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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 (52)
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XMP PHP
13 mai 2011, parDixit Wikipedia, XMP signifie :
Extensible Metadata Platform ou XMP est un format de métadonnées basé sur XML utilisé dans les applications PDF, de photographie et de graphisme. Il a été lancé par Adobe Systems en avril 2001 en étant intégré à la version 5.0 d’Adobe Acrobat.
Étant basé sur XML, il gère un ensemble de tags dynamiques pour l’utilisation dans le cadre du Web sémantique.
XMP permet d’enregistrer sous forme d’un document XML des informations relatives à un fichier : titre, auteur, historique (...) -
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. -
Installation en mode ferme
4 février 2011, parLe mode ferme permet d’héberger plusieurs sites de type MediaSPIP en n’installant qu’une seule fois son noyau fonctionnel.
C’est la méthode que nous utilisons sur cette même plateforme.
L’utilisation en mode ferme nécessite de connaïtre un peu le mécanisme de SPIP contrairement à la version standalone qui ne nécessite pas réellement de connaissances spécifique puisque l’espace privé habituel de SPIP n’est plus utilisé.
Dans un premier temps, vous devez avoir installé les mêmes fichiers que l’installation (...)
Sur d’autres sites (8428)
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Why does the compiler convert bool to integer and back to bool instead of returning the bool itself ?
22 juin 2016, par JackI was reading
VideoFileWriterclass fromAForge.Video.FFMPEGassembly via ILSPY (I was interested to see how a particular method works) and found this :public bool IsOpen {
[return: MarshalAs(UnmanagedType.U1)]
get {
return ((this.data != null) ? 1 : 0) != 0;
}
}What’s the reason to do that bool to integer than back to bool conversion rather just do
this.data != null? -
live Streaming video in server side not responding(Wowza -ffmpeg-JavaCV1.1)
12 février 2016, par Muthukumar SI am new to javaCV. I tried to record mp4 and flv videos using javaCV 1.1 in mobile side working nice. But i need server side didn’t show it. thanks I am using wowza media stream engine in server side. thanks for help
package com.example.javacv11;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ShortBuffer;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.bytedeco.javacv.FFmpegFrameRecorder;
import org.bytedeco.javacv.Frame;
import android.app.Activity;
import android.content.Context;
import android.content.pm.ActivityInfo;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.PowerManager;
import android.util.Log;
import android.view.Display;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
public class FirstActivity extends Activity implements OnClickListener {
private final static String CLASS_LABEL = "RecordActivity";
private final static String LOG_TAG = CLASS_LABEL;
private PowerManager.WakeLock mWakeLock;
private String ffmpeg_link = "rtmp://10.0.0.136:1935/live/myStream";
long startTime = 0;
boolean recording = false;
private FFmpegFrameRecorder recorder;
private boolean isPreviewOn = false;
private int sampleAudioRateInHz = 44100;
private int imageWidth = 320;
private int imageHeight = 240;
private int frameRate = 30;
/* audio data getting thread */
private AudioRecord audioRecord;
private AudioRecordRunnable audioRecordRunnable;
private Thread audioThread;
volatile boolean runAudioThread = true;
/* video data getting thread */
private Camera cameraDevice;
private CameraView cameraView;
private Frame yuvImage = null;
/* layout setting */
private final int bg_screen_bx = 232;
private final int bg_screen_by = 128;
private final int bg_screen_width = 700;
private final int bg_screen_height = 500;
private final int bg_width = 1123;
private final int bg_height = 715;
private final int live_width = 640;
private final int live_height = 480;
private int screenWidth, screenHeight;
private Button btnRecorderControl;
/* The number of seconds in the continuous record loop (or 0 to disable loop). */
final int RECORD_LENGTH = 10;
Frame[] images;
long[] timestamps;
ShortBuffer[] samples;
int imagesIndex, samplesIndex;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
