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Médias (1)
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MediaSPIP Simple : futur thème graphique par défaut ?
26 septembre 2013, par
Mis à jour : Octobre 2013
Langue : français
Type : Video
Autres articles (12)
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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 -
Supporting all media types
13 avril 2011, parUnlike most software and media-sharing platforms, MediaSPIP aims to manage as many different media types as possible. The following are just a few examples from an ever-expanding list of supported formats : images : png, gif, jpg, bmp and more audio : MP3, Ogg, Wav and more video : AVI, MP4, OGV, mpg, mov, wmv and more text, code and other data : OpenOffice, Microsoft Office (Word, PowerPoint, Excel), web (html, CSS), LaTeX, Google Earth and (...)
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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 (4536)
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Screen capture with libavcodec/ffmpeg, and write it to mp4 file
10 février 2015, par DrakkainenI’m trying to (programatically) record the screen with DirectShow screen driver. I wrote some quick and (very) dirty code to try to get that to work (http://pastebin.com/ZJuhZRCz) based on ffmpeg examples but I have lots of trouble figuring out what time_base/framerate to use. If i leave the time_base/framerate parts empty I only get a single still frame. If i change them to any values, the video just turns black.
I’m guessing it has something to do with the output file settings, but I just ran out of ideas on what to try. Any pointers/help would be greatly appreciated.
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using libav instead of ffmpeg
21 janvier 2015, par n00bieI want to streaming video over http, i am using ogg(theora + vorbis), now i have sender and receiver, and i can run them using command line :
Sender :
ffmpeg -f video4linux2 -s 320x240 -i /dev/mycam -codec:v libtheora -qscale:v 5 -f ogg http://127.0.0.1:8080Receiver :
sudo gst-launch-0.10 tcpserversrc port = 8080 ! oggdemux ! theoradec ! autovideosinkNow, sender sends both audio and video, but receiver plays only video.
It works perfect, but now i want not to use ffmpeg and use only libav* instead.
Here’s my class for streaming :
class VCORE_LIBRARY_EXPORT VVideoWriter : private boost::noncopyable
{
public:
VVideoWriter( );
~VVideoWriter( );
bool openFile( const std::string& name,
int fps, int videoBitrate, int width, int height,
int audioSampleRate, bool stereo, int audioBitrate );
void close( );
bool writeVideoFrame( const uint8_t* image, int64_t timestamp );
bool writeAudioFrame( const int16_t* data, int64_t timestamp );
int audioFrameSize( ) const;
private:
AVFrame *m_videoFrame;
AVFrame *m_audioFrame;
AVFormatContext *m_context;
AVStream *m_videoStream;
AVStream *m_audioStream;
int64_t m_startTime;
};Initialization :
bool VVideoWriter::openFile( const std::string& name,
int fps, int videoBitrate, int width, int height,
int audioSampleRate, bool stereo, int audioBitrate )
{
if( ! m_context )
{
// initalize the AV context
m_context = avformat_alloc_context( );
assert( m_context );
// get the output format
m_context->oformat = av_guess_format( "ogg", name.c_str( ), nullptr );
if( m_context->oformat )
{
strcpy( m_context->filename, name.c_str( ) );
auto codecID = AV_CODEC_ID_THEORA;
auto codec = avcodec_find_encoder( codecID );
if( codec )
{
m_videoStream = avformat_new_stream( m_context, codec );
assert( m_videoStream );
// initalize codec
auto codecContext = m_videoStream->codec;
