Recherche avancée

Médias (0)

Mot : - Tags -/api

Aucun média correspondant à vos critères n’est disponible sur le site.

Autres articles (52)

  • Supporting all media types

    13 avril 2011, par

    Unlike 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 (...)

  • Contribute to translation

    13 avril 2011

    You can help us to improve the language used in the software interface to make MediaSPIP more accessible and user-friendly. You can also translate the interface into any language that allows it to spread to new linguistic communities.
    To do this, we use the translation interface of SPIP where the all the language modules of MediaSPIP are available. Just subscribe to the mailing list and request further informantion on translation.
    MediaSPIP is currently available in French and English (...)

  • Taille des images et des logos définissables

    9 février 2011, par

    Dans beaucoup d’endroits du site, logos et images sont redimensionnées pour correspondre aux emplacements définis par les thèmes. L’ensemble des ces tailles pouvant changer d’un thème à un autre peuvent être définies directement dans le thème et éviter ainsi à l’utilisateur de devoir les configurer manuellement après avoir changé l’apparence de son site.
    Ces tailles d’images sont également disponibles dans la configuration spécifique de MediaSPIP Core. La taille maximale du logo du site en pixels, on permet (...)

Sur d’autres sites (4082)

  • Revision 74493 : Toujours réduire un peu, évite de charger de très grosses images pour pas ...

    28 juillet 2013, par kent1@… — Log

    Toujours réduire un peu, évite de charger de très grosses images pour pas grand chose

  • Creating a video from images using ffmpeg libav and libx264 ?

    11 janvier 2014, par marikaner

    I am trying to create a video from images using the ffmpeg library. The images have a size of 1920x1080 and are supposed to be encoded with H.264 using a .mkv container.
    I have come across various problems, thinking I am getting closer to a solution, but this one I am really stuck on. With the settings I use, the first X frames (around 40, depending on what and how many images I use for the video) of my video are not encoded. avcodec_encode_video2 does not return any error (return value is 0) with got_picture_ptr = 0.
    The result is a video that actually looks as expected, but the first seconds are weirdly jumpy.

    So this is how I create the video file :

    // m_codecContext is an instance variable of type AVCodecContext *
    
// m_formatCtx is an instance variable of type AVFormatContext *
    

    
// outputFileName is a valid filename ending with .mkv
    
AVOutputFormat *oformat = av_guess_format(NULL, outputFileName, NULL);
    
if (oformat == NULL)
    
{
    
    oformat = av_guess_format("mpeg", NULL, NULL);
    
}
    

    
// oformat->video_codec is AV_CODEC_ID_H264
    
AVCodec *codec = avcodec_find_encoder(oformat->video_codec);
    

    
m_codecContext = avcodec_alloc_context3(codec);
    
m_codecContext->codec_id = oformat->video_codec;
    
m_codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
    
m_codecContext->gop_size = 30;
    
m_codecContext->bit_rate = width * height * 4
    
m_codecContext->width = width;
    
m_codecContext->height = height;
    
m_codecContext->time_base = (AVRational){1,frameRate};
    
m_codecContext->max_b_frames = 1;
    
m_codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
    

    
m_formatCtx = avformat_alloc_context();
    
m_formatCtx->oformat = oformat;
    
m_formatCtx->video_codec_id = oformat->video_codec;
    

    
snprintf(m_formatCtx->filename, sizeof(m_formatCtx->filename), "%s", outputFileName);
    

    
AVStream *videoStream = avformat_new_stream(m_formatCtx, codec);
    
if(!videoStream)
    
{
    
   printf("Could not allocate stream\n");
    
}
    
videoStream->codec = m_codecContext;
    

    
if(m_formatCtx->oformat->flags & AVFMT_GLOBALHEADER)
    
{
    
   m_codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
    
}
    

    
avcodec_open2(m_codecContext, codec, NULL) < 0);
    
avio_open(&m_formatCtx->pb, outputFileName.toStdString().c_str(), AVIO_FLAG_WRITE);
    
avformat_write_header(m_formatCtx, NULL);

    this is how the frames are added :

    void VideoCreator::writeImageToVideo(const QSharedPointer<qimage> &amp;img, int frameIndex)
    
{
    
    AVFrame *frame = avcodec_alloc_frame();
    

