Recherche avancée
Médias (91)
-
Head down (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
-
Echoplex (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
-
Discipline (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
-
Letting you (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
-
1 000 000 (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
-
999 999 (wav version)
26 septembre 2011, par
Mis à jour : Avril 2013
Langue : English
Type : Audio
Autres articles (39)
-
Personnaliser les catégories
21 juin 2013, parFormulaire de création d’une catégorie
Pour ceux qui connaissent bien SPIP, une catégorie peut être assimilée à une rubrique.
Dans le cas d’un document de type catégorie, les champs proposés par défaut sont : Texte
On peut modifier ce formulaire dans la partie :
Administration > Configuration des masques de formulaire.
Dans le cas d’un document de type média, les champs non affichés par défaut sont : Descriptif rapide
Par ailleurs, c’est dans cette partie configuration qu’on peut indiquer le (...) -
Support audio et vidéo HTML5
10 avril 2011MediaSPIP utilise les balises HTML5 video et audio pour la lecture de documents multimedia en profitant des dernières innovations du W3C supportées par les navigateurs modernes.
Pour les navigateurs plus anciens, le lecteur flash Flowplayer est utilisé.
Le lecteur HTML5 utilisé a été spécifiquement créé pour MediaSPIP : il est complètement modifiable graphiquement pour correspondre à un thème choisi.
Ces technologies permettent de distribuer vidéo et son à la fois sur des ordinateurs conventionnels (...) -
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 (8881)
-
How to extract frames at 30 fps using FFMPEG APIs on Android ?
8 septembre 2016, par Amber BeriwalWe are working on a project that consumes
FFMPEGlibrary for video frame extraction on Android platform.On Windows, we have observed :
- Using CLI, ffmpeg is capable of extracting frames at 30 fps using command
ffmpeg -i input.flv -vf fps=1 out%d.png. - Using Xuggler, we are able to extract frames at 30 fps.
- Using FFMPEG APIs directly in code, we are getting frames at 30 fps.
But when we use FFMPEG APIs directly on Android (See Hardware Details), we are getting following results :
- 720p video (1280 x 720) - 16 fps (approx. 60 ms/frame)
- 1080p video (1920 x 1080) - 7 fps (approx. 140 ms/frame)
We haven’t tested Xuggler/CLI on Android yet.
Ideally, we should be able to get the data in constant time (approx. 30 ms/frame).
How can we get 30 fps on Android ?
Code being used on Android :
if (avformat_open_input(&pFormatCtx, pcVideoFile, NULL, NULL)) {
iError = -1; //Couldn't open file
}
if (!iError) {
//Retrieve stream information
if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
iError = -2; //Couldn't find stream information
}
//Find the first video stream
if (!iError) {
for (i = 0; i < pFormatCtx->nb_streams; i++) {
if (AVMEDIA_TYPE_VIDEO
== pFormatCtx->streams[i]->codec->codec_type) {
iFramesInVideo = pFormatCtx->streams[i]->nb_index_entries;
duration = pFormatCtx->streams[i]->duration;
begin = pFormatCtx->streams[i]->start_time;
time_base = (pFormatCtx->streams[i]->time_base.num * 1.0f)
/ pFormatCtx->streams[i]->time_base.den;
pCodecCtx = avcodec_alloc_context3(NULL);
if (!pCodecCtx) {
iError = -6;
break;
}
AVCodecParameters params = { 0 };
iReturn = avcodec_parameters_from_context(&params,
pFormatCtx->streams[i]->codec);
if (iReturn < 0) {
iError = -7;
break;
}
iReturn = avcodec_parameters_to_context(pCodecCtx, &params);
if (iReturn < 0) {
iError = -7;
break;
}
//pCodecCtx = pFormatCtx->streams[i]->codec;
iVideoStreamIndex = i;
break;
}
}
}
if (!iError) {
if (iVideoStreamIndex == -1) {
iError = -3; // Didn't find a video stream
}
}
if (!iError) {
// Find the decoder for the video stream
pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (pCodec == NULL) {