setContentView(R.layout.activity_first);
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, CLASS_LABEL);
mWakeLock.acquire();
initLayout();
}
@Override
protected void onResume() {
super.onResume();
if (mWakeLock == null) {
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, CLASS_LABEL);
mWakeLock.acquire();
}
}
@Override
protected void onPause() {
super.onPause();
if (mWakeLock != null) {
mWakeLock.release();
mWakeLock = null;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
recording = false;
if (cameraView != null) {
cameraView.stopPreview();
}
if(cameraDevice != null) {
cameraDevice.stopPreview();
cameraDevice.release();
cameraDevice = null;
}
if (mWakeLock != null) {
mWakeLock.release();
mWakeLock = null;
}
}
private void initLayout() {
/* get size of screen */
Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
screenWidth = display.getWidth();
screenHeight = display.getHeight();
RelativeLayout.LayoutParams layoutParam = null;
LayoutInflater myInflate = null;
myInflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
RelativeLayout topLayout = new RelativeLayout(this);
setContentView(topLayout);
LinearLayout preViewLayout = (LinearLayout) myInflate.inflate(R.layout.activity_first, null);
layoutParam = new RelativeLayout.LayoutParams(screenWidth, screenHeight);
topLayout.addView(preViewLayout, layoutParam);
/* add control button: start and stop */
btnRecorderControl = (Button) findViewById(R.id.recorder_control);
btnRecorderControl.setText("Start");
btnRecorderControl.setOnClickListener(this);
/* add camera view */
int display_width_d = (int) (1.0 * bg_screen_width * screenWidth / bg_width);
int display_height_d = (int) (1.0 * bg_screen_height * screenHeight / bg_height);
int prev_rw, prev_rh;
if (1.0 * display_width_d / display_height_d > 1.0 * live_width / live_height) {
prev_rh = display_height_d;
prev_rw = (int) (1.0 * display_height_d * live_width / live_height);
} else {
prev_rw = display_width_d;
prev_rh = (int) (1.0 * display_width_d * live_height / live_width);
}
layoutParam = new RelativeLayout.LayoutParams(prev_rw, prev_rh);
layoutParam.topMargin = (int) (1.0 * bg_screen_by * screenHeight / bg_height);
layoutParam.leftMargin = (int) (1.0 * bg_screen_bx * screenWidth / bg_width);
cameraDevice = Camera.open();
Log.i(LOG_TAG, "cameara open");
cameraView = new CameraView(this, cameraDevice);
topLayout.addView(cameraView, layoutParam);
Log.i(LOG_TAG, "cameara preview start: OK");
}
//---------------------------------------
// initialize ffmpeg_recorder
//---------------------------------------
private void initRecorder() {
Log.w(LOG_TAG,"init recorder");
if (RECORD_LENGTH > 0) {
imagesIndex = 0;
images = new Frame[RECORD_LENGTH * frameRate];
timestamps = new long[images.length];
for (int i = 0; i < images.length; i++) {
images[i] = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
timestamps[i] = -1;
}
} else if (yuvImage == null) {
yuvImage = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
Log.i(LOG_TAG, "create yuvImage");
}
Log.i(LOG_TAG, "ffmpeg_url: " + ffmpeg_link);
recorder = new FFmpegFrameRecorder(ffmpeg_link, imageWidth, imageHeight, 1);
recorder.setFormat("mp4");
recorder.setSampleRate(sampleAudioRateInHz);
// Set in the surface changed method
recorder.setFrameRate(frameRate);
Log.i(LOG_TAG, "recorder initialize success");
audioRecordRunnable = new AudioRecordRunnable();
audioThread = new Thread(audioRecordRunnable);
runAudioThread = true;
}
public void startRecording() {
initRecorder();
try {
recorder.start();
startTime = System.currentTimeMillis();
recording = true;
audioThread.start();
} catch (FFmpegFrameRecorder.Exception e) {
e.printStackTrace();
}
}
public void stopRecording() {
runAudioThread = false;
try {
audioThread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
audioRecordRunnable = null;
audioThread = null;
if (recorder != null && recording) {
if (RECORD_LENGTH > 0) {
Log.v(LOG_TAG,"Writing frames");
try {
int firstIndex = imagesIndex % samples.length;
int lastIndex = (imagesIndex - 1) % images.length;
if (imagesIndex <= images.length) {
firstIndex = 0;
lastIndex = imagesIndex - 1;
}
if ((startTime = timestamps[lastIndex] - RECORD_LENGTH * 1000000L) < 0) {
startTime = 0;
}
