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    Mediaspip core
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    10 avril 2011

    MediaSPIP 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.
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    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 (...)

  • De l’upload à la vidéo finale [version standalone]

    31 janvier 2010, par

    Le chemin d’un document audio ou vidéo dans SPIPMotion est divisé en trois étapes distinctes.
    Upload et récupération d’informations de la vidéo source
    Dans un premier temps, il est nécessaire de créer un article SPIP et de lui joindre le document vidéo "source".
    Au moment où ce document est joint à l’article, deux actions supplémentaires au comportement normal sont exécutées : La récupération des informations techniques des flux audio et video du fichier ; La génération d’une vignette : extraction d’une (...)

Sur d’autres sites (8710)

  • using ffmpeg libavcodec to decode a video file then encode to H264, media file's duration is zero

    1er septembre 2017, par Qing

    Need help, recently, I am using ffmpeg libavcodec to decode a video file then encode to H264 and write to an mp4 media container, finally, the media file’s duration is zero, the following is my code’s workflow：

    AVFormatContext*    input_format_context = NULL;
    
AVFormatContext*    output_format_context = NULL;
    
AVIOContext*        output_io_context = NULL;
    
AVCodecContext*     input_codec_context = NULL;
    
AVCodecContext*     output_codec_context = NULL;
    
AVCodec*            codec = NULL;
    
AVStream*           input_stream = NULL;
    
AVStream*           output_stream = NULL;
    
AVFrame*            frame = NULL;
    

    
int convert_init(const char* input_filename, const char* output_filename)
    
{
    
    /** Allocate a new encode context */
    
    avformat_open_input(&input_format_context, 
    
            input_filename, NULL, NULL); 
    

    
    /** Get information on the input file (number of streams etc.). */
    
    avformat_find_stream_info(input_format_context, NULL);  
    

    
    /** Open the output file to write to it. */
    
    avio_open(&output_io_context, output_filename, 
    
            AVIO_FLAG_WRITE);
    

    
    /** Create a new format context for the output container format. */
    
    output_format_context = avformat_alloc_context();
    

    
    /** Associate the output file (pointer) with the container format context. */
    
    output_format_context->pb = output_io_context;
    

    
    /** Guess the desired container format based on the file extension. */
    
    output_format_context->oformat = av_guess_format(NULL, 
    
            output_filename, NULL);
    

    
    av_strlcpy((output_format_context)->filename, output_filename, 
    
            sizeof(output_format_context->filename));
    

    
    /** stream0 is the video stream */
    
    AVStream* input_stream = input_format_context->streams[0];
    

    

    
    /** 
    
     * Init the input_codec_context 
    
     */
    

    
    /** Find a decoder for the audio stream. */
    
    codec = avcodec_find_decoder(input_stream->codecpar->codec_id);
    

    
    /** Allocate a new decode context */
    
    input_codec_context = avcodec_alloc_context3(codec);
    

    
    /** Initialize the stream parameters with demuxer information */
    
    avcodec_parameters_to_context(input_codec_context, 
    
            input_stream->codecpar);    
    

    
    /** Open the decoder for the stream. */
    
    avcodec_open2(input_codec_context, codec, NULL);                                
    

    
    /** 
    
     *  Create an output stream for writing encoded data 
    
     *
    
     *  AM I MISSING SOMETHING ?
    
     *
    
     */
    
    output_stream = avformat_new_stream(output_format_context, NULL);
    

    
    /** 
    
     * Init the output_codec_context 
    
     */
    
    /** Find a encoder for the output video stream, using H264. */
    
    codec = avcodec_find_encoder(AV_CODEC_ID_H264);     
    

    
    /** Allocate an encode context. */
    
    output_codec_context = avcodec_alloc_context3(codec);  
    

    
    /** 
    
     *  Setup encode context parameters.
    
     *  
    
     *  AM I MISSING SOMETHING ?
    
