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Autres articles (99)
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Personnaliser en ajoutant son logo, sa bannière ou son image de fond
5 septembre 2013, parCertains thèmes prennent en compte trois éléments de personnalisation : l’ajout d’un logo ; l’ajout d’une bannière l’ajout d’une image de fond ;
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Ecrire une actualité
21 juin 2013, parPrésentez les changements dans votre MédiaSPIP ou les actualités de vos projets sur votre MédiaSPIP grâce à la rubrique actualités.
Dans le thème par défaut spipeo de MédiaSPIP, les actualités sont affichées en bas de la page principale sous les éditoriaux.
Vous pouvez personnaliser le formulaire de création d’une actualité.
Formulaire de création d’une actualité Dans le cas d’un document de type actualité, les champs proposés par défaut sont : Date de publication ( personnaliser la date de publication ) (...) -
Publier sur MédiaSpip
13 juin 2013Puis-je poster des contenus à partir d’une tablette Ipad ?
Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir
Sur d’autres sites (16589)
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ClassX installation "codec not found" due to dependencies [migrated]
25 mars 2014, par khateebClassX is an interactive lecture streaming system developed in the Electrical Engineering Department at Stanford University.
Unlike conventional lecture capturing systems, ClassX requires very simple consumer-grade equipment and minimal human operation.I faced problems during installing it, I hope you have a solution.
BTW : I successfully installed it 2 years ago, but now I think the problem as the dependencies and Ubuntu versions are different than the versions we used two years ago.
Detailed description of the problem :
- I'm using Ubuntu 12.04
- I followed the instructions @ ClassX installation guide, and all steps till step 4 are successfully done (the encoder bin file generated).
- When trying to encode the video using the classX web system, it shows the encoding completed after few seconds.However, there are no tiles generated.
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I tried to execute the command at CX_log.txt, and the following error appears.
mahmoud@Mahmoud-HP-Pavilion-dv5-Notebook-PC : $ sudo perl /var/www/ClassXWebSystem/system/publishers/web/actions/encode.pl "/var/www/ClassXWebSystem/content/encoding/FALL_2013_2014/CS106A_FALL_2013_2014/lecSEven" "/var/www/ClassXWebSystem/content/encoding/FALL_2013_2014/CS106A_FALL_2013_2014/.encoding_1372706251" "/var/www/ClassXWebSystem/content/streaming/FALL_2013_2014/CS106A_FALL_2013_2014/lecSEven" "/var/www/ClassXWebSystem/system/publishers/bin" classx y n n
[sudo] password for mahmoud :
00068.jpg
..
.
00068.mp4
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/ClassXWebSystem/content/encoding/FALL_2013_2014/CS106A_FALL_2013_2014/.encoding_1372706251/00068.mp4' :
Metadata :
major_brand : isom
minor_version : 512
compatible_brands : isomiso2avc1mp41
encoder : Lavf52.39.0
Duration : 00:02:30.05, start : 0.000000, bitrate : 8141 kb/s
Stream #0.0(und) : Video : h264, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 8007 kb/s, 29.95 fps, 29.97 tbr, 2997 tbn, 59.94 tbc
Stream #0.1(und) : Audio : aac, 44100 Hz, stereo, s16, 128 kb/s
Output #0, mp4, to '/var/www/ClassXWebSystem/content/encoding/FALL_2013_2014/CS106A_FALL_2013_2014/.encoding_1372706251/stream0.mp4' :
Stream #0.0 : Video : [0][0][0][0] / 0x0000, yuv420p, 640x360, q=32-36, 64 kb/s, 90k tbn, 14.99 tbc
codec not found
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SDL2 won't play with more than 6 audio channels
13 juin 2020, par Hiko HaietoI am trying to stream (raw) video and audio from a capture device as part of my home media setup (with my pc acting similarly to a receiver in a typical home theatre setup), but the biggest problem I haven't been able to get past is that I haven't been able to get ffplay (using SDL2 as its audio backend) to work with all 8 channels in 7.1 streams - two simply get dropped, despite it recognising 8 channel input or me specifying a 7.1 layout.