if (lastIndex < firstIndex) {
lastIndex += images.length;
}
for (int i = firstIndex; i <= lastIndex; i++) {
long t = timestamps[i % timestamps.length] - startTime;
if (t >= 0) {
if (t > recorder.getTimestamp()) {
recorder.setTimestamp(t);
}
recorder.record(images[i % images.length]);
}
}
firstIndex = samplesIndex % samples.length;
lastIndex = (samplesIndex - 1) % samples.length;
if (samplesIndex <= samples.length) {
firstIndex = 0;
lastIndex = samplesIndex - 1;
}
if (lastIndex < firstIndex) {
lastIndex += samples.length;
}
for (int i = firstIndex; i <= lastIndex; i++) {
recorder.recordSamples(samples[i % samples.length]);
}
} catch (FFmpegFrameRecorder.Exception e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
recording = false;
Log.v(LOG_TAG,"Finishing recording, calling stop and release on recorder");
try {
recorder.stop();
recorder.release();
} catch (FFmpegFrameRecorder.Exception e) {
e.printStackTrace();
}
recorder = null;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (recording) {
stopRecording();
}
finish();
return true;
}
return super.onKeyDown(keyCode, event);
}
//---------------------------------------------
// audio thread, gets and encodes audio data
//---------------------------------------------
class AudioRecordRunnable implements Runnable {
@Override
public void run() {
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
// Audio
int bufferSize;
ShortBuffer audioData;
int bufferReadResult;
bufferSize = AudioRecord.getMinBufferSize(sampleAudioRateInHz,
AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleAudioRateInHz,
AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);
if (RECORD_LENGTH > 0) {
samplesIndex = 0;
samples = new ShortBuffer[RECORD_LENGTH * sampleAudioRateInHz * 2 / bufferSize + 1];
for (int i = 0; i < samples.length; i++) {
samples[i] = ShortBuffer.allocate(bufferSize);
}
} else {
audioData = ShortBuffer.allocate(bufferSize);
}
Log.d(LOG_TAG, "audioRecord.startRecording()");
audioRecord.startRecording();
/* ffmpeg_audio encoding loop */
while (runAudioThread) {
if (RECORD_LENGTH > 0) {
audioData = samples[samplesIndex++ % samples.length];
audioData.position(0).limit(0);
}
//Log.v(LOG_TAG,"recording? " + recording);
bufferReadResult = audioRecord.read(audioData.array(), 0, audioData.capacity());
audioData.limit(bufferReadResult);
if (bufferReadResult > 0) {
Log.v(LOG_TAG,"bufferReadResult: " + bufferReadResult);
// If "recording" isn't true when start this thread, it never get's set according to this if statement...!!!
// Why? Good question...
if (recording) {
if (RECORD_LENGTH <= 0) try {
recorder.recordSamples(audioData);
//Log.v(LOG_TAG,"recording " + 1024*i + " to " + 1024*i+1024);
} catch (FFmpegFrameRecorder.Exception e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
}
}
Log.v(LOG_TAG,"AudioThread Finished, release audioRecord");
/* encoding finish, release recorder */
if (audioRecord != null) {
audioRecord.stop();
audioRecord.release();
audioRecord = null;
Log.v(LOG_TAG,"audioRecord released");
}
}
}
//---------------------------------------------
// camera thread, gets and encodes video data
//---------------------------------------------
class CameraView extends SurfaceView implements SurfaceHolder.Callback, PreviewCallback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraView(Context context, Camera camera) {
super(context);
Log.w("camera","camera view");
mCamera = camera;
mHolder = getHolder();
mHolder.addCallback(CameraView.this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
mCamera.setPreviewCallback(CameraView.this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
stopPreview();
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera.release();
mCamera = null;
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Camera.Parameters camParams = mCamera.getParameters();
List sizes = camParams.getSupportedPreviewSizes();
// Sort the list in ascending order
Collections.sort(sizes, new Comparator() {
public int compare(final Camera.Size a, final Camera.Size b) {
return a.width * a.height - b.width * b.height;
}
});
// Pick the first preview size that is equal or bigger, or pick the last (biggest) option if we cannot
// reach the initial settings of imageWidth/imageHeight.