     *
    
     * */
    
    output_codec_context->bit_rate = input_codec_context->bit_rate;
    
    output_codec_context->width = input_codec_context->width;
    
    output_codec_context->height = input_codec_context->height;
    
    output_codec_context->time_base = (AVRational){1, 25};
    
    output_codec_context->framerate = (AVRational){25, 1};
    
    output_codec_context->gop_size = 10;
    
    output_codec_context->max_b_frames = 1;
    
    output_codec_context->pix_fmt = AV_PIX_FMT_YUV420P;
    
    output_codec_context->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    

    
    /** Setup output_stream codecpar. */
    
    avcodec_parameters_from_context(output_stream->codecpar, 
    
            codec_context);
    

    
    /** Alloc an av frame */
    
    frame = av_frame_alloc();           
    

    
}
    

    
void convert_it()
    
{
    
    AVPacket input_packet;
    
    AVPacket output_packet;
    

    
    /** Write the media file container header */
    
    avformat_write_header(output_format_context, NULL);
    

    
    /** 
    
     * decode frames and encode to H264 
    
     * */
    
    while (1) { 
    
        av_init_packet(&input_packet);
    
        input_packet.data = NULL;
    
        input_packet.size = 0;
    

    
        av_init_packet(&output_packet);
    
        output_packet.data = NULL;
    
        output_packet.size = 0;
    

    
        /** Read a frame to decode */
    
        av_read_frame(input_format_context, &input_packet);         
    
        if (av_read_frame is end of file) {
    
            break;
    
        }
    
        ...
    
        ...
    

    
        /** Decoding... */
    
        avcodec_send_packet(input_codec_context, &input_packet);
    
        ...
    
        ...
    

    
        /** Get a decoded frame */
    
        avcodec_receive_frame(input_codec_context, frame);
    
        ...
    
        ...
    

    
        /** Make the frame writable, is it necessary ?? */
    
        av_frame_make_writable(frame);
    

    
        /** Encode to H264 */
    
        avcodec_send_frame(output_codec_context, frame);
    
        ...
    
        ...
    

    
        /** Get a encoded packet */
    
        avcodec_receive_packet(output_codec_context, &output_packet);
    

    
        /** 
    
         * Write the packet to output.  
    
         * Here is the point! should I configure the parameters 
    
         * in packet such as 'pts', 'dts', 'duration', etc, if so, 
    
         * hwo? or I just directory write the packet to output? 
    
         */
    
        av_interleaved_write_frame(output_format_context, &packet);                 
    
    }
    

    
    /** Write the media file container trailer */
    
    av_write_trailer(output_format_context);
    

    
}
    

    
int main() {
    
    convert_init("./sample.avi", "./output.mp4");
    
    convert_it();
    

    
}

    using VLC or QuickTime to playback the output.mp4 file, it failed, cause the file duration is zero, when dragging the time progress bar， I can see the picture frame clearly, it seems that the encoding packet buffer data is correct, but the timestamp is error, am I missing something when configure the output_stream ? The following is message from ffprobe.

    ffprobe output.mp4
    
ffprobe version 3.3.3 Copyright (c) 2007-2017 the FFmpeg developers
    
  built with Apple LLVM version 8.1.0 (clang-802.0.42)
    
  configuration: --enable-shared --enable-libmp3lame
    
  libavutil      55. 58.100 / 55. 58.100
    
  libavcodec     57. 89.100 / 57. 89.100
    
  libavformat    57. 71.100 / 57. 71.100
    
  libavdevice    57.  6.100 / 57.  6.100
    
  libavfilter     6. 82.100 /  6. 82.100
    
  libswscale      4.  6.100 /  4.  6.100
    
  libswresample   2.  7.100 /  2.  7.100
    
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
    
  Metadata:
    
    major_brand     : isom
    
    minor_version   : 512
    
    compatible_brands: isomiso2avc1mp41
    
    encoder         : Lavf57.71.100
    
  Duration: 00:00:00.06, start: 0.000000, bitrate: 6902181 kb/s
    
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x408 [SAR 1:1 DAR 30:17], 13929056 kb/s, 90k fps, 90k tbr, 90k tbn, 50 tbc (default)
    
