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Spitfire Parade - Crisis
15 mai 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
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Publier une image simplement
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Autres articles (60)
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List of compatible distributions
26 avril 2011, parThe table below is the list of Linux distributions compatible with the automated installation script of MediaSPIP. Distribution nameVersion nameVersion number Debian Squeeze 6.x.x Debian Weezy 7.x.x Debian Jessie 8.x.x Ubuntu The Precise Pangolin 12.04 LTS Ubuntu The Trusty Tahr 14.04
If you want to help us improve this list, you can provide us access to a machine whose distribution is not mentioned above or send the necessary fixes to add (...) -
Le profil des utilisateurs
12 avril 2011, parChaque utilisateur dispose d’une page de profil lui permettant de modifier ses informations personnelle. Dans le menu de haut de page par défaut, un élément de menu est automatiquement créé à l’initialisation de MediaSPIP, visible uniquement si le visiteur est identifié sur le site.
L’utilisateur a accès à la modification de profil depuis sa page auteur, un lien dans la navigation "Modifier votre profil" est (...) -
Configurer la prise en compte des langues
15 novembre 2010, parAccéder à la configuration et ajouter des langues prises en compte
Afin de configurer la prise en compte de nouvelles langues, il est nécessaire de se rendre dans la partie "Administrer" du site.
De là, dans le menu de navigation, vous pouvez accéder à une partie "Gestion des langues" permettant d’activer la prise en compte de nouvelles langues.
Chaque nouvelle langue ajoutée reste désactivable tant qu’aucun objet n’est créé dans cette langue. Dans ce cas, elle devient grisée dans la configuration et (...)
Sur d’autres sites (4584)
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Failed to decode h264 key frame with DXVA2.0 because returned buffer is to small
16 mai 2023, par grill2010I hava a strange problem on Windows with DXVA2 h264 decoding. I recently figured out a ffmpeg decoding limitation for DXVA2 and D3D11VA on Windows and how to solve it, this solution completly fixes the problem with D3D11VA but DXVA2 still has some problems with certain keyframes. Upon further investigation it turned out that the decoding of these certain keyframes fail because the buffer returned from the IDirectXVideoDecoder_GetBuffer function was too small. FFmpeg is printing out these logs when the decoding fails :


Error: [h264 @ 0000028b2e5796c0] Buffer for type 5 was too small. size: 58752, dxva_size: 55296
Error: [h264 @ 0000028b2e5796c0] Failed to add bitstream or slice control buffer
Error: [h264 @ 0000028b2e5796c0] hardware accelerator failed to decode picture


Why is this returned buffer too low ? What kind of factors inside ffmpeg do have an effect on this buffer size or is this a limitation of DXVA2 in general ? All other decoders like Cuvid, D3D11VA or the software decoder are not affected by this problem and can decode all keyframes.


I have an example javacv project on github that can reproduce the problem. I also provide the source code of the main class here. The keyframe example data with prepended SPS and PPS in hex form can be downloaded here.


import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import org.bytedeco.ffmpeg.avcodec.AVCodec;
import org.bytedeco.ffmpeg.avcodec.AVCodecContext;
import org.bytedeco.ffmpeg.avcodec.AVCodecHWConfig;
import org.bytedeco.ffmpeg.avcodec.AVPacket;
import org.bytedeco.ffmpeg.avutil.AVBufferRef;
import org.bytedeco.ffmpeg.avutil.AVDictionary;
import org.bytedeco.ffmpeg.avutil.AVFrame;
import org.bytedeco.ffmpeg.avutil.LogCallback;
import org.bytedeco.javacpp.BytePointer;
import org.bytedeco.javacpp.IntPointer;
import org.bytedeco.javacpp.Pointer;
import org.tinylog.Logger;

import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.function.Consumer;

import static org.bytedeco.ffmpeg.avcodec.AVCodecContext.FF_THREAD_SLICE;
import static org.bytedeco.ffmpeg.global.avcodec.*;
import static org.bytedeco.ffmpeg.global.avutil.*;

public class App extends Application {

 /**** decoder variables ****/

 private AVHWContextInfo hardwareContext;

 private AVCodec decoder;
 private AVCodecContext m_VideoDecoderCtx;

 private AVCodecContext.Get_format_AVCodecContext_IntPointer formatCallback;

 private final int streamResolutionX = 1920;
 private final int streamResolutionY = 1080;