iError = -4;
}
}
if (!iError) {
// Open codec
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
iError = -5;
}
if (!iError) {
iNumBytes = av_image_get_buffer_size(AV_PIX_FMT_RGB24, pCodecCtx->width,
pCodecCtx->height, 1);
// initialize SWS context for software scaling
sws_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height,
pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,
AV_PIX_FMT_RGB24,
SWS_BILINEAR,
NULL,
NULL,
NULL);
if (!sws_ctx) {
iError = -7;
}
}
clock_gettime(CLOCK_MONOTONIC_RAW, &end);
delta_us = (end.tv_sec - start.tv_sec) * 1000000
+ (end.tv_nsec - start.tv_nsec) / 1000;
start = end;
//LOGI("Starting_Frame_Extraction: %lld", delta_us);
if (!iError) {
while (av_read_frame(pFormatCtx, &packet) == 0) {
// Is this a packet from the video stream?
if (packet.stream_index == iVideoStreamIndex) {
pFrame = av_frame_alloc();
if (NULL == pFrame) {
iError = -8;
break;
}
// Decode video frame
avcodec_decode_video2(pCodecCtx, pFrame, &iFrameFinished,
&packet);
if (iFrameFinished) {
//OUR CODE
}
av_frame_free(&pFrame);
pFrame = NULL;
}
av_packet_unref(&packet);
}
} - Using CLI, ffmpeg is capable of extracting frames at 30 fps using command
-
QSharedMemory in Real-Time process
21 novembre 2016, par Seungsoo KimI’m trying to use QSharedMemory Class to share video data between two processes.
So I tried like following method, but it has problem in simultaneous access of two processes.
Two process crashes when they access sequentially to same memory name(key) "SharedMemory".
I locked them while they’re used, but also it doesn’t work well.
How can i avoid this crash ??
-
Writing to SharedMemory - data type is and this function called by callback.
QBuffer buffer;
buffer.open(QBuffer::ReadWrite);
QDataStream out(&buffer);
QByteArray outArray = QByteArray::fromRawData(reinterpret_cast<const>(data), strlen(reinterpret_cast<const>(data)));
out << width << height << step << cameraId << strlen(reinterpret_cast<const>(data));
out.writeRawData(outArray.data(), outArray.size());
int size = buffer.size();
sharedMemory.setKey("SharedMemory");
if (!sharedMemory.isAttached()) {
printf("Cannot attach to shared memory to update!\n");
}
if (!sharedMemory.create(size))
{
printf("failed to allocate memory\n");
}
sharedMemory.lock();
char *to = (char*)sharedMemory.data();
const char *from = buffer.data().data();
memcpy(to, from,qMin(sharedMemory.size(),size));
sharedMemory.unlock();
</const></const></const> -
Using data in SharedMemory. - this function is called by QThread, interval 100ms
QSharedMemory sharedMemory("SharedMemory");
sharedMemory.lock();
if (!sharedMemory.attach()) {
printf("failed to attach to memory\n");
return;
}
QBuffer buffer;
QDataStream in(&buffer);
sharedMemory.create(1920 * 1080);
buffer.setData((char*)sharedMemory.constData(), sharedMemory.size());
buffer.open(QBuffer::ReadOnly);
sharedMemory.unlock();
sharedMemory.detach();
int r_width = 0;
int r_height = 0;
int r_cameraId = 0;
int r_step = 0;
int r_strlen = 0;
in >> r_width >> r_height >> r_step >> r_cameraId >> r_strlen;
char* receive = new char[r_strlen];
in.readRawData(receive, r_strlen);
//unsigned char* r_receive = new unsigned char[r_strlen];
//r_receive = (unsigned char*)receive;
QPixmap backBuffer = QPixmap::fromImage(QImage((unsigned char*)receive, r_width, r_height, r_step, QImage::Format::Format_RGB888));
ui.label->setPixmap(backBuffer.scaled(ui.label->size(), Qt::KeepAspectRatio));
ui.label->show();
please share your idea ! thank you !
-
-
Can not add tmcd stream using libavcodec to replicate behavior of ffmpeg -timecode option
2 août, par Sailor JerryI'm trying to replicate option of command line ffmpeg -timecode in my C/C++ code. For some reasons the tcmd stream is not written to the output file. However the av_dump_format shows it in run time


