ordinateurs conventionnels (...)
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Anomalie #4189 (Fermé) : extraire_multi mélange un /li /ul final avec le de langue ajouté p...
8 mars 2021, par cedric -intégré par https://git.spip.net/spip/spip/commit/2731ba05209cf61588923a5cd8cc4442cad6878e alea jacta est
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When compressing a set of images with libx264, why does frame rate affect final output size ?
3 avril 2018, par jd20I’m using ffmpeg to encode a set of images as a short timelapse video, using libx264 codec. My first attempt, I encoded it at 30 FPS, using :
ffmpeg -r 30 -pattern_type glob -i "*.jpg" -vcodec libx264 -crf 30 -pix_fmt yuv420p output.mp4
With 60 frames, that gives me a 163 KB file that’s 2 seconds long. Then I realized I needed it to be slower, so I re-ran the same command, but changed -r to 2. Now I have a file that’s 30 seconds long, but the size jumped to 891 KB ! The video quality looks perceptually the same.
How do I encode at a slower frame rate, without the final file size ballooning ?
Notes : Some theories I had, and things I checked. First, to make sure ffmpeg wasn’t duplicating frames in the longer verison, I check the I/P/B counts. The 30 FPS file had :
[libx264 @ 0x7f9b26001c00] frame I:1 Avg QP:30.67 size: 44649
[libx264 @ 0x7f9b26001c00] frame P:15 Avg QP:31.19 size: 5471
[libx264 @ 0x7f9b26001c00] frame B:44 Avg QP:31.45 size: 767The 2 FPS file had :
[libx264 @ 0x7fcd32842200] frame I:1 Avg QP:21.29 size: 90138
[libx264 @ 0x7fcd32842200] frame P:15 Avg QP:22.48 size: 33686
[libx264 @ 0x7fcd32842200] frame B:44 Avg QP:26.29 size: 6674So, the I/P/B counts are identical, but the QP is much lower for the 2 FPS file. To offset, I tried increasing -crf for the 2 FPS file, to get about the same target size, but that just gave me a very blurry video (had to go to crf=40). I tried messing with -minrate, -maxrate, -bt, none helped. I’m guessing there is some x264 codec setting which is frame rate dependent, but I’m at a loss trying to figure out which one (from what I understand, constant bitrate is affected by frame rate but CRF should not be, but maybe I’m misunderstanding it.
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When compressing a set of images with libx264, why does frame rate affect final output size ?
3 avril 2018, par jd20I’m using ffmpeg to encode a set of images as a short timelapse video, using libx264 codec. My first attempt, I encoded it at 30 FPS, using :
ffmpeg -r 30 -pattern_type glob -i "*.jpg" -vcodec libx264 -crf 30 -pix_fmt yuv420p output.mp4
With 60 frames, that gives me a 163 KB file that’s 2 seconds long. Then I realized I needed it to be slower, so I re-ran the same command, but changed -r to 2. Now I have a file that’s 30 seconds long, but the size jumped to 891 KB ! The video quality looks perceptually the same.
How do I encode at a slower frame rate, without the final file size ballooning ?
Notes : Some theories I had, and things I checked. First, to make sure ffmpeg wasn’t duplicating frames in the longer verison, I check the I/P/B counts. The 30 FPS file had :
[libx264 @ 0x7f9b26001c00] frame I:1 Avg QP:30.67 size: 44649
[libx264 @ 0x7f9b26001c00] frame P:15 Avg QP:31.19 size: 5471
[libx264 @ 0x7f9b26001c00] frame B:44 Avg QP:31.45 size: 767The 2 FPS file had :
[libx264 @ 0x7fcd32842200] frame I:1 Avg QP:21.29 size: 90138
[libx264 @ 0x7fcd32842200] frame P:15 Avg QP:22.48 size: 33686
[libx264 @ 0x7fcd32842200] frame B:44 Avg QP:26.29 size: 6674So, the I/P/B counts are identical, but the QP is much lower for the 2 FPS file. To offset, I tried increasing -crf for the 2 FPS file, to get about the same target size, but that just gave me a very blurry video (had to go to crf=40). I tried messing with -minrate, -maxrate, -bt, none helped. I’m guessing there is some x264 codec setting which is frame rate dependent, but I’m at a loss trying to figure out which one (from what I understand, constant bitrate is affected by frame rate but CRF should not be, but maybe I’m misunderstanding it.