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GetID3 - Boutons supplémentaires
9 avril 2013, par
Mis à jour : Avril 2013
Langue : français
Type : Image
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Core Media Video
4 avril 2013, par
Mis à jour : Juin 2013
Langue : français
Type : Video
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The pirate bay depuis la Belgique
1er avril 2013, par
Mis à jour : Avril 2013
Langue : français
Type : Image
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Bug de détection d’ogg
22 mars 2013, par
Mis à jour : Avril 2013
Langue : français
Type : Video
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Exemple de boutons d’action pour une collection collaborative
27 février 2013, par
Mis à jour : Mars 2013
Langue : français
Type : Image
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Exemple de boutons d’action pour une collection personnelle
27 février 2013, par
Mis à jour : Février 2013
Langue : English
Type : Image
Autres articles (56)
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Initialisation de MediaSPIP (préconfiguration)
20 février 2010, parLors de l’installation de MediaSPIP, celui-ci est préconfiguré pour les usages les plus fréquents.
Cette préconfiguration est réalisée par un plugin activé par défaut et non désactivable appelé MediaSPIP Init.
Ce plugin sert à préconfigurer de manière correcte chaque instance de MediaSPIP. Il doit donc être placé dans le dossier plugins-dist/ du site ou de la ferme pour être installé par défaut avant de pouvoir utiliser le site.
Dans un premier temps il active ou désactive des options de SPIP qui ne le (...) -
La sauvegarde automatique de canaux SPIP
1er avril 2010, parDans le cadre de la mise en place d’une plateforme ouverte, il est important pour les hébergeurs de pouvoir disposer de sauvegardes assez régulières pour parer à tout problème éventuel.
Pour réaliser cette tâche on se base sur deux plugins SPIP : Saveauto qui permet une sauvegarde régulière de la base de donnée sous la forme d’un dump mysql (utilisable dans phpmyadmin) mes_fichiers_2 qui permet de réaliser une archive au format zip des données importantes du site (les documents, les éléments (...)
Sur d’autres sites (9901)
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FFmpeg - avcodec_receive_frame returns AVERROR(EAGAIN)
8 novembre 2019, par JinxI’m using an QOpenGL widget to draw frames. However, I’m struggling to get frames by using
avcodec_receive_frame. It ended within the blockelse if (ret == AVERROR(EAGAIN))and returned -11. I have no idea what made this happen. Also I checked that codecs were fine, so I guess the problem wasn’t caused by codecs.MyDemux.cpp
AVPacket* MyDemux::allocatePacket()
{
AVPacket* packet = av_packet_alloc();
return packet;
}
AVFrame* MyDemux::allocateFrame()
{
AVFrame* frame = av_frame_alloc();
return frame;
}
int MyDemux::readFrame(AVPacket* packet)
{
mux.lock();
if (!formatCtx) {
std::cout << "formaetCtx is null" << std::endl;
mux.unlock();
return -1;
}
int ret = av_read_frame(formatCtx, packet);
if (ret == AVERROR_EOF) {
return -2;
}
if (ret != 0) {
mux.unlock();
av_packet_free(&packet);
return -1;
}
media_type = packet->stream_index;
mux.unlock();
return 0;
}MyDecode.cpp
void MyDecode::decode(AVFrame* frame, AVPacket* packet)
{
int ret;
ret = avcodec_send_packet(codecCtx, packet); // this returned 0
while (ret == 0) {
ret = avcodec_receive_frame(codecCtx, frame); // this returned -11
if (ret == AVERROR(EINVAL)) {
std::cout << "codec issue" << std::endl;
av_frame_free(&frame);
return;
}
else if (ret == AVERROR(EAGAIN)) { // program ends here
std::cout << "output is not available this state" << std::endl;
av_frame_free(&frame);
return;
}
else if (ret == AVERROR(EINVAL)) {
std::cout << "no more frames" << std::endl;
av_frame_free(&frame);
return;
}
}
}main.cpp
class MyThread : public QThread
{
public:
MyDemux demux;
MyDecode video_decode;
myDecode audio_decode;
MyVideoWidget* videoWidget;
AVPacket* packet;
AVFrame* frame;
void initThread()
{
char* url = "demo.mp4";
demux.openFile(url);
video_decode.openCodec(demux.copy_video_codec_par());
audio_decode.openCodec(demux.copy_audio_codec_par());
packet = demux.allocatePacket();
frame = demux.allocateFrame();
}
void run()
{
while (demux.readFrame(packet) != -2) {
if (demux.get_media_type() == 0) {
video_decode.decode(frame, packet);
videoWidget->paintFrame(frame);
}
else if (demux.get_media_type() == 1) {
}
}
video_decode.decode(frame, nullptr);
demux.clear();
demux.close();
}
}; -
ffmpeg : libavfilter API av_buffersink_get_frame returns alway EAGAIN
29 juin 2024, par aculnaigI want to resize an image with
libavfilterC API throughzscalefilter andlibplacebofilter but no matter how I callav_buffersink_get_frame, it always returnsEAGAINand no data is filled in thefiltered_frame.

