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La conservation du net art au musée. Les stratégies à l’œuvre
26 mai 2011
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (57)
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Ajouter notes et légendes aux images
7 février 2011, parPour pouvoir ajouter notes et légendes aux images, la première étape est d’installer le plugin "Légendes".
Une fois le plugin activé, vous pouvez le configurer dans l’espace de configuration afin de modifier les droits de création / modification et de suppression des notes. Par défaut seuls les administrateurs du site peuvent ajouter des notes aux images.
Modification lors de l’ajout d’un média
Lors de l’ajout d’un média de type "image" un nouveau bouton apparait au dessus de la prévisualisation (...) -
Prérequis à l’installation
31 janvier 2010, parPréambule
Cet article n’a pas pour but de détailler les installations de ces logiciels mais plutôt de donner des informations sur leur configuration spécifique.
Avant toute chose SPIPMotion tout comme MediaSPIP est fait pour tourner sur des distributions Linux de type Debian ou dérivées (Ubuntu...). Les documentations de ce site se réfèrent donc à ces distributions. Il est également possible de l’utiliser sur d’autres distributions Linux mais aucune garantie de bon fonctionnement n’est possible.
Il (...) -
HTML5 audio and video support
13 avril 2011, parMediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
For older browsers the Flowplayer flash fallback is used.
MediaSPIP allows for media playback on major mobile platforms with the above (...)
Sur d’autres sites (9813)
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How to create video using avcodec from jpeg images of type OpenCV::Mat ?
23 juillet 2015, par theateistI have colored jpeg images of
OpenCV::Mattype and I create from them video usingavcodec. The video that I get is upside-down, black & white and each row of each frame is shifted and I got diagonal line. What could be the reason for such output ?
Follow this link to watch the video I get using avcodec.
I’m usingacpicture_fillfunction to createavFramefromcv::Matframe !P.S.
Each cv::Mat cvFrame has width=810, height=610, step=2432
I noticed that avFrame (that is filled by acpicture_fill) haslinesize[0]=2430
I tried manually settingavFrame->linesizep0]=2432and not 2430 but it still didn’t helped.======== CODE =========================================================
AVCodec *encoder = avcodec_find_encoder(AV_CODEC_ID_H264);
AVStream *outStream = avformat_new_stream(outContainer, encoder);
avcodec_get_context_defaults3(outStream->codec, encoder);
outStream->codec->pix_fmt = AV_PIX_FMT_YUV420P;
outStream->codec->width = 810;
outStream->codec->height = 610;
//...
SwsContext *swsCtx = sws_getContext(outStream->codec->width, outStream->codec->height, PIX_FMT_RGB24,
outStream->codec->width, outStream->codec->height, outStream->codec->pix_fmt, SWS_BICUBIC, NULL, NULL, NULL);
for (uint i=0; i < frameNums; i++)
{
// get frame at location I using OpenCV
cv::Mat cvFrame;
myReader.getFrame(cvFrame, i);
cv::Size frameSize = cvFrame.size();
//Each cv::Mat cvFrame has width=810, height=610, step=2432
1. // create AVPicture from cv::Mat frame
2. avpicture_fill((AVPicture*)avFrame, cvFrame.data, PIX_FMT_RGB24, outStream->codec->width, outStream->codec->height);
3avFrame->width = frameSize.width;
4. avFrame->height = frameSize.height;
// rescale to outStream format
sws_scale(swsCtx, avFrame->data, avFrame->linesize, 0, outStream->codec->height, avFrameRescaledFrame->data, avFrameRescaledFrame ->linesize);
encoderRescaledFrame->pts=i;
avFrameRescaledFrame->width = frameSize.width;
avFrameRescaledFrame->height = frameSize.height;
av_init_packet(&avEncodedPacket);
avEncodedPacket.data = NULL;
avEncodedPacket.size = 0;
// encode rescaled frame
if(avcodec_encode_video2(outStream->codec, &avEncodedPacket, avFrameRescaledFrame, &got_frame) < 0) exit(1);
if(got_frame)
{
if (avEncodedPacket.pts != AV_NOPTS_VALUE)
avEncodedPacket.pts = av_rescale_q(avEncodedPacket.pts, outStream->codec->time_base, outStream->time_base);
if (avEncodedPacket.dts != AV_NOPTS_VALUE)
avEncodedPacket.dts = av_rescale_q(avEncodedPacket.dts, outStream->codec->time_base, outStream->time_base);
// outContainer is "mp4"
av_write_frame(outContainer, & avEncodedPacket);
av_free_packet(&encodedPacket);
}
}UPDATED
As @Alex suggested I changed the lines 1-4 with the code below
int width = frameSize.width, height = frameSize.height;
avpicture_alloc((AVPicture*)avFrame, AV_PIX_FMT_RGB24, outStream->codec->width, outStream->codec->height);
for (int h = 0; h < height; h++)
{
memcpy(&(avFrame->data[0][h*avFrame->linesize[0]]), &(cvFrame.data[h*cvFrame.step]), width*3);
}The video (here) I get now is almost perfect. It’s NOT upside-down, NOT black & white, BUT it seems that one of the RGB components is missing. Every brown/red colors became blue (in original images it should be vice-verse).
What could be the problem ? Could rescaling(sws_scale) toAV_PIX_FMT_YUV420Pformat causes this ? -
Creating a continuous stream for RTMP in Node.js
9 mars 2023, par hankthetank27I'm working on an app that downloads audio from youtube that will be streamed sequentially, similar to radio broadcast. I'm having trouble getting the individual tracks to stream continuously. My idea was to write the tracks sequentially into a readable stream that then is read by FFMPEG. Here is the code I'm having trouble with...


