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Rennes Emotion Map 2010-11
19 octobre 2011, par
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (50)
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Participer à sa traduction
10 avril 2011Vous pouvez nous aider à améliorer les locutions utilisées dans le logiciel ou à traduire celui-ci dans n’importe qu’elle nouvelle langue permettant sa diffusion à de nouvelles communautés linguistiques.
Pour ce faire, on utilise l’interface de traduction de SPIP où l’ensemble des modules de langue de MediaSPIP sont à disposition. ll vous suffit de vous inscrire sur la liste de discussion des traducteurs pour demander plus d’informations.
Actuellement MediaSPIP n’est disponible qu’en français et (...) -
Publier sur MédiaSpip
13 juin 2013Puis-je poster des contenus à partir d’une tablette Ipad ?
Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir -
HTML5 audio and video support
13 avril 2011, parMediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
For older browsers the Flowplayer flash fallback is used.
MediaSPIP allows for media playback on major mobile platforms with the above (...)
Sur d’autres sites (7845)
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FFMPEG Generate N Evenly Spaced PNG Screenshots
21 août 2023, par Kevin SylvestreI am trying to generate 8 screenshots for an uploaded video using FFMPEG. I currently have :





ffmpeg -i Trailer-720p.mov -r .2
 -vcodec png Preview-%d.png





Which generates a screenshot every 5 seconds. How can I add the ability to generate a screenshot for frames distributed over a percentage of total time. Thanks. Furthermore, is it possible to generate a screenshot at 50% for example ? Thanks.