    
    /* alloc image and output buffer */
    

    
    int size = m_codecContext->width * m_codecContext->height;
    
    int numBytes = avpicture_get_size(m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height);
    

    
    uint8_t *outbuf = (uint8_t *)malloc(numBytes);
    
    uint8_t *picture_buf = (uint8_t *)av_malloc(numBytes);
    

    
    int ret = av_image_fill_arrays(frame->data, frame->linesize, picture_buf, m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height, 1);
    

    
    frame->data[0] = picture_buf;
    
    frame->data[1] = frame->data[0] + size;
    
    frame->data[2] = frame->data[1] + size/4;
    
    frame->linesize[0] = m_codecContext->width;
    
    frame->linesize[1] = m_codecContext->width/2;
    
    frame->linesize[2] = m_codecContext->width/2;
    

    
    fflush(stdout);
    

    

    
    for (int y = 0; y &lt; m_codecContext->height; y++)
    
    {
    
        for (int x = 0; x &lt; m_codecContext->width; x++)
    
        {
    
            unsigned char b = img->bits()[(y * m_codecContext->width + x) * 4 + 0];
    
            unsigned char g = img->bits()[(y * m_codecContext->width + x) * 4 + 1];
    
            unsigned char r = img->bits()[(y * m_codecContext->width + x) * 4 + 2];
    

    
            unsigned char Y = (0.257 * r) + (0.504 * g) + (0.098 * b) + 16;
    

    
            frame->data[0][y * frame->linesize[0] + x] = Y;
    

    
            if (y % 2 == 0 &amp;&amp; x % 2 == 0)
    
            {
    
                unsigned char V = (0.439 * r) - (0.368 * g) - (0.071 * b) + 128;
    
                unsigned char U = -(0.148 * r) - (0.291 * g) + (0.439 * b) + 128;
    

    
                frame->data[1][y/2 * frame->linesize[1] + x/2] = U;
    
                frame->data[2][y/2 * frame->linesize[2] + x/2] = V;
    
            }
    
        }
    
    }
    

    
    int pts = frameIndex;//(1.0 / 30.0) * 90.0 * frameIndex;
    

    
    frame->pts = pts;//av_rescale_q(m_codecContext->coded_frame->pts, m_codecContext->time_base, formatCtx->streams[0]->time_base); //(1.0 / 30.0) * 90.0 * frameIndex;
    

    
    int got_packet_ptr;
    
    AVPacket packet;
    
    av_init_packet(&amp;packet);
    
    packet.data = outbuf;
    
    packet.size = numBytes;
    
    packet.stream_index = formatCtx->streams[0]->index;
    
    packet.flags |= AV_PKT_FLAG_KEY;
    
    packet.pts = packet.dts = pts;
    
    m_codecContext->coded_frame->pts = pts;
    

    
    ret = avcodec_encode_video2(m_codecContext, &amp;packet, frame, &amp;got_packet_ptr);
    
    if (got_packet_ptr != 0)
    
    {
    
        m_codecContext->coded_frame->pts = pts;  // Set the time stamp
    

    
        if (m_codecContext->coded_frame->pts != (0x8000000000000000LL))
    
        {
    
            pts = av_rescale_q(m_codecContext->coded_frame->pts, m_codecContext->time_base, formatCtx->streams[0]->time_base);
    
        }
    
        packet.pts = pts;
    
        if(m_codecContext->coded_frame->key_frame)
    
        {
    
           packet.flags |= AV_PKT_FLAG_KEY;
    
        }
    

    
        std::cout &lt;&lt; "pts: " &lt;&lt; packet.pts &lt;&lt; ", dts: "  &lt;&lt; packet.dts &lt;&lt; std::endl;
    

    
        av_interleaved_write_frame(formatCtx, &amp;packet);
    
        av_free_packet(&amp;packet);
    
    }
    

    
    free(picture_buf);
    
    free(outbuf);
    
    av_free(frame);
    
    printf("\n");
    
}
    
</qimage>

    and this is the cleanup :

    int numBytes = avpicture_get_size(m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height);
    
int got_packet_ptr = 1;
    

    
int ret;
    
//        for(; got_packet_ptr != 0; i++)
    
while (got_packet_ptr)
    
{
    
    uint8_t *outbuf = (uint8_t *)malloc(numBytes);
    

    
    AVPacket packet;
    
    av_init_packet(&amp;packet);
    
    packet.data = outbuf;
    
    packet.size = numBytes;
    

    
    ret = avcodec_encode_video2(m_codecContext, &amp;packet, NULL, &amp;got_packet_ptr);
    
    if (got_packet_ptr)
    
    {
    
        av_interleaved_write_frame(m_formatCtx, &amp;packet);
    
    }
    

    
    av_free_packet(&amp;packet);
    
    free(outbuf);
    
}
    

    
av_write_trailer(formatCtx);
    

    
avcodec_close(m_codecContext);
    
av_free(m_codecContext);
    
printf("\n");

    I assume it might be tied to the PTS and DTS values, but I have tried EVERYTHING. The frame index seems to make the most sense. The images are correct, I can save them to files without any problems. I am running out of ideas.
    I would be incredibly thankful if there was someone out there who knew better than me...

