Recherche avancée

Médias (1)

Mot : - Tags -/sintel

Autres articles (55)

  • List of compatible distributions

    26 avril 2011, par

    The table below is the list of Linux distributions compatible with the automated installation script of MediaSPIP. Distribution nameVersion nameVersion number Debian Squeeze 6.x.x Debian Weezy 7.x.x Debian Jessie 8.x.x Ubuntu The Precise Pangolin 12.04 LTS Ubuntu The Trusty Tahr 14.04
    If you want to help us improve this list, you can provide us access to a machine whose distribution is not mentioned above or send the necessary fixes to add (...)

  • Dépôt de média et thèmes par FTP

    31 mai 2013, par

    L’outil MédiaSPIP traite aussi les média transférés par la voie FTP. Si vous préférez déposer par cette voie, récupérez les identifiants d’accès vers votre site MédiaSPIP et utilisez votre client FTP favori.
    Vous trouverez dès le départ les dossiers suivants dans votre espace FTP : config/ : dossier de configuration du site IMG/ : dossier des média déjà traités et en ligne sur le site local/ : répertoire cache du site web themes/ : les thèmes ou les feuilles de style personnalisées tmp/ : dossier de travail (...)

  • Qualité du média après traitement

    21 juin 2013, par

    Le bon réglage du logiciel qui traite les média est important pour un équilibre entre les partis ( bande passante de l’hébergeur, qualité du média pour le rédacteur et le visiteur, accessibilité pour le visiteur ). Comment régler la qualité de son média ?
    Plus la qualité du média est importante, plus la bande passante sera utilisée. Le visiteur avec une connexion internet à petit débit devra attendre plus longtemps. Inversement plus, la qualité du média est pauvre et donc le média devient dégradé voire (...)

Sur d’autres sites (6112)

  • How Opensl es on android control the audio speed ?

    6 décembre 2013, par user1882379

    I use NDK+FFMPEG on android to decode an video file, and transfer the decoded pcm data to opensles for play audio .I register the opengles for the pcm format：

      SLDataFormat_PCM format_pcm;
    
    format_pcm.formatType = SL_DATAFORMAT_PCM;
    
    format_pcm.numChannels = channel;
    
    format_pcm.samplesPerSec = rate * 1000;
    
    format_pcm.bitsPerSample = SL_PCMSAMPLEFORMAT_FIXED_16;
    
    format_pcm.containerSize = SL_PCMSAMPLEFORMAT_FIXED_16;

    also I convert the decoded pcm data to AV_SAMPLE_FMT_S16 format using swr_convert(...), but the play audio speed is very fast. but if you use sdl , the play speed is normal. It would be sdl can control the play audio speed, but opensles can not. I do not know whether it is my mistake using opensles or opensles can not control audio speed(need application to control)？

  • OpenCV's VideoCapture::open Video Source Dialog

    13 novembre 2015, par swtdrgn

    In my current project, when I call VideoCapture::open(camera device index) and the camera is in used by another program, it shows a Video Source dialog and returns true when I select a device that is already in use.

    However, in my [previous] experiment project, when I called VideoCapture::open(camera device index), it doesn’t show this dialog.

    I want to know what is causing the Video Source dialog to show and the program to behave differently from the experimental project.

    This is the source code to the experiment project :

    int main (int argc, char *argv[])
    
{
    

    
    //vars
    
    time_duration td, td1;
    
    ptime nextFrameTimestamp, currentFrameTimestamp, initialLoopTimestamp, finalLoopTimestamp;
    
    int delayFound = 0;
    
    int totalDelay= 0;
    

    
    // initialize capture on default source
    
    VideoCapture capture;
    
    std::cout << "capture.open(0): " << capture.open(0) << std::endl;
    
    std::cout << "NOOO" << std::endl;
    
    namedWindow("video", 1);
    

    
    // set framerate to record and capture at
    
    int framerate = 15;
    

    
    // Get the properties from the camera
    
    double width = capture.get(CV_CAP_PROP_FRAME_WIDTH);
    
    double height = capture.get(CV_CAP_PROP_FRAME_HEIGHT);
    

    
    // print camera frame size
    
    //cout << "Camera properties\n";
    
    //cout << "width = " << width << endl <<"height = "<< height << endl;
    

    
    // Create a matrix to keep the retrieved frame
    
    Mat frame;
    

    
    // Create the video writer
    
    VideoWriter video("capture.avi",0, framerate, cvSize((int)width,(int)height) );
    

    
    // initialize initial timestamps
    
    nextFrameTimestamp = microsec_clock::local_time();
    
    currentFrameTimestamp = nextFrameTimestamp;
    
    td = (currentFrameTimestamp - nextFrameTimestamp);
    

