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  • Configuration spécifique pour PHP5

    4 février 2011, par

    PHP5 est obligatoire, vous pouvez l’installer en suivant ce tutoriel spécifique.
    Il est recommandé dans un premier temps de désactiver le safe_mode, cependant, s’il est correctement configuré et que les binaires nécessaires sont accessibles, MediaSPIP devrait fonctionner correctement avec le safe_mode activé.
    Modules spécifiques
    Il est nécessaire d’installer certains modules PHP spécifiques, via le gestionnaire de paquet de votre distribution ou manuellement : php5-mysql pour la connectivité avec la (...)

  • Publier sur MédiaSpip

    13 juin 2013

    Puis-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

  • Submit bugs and patches

    13 avril 2011

    Unfortunately a software is never perfect.
    If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
    If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
    You may also (...)

Sur d’autres sites (10656)

  • Modifying FFmpeg and OpenCV source code to capture the RTP timestamp for each packet in NTP format

    22 août 2019, par Fr0sty

    I was trying a little experiment in order to get the timestamps of the RTP packets using the VideoCapture class from Opencv’s source code in python, also had to modify FFmpeg to accommodate the changes in Opencv.

    Since I read about the RTP packet format.Wanted to fiddle around and see if I could manage to find a way to get the NTP timestamps. Was unable to find any reliable help in trying to get RTP timestamps. So tried out this little hack.

    Credits to ryantheseer on github for the modified code.

    Version of FFmpeg : 3.2.3
    Version of Opencv : 3.2.0

    In Opencv source code :

    modules/videoio/include/opencv2/videoio.hpp :

    Added two getters for the RTP timestamp :

    .....   
    
    /** @brief Gets the upper bytes of the RTP time stamp in NTP format (seconds).
    
    */
    
    CV_WRAP virtual int64 getRTPTimeStampSeconds() const;
    

    
    /** @brief Gets the lower bytes of the RTP time stamp in NTP format (fraction of seconds).
    
    */
    
    CV_WRAP virtual int64 getRTPTimeStampFraction() const;
    
.....

    modules/videoio/src/cap.cpp :

    Added an import and added the implementation of the timestamp getter :

    ....
    
#include <cstdint>
    
....
    
....
    
static inline uint64_t icvGetRTPTimeStamp(const CvCapture* capture)
    
{
    
  return capture ? capture->getRTPTimeStamp() : 0;
    
}
    
...
    
</cstdint>

    Added the C++ timestamp getters in the VideoCapture class :

     ....
    
/**@brief Gets the upper bytes of the RTP time stamp in NTP format (seconds).
    
*/
    
int64 VideoCapture::getRTPTimeStampSeconds() const
    
{
    
    int64 seconds = 0;
    
    uint64_t timestamp = 0;
    
    //Get the time stamp from the capture object
    
    if (!icap.empty())
    
        timestamp = icap->getRTPTimeStamp();
    
    else
    
        timestamp = icvGetRTPTimeStamp(cap);
    
    //Take the top 32 bytes of the time stamp
    
    seconds = (int64)((timestamp &amp; 0xFFFFFFFF00000000) / 0x100000000);
    
    return seconds;
    
}
    

    
/**@brief Gets the lower bytes of the RTP time stamp in NTP format (seconds).
    
*/
    
int64 VideoCapture::getRTPTimeStampFraction() const
    
{
    
    int64 fraction = 0;
    
    uint64_t timestamp = 0;
    
    //Get the time stamp from the capture object
    
    if (!icap.empty())
    
        timestamp = icap->getRTPTimeStamp();
    
    else
    
        timestamp = icvGetRTPTimeStamp(cap);
    
    //Take the bottom 32 bytes of the time stamp
    
    fraction = (int64)((timestamp &amp; 0xFFFFFFFF));
    
    return fraction;
    
}
    
...

    modules/videoio/src/cap_ffmpeg.cpp :

    Added an import :

    ...
    
#include <cstdint>
    
...
    
</cstdint>

    Added a method reference definition :

    ...
    
static CvGetRTPTimeStamp_Plugin icvGetRTPTimeStamp_FFMPEG_p = 0;
    
...

    Added the method to the module initializer method :

    ...
    
if( icvFFOpenCV )
    
...
    
...
    
  icvGetRTPTimeStamp_FFMPEG_p =
    
                (CvGetRTPTimeStamp_Plugin)GetProcAddress(icvFFOpenCV, "cvGetRTPTimeStamp_FFMPEG");
    
...
    
...
    
icvWriteFrame_FFMPEG_p != 0 &amp;&amp;
    
icvGetRTPTimeStamp_FFMPEG_p !=0)
    
...
    

    
icvGetRTPTimeStamp_FFMPEG_p = (CvGetRTPTimeStamp_Plugin)cvGetRTPTimeStamp_FFMPEG;

    Implemented the getter interface :

    ...
    
virtual uint64_t getRTPTimeStamp() const
    
    {
    
        return ffmpegCapture ? icvGetRTPTimeStamp_FFMPEG_p(ffmpegCapture) : 0;
    
    } 
    
...