I have been able to confirm that all 8 channels are present in the source by first using ffmpeg to save the output of a speaker test to a file and playing that back with both mplayer (which works) and ffplay (which doesn't). I also wrote some minimal code to play the audio directly through SDL's API with the same result, so it's not the fault of ffplay. I might simply use mplayer if it weren't for the fact that piping output from ffmpeg adds too much latency for real-time use. I am using libSDL version 2.0.12 and ffplay 4.2.3, both of which are the latest at the time of writing and are ostensibly supposed to support 7.1 audio.



Using output recorded from
speaker-test -c 8
, I am using the following to play it back in mplayer :


mplayer -channels 8 -rawaudio channels=8 -format s16le -demuxer rawaudio speaker-test.pcm




and the following to play it back in ffplay :



ffplay -f s16le -ac 8 -af 'channelmap=channel_layout=7.1' speaker-test.pcm




No matter what I try, the two side channels get dropped. I couldn't figure out how to play raw pcm in SDL, so I repeated the same tests with wav output and used the following code to play it back :



#include <sdl2></sdl2>SDL.h>

int main(int argc, char **argv) {
 SDL_Init(SDL_INIT_AUDIO);
 SDL_AudioSpec wavSpec;
 Uint32 wavLength;
 Uint8 *wavBuffer;
 SDL_LoadWAV("speaker-test.wav", &wavSpec, &wavBuffer, &wavLength);
 SDL_AudioDeviceID deviceID = SDL_OpenAudioDevice(NULL, 0, &wavSpec, NULL, 0);
 SDL_QueueAudio(deviceID, wavBuffer, wavLength);
 SDL_PauseAudioDevice(deviceID, 0);
 SDL_Delay(30000);
 SDL_CloseAudioDevice(deviceID);
 SDL_FreeWAV(wavBuffer);
 SDL_Quit();
 return 0;
}




The above code exhibits the same behaviour of dropping the two additional side channels, despite it being the latest version of SDL that should have supported 7.1 for many releases now. Why might this be happening, and how might I fix it ?


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Inconsistent behaviour of ffmpeg -i flag
19 mai 2021, par zeebrahI'm trying to write a Bash script that would download an audio track from youtube and convert it to Apple ringtone format, which is .m4r. The tools I employ are
youtube-dl
andffmpeg
. The former seems to work fine but I have a strange issue with the latter. When I try to pass the name of the file parametrically, shell prints that file or directory can't be found.

I use the same method for unwraping user input (or my defaults) for both commands but it only seems to work with
youtube-dl
.

Example of what doesn't work and print the text above. Obviously, all the files are in fact there and accessible


youtube-dl -i --extract-audio --audio-format m4a -o $filepath_interim --audio-quality 0 $video_link
ffmpeg -i $filepath_interim -acodec copy -f ipod -ss $offset -t $length $filepath_out



So, I tried to do it with
''
strings,$(command)
syntax, it all failed. I only found one way to make it work, which is to hard code the values of the paths but this defeats the whole purpose of my script.

youtube-dl -i --extract-audio --audio-format m4a -o $filepath_interim --audio-quality 0 $video_link
ffmpeg -i ~/Downloads/ringtone.m4a -acodec copy -f ipod -ss $offset -t $length ~/Downloads/ringtone.m4r



I want to figure out why this keeps happening, whether it is in any way specific to
ffmpeg
or am I just missing some piece of knowledge about$
name unwrapping.

Minimal Working Example. Run with bash or pack in script and run. If your path to
bash
is different, please change the shebang :

#!/usr/local/bin/bash
# initialise
filepath_interim="~/Downloads/ringtone.m4a"
filepath_out="~/Downloads/ringtone.m4r"
video_link="https://www.youtube.com/watch?v=dQw4w9WgXcQ"
offset=0
length=30

# main part
youtube-dl -i --extract-audio --audio-format m4a -o $filepath_interim --audio-quality 0 $video_link
ffmpeg -i $filepath_interim -acodec copy -f ipod -ss $offset -t $length $filepath_out