    Cheers,
    marikaner

    UPDATE :

    If this is of any help this is the output at the end of the video encoding :

    [libx264 @ 0x7fffc00028a0] frame I:19    Avg QP:14.24  size:312420
    
[libx264 @ 0x7fffc00028a0] frame P:280   Avg QP:19.16  size:148867
    
[libx264 @ 0x7fffc00028a0] frame B:181   Avg QP:21.31  size: 40540
    
[libx264 @ 0x7fffc00028a0] consecutive B-frames: 24.6% 75.4%
    
[libx264 @ 0x7fffc00028a0] mb I  I16..4: 30.9% 45.5% 23.7%
    
[libx264 @ 0x7fffc00028a0] mb P  I16..4:  4.7%  9.1%  4.5%  P16..4: 23.5% 16.6% 12.6%  0.0%  0.0%    skip:28.9%
    
[libx264 @ 0x7fffc00028a0] mb B  I16..4:  0.6%  0.5%  0.3%  B16..8: 26.7% 11.0%  5.5%  direct: 3.9%  skip:51.5%  L0:39.4% L1:45.0% BI:15.6%
    
[libx264 @ 0x7fffc00028a0] final ratefactor: 19.21
    
[libx264 @ 0x7fffc00028a0] 8x8 transform intra:48.2% inter:47.3%
    
[libx264 @ 0x7fffc00028a0] coded y,uvDC,uvAC intra: 54.9% 53.1% 30.4% inter: 25.4% 13.5% 4.2%
    
[libx264 @ 0x7fffc00028a0] i16 v,h,dc,p: 41% 29% 11% 19%
    
[libx264 @ 0x7fffc00028a0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 26% 31%  3%  4%  3%  7%  3%  6%
    
[libx264 @ 0x7fffc00028a0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 26% 14%  4%  5%  4%  7%  4%  7%
    
[libx264 @ 0x7fffc00028a0] i8c dc,h,v,p: 58% 26% 13%  3%
    
[libx264 @ 0x7fffc00028a0] Weighted P-Frames: Y:17.1% UV:3.6%
    
[libx264 @ 0x7fffc00028a0] ref P L0: 63.1% 21.4% 11.4%  4.1%  0.1%    
    
[libx264 @ 0x7fffc00028a0] ref B L0: 85.7% 14.3%
    
[libx264 @ 0x7fffc00028a0] kb/s:27478.30

  • Creating a video from images using ffmpeg libav and libx264 ?

    11 janvier 2014, par marikaner

    I am trying to create a video from images using the ffmpeg library. The images have a size of 1920x1080 and are supposed to be encoded with H.264 using a .mkv container.
    I have come across various problems, thinking I am getting closer to a solution, but this one I am really stuck on. With the settings I use, the first X frames (around 40, depending on what and how many images I use for the video) of my video are not encoded. avcodec_encode_video2 does not return any error (return value is 0) with got_picture_ptr = 0.
    The result is a video that actually looks as expected, but the first seconds are weirdly jumpy.

    So this is how I create the video file :

    // m_codecContext is an instance variable of type AVCodecContext *
    
// m_formatCtx is an instance variable of type AVFormatContext *
    

    
// outputFileName is a valid filename ending with .mkv
    
AVOutputFormat *oformat = av_guess_format(NULL, outputFileName, NULL);
    
if (oformat == NULL)
    
{
    
    oformat = av_guess_format("mpeg", NULL, NULL);
    
}
    

    
// oformat->video_codec is AV_CODEC_ID_H264
    
AVCodec *codec = avcodec_find_encoder(oformat->video_codec);
    

    
m_codecContext = avcodec_alloc_context3(codec);
    
m_codecContext->codec_id = oformat->video_codec;
    
m_codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
    
m_codecContext->gop_size = 30;
    
m_codecContext->bit_rate = width * height * 4
    
m_codecContext->width = width;
    
m_codecContext->height = height;
    
m_codecContext->time_base = (AVRational){1,frameRate};
    
m_codecContext->max_b_frames = 1;
    
m_codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
    

    
m_formatCtx = avformat_alloc_context();
    
m_formatCtx->oformat = oformat;
    
m_formatCtx->video_codec_id = oformat->video_codec;
    

    
snprintf(m_formatCtx->filename, sizeof(m_formatCtx->filename), "%s", outputFileName);
    