    In FFmpeg’s source code :

    libavcodec/avcodec.h :

    Added the NTP timestamp definition to the AVPacket struct :

    typedef struct AVPacket {
    
...
    
...
    
uint64_t rtp_ntp_time_stamp;
    
}

    libavformat/rtpdec.c :

    Store the ntp time stamp in the struct in the finalize_packet method :

    static void finalize_packet(RTPDemuxContext *s, AVPacket *pkt, uint32_t timestamp)
    
{
    
    uint64_t offsetTime = 0;
    
    uint64_t rtp_ntp_time_stamp = timestamp;
    
...
    
...
    
/*RM: Sets the RTP time stamp in the AVPacket */
    
    if (!s->last_rtcp_ntp_time || !s->last_rtcp_timestamp)
    
        offsetTime = 0;
    
    else
    
        offsetTime = s->last_rtcp_ntp_time - ((uint64_t)(s->last_rtcp_timestamp) * 65536);
    
    rtp_ntp_time_stamp = ((uint64_t)(timestamp) * 65536) + offsetTime;
    
    pkt->rtp_ntp_time_stamp = rtp_ntp_time_stamp;

    libavformat/utils.c :

    Copy the ntp time stamp from the packet to the frame in the read_frame_internal method :

    static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
    
{
    
    ...
    
    uint64_t rtp_ntp_time_stamp = 0;
    
...
    
    while (!got_packet &amp;&amp; !s->internal->parse_queue) {
    
          ...
    
          //COPY OVER the RTP time stamp TODO: just create a local copy
    
          rtp_ntp_time_stamp = cur_pkt.rtp_ntp_time_stamp;
    

    

    
          ...
    

    

    
  #if FF_API_LAVF_AVCTX
    
    update_stream_avctx(s);
    
  #endif
    

    
  if (s->debug &amp; FF_FDEBUG_TS)
    
      av_log(s, AV_LOG_DEBUG,
    
           "read_frame_internal stream=%d, pts=%s, dts=%s, "
    
           "size=%d, duration=%"PRId64", flags=%d\n",
    
           pkt->stream_index,
    
           av_ts2str(pkt->pts),
    
           av_ts2str(pkt->dts),
    
           pkt->size, pkt->duration, pkt->flags);
    
pkt->rtp_ntp_time_stamp = rtp_ntp_time_stamp; #Just added this line in the if statement.
    
return ret;

    My python code to utilise these changes :

    import cv2
    

    
uri = 'rtsp://admin:password@192.168.1.67:554'
    
cap = cv2.VideoCapture(uri)
    

    
while True:
    
    frame_exists, curr_frame = cap.read()
    
    # if frame_exists:
    
    k = cap.getRTPTimeStampSeconds()
    
    l = cap.getRTPTimeStampFraction()
    
    time_shift = 0x100000000
    
    #because in the getRTPTimeStampSeconds() 
    
    #function, seconds was multiplied by 0x10000000 
    
    seconds = time_shift * k
    
    m = (time_shift * k) + l
    
    print("Imagetimestamp: %i" % m)
    
cap.release()

    What I am getting as my output :

        Imagetimestamp: 0
    
    Imagetimestamp: 212041451700224
    
    Imagetimestamp: 212041687629824
    
    Imagetimestamp: 212041923559424
    
    Imagetimestamp: 212042159489024
    
    Imagetimestamp: 212042395418624
    
    Imagetimestamp: 212042631348224
    
    ...

    What astounded me the most was that when i powered off the ip camera and powered it back on, timestamp would start from 0 then quickly increments. I read NTP time format is relative to January 1, 1900 00:00. Even when I tried calculating the offset, and accounting between now and 01-01-1900, I still ended up getting a crazy high number for the date.

    Don’t know if I calculated it wrong. I have a feeling it’s very off or what I am getting is not the timestamp.

  • My first released WordPress plugin

    23 septembre 2010, par silvia

    I’m pretty proud of this, which is why I’m dedicating a short blog post to it : today, John and I released my first WordPress plugin as open source to the WordPress plugins site. It’s got the boring name “External Videos” and builds a bridge between your WordPress instance and videos of channels on a (...)

  • Capturing RTP Timestamps

    10 septembre 2019, par m00ncake

    I was trying a little experiment in order to get the timestamps of the RTP packets using the VideoCapture class from Opencv’s source code in python, also had to modify FFmpeg to accommodate the changes in Opencv.

    Since I read about the RTP packet format.Wanted to fiddle around and see if I could manage to find a way to get the NTP timestamps. Was unable to find any reliable help in trying to get RTP timestamps. So tried out this little hack.

    Credits to ryantheseer on github for the modified code.