bool globalHeader = m_context->oformat->flags & AVFMT_GLOBALHEADER;
if( globalHeader )
codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
codecContext->codec_id = codecID;
codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
codecContext->width = width;
codecContext->height = height;
codecContext->time_base.den = fps;
codecContext->time_base.num = 1;
codecContext->bit_rate = videoBitrate;
codecContext->pix_fmt = PIX_FMT_YUV420P;
codecContext->flags |= CODEC_FLAG_QSCALE;
codecContext->global_quality = FF_QP2LAMBDA * 5;
int res = avcodec_open2( codecContext, codec, nullptr );
if( res >= 0 )
{
auto codecID = AV_CODEC_ID_VORBIS;
auto codec = avcodec_find_encoder( codecID );
if( codec )
{
m_audioStream = avformat_new_stream( m_context, codec );
assert( m_audioStream );
// initalize codec
auto codecContext = m_audioStream->codec;
bool globalHeader = m_context->oformat->flags & AVFMT_GLOBALHEADER;
if( globalHeader )
codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
codecContext->codec_id = codecID;
codecContext->codec_type = AVMEDIA_TYPE_AUDIO;
codecContext->sample_fmt = AV_SAMPLE_FMT_FLTP;
codecContext->bit_rate = audioBitrate;
codecContext->sample_rate = audioSampleRate;
codecContext->channels = stereo ? 2 : 1;
codecContext->channel_layout = stereo ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
res = avcodec_open2( codecContext, codec, nullptr );
if( res >= 0 )
{
// try to open the file
if( avio_open( &m_context->pb, m_context->filename, AVIO_FLAG_WRITE ) >= 0 )
{
m_audioFrame->nb_samples = codecContext->frame_size;
m_audioFrame->format = codecContext->sample_fmt;
m_audioFrame->channel_layout = codecContext->channel_layout;
boost::posix_time::ptime time_t_epoch( boost::gregorian::date( 1970, 1, 1 ) );
m_context->start_time_realtime = ( boost::posix_time::microsec_clock::universal_time( ) - time_t_epoch ).total_microseconds( );
m_startTime = -1;
// write the header
if( avformat_write_header( m_context, nullptr ) >= 0 )
{
return true;
}
else std::cerr << "VVideoWriter: failed to write video header" << std::endl;
}
else std::cerr << "VVideoWriter: failed to open video file " << name << std::endl;
}
else std::cerr << "VVideoWriter: failed to initialize audio codec" << std::endl;
}
else std::cerr << "VVideoWriter: requested audio codec is not supported" << std::endl;
}
else std::cerr << "VVideoWriter: failed to initialize video codec" << std::endl;
}
else std::cerr << "VVideoWriter: requested video codec is not supported" << std::endl;
}
else std::cerr << "VVideoWriter: requested video format is not supported" << std::endl;
avformat_free_context( m_context );
m_context = nullptr;
m_videoStream = nullptr;
m_audioStream = nullptr;
}
return false;
}Writing video :
bool VVideoWriter::writeVideoFrame( const uint8_t* image, int64_t timestamp )
{
if( m_context ) {
auto codecContext = m_videoStream->codec;
avpicture_fill( reinterpret_cast( m_videoFrame ),
const_cast( image ),
codecContext->pix_fmt, codecContext->width, codecContext->height );
AVPacket pkt;
av_init_packet( & pkt );
pkt.data = nullptr;
pkt.size = 0;
int gotPacket = 0;
if( ! avcodec_encode_video2( codecContext, &pkt, m_videoFrame, & gotPacket ) ) {
if( gotPacket == 1 ) {
pkt.stream_index = m_videoStream->index;
int res;
{
pkt.pts = AV_NOPTS_VALUE;
pkt.dts = AV_NOPTS_VALUE;
pkt.stream_index = m_videoStream->index;
res = av_write_frame( m_context, &pkt );
}
av_free_packet( & pkt );
return res >= 0;
}
assert( ! pkt.size );
return true;
}
}
return false;
}Writing audio (now i write test dummy audio) :
bool VVideoWriter::writeAudioFrame( const int16_t* data, int64_t timestamp )
{
if( m_context ) {