    
AVStream *videoStream = avformat_new_stream(m_formatCtx, codec);
    
if(!videoStream)
    
{
    
   printf("Could not allocate stream\n");
    
}
    
videoStream->codec = m_codecContext;
    

    
if(m_formatCtx->oformat->flags &amp; AVFMT_GLOBALHEADER)
    
{
    
   m_codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
    
}
    

    
avcodec_open2(m_codecContext, codec, NULL) &lt; 0);
    
avio_open(&amp;m_formatCtx->pb, outputFileName.toStdString().c_str(), AVIO_FLAG_WRITE);
    
avformat_write_header(m_formatCtx, NULL);

    this is how the frames are added :

    void VideoCreator::writeImageToVideo(const QSharedPointer<qimage> &amp;img, int frameIndex)
    
{
    
    AVFrame *frame = avcodec_alloc_frame();
    

    
    /* alloc image and output buffer */
    

    
    int size = m_codecContext->width * m_codecContext->height;
    
    int numBytes = avpicture_get_size(m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height);
    

    
    uint8_t *outbuf = (uint8_t *)malloc(numBytes);
    
    uint8_t *picture_buf = (uint8_t *)av_malloc(numBytes);
    

    
    int ret = av_image_fill_arrays(frame->data, frame->linesize, picture_buf, m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height, 1);
    

    
    frame->data[0] = picture_buf;
    
    frame->data[1] = frame->data[0] + size;
    
    frame->data[2] = frame->data[1] + size/4;
    
    frame->linesize[0] = m_codecContext->width;
    
    frame->linesize[1] = m_codecContext->width/2;
    
    frame->linesize[2] = m_codecContext->width/2;
    

    
    fflush(stdout);
    

    

    
    for (int y = 0; y &lt; m_codecContext->height; y++)
    
    {
    
        for (int x = 0; x &lt; m_codecContext->width; x++)
    
        {
    
            unsigned char b = img->bits()[(y * m_codecContext->width + x) * 4 + 0];
    
            unsigned char g = img->bits()[(y * m_codecContext->width + x) * 4 + 1];
    
            unsigned char r = img->bits()[(y * m_codecContext->width + x) * 4 + 2];
    

    
            unsigned char Y = (0.257 * r) + (0.504 * g) + (0.098 * b) + 16;
    

    
            frame->data[0][y * frame->linesize[0] + x] = Y;
    

    
            if (y % 2 == 0 &amp;&amp; x % 2 == 0)
    
            {
    
                unsigned char V = (0.439 * r) - (0.368 * g) - (0.071 * b) + 128;
    
                unsigned char U = -(0.148 * r) - (0.291 * g) + (0.439 * b) + 128;
    

    
                frame->data[1][y/2 * frame->linesize[1] + x/2] = U;
    
                frame->data[2][y/2 * frame->linesize[2] + x/2] = V;
    
            }
    
        }
    
    }
    

    
    int pts = frameIndex;//(1.0 / 30.0) * 90.0 * frameIndex;
    

    
    frame->pts = pts;//av_rescale_q(m_codecContext->coded_frame->pts, m_codecContext->time_base, formatCtx->streams[0]->time_base); //(1.0 / 30.0) * 90.0 * frameIndex;
    

    
    int got_packet_ptr;
    
    AVPacket packet;
    
    av_init_packet(&amp;packet);
    
    packet.data = outbuf;
    
    packet.size = numBytes;
    
    packet.stream_index = formatCtx->streams[0]->index;
    
    packet.flags |= AV_PKT_FLAG_KEY;
    
    packet.pts = packet.dts = pts;
    
    m_codecContext->coded_frame->pts = pts;
    

    
    ret = avcodec_encode_video2(m_codecContext, &amp;packet, frame, &amp;got_packet_ptr);
    
    if (got_packet_ptr != 0)
    
    {
    
        m_codecContext->coded_frame->pts = pts;  // Set the time stamp
    

    
        if (m_codecContext->coded_frame->pts != (0x8000000000000000LL))
    
