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#7 Ambience
16 octobre 2011, par
Mis à jour : Juin 2015
Langue : English
Type : Audio
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#6 Teaser Music
16 octobre 2011, par
Mis à jour : Février 2013
Langue : English
Type : Audio
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#5 End Title
16 octobre 2011, par
Mis à jour : Février 2013
Langue : English
Type : Audio
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#3 The Safest Place
16 octobre 2011, par
Mis à jour : Février 2013
Langue : English
Type : Audio
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#4 Emo Creates
15 octobre 2011, par
Mis à jour : Février 2013
Langue : English
Type : Audio
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#2 Typewriter Dance
15 octobre 2011, par
Mis à jour : Février 2013
Langue : English
Type : Audio
Autres articles (75)
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MediaSPIP v0.2
21 juin 2013, parMediaSPIP 0.2 est la première version de MediaSPIP stable.
Sa date de sortie officielle est le 21 juin 2013 et est annoncée ici.
Le fichier zip ici présent contient uniquement les sources de MediaSPIP en version standalone.
Comme pour la version précédente, il est nécessaire d’installer manuellement l’ensemble des dépendances logicielles sur le serveur.
Si vous souhaitez utiliser cette archive pour une installation en mode ferme, il vous faudra également procéder à d’autres modifications (...) -
Creating farms of unique websites
13 avril 2011, parMediaSPIP platforms can be installed as a farm, with a single "core" hosted on a dedicated server and used by multiple websites.
This allows (among other things) : implementation costs to be shared between several different projects / individuals rapid deployment of multiple unique sites creation of groups of like-minded sites, making it possible to browse media in a more controlled and selective environment than the major "open" (...)
Sur d’autres sites (11266)
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libavformat/libavcodec : Why am I getting a significantly shorter video than expected ?
2 mars 2023, par itzjackyscodeThe MVE below is a simple test program that should encode 6 s (360 frames) of video. When I import the exported video (
output.mkv) into a video editor, I see that it is only a fraction of a second. Why is this ? How do I fix it ?

MVE


#include <cstddef>
#include <cstdio>
#include <iostream>
extern "C" {
#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavutil></libavutil>imgutils.h>
#include <libswscale></libswscale>swscale.h>
}

namespace av {
 // ERROR HANDLING
 // ==============

 class av_category_t final : public std::error_category {
 public:
 inline const char* name() const noexcept override { return "av_category"; }

 inline std::string message(int code) const noexcept override {
 thread_local static char msg_buffer[AV_ERROR_MAX_STRING_SIZE];
 av_strerror(code, msg_buffer, sizeof(msg_buffer));
 return std::string(msg_buffer);
 }
 };

 inline const std::error_category& av_category() {
 static av_category_t result;
 return result;
 }

 // helper function to create a std::system_error.
 inline std::system_error av_error(int code) {
 return std::system_error(code, av_category());
 }

 // Allocate or reallocate buffers in a video frame.
 inline void alloc_video_frame(
 AVFrame* frame, int width, int height, AVPixelFormat pix_fmt
 ) {
 int err;
 if (frame->width != width || frame->height != height || 
 frame->format != pix_fmt || !av_frame_is_writable(frame)) {
 // unref the old data if any
 if (frame->buf[0] != nullptr) {
 av_frame_unref(frame);
 }

 // reset parameters
 frame->width = width;
 frame->height = height;
 frame->format = pix_fmt;

 // reallocate
 if ((err = av_frame_get_buffer(frame, 0)) < 0)
 throw av_error(err);
 }
 }
 inline void alloc_video_frame(AVFrame* frame, const AVCodecContext* ctx) {
 alloc_video_frame(frame, ctx->width, ctx->height, ctx->pix_fmt);
 }
} // namespace av

void fill_rgb(AVFrame* tmp, AVFrame* dst, uint32_t col) {
 static SwsContext* sws = nullptr;
 int err;
 
 av::alloc_video_frame(tmp, dst->width, dst->height, AV_PIX_FMT_0RGB32);
 for (int i = 0; i < tmp->height; i++) {
 for (int j = 0; j < tmp->width; j++) {
 void* p = tmp->data[0] + (i * tmp->linesize[0]) + (j * 4);
 *((uint32_t*) p) = col;
 }
 }
 
 sws = sws_getCachedContext(sws,
 // src params
 tmp->width, tmp->height, (AVPixelFormat) tmp->format,
 // dst params
 dst->width, dst->height, (AVPixelFormat) dst->format,
 // stuff
 0, nullptr, nullptr, nullptr
 );
 if ((err = sws_scale_frame(sws, dst, tmp)) < 0)
 throw av::av_error(err);
}

int32_t hue_c(int deg) {
 deg %= 360;
 int rem = deg % 60;
 switch (deg / 60) {
 case 0: return 0xFF0000 | ((deg * 256 / 60) << 8);
 case 1: return 0x00FF00 | (((60 - deg) * 256 / 60) << 16);
 case 2: return 0x00FF00 | ((deg * 256 / 60) << 0);
 case 3: return 0x0000FF | (((60 - deg) * 256 / 60) << 8);
 case 4: return 0x00FF00 | ((deg * 256 / 60) << 16);
 case 5: return 0xFF0000 | (((60 - deg) * 256 / 60) << 0);
 }
 return 0xFFFFFF;
}

int main() {
 int res;