    
    // start thread to begin capture and populate Mat frame
    
    boost::thread captureThread(captureFunc, &frame, &capture);
    
    // loop infinitely
    
    for(bool q=true;q;)
    
    {
    
        if(frame.empty()){continue;}
    
        //if(cvWaitKey( 5 ) == 'q'){ q=false; }
    
        // wait for X microseconds until 1second/framerate time has passed after previous frame write
    
        while(td.total_microseconds() < 1000000/framerate){
    
            //determine current elapsed time
    
            currentFrameTimestamp = microsec_clock::local_time();
    
            td = (currentFrameTimestamp - nextFrameTimestamp);
    
            if(cvWaitKey( 5 ) == 'q'){
    
                std::cout << "B" << std::endl;
    
                q=false;
    
                boost::posix_time::time_duration timeout = boost::posix_time::milliseconds(0);
    
                captureThread.timed_join(timeout);
    
                break;
    
            }
    
        }
    

    
        // determine time at start of write
    
        initialLoopTimestamp = microsec_clock::local_time();
    

    
        // Save frame to video
    
        video << frame;
    
        imshow("video", frame);
    

    
        //write previous and current frame timestamp to console
    
        cout << nextFrameTimestamp << " " << currentFrameTimestamp << " ";
    

    
        // add 1second/framerate time for next loop pause
    
        nextFrameTimestamp = nextFrameTimestamp + microsec(1000000/framerate);
    

    
        // reset time_duration so while loop engages
    
        td = (currentFrameTimestamp - nextFrameTimestamp);
    

    
        //determine and print out delay in ms, should be less than 1000/FPS
    
        //occasionally, if delay is larger than said value, correction will occur
    
        //if delay is consistently larger than said value, then CPU is not powerful
    
        // enough to capture/decompress/record/compress that fast.
    
        finalLoopTimestamp = microsec_clock::local_time();
    
        td1 = (finalLoopTimestamp - initialLoopTimestamp);
    
        delayFound = td1.total_milliseconds();
    
        cout << delayFound << endl;
    

    
        //output will be in following format
    
        //[TIMESTAMP OF PREVIOUS FRAME] [TIMESTAMP OF NEW FRAME] [TIME DELAY OF WRITING]
    
        if(!q || cvWaitKey( 5 ) == 'q'){
    
            std::cout << "C" << std::endl;
    
            q=false;
    
            boost::posix_time::time_duration timeout = boost::posix_time::milliseconds(0);
    
            captureThread.timed_join(timeout);
    
            break;
    
        }
    
    }
    

    
    // Exit
    
    return 0;
    
}

    Video Source Dialog

  • FFmpeg encoding produces slightly incompatible MKV/MP4 container

    11 juin 2018, par james2048

    I’ve been using the FFmpeg libraries to read and write media files using the C API.

    So far, reading seems to be pretty straightforward. I am able to read frames which I can then process, convert to RGB, process, and then convert back to YUV420 to be encoded.

    The encoded files play back with VLC media player fine, and Windows Media Player if I have a codec pack installed. However, they do behave strangely : the stock Windows 10 player won’t play them, same for Adobe Premiere. Also thumbnailers don’t work on it.
    Basically it seems like nothing other than VLC or FFmpeg itself can play/process the file. I have seen this with both MP4 and MKV, so it is not a format-specific issue.

    The problems go away once you remux the file with FFmpeg, for example "ffmpeg -i input.mkv -c copy output.mkv". Everything can play the file correctly.
    Also, the "remuxing.c" sample from the official samples works as well, with the same library version and compilers that I’m using (Visual Studio 2017, FFmpeg compiled with MinGW). It will fix the file and make it playable in all software.

    I’m not sure what could be causing this. I also don’t understand what the remuxing "fixed". It must be a container issue as the frames aren’t touched by remuxing.
    I have analysed the output MKVs with FFprobe -show_packets. It seems to have budged the packet timestamps a little constant factor, and the output stream now has
    is_avc=true and nal_length_size=4 instead of is_avc=false and nal_length_size=0, but apart from that the files are identical.

    Now here’s the output of FFprobe with the 3 last test packets, stream info and format info for both streams. As you can see, they are identical except for a couple of field. But something in here must have been "fixed" during remuxing to make it work.