auto codecContext = m_audioStream->codec;
int buffer_size = av_samples_get_buffer_size(nullptr, codecContext->channels, codecContext->frame_size, codecContext->sample_fmt, 0);
float *samples = (float*)av_malloc(buffer_size);
for (int i = 0; i < buffer_size / sizeof(float); i++)
samples[i] = 1000. * sin((double)i/2.);
int ret = avcodec_fill_audio_frame( m_audioFrame, codecContext->channels, codecContext->sample_fmt, (const uint8_t*)samples, buffer_size, 0);
assert( ret >= 0 );
(void)(ret);
AVPacket pkt;
av_init_packet( & pkt );
pkt.data = nullptr;
pkt.size = 0;
int gotPacket = 0;
if( ! avcodec_encode_audio2( codecContext, &pkt, m_audioFrame, & gotPacket ) ) {
if( gotPacket == 1 ) {
pkt.stream_index = m_audioStream->index;
int res;
{
pkt.pts = AV_NOPTS_VALUE;
pkt.dts = AV_NOPTS_VALUE;
pkt.stream_index = m_audioStream->index;
res = av_write_frame( m_context, &pkt );
}
av_free_packet( & pkt );
return res >= 0;
}
assert( ! pkt.size );
return true;
}
return false;
}
return false;
}Here’s test example (i send video from webcam and dummy audio) :
class TestVVideoWriter : public sigslot::has_slots<>
{
public:
TestVVideoWriter( ) :
m_fileOpened( false )
{
}
void onCapturedFrame( cricket::VideoCapturer*, const cricket::CapturedFrame* capturedFrame )
{
if( m_fileOpened ) {
m_writer.writeVideoFrame( reinterpret_cast<const>( capturedFrame->data ),
capturedFrame->time_stamp / 1000 );
m_writer.writeAudioFrame( nullptr , 0 );
} else {
m_fileOpened = m_writer.openFile( "http://127.0.0.1:8080",
15, 40000, capturedFrame->width, capturedFrame->height,
16000, false, 64000 );
}
}
public:
vcore::VVideoWriter m_writer;
bool m_fileOpened;
};
TestVVideoWriter testWriter;
BOOST_AUTO_TEST_SUITE(TEST_VIDEO_WRITER)
BOOST_AUTO_TEST_CASE(testWritingVideo)
{
cricket::LinuxDeviceManager deviceManager;
std::vector devs;
if( deviceManager.GetVideoCaptureDevices( &devs ) ) {
if( devs.size( ) ) {
boost::shared_ptr camera( deviceManager.CreateVideoCapturer( devs[ 0 ] ) );
if( camera ) {
cricket::VideoFormat format( 320, 240, cricket::VideoFormat::FpsToInterval( 30 ),
camera->GetSupportedFormats( )->front( ).fourcc );
cricket::VideoFormat best;
if( camera->GetBestCaptureFormat( format, &best ) ) {
camera->SignalFrameCaptured.connect( &testWriter, &TestVVideoWriter::onCapturedFrame );
if( camera->Start( best ) != cricket::CS_FAILED ) {
boost::this_thread::sleep( boost::posix_time::seconds( 10 ) );
return;
}
}
}
}
}
std::cerr << "Problem has occured with camera" << std::endl;
}
BOOST_AUTO_TEST_SUITE_END() // TEST_VIDEO_WRITER
</const>But, in this case, gstreamer start playing video only when my test program stop executing (after 10 seconds in this case). It does not suit me, i want gstreamer start playing immediately after starting my test program.
Could someone help me ?
P.S. Sorry for my English.
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Is there something equivalent to FilterKit for android ?
29 octobre 2014, par Varun JainI am looking to put filters on a video after it has been recorded. Explored FFMPEG but it is way too slow (take 10-15 seconds for a 20 second video). The instagram app does it in under 1-2 seconds every time. Sample FFMPEG code I am using :
ffmpeg -y -i vid_0.mp4 -preset ultrafast -vf format=gray,format=yuv422p -vsync 2 webcam.mp4Is there a library similar to FilterKit for android ? Is there a feasible way in which I can use FilterKit on Android ? Any other approach to apply filters on video would also be welcome.
Note : I am not talking about giving the user a preview, that is easily done by using a surface view. I need to convert the video.
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