 AVFormatContext* fmt_ctx;
 AVStream* vstream;
 const AVCodec* vcodec;
 AVCodecContext* vcodec_ctx;

 AVFrame* vframe;
 AVFrame* vframe2;
 AVPacket* vpacket;

 int64_t pts = 0;

 // init frame
 res = avformat_alloc_output_context2(&fmt_ctx, NULL, NULL, "output.mkv");
 if (res < 0)
 return 1;

 // get encoder
 vcodec = avcodec_find_encoder(AV_CODEC_ID_VP8);

 // allocate everything else
 vstream = avformat_new_stream(fmt_ctx, vcodec);
 vcodec_ctx = avcodec_alloc_context3(vcodec);
 vframe = av_frame_alloc();
 vframe2 = av_frame_alloc();
 vpacket = av_packet_alloc();
 if (!vstream || !vcodec_ctx || !vframe || !vpacket) {
 return 1;
 }

 // set PTS counter
 pts = 0;

 // codec: size parameters
 vcodec_ctx->width = 640;
 vcodec_ctx->height = 480;
 vcodec_ctx->sample_aspect_ratio = {1, 1};

 // codec: pixel formats
 vcodec_ctx->pix_fmt = AV_PIX_FMT_YUV420P;

 // codec: bit rate et al.
 vcodec_ctx->bit_rate = 2e6;
 vcodec_ctx->rc_buffer_size = 4e6;
 vcodec_ctx->rc_max_rate = 2e6;
 vcodec_ctx->rc_min_rate = 2.5e6;

 // codec: frame rate
 vcodec_ctx->time_base = {1, 60};
 vstream->time_base = {1, 60};
 vstream->avg_frame_rate = {60, 1};

 // open codec
 res = avcodec_open2(vcodec_ctx, vcodec, NULL);
 if (res < 0)
 throw av::av_error(res);
 res = avcodec_parameters_from_context(vstream->codecpar, vcodec_ctx);
 if (res < 0)
 throw av::av_error(res);
 
 // open file
 if (!(fmt_ctx->oformat->flags & AVFMT_NOFILE)) {
 res = avio_open(&fmt_ctx->pb, "output.mkv", AVIO_FLAG_WRITE);
 if (res < 0)
 throw av::av_error(res);
 }
 
 // write format header
 res = avformat_write_header(fmt_ctx, NULL);
 if (res < 0)
 throw av::av_error(res);

 // encode loop
 for (int i = 0; i < 360; i++) {
 av::alloc_video_frame(vframe, vcodec_ctx);

 // gen data and store to vframe
 fill_rgb(vframe2, vframe, hue_c(i));
 
 // set timing info
 vframe->time_base = vcodec_ctx->time_base;
 vframe->pts = i;

 // send to encoder
 avcodec_send_frame(vcodec_ctx, vframe);
 while ((res = avcodec_receive_packet(vcodec_ctx, vpacket)) == 0) {
 printf("DTS: %ld, PTS: %ld\n", vpacket->dts, vpacket->pts);
 
 if ((res = av_interleaved_write_frame(fmt_ctx, vpacket)) < 0)
 throw av::av_error(res);
 
 }
 if (res != AVERROR_EOF && res != AVERROR(EAGAIN))
 return -1;
 }
 
 if ((res = av_write_trailer(fmt_ctx)) < 0)
 throw av::av_error(res);
 
 av_frame_free(&vframe);
 av_frame_free(&vframe2);
 av_packet_free(&vpacket);
 avcodec_free_context(&vcodec_ctx);
 
 avformat_free_context(fmt_ctx);
}
</iostream></cstdio></cstddef>

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How to get 1 frame per second in ffmpeg video to images ? Getting more images than expected
15 septembre 2021, par code0x00I am trying to extract images from a video 1 frame per second but i am getting more images than i expect.


for eg. :


When i run below command :


ffmpeg -i filename.mp4 -r 1 img%d.jpg


It is a 20 second video but creating 22 images.


it should create 21 images.


Why it is creating one extra image ?


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FFmpeg doesn't recognize correct input height in hstack command
23 mars 2021, par lach_codesHaving an issue with an
hstackFFmpeg command that has stumped me.

input1andinput2are both vertical 360x640 videos. I am croppinginput1to a square, merging it vertically withinput2, then cropping a vertical strip off each side of the resulting video and horizontally merging these three videos (left strip, middle vertically-stacked video, right strip).

ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex [0:v]crop=360:360:0:140,fps=30[v0],[1:v]fps=30[v1],[v0][v1]vstack=inputs=2[m],[m]crop=101:ih:0:0[l],[m]crop=101:ih:259:0[r],[l][m][r]hstack=inputs=3[v];[0:a][1:a]amix[a] -map [v] -map [a] -preset ultrafast ./stackedOutput.mp4


When I run this, I get an error :


[Parsed_hstack_6 @ 0x7ff5394482c0] Input 1 height 640 does not match input 0 height 1000. [Parsed_hstack_6 @ 0x7ff5394482c0] Failed to configure output pad on Parsed_hstack_6


(Full FFmpeg output here.)


But the height of
[m](Input 1inhstack) is not640, it's1000. I have verified this when the commands are run independently.

Why is FFmpeg not recognizing the correct height of
[m]? Any help or pointers greatly appreciated ! Thanks in advance !

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