 // AV_HWDEVICE_TYPE_CUDA // example works with cuda
 // AV_HWDEVICE_TYPE_DXVA2 // producing Invalid data found on keyframe
 // AV_HWDEVICE_TYPE_D3D11VA // producing Invalid data found on keyframe
 private static final int HW_DEVICE_TYPE = AV_HWDEVICE_TYPE_DXVA2;

 private static final boolean USE_HW_ACCEL = true;

 private static final boolean USE_AV_EF_EXPLODE = true;

 public static void main(final String[] args) {
 //System.setProperty("prism.order", "d3d,sw");
 System.setProperty("prism.vsync", "false");
 Application.launch(App.class);
 }

 @Override
 public void start(final Stage primaryStage) {
 final Pane dummyPane = new Pane();
 dummyPane.setStyle("-fx-background-color: black");
 final Scene scene = new Scene(dummyPane, this.streamResolutionX, this.streamResolutionY);
 primaryStage.setScene(scene);
 primaryStage.show();
 primaryStage.setMinWidth(480);
 primaryStage.setMinHeight(360);

 this.initializeFFmpeg(result -> {
 if (!result) {
 Logger.error("FFmpeg could not be initialized correctly, terminating program");
 System.exit(1);
 return;
 }
 scene.setRoot(new StackPane());
 this.performTestFramesFeeding();
 });
 }

 private void initializeFFmpeg(final Consumer<boolean> finishHandler) {
 FFmpegLogCallback.setLevel(AV_LOG_DEBUG); // Increase log level until the first frame is decoded
 FFmpegLogCallback.set();
 Pointer pointer = new Pointer((Pointer) null);
 AVCodec c;
 while ((c = av_codec_iterate(pointer)) != null) {
 if (av_codec_is_decoder(c) > 0)
 Logger.debug("{}:{} ", c.name().getString(), c.type());
 }

 this.decoder = avcodec_find_decoder(AV_CODEC_ID_H264); // usually decoder name is h264 and without hardware support it's yuv420p otherwise nv12
 if (this.decoder == null) {
 Logger.error("Unable to find decoder for format {}", "h264");
 finishHandler.accept(false);
 return;
 }
 Logger.info("Current decoder name: {}, {}", this.decoder.name().getString(), this.decoder.long_name().getString());

 if (true) {
 for (; ; ) {
 this.m_VideoDecoderCtx = avcodec_alloc_context3(this.decoder);
 if (this.m_VideoDecoderCtx == null) {
 Logger.error("Unable to find decoder for format AV_CODEC_ID_H264");
 if (this.hardwareContext != null) {
 this.hardwareContext.free();
 this.hardwareContext = null;
 }
 continue;
 }

 if (App.USE_HW_ACCEL) {
 this.hardwareContext = this.createHardwareContext();
 if (this.hardwareContext != null) {
 Logger.info("Set hwaccel support");
 this.m_VideoDecoderCtx.hw_device_ctx(this.hardwareContext.hwContext()); // comment to disable hwaccel
 }
 } else {
 Logger.info("Hwaccel manually disabled");
 }

 // Always request low delay decoding
 this.m_VideoDecoderCtx.flags(this.m_VideoDecoderCtx.flags() | AV_CODEC_FLAG_LOW_DELAY);

 // Allow display of corrupt frames and frames missing references
 this.m_VideoDecoderCtx.flags(this.m_VideoDecoderCtx.flags() | AV_CODEC_FLAG_OUTPUT_CORRUPT);
 this.m_VideoDecoderCtx.flags2(this.m_VideoDecoderCtx.flags2() | AV_CODEC_FLAG2_SHOW_ALL);

 if (App.USE_AV_EF_EXPLODE) {
 // Report decoding errors to allow us to request a key frame
 this.m_VideoDecoderCtx.err_recognition(this.m_VideoDecoderCtx.err_recognition() | AV_EF_EXPLODE);
 }