#include 
#include 
#include 
#include 
#include 

#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavfilter></libavfilter>avfilter.h>
#include <libavfilter></libavfilter>buffersrc.h>
#include <libavfilter></libavfilter>buffersink.h>
#include <libavutil></libavutil>log.h>

int main(int argc, char **argv)
{
 if (argc != 2) {
 fprintf(stderr, "usage: %s <filename>\n", argv[0]);
 exit(EXIT_FAILURE);
 }

 const char *src_name = argv[1];
 const char *dst_name = basename(src_name);
 int ret = 0;

 const enum AVPixelFormat src_format = AV_PIX_FMT_YUV422P;

 av_log_set_level(AV_LOG_TRACE);

 AVFormatContext *fmt_ctx = avformat_alloc_context();
 if (fmt_ctx == NULL) {
 av_log(NULL, AV_LOG_TRACE, "avformat_alloc_context(): failed.\n");
 exit(EXIT_SUCCESS);
 }
 if ((ret = avformat_open_input(&fmt_ctx, src_name, NULL, NULL)) != 0) {
 av_log(NULL, AV_LOG_TRACE, "avformat_open_input(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 AVCodecContext *dec_ctx;
 AVCodec *dec;

 if ((ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "av_find_best_stream(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 dec_ctx = avcodec_alloc_context3(dec);
 if (dec_ctx == NULL) {
 av_log(NULL, AV_LOG_TRACE, "avcodec_alloc_context3(): failed.\n");
 exit(EXIT_SUCCESS);
 }
 if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avcodec_open2(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 AVFrame *frame = av_frame_alloc();
 if (frame == NULL) {
 av_log(NULL, AV_LOG_TRACE, "av_frame_alloc(): failed.\n");
 exit(EXIT_SUCCESS);
 }
 AVPacket *packet = av_packet_alloc();
 if (packet == NULL) {
 av_log(NULL, AV_LOG_TRACE, "av_packet_alloc(): failed.\n");
 exit(EXIT_SUCCESS);
 }

 if ((ret = av_read_frame(fmt_ctx, packet)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "av_read_frame(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 ret = avcodec_send_packet(dec_ctx, packet);
 if (ret == AVERROR(EAGAIN)) {
 av_log(NULL, AV_LOG_TRACE, "avcodec_send_packet(): %s.\n", av_err2str(ret));
 avcodec_receive_frame(dec_ctx, frame);
 avcodec_send_packet(dec_ctx, packet);
 }
 
 if ((ret = avcodec_receive_frame(dec_ctx, frame)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avcodec_receive_frame(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 av_packet_unref(packet);

 av_log(NULL, AV_LOG_TRACE, "filename: %s, w: %d, h: %d, fmt: %d\n", src_name, frame->width, frame->height, frame->format);

 AVFilterGraph *filter_graph = avfilter_graph_alloc();

 char buffersrc_args[512];
 snprintf(buffersrc_args, sizeof(buffersrc_args), "video_size=%dx%d:pix_fmt=%d:time_base=1/25", frame->width, frame->height, frame->format); 

 AVFilterContext *buffersrc_ctx;
 if ((ret = avfilter_graph_create_filter(&buffersrc_ctx, avfilter_get_by_name("buffer"), NULL, buffersrc_args, NULL, filter_graph)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_graph_create_filter(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 char libplacebo_args[512];
 snprintf(libplacebo_args, sizeof(libplacebo_args), "format=yuv420p:colorspace=bt470bg:color_primaries=bt709:color_trc=iec61966-2-1:range=pc:w=(iw/2):h=(ih/2):downscaler=none:dithering=none");
 AVFilterContext *libplacebo_ctx;
 if ((ret = avfilter_graph_create_filter(&libplacebo_ctx, avfilter_get_by_name("libplacebo"), NULL, libplacebo_args, NULL, filter_graph)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_graph_create_filter(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 AVFilterContext *buffersink_ctx;
 if ((ret = avfilter_graph_create_filter(&buffersink_ctx, avfilter_get_by_name("buffersink"), NULL, NULL, NULL, filter_graph)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_graph_create_filter(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 if ((ret = avfilter_link(buffersrc_ctx, 0, libplacebo_ctx, 0)) != 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_link(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 if ((ret = avfilter_link(libplacebo_ctx, 0, buffersink_ctx, 0)) != 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_link(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 
 if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "avfilter_graph_config(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }

