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Rennes Emotion Map 2010-11
19 octobre 2011, par
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (85)
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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 (...) -
Organiser par catégorie
17 mai 2013, parDans MédiaSPIP, une rubrique a 2 noms : catégorie et rubrique.
Les différents documents stockés dans MédiaSPIP peuvent être rangés dans différentes catégories. On peut créer une catégorie en cliquant sur "publier une catégorie" dans le menu publier en haut à droite ( après authentification ). Une catégorie peut être rangée dans une autre catégorie aussi ce qui fait qu’on peut construire une arborescence de catégories.
Lors de la publication prochaine d’un document, la nouvelle catégorie créée sera proposée (...) -
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 (4507)
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Revision 37011 : Un petit test pour voir si ffmpeg2theora est dispo sur le serveur (pour ...
6 avril 2010, par kent1@… — LogUn petit test pour voir si ffmpeg2theora est dispo sur le serveur (pour l’utiliser au cas où plus tard)
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ffmpeg memory leak when opening libx264 encoder
18 octobre 2023, par ksb496I have spotted a memory leak issue when I use the libx264 encoder in the FFmpeg C API. Specifically, when it comes to deallocate memory after encoding a video. After tracking the factor that causes it, I realized that it happens after invoking
avcodec_open2, which allocates some memory that afterwards cannot be freed. Once the video is processed, callingavcodec_closeand thenavcodec_free_contextdoes not entirely free all the allocated memory.

After some investigation, I found out that the problem could be located in
AVCodecContext::priv_databeing allocated but not being freed afterwards. In this question a solution to the issue is proposed. However, I tried to implement it without success (the memory being leaked seems to be exactly the same).

As a matter of fact, the following simple code (which includes the patch that was proposed in the aforementioned question), in which the codec is being opened and closed multiple times without even writing a single frame or allocating an
AVFormatContext, illustrates the memory leak.

#include 
extern "C"{
#include 
#include <libavcodec></libavcodec>avcodec.h>
#include <libavutil></libavutil>opt.h>
}

int main()
{
 avcodec_register_all();

 AVCodec *codec;
 AVCodecContext *c;
 for (int n=0; n<2000; n++)
 {
 codec = avcodec_find_encoder_by_name("libx264");
 c=avcodec_alloc_context3(codec);
 c->pix_fmt=AV_PIX_FMT_YUV420P;
 c->width=1920;
 c->height=1080;
 c->time_base=(AVRational){1, 30};
 c->framerate=(AVRational){30, 1};
 avcodec_open2(c, codec, NULL);
 avcodec_close(c);
 av_opt_free(c->priv_data);
 av_freep(&c->priv_data);
 avcodec_free_context(&c);
 }
 return 0;
}


It must be remarked that if the line
codec = avcodec_find_encoder_by_name("libx264")is replaced to an invocation to an internal/native encoder, e.g.,codec = avcodec_find_encoder(AV_CODEC_ID_MPEG4), then the memory leak issue completely disappears. Hence, it certainly seems to be an issue related to some private data of the external encoder not being properly freed.

It is also worth mentioning that I am using an old version of ffmpeg and libx264. To be more precise, ffmpeg version 2.8git and libx264 version 0.136.x. For technical reasons that are beyond the scope of this question, it is not possible to upgrade the libraries to newer versions onto the project in which these are being used. I am fully aware that most of the involved ffmpeg/libx264 code has been probably changed along the years and many functions became deprecated or fixed, and thus reporting this as a possible bug in the ffmpeg developer's mailbox is out of the question.


Nevertheless, I am still asking this here because I would like to know whether it is just some mistake on my end and/or something I am not taking into account when it comes to free all the memory relative to an external encoder (best case scenario). Otherwise, I would like to know whether there can be some reasonably cheap solution through some custom code or function that can be implemented as a patch (assuming it is indeed an issue related to ffmpeg/libx264), no matter if it makes the whole deallocation code less elegant or concise. If someone is still working on these older versions of ffmpeg and can come up with a workaround, that would be highly appreciated.


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ffmpeg memory leak when opening libx264 encoder
18 octobre 2023, par ksb496I have spotted a memory leak issue when I use the libx264 encoder in the FFmpeg C API. Specifically, when it comes to deallocate memory after encoding a video. After tracking the factor that causes it, I realized that it happens after invoking
avcodec_open2, which allocates some memory that afterwards cannot be freed. Once the video is processed, callingavcodec_closeand thenavcodec_free_contextdoes not entirely free all the allocated memory.

After some investigation, I found out that the problem could be located in
AVCodecContext::priv_databeing allocated but not being freed afterwards. In this question a solution to the issue is proposed. However, I tried to implement it without success (the memory being leaked seems to be exactly the same).

As a matter of fact, the following simple code (which includes the patch that was proposed in the aforementioned question), in which the codec is being opened and closed multiple times without even writing a single frame or allocating an
AVFormatContext, illustrates the memory leak.

#include 
extern "C"{
#include 
#include <libavcodec></libavcodec>avcodec.h>
#include <libavutil></libavutil>opt.h>
}

int main()
{
 avcodec_register_all();

 AVCodec *codec;
 AVCodecContext *c;
 for (int n=0; n<2000; n++)
 {
 codec = avcodec_find_encoder_by_name("libx264");
 c=avcodec_alloc_context3(codec);
 c->pix_fmt=AV_PIX_FMT_YUV420P;
 c->width=1920;
 c->height=1080;
 c->time_base=(AVRational){1, 30};
 c->framerate=(AVRational){30, 1};
 avcodec_open2(c, codec, NULL);
 avcodec_close(c);
 av_opt_free(c->priv_data);
 av_freep(&c->priv_data);
 avcodec_free_context(&c);
 }
 return 0;
}


It must be remarked that if the line
codec = avcodec_find_encoder_by_name("libx264")is replaced to an invocation to an internal/native encoder, e.g.,codec = avcodec_find_encoder(AV_CODEC_ID_MPEG4), then the memory leak issue completely disappears. Hence, it certainly seems to be an issue related to some private data of the external encoder not being properly freed.

It is also worth mentioning that I am using an old version of ffmpeg and libx264. To be more precise, ffmpeg version 2.8git and libx264 version 0.136.x. For technical reasons that are beyond the scope of this question, it is not possible to upgrade the libraries to newer versions onto the project in which these are being used. I am fully aware that most of the involved ffmpeg/libx264 code has been probably changed along the years and many functions became deprecated or fixed, and thus reporting this as a possible bug in the ffmpeg developer's mailbox is out of the question.


Nevertheless, I am still asking this here because I would like to know whether it is just some mistake on my end and/or something I am not taking into account when it comes to free all the memory relative to an external encoder (best case scenario). Otherwise, I would like to know whether there can be some reasonably cheap solution through some custom code or function that can be implemented as a patch (assuming it is indeed an issue related to ffmpeg/libx264), no matter if it makes the whole deallocation code less elegant or concise. If someone is still working on these older versions of ffmpeg and can come up with a workaround, that would be highly appreciated.


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