 // Enable slice multi-threading for software decoding
 if (this.m_VideoDecoderCtx.hw_device_ctx() == null) { // if not hw accelerated
 this.m_VideoDecoderCtx.thread_type(this.m_VideoDecoderCtx.thread_type() | FF_THREAD_SLICE);
 this.m_VideoDecoderCtx.thread_count(2/*AppUtil.getCpuCount()*/);
 } else {
 // No threading for HW decode
 this.m_VideoDecoderCtx.thread_count(1);
 }

 this.m_VideoDecoderCtx.width(this.streamResolutionX);
 this.m_VideoDecoderCtx.height(this.streamResolutionY);
 this.m_VideoDecoderCtx.pix_fmt(this.getDefaultPixelFormat());

 this.formatCallback = new AVCodecContext.Get_format_AVCodecContext_IntPointer() {
 @Override
 public int call(final AVCodecContext context, final IntPointer pixelFormats) {
 final boolean hwDecodingSupported = context.hw_device_ctx() != null && App.this.hardwareContext != null;
 final int preferredPixelFormat = hwDecodingSupported ?
 App.this.hardwareContext.hwConfig().pix_fmt() :
 context.pix_fmt();
 int i = 0;
 while (true) {
 final int currentSupportedFormat = pixelFormats.get(i++);
 System.out.println("Supported pixel formats " + currentSupportedFormat);
 if (currentSupportedFormat == AV_PIX_FMT_NONE) {
 break;
 }
 }

 i = 0;
 while (true) {
 final int currentSupportedFormat = pixelFormats.get(i++);
 if (currentSupportedFormat == preferredPixelFormat) {
 Logger.info("[FFmpeg]: pixel format in format callback is {}", currentSupportedFormat);
 return currentSupportedFormat;
 }
 if (currentSupportedFormat == AV_PIX_FMT_NONE) {
 break;
 }
 }

 i = 0;
 while (true) { // try again and search for yuv
 final int currentSupportedFormat = pixelFormats.get(i++);
 if (currentSupportedFormat == AV_PIX_FMT_YUV420P) {
 Logger.info("[FFmpeg]: Not found in first match so use {}", AV_PIX_FMT_YUV420P);
 return currentSupportedFormat;
 }
 if (currentSupportedFormat == AV_PIX_FMT_NONE) {
 break;
 }
 }

 i = 0;
 while (true) { // try again and search for nv12
 final int currentSupportedFormat = pixelFormats.get(i++);
 if (currentSupportedFormat == AV_PIX_FMT_NV12) {
 Logger.info("[FFmpeg]: Not found in second match so use {}", AV_PIX_FMT_NV12);
 return currentSupportedFormat;
 }
 if (currentSupportedFormat == AV_PIX_FMT_NONE) {
 break;
 }
 }

 Logger.info("[FFmpeg]: pixel format in format callback is using fallback {}", AV_PIX_FMT_NONE);
 return AV_PIX_FMT_NONE;
 }
 };
 this.m_VideoDecoderCtx.get_format(this.formatCallback);

 final AVDictionary options = new AVDictionary(null);
 final int result = avcodec_open2(this.m_VideoDecoderCtx, this.decoder, options);
 if (result < 0) {
 Logger.error("avcodec_open2 was not successful");
 finishHandler.accept(false);
 return;
 }
 av_dict_free(options);
 break;
 }
 }

 if (this.decoder == null || this.m_VideoDecoderCtx == null) {
 finishHandler.accept(false);
 return;
 }
 finishHandler.accept(true);
 }

 private AVHWContextInfo createHardwareContext() {
 AVHWContextInfo result = null;
 for (int i = 0; ; i++) {
 final AVCodecHWConfig config = avcodec_get_hw_config(this.decoder, i);
 if (config == null) {
 break;
 }

 if ((config.methods() & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX) < 0) {
 continue;
 }
 final int device_type = config.device_type();
 if (device_type != App.HW_DEVICE_TYPE) {
 continue;
 }
 final AVBufferRef hw_context = av_hwdevice_ctx_alloc(device_type);
 if (hw_context == null || av_hwdevice_ctx_create(hw_context, device_type, (String) null, null, 0) < 0) {
 Logger.error("HW accel not supported for type {}", device_type);
 av_free(config);
 av_free(hw_context);
 } else {
 Logger.info("HW accel created for type {}", device_type);
 result = new AVHWContextInfo(config, hw_context);
 }
 break;
 }

