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  • 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

  • Merge commit ’8000206abcc82491c2a8c71e494c5477ede7264c’

    22 juillet 2013, par Michael Niedermayer
    Merge commit ’8000206abcc82491c2a8c71e494c5477ede7264c’

    * commit ’8000206abcc82491c2a8c71e494c5477ede7264c’ :
    
  libspeexdec : fix detection of final terminator code
    

    See : f3c9d66bafde9b8586bd63dd3307daa87352af75
    
Merged-by : Michael Niedermayer <michaelni@gmx.at>

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