import ytdl from "ytdl-core";
import ffmpeg from 'fluent-ffmpeg';
import { Readable } from "node:stream"

export async function startAudioStream(): Promise<void>{

 const mainStream = await createStreamedQueue()

 ffmpeg(mainStream)
 .inputOptions([
 '-re'
 ])
 .outputOption([
 // '-c:v libx264',
 // '-preset veryfast',
 // '-tune zerolatency',
 '-c:a aac',
 '-ar 44100',
 ])
 .save('rtmp://localhost/live/main.flv');
};

async function createStreamedQueue(): Promise<readable>{

 function createStream(): Readable{
 const stream = new Readable({
 read(){},
 highWaterMark: 1024 * 512,
 });
 stream._destroy = () => { stream.destroyed = true };
 return stream;
 }

 const mainStream = createStream();

 const ref1 = 'https://youtu.be/lLCEUpIg8rE'
 const ref2 = 'https://youtu.be/bRdyzdXJ0KA';

 function queueSong(src: string, stream: Readable): Promise<void>{
 return new Promise<void>((resolve, reject) => {
 ytdl(src, {
 filter: 'audioonly',
 quality: 'highestaudio'
 })
 .on('data', (data) => {
 stream.push(data);
 })
 .on('end', () => {
 resolve();
 })
 .on('error', (err) => {
 console.error('Error downloading file from YouTube.', err);
 reject(err);
 })
 })
 }
 
 await queueSong(ref1, mainStream);
 // console.log('after firsrt: ', mainStream)
 await queueSong(ref2, mainStream);
 // console.log('after second: ', mainStream)
 return mainStream;
};
</void></void></readable></void>

To start,
startAudioStreamis called to initiate a readable stream of audio to an RTMP server via FFMPEG. That is working fine. The part I'm having trouble with is "queuing" the tracks into the stream that's being fed into FFMPEG. Right now, I have a "main" stream that each songs data is being pushed into, as you can see inqueueSong. At the end of ytdl stream, the promise is resolved, allowing for the next song to be queued and its data to be pushed intomainStream. The issue that I'm experiencing is that the audio fromref1is only every played.

I can see in the logs that
mainStreamdoes grow in length after each call toqueueSong, but still will only stream the audio from the first track. My initial thought was that there is a terminating character at the of the last data chunk thats being written to the steam for each song ? But maybe im getting screwed up on how streams work...

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FFmpeg output video is not seekable. Output video is not playing instantly instead browser loads it completely then plays it
19 février 2024, par Mohit56Hi I am using ffmpeg to transcode video. In my code I have used 'fluent-ffmpeg' npm package with nodeJs and 'aws-sdk' to save output video by writestream into s3 bucket.


Problem
-> Video is getting transcoded and I am successfully able to save the video into s3 bucket but. As I paste the object_url of that video into browser and try to play, but that video is not playing instantly I have checked on 'developer console tool' browser is loading all the video once that is done then only it starts playing that is a problem.


->Let say if I have output video of size 10GB on that case browser will load all 10GB data then only it will start playing that video.


->If I am not using writestream approach and directly upload the video into local directory first then upload into s3 bucket, In this case if I play the video using object URL then that video plays instantly. In this case I don't have to wait for whole 10GB video to load then play it which is good.


-> Can anybody help me to fix my writestream solution because I don't want to save the output video into my localdirectory. I want to writestream the output video directly into s3 bucket.


Code Snippet


const ffmpeg = require('fluent-ffmpeg');
const AWS = require('aws-sdk'); 
const stream = require("stream");

//set up your aws connection

const command = ffmpeg(inputVideoURL) 
.outputOptions(['-movflags', 'frag_keyframe']) 
.size('854x480') // set the desired resolution (480p) .outputFormat('mp4') 
.videoCodec('libx264') 
.audioCodec('aac') 
.on('progress',(p)=>{ console.log(p) }) 
.on('stderr',(err)=>console.log(err)) 
.on('start', commandLine => console.log('Spawned FFmpeg with command: ' + commandLine)) 
.on('end', () => console.log('Transcoding finished.')) 
.on('error', err => console.error('Error:', err))

//=>To save file into s3 using write steam. command.writeToStream(uploadFolderFileWriteStream('StreamCheck/output2.mp4'));

function uploadFolderFileWriteStream(fileName) { try { const pass = new stream.PassThrough();

const params = {
 Bucket: bucketName,
 Key: fileName,
 Body: pass,
 ACL: "public-read",
 ContentType:'video/mp4' ,
};

const upload = s3.upload(params);

upload.on('error', function(err) {
 console.log("Error uploading to S3:", err);
});

upload.send(function(err, data) {
 if(err) console.log(err);
 else console.log("Upload to S3 completed:", data);
});

return pass;

} catch (err) { console.log("[S3 createWriteStream]", err); } }


I have tried below option as well be all of them not worked 
-> .addOption("-movflags frag_keyframe+empty_moov") 
-> .addOption('-movflags', 'frag_keyframe+empty_moov') 
-> .addOutputOption("-movflags +faststart")
-> .addOption('-movflags', 'faststart+frag_keyframe+empty_moov+default_base_moof')


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