 return result;
 }

 @Override
 public void stop() {
 this.releaseNativeResources();
 }

 /*****************************/
 /*** test frame processing ***/
 /*****************************/
 
 private void performTestFramesFeeding() {
 final AVPacket pkt = av_packet_alloc();
 if (pkt == null) {
 return;
 }
 try (final BytePointer bp = new BytePointer(65_535 * 15)) {


 for (int i = 0; i < 1; i++) {
 final byte[] frameData = AVTestFrames.h264KeyTestFrame;

 bp.position(0);

 bp.put(frameData);
 bp.limit(frameData.length);

 pkt.data(bp);
 pkt.capacity(bp.capacity());
 pkt.size(frameData.length);
 pkt.position(0);
 pkt.limit(frameData.length);
 //pkt.flags(AV_PKT_FLAG_KEY);
 final AVFrame avFrame = av_frame_alloc();
 System.out.println("frameData.length " + frameData.length);

 final int err = avcodec_send_packet(this.m_VideoDecoderCtx, pkt); //fill_scaling_lists
 if (err < 0) {
 final BytePointer buffer = new BytePointer(512);
 av_strerror(err, buffer, buffer.capacity());
 final String string = buffer.getString();
 System.out.println("Error on decoding test frame " + err + " message " + string);
 av_frame_free(avFrame);
 return;
 }

 final int result = avcodec_receive_frame(this.m_VideoDecoderCtx, avFrame);
 final AVFrame decodedFrame;
 if (result == 0) {
 if (this.m_VideoDecoderCtx.hw_device_ctx() == null) {
 decodedFrame = avFrame;
 System.out.println("SUCESS with SW decoding");
 } else {
 final AVFrame hwAvFrame = av_frame_alloc();
 if (av_hwframe_transfer_data(hwAvFrame, avFrame, 0) < 0) {
 System.out.println("Failed to transfer frame from hardware");
 av_frame_unref(hwAvFrame);
 decodedFrame = avFrame;
 } else {
 av_frame_unref(avFrame);
 decodedFrame = hwAvFrame;
 System.out.println("SUCESS with HW decoding");
 }
 }

 av_frame_unref(decodedFrame);
 } else {
 final BytePointer buffer = new BytePointer(512);
 av_strerror(result, buffer, buffer.capacity());
 final String string = buffer.getString();
 System.out.println("error " + result + " message " + string);
 av_frame_free(avFrame);
 }
 }
 } finally {
 if (pkt.stream_index() != -1) {
 av_packet_unref(pkt);
 }
 pkt.releaseReference();
 }
 }

 final Object releaseLock = new Object();
 private volatile boolean released = false;

 private void releaseNativeResources() {
 if (this.released) {
 return;
 }
 this.released = true;
 synchronized (this.releaseLock) {
 // Close the video codec
 if (this.m_VideoDecoderCtx != null) {
 avcodec_free_context(this.m_VideoDecoderCtx);
 this.m_VideoDecoderCtx = null;
 }

 // close the format callback
 if (this.formatCallback != null) {
 this.formatCallback.close();
 this.formatCallback = null;
 }

 // close hw context
 if (this.hardwareContext != null) {
 this.hardwareContext.free();
 }
 }
 }

 private int getDefaultPixelFormat() {
 return AV_PIX_FMT_YUV420P; // Always return yuv420p here
 }