    Metadata:
    
      handler_name    : VideoHandler

  • using ffmpeg libavcodec encode video stream to H264, why duration is zero

    26 mars 2019, par Qing

    Need help, recently, I am using ffmpeg libavcodec to decode a video file then encode to H264 and write to an mp4 media container, finally, the media file’s duration is zero, the following is my code’s workflow：

    AVFormatContext*    input_format_context = NULL;
    
AVFormatContext*    output_format_context = NULL;
    
AVIOContext*        output_io_context = NULL;
    
AVCodecContext*     input_codec_context = NULL;
    
AVCodecContext*     output_codec_context = NULL;
    
AVCodec*            codec = NULL;
    
AVStream*           input_stream = NULL;
    
AVStream*           output_stream = NULL;
    
AVFrame*            frame = NULL;
    

    
int convert_init(const char* input_filename, const char* output_filename)
    
{
    
    /** Allocate a new encode context */
    
    avformat_open_input(&input_format_context, 
    
            input_filename, NULL, NULL); 
    

    
    /** Get information on the input file (number of streams etc.). */
    
    avformat_find_stream_info(input_format_context, NULL);  
    

    
    /** Open the output file to write to it. */
    
    avio_open(&output_io_context, output_filename, 
    
            AVIO_FLAG_WRITE);
    

    
    /** Create a new format context for the output container format. */
    
    output_format_context = avformat_alloc_context();
    

    
    /** Associate the output file (pointer) with the container format context. */
    
    output_format_context->pb = output_io_context;
    

    
    /** Guess the desired container format based on the file extension. */
    
    output_format_context->oformat = av_guess_format(NULL, 
    
            output_filename, NULL);
    

    
    av_strlcpy((output_format_context)->filename, output_filename, 
    
            sizeof(output_format_context->filename));
    

    
    /** stream0 is the video stream */
    
    AVStream* input_stream = input_format_context->streams[0];
    

    

    
    /** 
    
     * Init the input_codec_context 
    
     */
    

    
    /** Find a decoder for the audio stream. */
    
    codec = avcodec_find_decoder(input_stream->codecpar->codec_id);
    

    
    /** Allocate a new decode context */
    
    input_codec_context = avcodec_alloc_context3(codec);
    

    
    /** Initialize the stream parameters with demuxer information */
    
    avcodec_parameters_to_context(input_codec_context, 
    
            input_stream->codecpar);    
    

    
    /** Open the decoder for the stream. */
    
    avcodec_open2(input_codec_context, codec, NULL);                                
    

    
    /** 
    
     *  Create an output stream for writing encoded data 
    
     *
    
     *  AM I MISSING SOMETHING ?
    
     *
    
     */
    
    output_stream = avformat_new_stream(output_format_context, NULL);
    

    
    /** 
    
     * Init the output_codec_context 
    
     */
    
    /** Find a encoder for the output video stream, using H264. */
    
    codec = avcodec_find_encoder(AV_CODEC_ID_H264);     
    

    
    /** Allocate an encode context. */
    
    output_codec_context = avcodec_alloc_context3(codec);  
    

    
    /** 
    
     *  Setup encode context parameters.
    
     *  
    
     *  AM I MISSING SOMETHING ?
    
     *
    
     * */
    
    output_codec_context->bit_rate = input_codec_context->bit_rate;
    
    output_codec_context->width = input_codec_context->width;
    
    output_codec_context->height = input_codec_context->height;
    
    output_codec_context->time_base = (AVRational){1, 25};
    
    output_codec_context->framerate = (AVRational){25, 1};
    
    output_codec_context->gop_size = 10;
    
    output_codec_context->max_b_frames = 1;
    
    output_codec_context->pix_fmt = AV_PIX_FMT_YUV420P;
    
    output_codec_context->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    

    
    /** Setup output_stream codecpar. */
    
    avcodec_parameters_from_context(output_stream->codecpar, 
    
            codec_context);
    

    
    /** Alloc an av frame */
    
    frame = av_frame_alloc();           
    

    
}
    

    
void convert_it()
    
{
    
    AVPacket input_packet;
    
    AVPacket output_packet;
    

    
    /** Write the media file container header */
    
    avformat_write_header(output_format_context, NULL);
    

    
    /** 
    
     * decode frames and encode to H264 
    
     * */
    
    while (1) { 
    
        av_init_packet(&input_packet);
    
        input_packet.data = NULL;
    
        input_packet.size = 0;
    

    
        av_init_packet(&output_packet);
    
        output_packet.data = NULL;
    
        output_packet.size = 0;
    

    
        /** Read a frame to decode */
    
        av_read_frame(input_format_context, &input_packet);         
    
        if (av_read_frame is end of file) {
    
            break;
    
        }
    
        ...
    