    [PACKET]
    
codec_type=video
    
stream_index=0
    
pts=59050
    
pts_time=59.050000
    
dts=58890
    
dts_time=58.890000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=427
    
pos=277358
    
flags=__
    
[/PACKET]
    
[PACKET]
    
codec_type=video
    
stream_index=0
    
pts=58970
    
pts_time=58.970000
    
dts=58970
    
dts_time=58.970000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=205
    
pos=277792
    
flags=__
    
[/PACKET]
    
[PACKET]
    
codec_type=video
    
stream_index=0
    
pts=59130
    
pts_time=59.130000
    
dts=59050
    
dts_time=59.050000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=268
    
pos=278004
    
flags=__
    
[/PACKET]
    
[STREAM]
    
index=0
    
codec_name=h264
    
codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
    
profile=Main
    
codec_type=video
    
codec_time_base=1/2000
    
codec_tag_string=[0][0][0][0]
    
codec_tag=0x0000
    
width=720
    
height=576
    
coded_width=720
    
coded_height=576
    
has_b_frames=2
    
sample_aspect_ratio=N/A
    
display_aspect_ratio=N/A
    
pix_fmt=yuv420p
    
level=50
    
color_range=unknown
    
color_space=unknown
    
color_transfer=unknown
    
color_primaries=unknown
    
chroma_location=left
    
field_order=progressive
    
timecode=N/A
    
refs=1
    
is_avc=false
    
nal_length_size=0
    
id=N/A
    
r_frame_rate=299/12
    
avg_frame_rate=1000/1
    
time_base=1/1000
    
start_pts=0
    
start_time=0.000000
    
duration_ts=N/A
    
duration=N/A
    
bit_rate=N/A
    
max_bit_rate=N/A
    
bits_per_raw_sample=8
    
nb_frames=N/A
    
nb_read_frames=N/A
    
nb_read_packets=737
    
DISPOSITION:default=1
    
DISPOSITION:dub=0
    
DISPOSITION:original=0
    
DISPOSITION:comment=0
    
DISPOSITION:lyrics=0
    
DISPOSITION:karaoke=0
    
DISPOSITION:forced=0
    
DISPOSITION:hearing_impaired=0
    
DISPOSITION:visual_impaired=0
    
DISPOSITION:clean_effects=0
    
DISPOSITION:attached_pic=0
    
DISPOSITION:timed_thumbnails=0
    
TAG:DURATION=00:00:59.211000000
    
[/STREAM]
    
[FORMAT]
    
filename=testEncLeft.mkv
    
nb_streams=1
    
nb_programs=0
    
format_name=matroska,webm
    
format_long_name=Matroska / WebM
    
start_time=0.000000
    
duration=59.211000
    
size=278349
    
bit_rate=37607
    
probe_score=100
    
TAG:COMMENT=Slickline Player Export
    
TAG:ENCODER=Lavf57.83.100
    
[/FORMAT]

    And the info after remuxing, which works :

    [PACKET]
    
codec_type=video
    
stream_index=0
    
pts=59050
    
pts_time=59.050000
    
dts=58890
    
dts_time=58.890000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=427
    
pos=277418
    
flags=__
    
[/PACKET]
    
[PACKET]
    
codec_type=video
    
stream_index=0
    
pts=58970
    
pts_time=58.970000
    
dts=58970
    
dts_time=58.970000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=205
    
pos=277852
    
flags=__
    
[/PACKET]
    
[PACKET]
    
codec_type=video
    
stream_index=0
    
pts=59130
    
pts_time=59.130000
    
dts=59050
    
dts_time=59.050000
    
duration=1
    
duration_time=0.001000
    
convergence_duration=N/A
    
convergence_duration_time=N/A
    
size=268
    
pos=278064
    
flags=__
    
[/PACKET]
    
[STREAM]
    
index=0
    
codec_name=h264
    
codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
    
profile=Main
    
codec_type=video
    
codec_time_base=1/2000
    
codec_tag_string=[0][0][0][0]
    
codec_tag=0x0000
    
width=720
    
height=576
    
coded_width=720
    
coded_height=576
    
has_b_frames=2
    
sample_aspect_ratio=N/A
    
display_aspect_ratio=N/A
    
pix_fmt=yuv420p
    
level=50
    
color_range=unknown
    
color_space=unknown
    
color_transfer=unknown
    
color_primaries=unknown
    
chroma_location=left
    
field_order=progressive
    
timecode=N/A
    
refs=1
    
is_avc=true
    
nal_length_size=4
    
id=N/A
    
r_frame_rate=299/12
    
avg_frame_rate=1000/1
    
time_base=1/1000
    
start_pts=0
    
start_time=0.000000
    
duration_ts=N/A
    
duration=N/A
    
bit_rate=N/A
    
max_bit_rate=N/A
    
bits_per_raw_sample=8
    
nb_frames=N/A
    
nb_read_frames=N/A
    
nb_read_packets=737
    
DISPOSITION:default=1
    
DISPOSITION:dub=0
    
DISPOSITION:original=0
    
DISPOSITION:comment=0
    
DISPOSITION:lyrics=0
    
DISPOSITION:karaoke=0
    
DISPOSITION:forced=0
    
DISPOSITION:hearing_impaired=0
    
DISPOSITION:visual_impaired=0
    
DISPOSITION:clean_effects=0
    
DISPOSITION:attached_pic=0
    
DISPOSITION:timed_thumbnails=0
    
TAG:DURATION=00:00:59.212000000
    
[/STREAM]
    