 /*********************/
 /*** inner classes ***/
 /*********************/

 public static final class HexUtil {

 private HexUtil() {
 }

 public static byte[] unhexlify(final String argbuf) {
 final int arglen = argbuf.length();
 if (arglen % 2 != 0) {
 throw new RuntimeException("Odd-length string");
 } else {
 final byte[] retbuf = new byte[arglen / 2];

 for (int i = 0; i < arglen; i += 2) {
 final int top = Character.digit(argbuf.charAt(i), 16);
 final int bot = Character.digit(argbuf.charAt(i + 1), 16);
 if (top == -1 || bot == -1) {
 throw new RuntimeException("Non-hexadecimal digit found");
 }

 retbuf[i / 2] = (byte) ((top << 4) + bot);
 }

 return retbuf;
 }
 }
 }

 public static final class AVHWContextInfo {
 private final AVCodecHWConfig hwConfig;
 private final AVBufferRef hwContext;

 private volatile boolean freed = false;

 public AVHWContextInfo(final AVCodecHWConfig hwConfig, final AVBufferRef hwContext) {
 this.hwConfig = hwConfig;
 this.hwContext = hwContext;
 }

 public AVCodecHWConfig hwConfig() {
 return this.hwConfig;
 }

 public AVBufferRef hwContext() {
 return this.hwContext;
 }

 public void free() {
 if (this.freed) {
 return;
 }
 this.freed = true;
 av_free(this.hwConfig);
 av_free(this.hwContext);
 }


 @Override
 public boolean equals(Object o) {
 if (this == o) return true;
 if (o == null || getClass() != o.getClass()) return false;
 AVHWContextInfo that = (AVHWContextInfo) o;
 return freed == that.freed && Objects.equals(hwConfig, that.hwConfig) && Objects.equals(hwContext, that.hwContext);
 }

 @Override
 public int hashCode() {
 return Objects.hash(hwConfig, hwContext, freed);
 }

 @Override
 public String toString() {
 return "AVHWContextInfo[" +
 "hwConfig=" + this.hwConfig + ", " +
 "hwContext=" + this.hwContext + ']';
 }
 }

 public static final class AVTestFrames {

 private AVTestFrames() {

 }

 static {
 InputStream inputStream = null;
 try {
 inputStream = AVTestFrames.class.getClassLoader().getResourceAsStream("h264_test_key_frame.txt");
 final byte[] h264TestFrameBuffer = inputStream == null ? new byte[0] : inputStream.readAllBytes();
 final String h264TestFrame = new String(h264TestFrameBuffer, StandardCharsets.UTF_8);
 AVTestFrames.h264KeyTestFrame = HexUtil.unhexlify(h264TestFrame);
 } catch (final IOException e) {
 Logger.error(e, "Could not parse test frame");
 } finally {
 if (inputStream != null) {
 try {
 inputStream.close();
 } catch (final IOException e) {
 Logger.error(e, "Could not close test frame input stream");
 }
 }
 }
 }

 public static byte[] h264KeyTestFrame;
 }

 public static class FFmpegLogCallback extends LogCallback {

 private static final org.bytedeco.javacpp.tools.Logger logger = org.bytedeco.javacpp.tools.Logger.create(FFmpegLogCallback.class);

 static final FFmpegLogCallback instance = new FFmpegLogCallback().retainReference();

 public static FFmpegLogCallback getInstance() {
 return instance;
 }

 /**
 * Calls {@code avutil.setLogCallback(getInstance())}.
 */
 public static void set() {
 setLogCallback(getInstance());
 }

 /**
 * Returns {@code av_log_get_level()}.
 **/
 public static int getLevel() {
 return av_log_get_level();
 }

 /**
 * Calls {@code av_log_set_level(level)}.
 **/
 public static void setLevel(int level) {
 av_log_set_level(level);
 }

 @Override
 public void call(int level, BytePointer msg) {
 switch (level) {
 case AV_LOG_PANIC, AV_LOG_FATAL, AV_LOG_ERROR -> logger.error(msg.getString());
 case AV_LOG_WARNING -> logger.warn(msg.getString());
 case AV_LOG_INFO -> logger.info(msg.getString());
 case AV_LOG_VERBOSE, AV_LOG_DEBUG, AV_LOG_TRACE -> logger.debug(msg.getString());
 default -> {
 assert false;
 }
 }
 }
 }
}
</boolean>