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Adding a forced delay to ffmpeg
26 août 2017, par GlitchedTurtleI am looking to capture a stream with ffmpeg and then relay it to something else in nodejs. The problem is, the host i will be using will sometimes lag and I would like to prevent this by adding a forced delay. Is this possible with ffmpeg or will I have to add this in with code ?
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FFMPEG : AV out of sync when writing a part of a video to a new file
30 mars 2017, par IT_LaymanI’m developing a data preprocessing program for a computer vision project using FFMPEG and Face detection API. In this program, I need to extract the shots that contain human faces from a given input video file and output them into a new file. But when I played the output video file generated by that program, the video and audio track was out of sync. I think a possible reason is that the timestamp of video frame or audio frame is set incorrectly, but I can’t fix it by myself as I’m not very familiar with FFMPEG library, Please help me solving this out-of-sync issue.
To simplify the code shown below, I have removed all face detection code and use an empty function called
faceDetectto represent it instead.// ffmpegAPI.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
extern "C" {
#include <libavutil></libavutil>opt.h>
#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavutil></libavutil>avutil.h>
#include <libavutil></libavutil>channel_layout.h>
#include <libavutil></libavutil>common.h>
#include <libavutil></libavutil>imgutils.h>
#include <libavutil></libavutil>mathematics.h>
#include <libavutil></libavutil>samplefmt.h>
#include <libavutil></libavutil>pixdesc.h>
#include <libswscale></libswscale>swscale.h>
}
bool faceDetect(AVFrame *frame)
{
/*...*/
return true;
}
int main(int argc, char **argv)
{
int64_t videoPts = 0, audioPts = 0;
int samples_count = 0;
AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
AVOutputFormat *ofmt = NULL;
AVPacket pkt;
AVFrame *frame = NULL;
int videoindex = -1; int audioindex = -1;
double videoTime = DBL_MAX;
const char *in_filename, *out_filename;
int ret, i;
in_filename = "C:\\input.flv";//Input file name
out_filename = "C:\\output.avi";//Output file name
av_register_all();
//Open input file
if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
fprintf(stderr, "Could not open input file '%s'", in_filename);
goto end;
}
//Find input streams
if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
fprintf(stderr, "Failed to retrieve input stream information");
goto end;
}
//Retrive AV stream information
for (i = 0; i < ifmt_ctx->nb_streams; i++)
{
AVStream *stream;
AVCodecContext *codec_ctx;
stream = ifmt_ctx->streams[i];//Get current stream
codec_ctx = stream->codec;//Get current stream codec
if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
{
videoindex = i;//video stream index
}
else if (codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO)
{
audioindex = i;//audio stream index
}
if (videoindex == -1)//no video stream is found
{
printf("can't find video stream\n");
goto end;
}
}
av_dump_format(ifmt_ctx, 0, in_filename, 0);
//Configure output
avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
if (!ofmt_ctx) {
fprintf(stderr, "Could not create output context\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ofmt = ofmt_ctx->oformat;
//Configure output streams
for (i = 0; i < ifmt_ctx->nb_streams; i++) {//Traversal input streams
AVStream *in_stream = ifmt_ctx->streams[i];//Get current stream
AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);//Create a corresponding output stream
if (!out_stream) {
fprintf(stderr, "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
//Copy codec from current input stream to corresponding output stream
ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
if (ret < 0) {
fprintf(stderr, "Failed to copy context from input to output stream codec context\n");
goto end;
}
if (i == videoindex)//Video stream
{
if (out_stream->codec->codec_id == AV_CODEC_ID_H264)
{
out_stream->codec->me_range = 16;
out_stream->codec->max_qdiff = 4;
out_stream->codec->qmin = 10;
out_stream->codec->qmax = 51;
out_stream->codec->qcompress = 1;
}
}
AVCodecContext *codec_ctx = out_stream->codec;
if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
|| codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
//Find codec encoder
AVCodec *encoder = avcodec_find_encoder(codec_ctx->codec_id);
if (!encoder) {
av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
ret = AVERROR_INVALIDDATA;
goto end;
}
//Open encoder
ret = avcodec_open2(codec_ctx, encoder, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
goto end;
}
out_stream->codec->codec_tag = 0;
if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}
//Open the decoder for input stream
codec_ctx = in_stream->codec;
if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
|| codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
ret = avcodec_open2(codec_ctx,
avcodec_find_decoder(codec_ctx->codec_id), NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);
}
}
}
av_dump_format(ofmt_ctx, 0, out_filename, 1);
//Open output file for writing
if (!(ofmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
if (ret < 0) {
fprintf(stderr, "Could not open output file '%s'", out_filename);
goto end;
}
}
//Write video header
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
fprintf(stderr, "Error occurred when opening output file\n");
goto end;
}
//Write frames in a loop
while (1) {
AVStream *in_stream, *out_stream;
//Read one frame from the input file
ret = av_read_frame(ifmt_ctx, &pkt);
if (ret < 0)
break;
in_stream = ifmt_ctx->streams[pkt.stream_index];//Get current input stream
out_stream = ofmt_ctx->streams[pkt.stream_index];//Get current output stream
if (pkt.stream_index == videoindex)//video frame
{
int got_frame;
frame = av_frame_alloc();
if (!frame) {
ret = AVERROR(ENOMEM);
break;
}
//Readjust packet timestamp for decoding
av_packet_rescale_ts(&pkt,
in_stream->time_base,
in_stream->codec->time_base);
//Decode video frame
int len = avcodec_decode_video2(in_stream->codec, frame, &got_frame, &pkt);
if (len < 0)
{
av_frame_free(&frame);
av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
break;
}
if (got_frame)//Got a decoded video frame
{
int64_t pts = av_frame_get_best_effort_timestamp(frame);
//determine if the frame image contains human face
bool result = faceDetect(frame);
if (result) //face contained
{
videoTime = pts* av_q2d(out_stream->time_base);
frame->pts = videoPts++;//Set pts of video frame
AVPacket enc_pkt;
av_log(NULL, AV_LOG_INFO, "Encoding video frame\n");
//Create packet for encoding
enc_pkt.data = NULL;
enc_pkt.size = 0;
av_init_packet(&enc_pkt);
//Encoding frame
ret = avcodec_encode_video2(out_stream->codec, &enc_pkt,
frame, &got_frame);
av_frame_free(&frame);
if (!(got_frame))
ret = 0;
/* Configure encoding properties */
enc_pkt.stream_index = videoindex;
av_packet_rescale_ts(&enc_pkt,
out_stream->codec->time_base,
out_stream->time_base);
av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");
/* Write encoded frame */
ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
if (ret < 0)
break;
}
else //no face contained
{
//Set the videoTime as maximum double value,
//making the corresponding audio frame not been processed
if (videoTime < DBL_MAX)
videoTime = DBL_MAX;
}
}
else
{
av_frame_free(&frame);
}
}
else//Audio frame
{
//Get current frame time
double audioTime = pkt.pts * av_q2d(in_stream->time_base);
if (audioTime >= videoTime)
{//The current frame should be written into output file
int got_frame;
frame = av_frame_alloc();
if (!frame) {
ret = AVERROR(ENOMEM);
break;
}
//Readjust packet timestamp for decoding
av_packet_rescale_ts(&pkt,
in_stream->time_base,
in_stream->codec->time_base);
//Decode audio frame
int len = avcodec_decode_audio4(in_stream->codec, frame, &got_frame, &pkt);
if (len < 0)
{
av_frame_free(&frame);
av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
break;
}
if (got_frame)//Got a decoded audio frame
{
//Set pts of audio frame
frame->pts = audioPts;
audioPts += frame->nb_samples;
AVPacket enc_pkt;
av_log(NULL, AV_LOG_INFO, "Encoding audio frame");
//Create packet for encoding
enc_pkt.data = NULL;
enc_pkt.size = 0;
av_init_packet(&enc_pkt);
//Encode audio frame
ret = avcodec_encode_audio2(out_stream->codec, &enc_pkt,
frame, &got_frame);
av_frame_free(&frame);
if (!(got_frame))
ret = 0;
/* Configure encoding properties */
enc_pkt.stream_index = audioindex;
av_packet_rescale_ts(&enc_pkt,
out_stream->codec->time_base,
out_stream->time_base);
av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");
/* Write encoded frame */
ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
if (ret < 0)
break;
}
else //Shouldn't be written
{
av_frame_free(&frame);
}
}
}
av_packet_unref(&pkt);
}
//Write video trailer
av_write_trailer(ofmt_ctx);
end://Clean up
av_log(NULL, AV_LOG_INFO, "Clean up\n");
av_frame_free(&frame);
for (i = 0; i < ifmt_ctx->nb_streams; i++) {
avcodec_close(ifmt_ctx->streams[i]->codec);
if (ofmt_ctx && ofmt_ctx->nb_streams > i && ofmt_ctx->streams[i] && ofmt_ctx->streams[i]->codec)
avcodec_close(ofmt_ctx->streams[i]->codec);
}
avformat_close_input(&ifmt_ctx);
/* Close output file */
if (ofmt_ctx && !(ofmt_ctx->oformat->flags & AVFMT_NOFILE))
avio_closep(&ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);
if (ret < 0 && ret != AVERROR_EOF) {
char buf[256];
av_strerror(ret, buf, sizeof(buf));
av_log(NULL, AV_LOG_ERROR, "Error occurred:%s\n", buf);
system("Pause");
return 1;
}
//Program end
printf("The End.\n");
system("Pause");
return 0;
}
</iostream>
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