 AVFrame *filtered_frame = av_frame_alloc();
 if (filtered_frame == NULL) {
 av_log(NULL, AV_LOG_TRACE, "av_frame_alloc(): failed.\n");
 exit(EXIT_SUCCESS);
 }
 if ((ret = av_buffersrc_add_frame(buffersrc_ctx, frame)) < 0) {
 av_log(NULL, AV_LOG_TRACE, "av_buffersrc_add_frame(): %s.\n", av_err2str(ret));
 exit(EXIT_SUCCESS);
 }
 
 while (1) {
 int ret = av_buffersink_get_frame(buffersink_ctx, filtered_frame);
 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
 break;
 if (ret < 0) {
 av_log(NULL, AV_LOG_TRACE, "av_buffersink_get_frame(): %s.\n", av_err2str(ret));
 exit(EXIT_FAILURE);
 } 
 }

 av_log(NULL, AV_LOG_TRACE, "filename: %s, w: %d, h: %d, f: %d\n", dst_name, filtered_frame->width, filtered_frame->height, filtered_frame->format);

 AVCodecContext *enc_ctx;
 AVCodec *enc;
 AVPacket *enc_packet = av_packet_alloc();

 enc = avcodec_find_encoder_by_name("mjpeg");
 enc_ctx = avcodec_alloc_context3(enc);
 enc_ctx->width = filtered_frame->width;
 enc_ctx->height = filtered_frame->height;
 enc_ctx->bit_rate = dec_ctx->bit_rate * 1024;
 enc_ctx->time_base = (AVRational) {1, 25};
 enc_ctx->framerate = (AVRational) {25, 1};
 enc_ctx->pix_fmt = filtered_frame->format;
 enc_ctx->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL;
 enc_ctx->compression_level = 0;
 enc_ctx->color_range = AVCOL_RANGE_JPEG;

 avcodec_open2(enc_ctx, enc, NULL);

 avcodec_send_frame(enc_ctx, filtered_frame);
 avcodec_receive_packet(enc_ctx, enc_packet);

 FILE *dst_file = fopen(dst_name, "wb");
 fwrite(enc_packet->data, 1, enc_packet->size, dst_file);
 fclose(dst_file);

 av_packet_unref(enc_packet);
 av_frame_free(&frame);
 av_frame_free(&filtered_frame);
 
 avfilter_graph_free(&filter_graph);

 avformat_close_input(&fmt_ctx);
 avformat_free_context(fmt_ctx);
 
 exit(EXIT_SUCCESS);
}
</filename>

and here are the logs




PS : the logs were so many I could paste in stackoverflow


-
FFmpeg - avcodec_receive_frame returns 0 but frames are invalid
9 juillet 2019, par JinxI’ve been trying to extract images from videos, but not those with PNG codec. My code works fine with those with JPEG.
avcodec_receive_frameworked successfully but the data of the frames was like trash ? Do I have to do something special to demuxing when dealing with PNG ?Exception thrown at 0x00007FFF7DF34B9A (msvcrt.dll) in Program.exe : 0xC0000005 : Access violation reading location 0x00000000000003F0 when calling
avcodec_send_framein mysaveImagefunction, which means I was accessing invalid or unalloacted memory I guess. How this happened ?
Just suppose all the function calls returned 0 until exception thrown.
Decoding :
bool ImageExtractor::decode() {
// some other code here
ret = avcodec_send_packet(codec_ctx, packet); // returned 0
ret = avcodec_receive_frame(codec_ctx, frame); // returned 0
if (ret == 0) {
if (count >= target_frame) {
snprintf(buf, sizeof(buf), "%s/%d.png", destination.toLocal8Bit().data(), count);
saveImage(frame, buf); // a function that writes images on disk
}
// some other code here
}
bool ImageExtractor::saveImage(AVFrame *frame, char *destination) {
AVFormatContext *imgFmtCtx = avformat_alloc_context();
pFormatCtx->oformat = av_guess_format("mjpeg", NULL, NULL);
// some other code here
if (!frame)
std::cout << "invalid frame \n";
if (!imgCodecCtx) // AV_CODEC_ID_MJPEG(7)
std::cout << "invalid codec ctx \n";
ret = avcodec_send_frame(imgCodecCtx, frame); // everything stopped here
}Demuxing :
avformat_open_input(&format_ctx, source.toLocal8Bit(), nullptr, nullptr);
vsi = av_find_best_stream(format_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, nullptr, 0);
codec_par = avcodec_parameters_alloc();
avcodec_parameters_copy(codec_par, format_ctx->streams[vsi]->codecpar);
AVCodec* codec = avcodec_find_decoder(codec_par->codec_id); // AV_CODEC_ID_PNG(61)
codec_ctx = avcodec_alloc_context3(codec);
avcodec_parameters_to_context(codec_ctx, codec_par);
avcodec_parameters_free(&codec_par);
avcodec_open2(codec_ctx, codec, 0);
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