-
Help us Reset The Net today on June 5th
This blog post explains why the Piwik project is joining ResetTheNet online protest and how you can help make a difference against mass surveillance. It also includes an infographic and links to useful resources which may be of interest to you.
Snowden revelations, a year ago today
On June 5, 2013 the Guardian newspaper published the first of Edward Snowden’s astounding revelations. It was the first of a continuous stream of stories that pointed out what we’ve suspected for a long time : that the world’s digital communications are being continuously spied upon by nation states with precious little oversight.
Unfortunately, mass surveillance is affecting the internet heavily. The Internet is a powerful force that can promote democracy, innovation, and creativity, but it’s being subverted as a tool for government spying. That is why Piwik has decided to join Reset The Net.
June 5, 2014 marks a new year : a year that will not just be about listening to the inside story of mass surveillance, but a new year of fighting back !
How do I protect myself and others ?
Reset the Net is asking everyone to help by installing free software tools that are designed to protect your privacy on a computer or a mobile device.
Reset the Net is also calling on websites and developers to add surveillance resistant features such as HTTPS and forward secrecy.
Participate in ResetTheNet online protest
Have you got your own website, blog or tumblr ? Maybe you can show the Internet Defense League’s “Cat Signal !” on your website.Get the code now to run the Reset the Net splash screen or banner to help make privacy viral on June 5th.
Message from Edward Snowden
Evan from FFTF sent us this message from Edward Snowden and we thought we would share it with you :
One year ago, we learned that the internet is under surveillance, and our activities are being monitored to create permanent records of our private lives — no matter how innocent or ordinary those lives might be.
Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same. That’s why I’m asking you to join me on June 5th for Reset the Net, when people and companies all over the world will come together to implement the technological solutions that can put an end to the mass surveillance programs of any government. This is the beginning of a moment where we the people begin to protect our universal human rights with the laws of nature rather than the laws of nations.
We have the technology, and adopting encryption is the first effective step that everyone can take to end mass surveillance. That’s why I am excited for Reset the Net — it will mark the moment when we turn political expression into practical action, and protect ourselves on a large scale.
Join us on June 5th, and don’t ask for your privacy. Take it back.
– Message by Edward Snowden
ResetTheNet privacy pack infographic
Additional Resources
Configure Piwik for Security and Privacy
- Turn on automatic SSL redirection in your Piwik.
- Configure Piwik for advanced Privacy.
- Best security practises for Piwik.
More info
- Learn why this matters (EFF)
- Data Privacy Day – Why is privacy important ? (Piwik)
- Web Analytics Privacy (Piwik)
-
Neutral net or neutered
4 juin 2013, par Mans — Law and libertyIn recent weeks, a number of high-profile events, in the UK and elsewhere, have been quickly seized upon to promote a variety of schemes for monitoring or filtering Internet access. These proposals, despite their good intentions of protecting children or fighting terrorism, pose a serious threat to fundamental liberties. Although at a glance the ideas may seem like a reasonable price to pay for the prevention of some truly hideous crimes, there is more than first meets the eye. Internet regulation in any form whatsoever is the thin end of a wedge at whose other end we find severely restricted freedom of expression of the kind usually associated with oppressive dictatorships. Where the Internet was once a novelty, it now forms an integrated part of modern society ; regulating the Internet means regulating our lives.
Terrorism
Following the brutal murder of British soldier Lee Rigby in Woolwich, attempts were made in the UK to revive the controversial Communications Data Bill, also dubbed the snooper’s charter. The bill would give police and security services unfettered access to details (excluding content) of all digital communication in the UK without needing so much as a warrant.
The powers afforded by the snooper’s charter would, the argument goes, enable police to prevent crimes such as the one witnessed in Woolwich. True or not, the proposal would, if implemented, also bring about infrastructure for snooping on anyone at any time for any purpose. Once available, the temptation may become strong to extend, little by little, the legal use of these abilities to cover ever more everyday activities, all in the name of crime prevention, of course.
In the emotional aftermath of a gruesome act, anything with the promise of preventing it happening again may seem like a good idea. At times like these it is important, more than ever, to remain rational and carefully consider all the potential consequences of legislation, not only the intended ones.
Hate speech
Hand in hand with terrorism goes hate speech, preachings designed to inspire violence against people of some singled-out nation, race, or other group. Naturally, hate speech is often to be found on the Internet, where it can reach large audiences while the author remains relatively protected. Naturally, we would prefer for it not to exist.