Here is my minimal test


#include <iostream>
extern "C" {
#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavutil></libavutil>avutil.h>
#include <libswscale></libswscale>swscale.h>
#include <libavutil></libavutil>opt.h>
#include <libavutil></libavutil>imgutils.h>
#include <libavutil></libavutil>samplefmt.h>
}
bool checkProResAvailability() {
 const AVCodec* codec = avcodec_find_encoder_by_name("prores_ks");
 if (!codec) {
 std::cerr << "ProRes codec not available. Please install FFmpeg with ProRes support." << std::endl;
 return false;
 }
 return true;
}

int main(){
 av_log_set_level(AV_LOG_INFO);

 const char* outputFileName = "test_tmcd.mov";
 AVFormatContext* formatContext = nullptr;
 AVCodecContext* videoCodecContext = nullptr;

 if (!checkProResAvailability()) {
 return -1;
 }

 std::cout << "Creating test file with tmcd stream: " << outputFileName << std::endl;

 // Allocate the output format context
 if (avformat_alloc_output_context2(&formatContext, nullptr, "mov", outputFileName) < 0) {
 std::cerr << "Failed to allocate output context!" << std::endl;
 return -1;
 }

 if (avio_open(&formatContext->pb, outputFileName, AVIO_FLAG_WRITE) < 0) {
 std::cerr << "Failed to open output file!" << std::endl;
 avformat_free_context(formatContext);
 return -1;
 }

 // Find ProRes encoder
 const AVCodec* videoCodec = avcodec_find_encoder_by_name("prores_ks");
 if (!videoCodec) {
 std::cerr << "Failed to find the ProRes encoder!" << std::endl;
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 // Video stream setup
 AVStream* videoStream = avformat_new_stream(formatContext, nullptr);
 if (!videoStream) {
 std::cerr << "Failed to create video stream!" << std::endl;
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 videoCodecContext = avcodec_alloc_context3(videoCodec);
 if (!videoCodecContext) {
 std::cerr << "Failed to allocate video codec context!" << std::endl;
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 videoCodecContext->width = 1920;
 videoCodecContext->height = 1080;
 videoCodecContext->pix_fmt = AV_PIX_FMT_YUV422P10;
 videoCodecContext->time_base = (AVRational){1, 30}; // Set FPS: 30
 videoCodecContext->bit_rate = 2000000;

 if (avcodec_open2(videoCodecContext, videoCodec, nullptr) < 0) {
 std::cerr << "Failed to open ProRes codec!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 if (avcodec_parameters_from_context(videoStream->codecpar, videoCodecContext) < 0) {
 std::cerr << "Failed to copy codec parameters to video stream!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 videoStream->time_base = videoCodecContext->time_base;

 // Timecode stream setup
 AVStream* timecodeStream = avformat_new_stream(formatContext, nullptr);
 if (!timecodeStream) {
 std::cerr << "Failed to create timecode stream!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 timecodeStream->codecpar->codec_type = AVMEDIA_TYPE_DATA;
 timecodeStream->codecpar->codec_id = AV_CODEC_ID_TIMED_ID3;
 timecodeStream->codecpar->codec_tag = MKTAG('t', 'm', 'c', 'd'); // Timecode tag
 timecodeStream->time_base = (AVRational){1, 30}; // FPS: 30

 if (av_dict_set(&timecodeStream->metadata, "timecode", "00:00:30:00", 0) < 0) {
 std::cerr << "Failed to set timecode metadata!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 // Write container header
 if (avformat_write_header(formatContext, nullptr) < 0) {
 std::cerr << "Failed to write file header!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 // Encode a dummy video frame
 AVFrame* frame = av_frame_alloc();
 if (!frame) {
 std::cerr << "Failed to allocate video frame!" << std::endl;
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 frame->format = videoCodecContext->pix_fmt;
 frame->width = videoCodecContext->width;
 frame->height = videoCodecContext->height;

 if (av_image_alloc(frame->data, frame->linesize, frame->width, frame->height, videoCodecContext->pix_fmt, 32) < 0) {
 std::cerr << "Failed to allocate frame buffer!" << std::endl;
 av_frame_free(&frame);
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);
 return -1;
 }