        {
    
            pts = av_rescale_q(m_codecContext->coded_frame->pts, m_codecContext->time_base, formatCtx->streams[0]->time_base);
    
        }
    
        packet.pts = pts;
    
        if(m_codecContext->coded_frame->key_frame)
    
        {
    
           packet.flags |= AV_PKT_FLAG_KEY;
    
        }
    

    
        std::cout &lt;&lt; "pts: " &lt;&lt; packet.pts &lt;&lt; ", dts: "  &lt;&lt; packet.dts &lt;&lt; std::endl;
    

    
        av_interleaved_write_frame(formatCtx, &amp;packet);
    
        av_free_packet(&amp;packet);
    
    }
    

    
    free(picture_buf);
    
    free(outbuf);
    
    av_free(frame);
    
    printf("\n");
    
}
    
</qimage>

    and this is the cleanup :

    int numBytes = avpicture_get_size(m_codecContext->pix_fmt, m_codecContext->width, m_codecContext->height);
    
int got_packet_ptr = 1;
    

    
int ret;
    
//        for(; got_packet_ptr != 0; i++)
    
while (got_packet_ptr)
    
{
    
    uint8_t *outbuf = (uint8_t *)malloc(numBytes);
    

    
    AVPacket packet;
    
    av_init_packet(&amp;packet);
    
    packet.data = outbuf;
    
    packet.size = numBytes;
    

    
    ret = avcodec_encode_video2(m_codecContext, &amp;packet, NULL, &amp;got_packet_ptr);
    
    if (got_packet_ptr)
    
    {
    
        av_interleaved_write_frame(m_formatCtx, &amp;packet);
    
    }
    

    
    av_free_packet(&amp;packet);
    
    free(outbuf);
    
}
    

    
av_write_trailer(formatCtx);
    

    
avcodec_close(m_codecContext);
    
av_free(m_codecContext);
    
printf("\n");

    I assume it might be tied to the PTS and DTS values, but I have tried EVERYTHING. The frame index seems to make the most sense. The images are correct, I can save them to files without any problems. I am running out of ideas.
    I would be incredibly thankful if there was someone out there who knew better than me...

    Cheers,
    marikaner

    UPDATE :

    If this is of any help this is the output at the end of the video encoding :

    [libx264 @ 0x7fffc00028a0] frame I:19    Avg QP:14.24  size:312420
    
[libx264 @ 0x7fffc00028a0] frame P:280   Avg QP:19.16  size:148867
    
[libx264 @ 0x7fffc00028a0] frame B:181   Avg QP:21.31  size: 40540
    
[libx264 @ 0x7fffc00028a0] consecutive B-frames: 24.6% 75.4%
    
[libx264 @ 0x7fffc00028a0] mb I  I16..4: 30.9% 45.5% 23.7%
    
[libx264 @ 0x7fffc00028a0] mb P  I16..4:  4.7%  9.1%  4.5%  P16..4: 23.5% 16.6% 12.6%  0.0%  0.0%    skip:28.9%
    
[libx264 @ 0x7fffc00028a0] mb B  I16..4:  0.6%  0.5%  0.3%  B16..8: 26.7% 11.0%  5.5%  direct: 3.9%  skip:51.5%  L0:39.4% L1:45.0% BI:15.6%
    
[libx264 @ 0x7fffc00028a0] final ratefactor: 19.21
    
[libx264 @ 0x7fffc00028a0] 8x8 transform intra:48.2% inter:47.3%
    
[libx264 @ 0x7fffc00028a0] coded y,uvDC,uvAC intra: 54.9% 53.1% 30.4% inter: 25.4% 13.5% 4.2%
    
[libx264 @ 0x7fffc00028a0] i16 v,h,dc,p: 41% 29% 11% 19%
    
[libx264 @ 0x7fffc00028a0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 26% 31%  3%  4%  3%  7%  3%  6%
    
[libx264 @ 0x7fffc00028a0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 26% 14%  4%  5%  4%  7%  4%  7%
    
[libx264 @ 0x7fffc00028a0] i8c dc,h,v,p: 58% 26% 13%  3%
    
[libx264 @ 0x7fffc00028a0] Weighted P-Frames: Y:17.1% UV:3.6%
    
[libx264 @ 0x7fffc00028a0] ref P L0: 63.1% 21.4% 11.4%  4.1%  0.1%    
    
[libx264 @ 0x7fffc00028a0] ref B L0: 85.7% 14.3%
    
[libx264 @ 0x7fffc00028a0] kb/s:27478.30

Navigation