To fulfil the utopian desire of a clean Internet, some advocate mandatory filtering by Internet service providers and search engines to remove this unwanted content. Exactly how such censoring might be implemented is however rarely dwelt upon, much less the consequences inadvertent blocking of innocent material might have.
Pornography
Another common target of calls for filtering is pornography. While few object to the blocking of child pornography, at least in principle, the debate runs hotter when it comes to the legal variety. Pornography, it is claimed, promotes violence towards women and is immoral or generally offensive. As such it ought to be blocked in the name of the greater good.
The conviction last week of paedophile Mark Bridger for the abduction and murder of five-year-old April Jones renewed the debate about filtering of pornography in the UK ; his laptop was found to contain child pornography. John Carr of the UK government’s Council on Child Internet Safety went so far as suggesting a default blocking of all pornography, access being granted to an Internet user only once he or she had registered with some unspecified entity. Registering people wishing only to access perfectly legal material is not something we do in a democracy.
The reality is that Google and other major search engines already remove illegal images from search results and report them to the appropriate authorities. In the UK, the Internet Watch Foundation, a non-government organisation, maintains a blacklist of what it deems ‘potentially criminal’ content, and many Internet service providers block access based on this list.
While well-intentioned, the IWF and its blacklist should raise some concerns. Firstly, a vigilante organisation operating in secret and with no government oversight acting as the nation’s morality police has serious implications for freedom of speech. Secondly, the blocks imposed are sometimes more far-reaching than intended. In one incident, an attempt to block the cover image of the Scorpions album Virgin Killer hosted by Wikipedia (in itself a dubious decision) rendered the entire related article inaccessible as well as interfered with editing.
Net neutrality
Content filtering, or more precisely the lack thereof, is central to the concept of net neutrality. Usually discussed in the context of Internet service providers, this is the principle that the user should have equal, unfiltered access to all content. As a consequence, ISPs should not be held responsible for the content they deliver. Compare this to how the postal system works.
The current debate shows that the principle of net neutrality is important not only at the ISP level, but should also include providers of essential services on the Internet. This means search engines should not be responsible for or be required to filter results, email hosts should not be required to scan users’ messages, and so on. No mandatory censoring can be effective without infringing the essential liberties of freedom of speech and press.
Social networks operate in a less well-defined space. They are clearly not part of the essential Internet infrastructure, and they require that users sign up and agree to their terms and conditions. Because of this, they can include restrictions that would be unacceptable for the Internet as a whole. At the same time, social networks are growing in importance as means of communication between people, and as such they have a moral obligation to act fairly and apply their rules in a transparent manner.
Facebook was recently under fire, accused of not taking sufficient measures to curb ‘hate speech,’ particularly against women. Eventually they pledged to review their policies and methods, and reducing the proliferation of such content will surely make the web a better place. Nevertheless, one must ask how Facebook (or another social network) might react to similar pressure from, say, a religious group demanding removal of ‘blasphemous’ content. What about demands from a foreign government ? Only yesterday, the Turkish prime minister Erdogan branded Twitter ‘a plague’ in a TV interview.
Rather than impose upon Internet companies the burden of law enforcement, we should provide them the latitude to set their own policies as well as the legal confidence to stand firm in the face of unreasonable demands. The usual market forces will promote those acting responsibly.
Further reading
- Tory-Labour pact could save data bill, says Lord Howard
- Internet companies warn May over ‘snooper’s charter’
- Snooper’s charter ‘should be replaced by strengthening of existing powers’
- Exclusive : ‘Snooper’s charter’ would not have prevented Woolwich attack, says MI5
- Search engines urged to block more online porn sites
- Why technology must be the solution to child abuse material online
- Google must take more action to police explicit content, says Vince Cable
- Facebook bows to campaign groups over ‘hate speech’
- Facebook sexism campaign attracts thousands online
- Türkischer Ministerpräsident : Twitter ist eine Plage
- Valls : « La traque sur Internet doit être une priorité pour nous »
- La Cnil, futur juge d’Internet
- “National security matter” : Third agency caught unilaterally blocking web sites
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