        ...
    

    
        /** Decoding... */
    
        avcodec_send_packet(input_codec_context, &input_packet);
    
        ...
    
        ...
    

    
        /** Get a decoded frame */
    
        avcodec_receive_frame(input_codec_context, frame);
    
        ...
    
        ...
    

    
        /** Make the frame writable, is it necessary ?? */
    
        av_frame_make_writable(frame);
    

    
        /** Encode to H264 */
    
        avcodec_send_frame(output_codec_context, frame);
    
        ...
    
        ...
    

    
        /** Get a encoded packet */
    
        avcodec_receive_packet(output_codec_context, &output_packet);
    

    
        /** 
    
         * Write the packet to output.  
    
         * Here is the point! should I configure the parameters 
    
         * in packet such as 'pts', 'dts', 'duration', etc, if so, 
    
         * hwo? or I just directly write the packet into output? 
    
         */
    
        av_interleaved_write_frame(output_format_context, &packet);                 
    
    }
    

    
    /** Write the media file container trailer */
    
    av_write_trailer(output_format_context);
    

    
}
    

    
int main() {
    
    convert_init("./sample.avi", "./output.mp4");
    
    convert_it();
    

    
}

    using VLC or QuickTime to playback the output.mp4 file, it failed, cause the file duration is zero, when dragging the time progress bar， I can see the picture frame clearly, it seems that the encoding packet buffer data is correct, but the timestamp is error, am I missing something when configure the output_stream or packet ? The following is message from ffprobe.

    ffprobe output.mp4
    
ffprobe version 3.3.3 Copyright (c) 2007-2017 the FFmpeg developers
    
  built with Apple LLVM version 8.1.0 (clang-802.0.42)
    
  configuration: --enable-shared --enable-libmp3lame
    
  libavutil      55. 58.100 / 55. 58.100
    
  libavcodec     57. 89.100 / 57. 89.100
    
  libavformat    57. 71.100 / 57. 71.100
    
  libavdevice    57.  6.100 / 57.  6.100
    
  libavfilter     6. 82.100 /  6. 82.100
    
  libswscale      4.  6.100 /  4.  6.100
    
  libswresample   2.  7.100 /  2.  7.100
    
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
    
  Metadata:
    
    major_brand     : isom
    
    minor_version   : 512
    
    compatible_brands: isomiso2avc1mp41
    
    encoder         : Lavf57.71.100
    
  Duration: 00:00:00.06, start: 0.000000, bitrate: 6902181 kb/s
    
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x408 [SAR 1:1 DAR 30:17], 13929056 kb/s, 90k fps, 90k tbr, 90k tbn, 50 tbc (default)
    
    Metadata:
    
      handler_name    : VideoHandler

  • How to make use of "&" command in TCL version 8.0 to make a proc or exec command run in background i.e in parallel on windows 7 ?

    21 novembre 2017, par M. D. P

    I am working on a project where I am using FFMPEG to capture video. The FFMPEG command is :

    ffmpeg -f dshow  -t 00:00:10 -i "video=Integrated Webcam" -b 5000k -s 1280x720 c:/test/sample.avi

    The link : https://www.tcl.tk/man/tcl8.5/tutorial/Tcl26.html make the use of the command :

    exec myprog &

    Here they have not specified what is myprog.

    The link : Running shell commands in background, in a tcl proc make the use of command :

     eval exec [linsert $args 0 exec] >> $tempFile &

    Here the command is not accepted as eval and exec is one after another, so it takes exec as a variable.

    Help me, with the write right command which can be used to capture my video in the background with TCL version 8.0 and Windows 7.

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