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The Slip - Artworks
26 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Texte
Autres articles (111)
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Other interesting software
13 avril 2011, parWe don’t claim to be the only ones doing what we do ... and especially not to assert claims to be the best either ... What we do, we just try to do it well and getting better ...
The following list represents softwares that tend to be more or less as MediaSPIP or that MediaSPIP tries more or less to do the same, whatever ...
We don’t know them, we didn’t try them, but you can take a peek.
Videopress
Website : http://videopress.com/
License : GNU/GPL v2
Source code : (...) -
Les formats acceptés
28 janvier 2010, parLes commandes suivantes permettent d’avoir des informations sur les formats et codecs gérés par l’installation local de ffmpeg :
ffmpeg -codecs ffmpeg -formats
Les format videos acceptés en entrée
Cette liste est non exhaustive, elle met en exergue les principaux formats utilisés : h264 : H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 m4v : raw MPEG-4 video format flv : Flash Video (FLV) / Sorenson Spark / Sorenson H.263 Theora wmv :
Les formats vidéos de sortie possibles
Dans un premier temps on (...) -
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 (...)
Sur d’autres sites (10602)
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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


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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); -
Android : BitmapFactory.decodeStream() returns null after first success
27 avril 2014, par giraffeMy code is intended to update an ImageView with an image from a server when a UI button is pressed.
The client side code shown below is a Runnable that runs when the button is pressed. The server is a desktop Java application with ffmpeg running in the background, continuously updating image.png with an image from the webcam. When the button is pressed on the Android app, the Android app attempts to receive image.png from the server, and because ffmpeg is constantly updating this image, it should be the most recent image taken with the server’s webcam.
My problem is that the first button press shows the correct image, but every subsequent button press will just clear out my ImageView. BitmapFactory.decodeStream() is returning null every time I call it after the first time.
Client side (runs when button is pressed) :
InputStream inputStream = s.getInputStream();
img = BitmapFactory.decodeStream(inputStream);
jpgView.setImageBitmap(img);
jpgView.invalidate();Server side :
ServerSocket sock = new ServerSocket(PORT_NUMBER);
Socket clientSocket = sock.accept();
for (;;) {
File f = new File("C:/folder/image.png");
FileInputStream fileInput = new FileInputStream(f);
BufferedInputStream bufferedInput = new BufferedInputStream(fileInput);
OutputStream outStream = clientSocket.getOutputStream();
try {
byte[] outBuffer = new byte[fSize];
int bRead = bufferedInput.read(outBuffer, 0, outBuffer.length);
outStream.write(outBuffer, 0, bRead);
outStream.flush();
} catch (Exception e) {
e.printStackTrace();
} finally {
bufferedInput.close();
}
}
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