[FORMAT]
    
filename=fixedLeft.mkv
    
nb_streams=1
    
nb_programs=0
    
format_name=matroska,webm
    
format_long_name=Matroska / WebM
    
start_time=0.000000
    
duration=59.212000
    
size=278409
    
bit_rate=37615
    
probe_score=100
    
TAG:COMMENT=Slickline Player Export
    
TAG:ENCODER=Lavf58.12.100
    
[/FORMAT]

    Here is how I’m setting up the output context, for reference : it’s pretty standard, following the sample code.

    int ret;
    

    
avformat_alloc_output_context2(&outputFormatCtx, nullptr, nullptr, outFilePath.c_str());
    

    
av_dict_set(&outputFormatCtx->metadata, "comment", "FFmpeg Export", 0);
    

    
if (!outputFormatCtx)
    
{
    
    LOG_AND_THROW("Could not allocate output context");
    
}
    

    
outputVideoStream = avformat_new_stream(outputFormatCtx, nullptr);
    
outputVideoStream->time_base = AVRational{ 1, AV_TIME_BASE }; // Stream timebase will be used by codec
    

    
if (!outputVideoStream)
    
{
    
    LOG_AND_THROW("Failed allocating output stream");
    
}
    

    
// defaults to "libx264"
    
AVCodec *outCodec = avcodec_find_encoder_by_name(selectedCodecName.c_str());
    

    
if (!outCodec)
    
{
    
    LOG_AND_THROW("Failed finding output codec");
    
}
    

    
AVDictionary *opts = nullptr;
    

    
if (selectedCodecName == "libx264")
    
{
    
    opts = getX264CodecOptions();
    
}
    

    
encoderCtx = avcodec_alloc_context3(outCodec);
    

    
if (!encoderCtx)
    
{
    
    LOG_AND_THROW("Failed to allocate the encoder context");
    
}
    

    
encoderCtx->width = width;
    
encoderCtx->height = height;
    
encoderCtx->pix_fmt = AV_PIX_FMT_YUV420P;
    
// time base for the frames we will provide to the encoder
    
encoderCtx->time_base = AVRational{ 1, AV_TIME_BASE };
    
// convert framerate from double to rational
    
encoderCtx->framerate = AVRational{ (int)(frameRate * AV_TIME_BASE), AV_TIME_BASE};
    

    
// Match encoderCtx time base for the stream
    
outputVideoStream->time_base = encoderCtx->time_base;
    

    
ret = avcodec_open2(encoderCtx, outCodec, &opts);
    

    
if (ret < 0)
    
{
    
    LOG_AND_THROW_PARAM("Cannot open video encoder for stream: %d", ret);
    
}
    

    
// Fill in some params for MP4 stream, details about encoder
    
ret = avcodec_parameters_from_context(outputVideoStream->codecpar, encoderCtx);
    

    
if (ret < 0)
    
{
    
    LOG_AND_THROW_PARAM("Failed to copy encoder parameters to output stream: %d", ret);
    
}
    

    
if (outputFormatCtx->oformat->flags & AVFMT_GLOBALHEADER)
    
{
    
    encoderCtx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    
}
    

    
av_dump_format(outputFormatCtx, 0, filePath.c_str(), 1);
    

    
// End of encoder settings, setting up MP4
    
if (!(outputFormatCtx->oformat->flags & AVFMT_NOFILE))
    
{
    
    ret = avio_open(&outputFormatCtx->pb, outFilePath.c_str(), AVIO_FLAG_WRITE);
    

    
    if (ret < 0)
    
    {
    
        LOG_AND_THROW_PARAMSTR("Could not open output file '%s'", outFilePath.c_str());
    
    }
    
}
    

    
ret = avformat_write_header(outputFormatCtx, nullptr);
    

    
if (ret < 0)
    
{
    
    LOG_AND_THROW_PARAM("Error occurred when opening output file for writing: %d", ret);
    
}

    Can anyone help me figure out why the container is not playing properly ?

    Thanks in advance.

    -James

Navigation