for (int i = 0; i < sizes.size(); i++) {
if ((sizes.get(i).width >= imageWidth && sizes.get(i).height >= imageHeight) || i == sizes.size() - 1) {
imageWidth = sizes.get(i).width;
imageHeight = sizes.get(i).height;
Log.v(LOG_TAG, "Changed to supported resolution: " + imageWidth + "x" + imageHeight);
break;
}
}
camParams.setPreviewSize(imageWidth, imageHeight);
Log.v(LOG_TAG,"Setting imageWidth: " + imageWidth + " imageHeight: " + imageHeight + " frameRate: " + frameRate);
camParams.setPreviewFrameRate(frameRate);
Log.v(LOG_TAG,"Preview Framerate: " + camParams.getPreviewFrameRate());
mCamera.setParameters(camParams);
startPreview();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
try {
mHolder.addCallback(null);
mCamera.setPreviewCallback(null);
} catch (RuntimeException e) {
// The camera has probably just been released, ignore.
}
}
public void startPreview() {
if (!isPreviewOn && mCamera != null) {
isPreviewOn = true;
mCamera.startPreview();
}
}
public void stopPreview() {
if (isPreviewOn && mCamera != null) {
isPreviewOn = false;
mCamera.stopPreview();
}
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
startTime = System.currentTimeMillis();
return;
}
if (RECORD_LENGTH > 0) {
int i = imagesIndex++ % images.length;
yuvImage = images[i];
timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
}
/* get video data */
if (yuvImage != null && recording) {
((ByteBuffer)yuvImage.image[0].position(0)).put(data);
if (RECORD_LENGTH <= 0) try {
Log.v(LOG_TAG,"Writing Frame");
long t = 1000 * (System.currentTimeMillis() - startTime);
if (t > recorder.getTimestamp()) {
recorder.setTimestamp(t);
}
recorder.record(yuvImage);
} catch (FFmpegFrameRecorder.Exception e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
}
}
@Override
public void onClick(View v) {
if (!recording) {
startRecording();
Log.w(LOG_TAG, "Start Button Pushed");
btnRecorderControl.setText("Stop");
} else {
// This will trigger the audio recording loop to stop and then set isRecorderStart = false;
stopRecording();
Log.w(LOG_TAG, "Stop Button Pushed");
btnRecorderControl.setText("Start");
}
}
} -
av_frame_alloc is returning null
22 mai 2014, par user1789711I am just starting to use the ffmpeg library using C++, while trying to decode my video file I am facing an error in one of the steps when trying to allocate an avFrame by using the function av_frame_alloc which is supposed to return an avFrame, however it is returning NULL which indicates that the allocation has failed. I have tried to search on web but couldn’t find any relevant information, and here is my code so far :
extern "C"
{
# pragma comment (lib, "avformat.lib")
#define __STDC_CONSTANT_MACROS
#include "libavcodec\avcodec.h"
#include "libavutil\frame.h"
#include "libavformat\avformat.h"
}
#include <iostream>
using namespace std;
int main(int argc, char* argv[])
{
char * filename="D:\\MOV_0051.mp4";
av_register_all();
AVFormatContext *pFormatCtx=NULL;
if(avformat_open_input(&pFormatCtx,filename,0,0) !=0)
{
cout<<"failed to open file";
return -1;
}
AVCodecContext *pCodecCtx=NULL;
int i=av_find_default_stream_index(pFormatCtx);
pCodecCtx=pFormatCtx->streams[i]->codec;
AVCodec *pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL)
cout<<"codec not supported";
if(avcodec_open2(pCodecCtx,pCodec,NULL)<0)
{
return -1;
cout<<"codec not opened";
}
if(avcodec_is_open(pCodecCtx)<0)
return -1;
AVFrame *pFrame;
pFrame=av_frame_alloc();
//this is were the problem in happening everything else is working just fine
if(av_frame_alloc()==NULL)
cout<<"worked";
else
cout<<"not wroking";
cin>>i;
return 0;
}
</iostream>
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