 // Fill frame with black
 memset(frame->data[0], 0, frame->linesize[0] * frame->height); // Y plane
 memset(frame->data[1], 128, frame->linesize[1] * frame->height / 2); // U plane
 memset(frame->data[2], 128, frame->linesize[2] * frame->height / 2); // V plane

 // Encode the frame
 AVPacket packet;
 av_init_packet(&packet);
 packet.data = nullptr;
 packet.size = 0;

 if (avcodec_send_frame(videoCodecContext, frame) == 0) {
 if (avcodec_receive_packet(videoCodecContext, &packet) == 0) {
 packet.stream_index = videoStream->index;
 av_interleaved_write_frame(formatContext, &packet);
 av_packet_unref(&packet);
 }
 }

 av_frame_free(&frame);

 // Write a dummy packet for the timecode stream
 AVPacket tmcdPacket;
 av_init_packet(&tmcdPacket);
 tmcdPacket.stream_index = timecodeStream->index;
 tmcdPacket.flags |= AV_PKT_FLAG_KEY;
 tmcdPacket.data = nullptr; // Empty packet for timecode
 tmcdPacket.size = 0;
 tmcdPacket.pts = 0; // Set necessary PTS
 tmcdPacket.dts = 0;
 av_interleaved_write_frame(formatContext, &tmcdPacket);

 // Write trailer
 if (av_write_trailer(formatContext) < 0) {
 std::cerr << "Failed to write file trailer!" << std::endl;
 }

 av_dump_format(formatContext, 0, "test.mov", 1);

 // Cleanup
 avcodec_free_context(&videoCodecContext);
 avio_close(formatContext->pb);
 avformat_free_context(formatContext);

 std::cout << "Test file with timecode created successfully: " << outputFileName << std::endl;

 return 0;
}
</iostream>

The code output is :


Creating test file with tmcd stream: test_tmcd.mov
[prores_ks @ 0x11ce05790] Autoselected HQ profile to keep best quality. It can be overridden through -profile option.
[mov @ 0x11ce04f20] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
[mov @ 0x11ce04f20] Encoder did not produce proper pts, making some up.
Output #0, mov, to 'test.mov':
 Metadata:
 encoder : Lavf61.7.100
 Stream #0:0: Video: prores (HQ) (apch / 0x68637061), yuv422p10le, 1920x1080, q=2-31, 2000 kb/s, 15360 tbn
 Stream #0:1: Data: timed_id3 (tmcd / 0x64636D74)
 Metadata:
 timecode : 00:00:30:00
Test file with timecode created successfully: test_tmcd.mov


The ffprobe output is :


$ ffprobe test_tmcd.mov
ffprobe version 7.1.1 Copyright (c) 2007-2025 the FFmpeg developers
 built with Apple clang version 16.0.0 (clang-1600.0.26.6)
 configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.1.1_3 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
 libavutil 59. 39.100 / 59. 39.100
 libavcodec 61. 19.101 / 61. 19.101
 libavformat 61. 7.100 / 61. 7.100
 libavdevice 61. 3.100 / 61. 3.100
 libavfilter 10. 4.100 / 10. 4.100
 libswscale 8. 3.100 / 8. 3.100
 libswresample 5. 3.100 / 5. 3.100
 libpostproc 58. 3.100 / 58. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test_tmcd.mov':
 Metadata:
 major_brand : qt 
 minor_version : 512
 compatible_brands: qt 
 encoder : Lavf61.7.100
 Duration: N/A, start: 0.000000, bitrate: N/A
 Stream #0:0[0x1]: Video: prores (HQ) (apch / 0x68637061), yuv422p10le, 1920x1080, 15360 tbn (default)
 Metadata:
 handler_name : VideoHandler
 vendor_id : FFMP
$ 



Spent hours with all AI models, no help. Appeal to the human intelligence now


Syndiquer tout le site