    Version of FFmpeg : 3.2.3
    Version of Opencv : 3.2.0

    In Opencv source code :

    modules/videoio/include/opencv2/videoio.hpp :

    Added two getters for the RTP timestamp :

    .....   
    
    /** @brief Gets the upper bytes of the RTP time stamp in NTP format (seconds).
    
    */
    
    CV_WRAP virtual int64 getRTPTimeStampSeconds() const;
    

    
    /** @brief Gets the lower bytes of the RTP time stamp in NTP format (fraction of seconds).
    
    */
    
    CV_WRAP virtual int64 getRTPTimeStampFraction() const;
    
.....

    modules/videoio/src/cap.cpp :

    Added an import and added the implementation of the timestamp getter :

    ....
    
#include <cstdint>
    
....
    
....
    
static inline uint64_t icvGetRTPTimeStamp(const CvCapture* capture)
    
{
    
  return capture ? capture->getRTPTimeStamp() : 0;
    
}
    
...
    
</cstdint>

    Added the C++ timestamp getters in the VideoCapture class :

     ....
    
/**@brief Gets the upper bytes of the RTP time stamp in NTP format (seconds).
    
*/
    
int64 VideoCapture::getRTPTimeStampSeconds() const
    
{
    
    int64 seconds = 0;
    
    uint64_t timestamp = 0;
    
    //Get the time stamp from the capture object
    
    if (!icap.empty())
    
        timestamp = icap->getRTPTimeStamp();
    
    else
    
        timestamp = icvGetRTPTimeStamp(cap);
    
    //Take the top 32 bytes of the time stamp
    
    seconds = (int64)((timestamp &amp; 0xFFFFFFFF00000000) / 0x100000000);
    
    return seconds;
    
}
    

    
/**@brief Gets the lower bytes of the RTP time stamp in NTP format (seconds).
    
*/
    
int64 VideoCapture::getRTPTimeStampFraction() const
    
{
    
    int64 fraction = 0;
    
    uint64_t timestamp = 0;
    
    //Get the time stamp from the capture object
    
    if (!icap.empty())
    
        timestamp = icap->getRTPTimeStamp();
    
    else
    
        timestamp = icvGetRTPTimeStamp(cap);
    
    //Take the bottom 32 bytes of the time stamp
    
    fraction = (int64)((timestamp &amp; 0xFFFFFFFF));
    
    return fraction;
    
}
    
...

    modules/videoio/src/cap_ffmpeg.cpp :

    Added an import :

    ...
    
#include <cstdint>
    
...
    
</cstdint>

    Added a method reference definition :

    ...
    
static CvGetRTPTimeStamp_Plugin icvGetRTPTimeStamp_FFMPEG_p = 0;
    
...

    Added the method to the module initializer method :

    ...
    
if( icvFFOpenCV )
    
...
    
...
    
  icvGetRTPTimeStamp_FFMPEG_p =
    
                (CvGetRTPTimeStamp_Plugin)GetProcAddress(icvFFOpenCV, "cvGetRTPTimeStamp_FFMPEG");
    
...
    
...
    
icvWriteFrame_FFMPEG_p != 0 &amp;&amp;
    
icvGetRTPTimeStamp_FFMPEG_p !=0)
    
...
    

    
icvGetRTPTimeStamp_FFMPEG_p = (CvGetRTPTimeStamp_Plugin)cvGetRTPTimeStamp_FFMPEG;

    Implemented the getter interface :

    ...
    
virtual uint64_t getRTPTimeStamp() const
    
    {
    
        return ffmpegCapture ? icvGetRTPTimeStamp_FFMPEG_p(ffmpegCapture) : 0;
    
    } 
    
...

    In FFmpeg’s source code :

    libavcodec/avcodec.h :

    Added the NTP timestamp definition to the AVPacket struct :

    typedef struct AVPacket {
    
...
    
...
    
uint64_t rtp_ntp_time_stamp;
    
}

    libavformat/rtpdec.c :

    Store the ntp time stamp in the struct in the finalize_packet method :

    static void finalize_packet(RTPDemuxContext *s, AVPacket *pkt, uint32_t timestamp)
    
{
    
    uint64_t offsetTime = 0;
    
    uint64_t rtp_ntp_time_stamp = timestamp;
    
...
    
...
    
/*RM: Sets the RTP time stamp in the AVPacket */
    
    if (!s->last_rtcp_ntp_time || !s->last_rtcp_timestamp)
    
        offsetTime = 0;
    
    else
    
        offsetTime = s->last_rtcp_ntp_time - ((uint64_t)(s->last_rtcp_timestamp) * 65536);
    
    rtp_ntp_time_stamp = ((uint64_t)(timestamp) * 65536) + offsetTime;
    
    pkt->rtp_ntp_time_stamp = rtp_ntp_time_stamp;

    libavformat/utils.c :

    Copy the ntp time stamp from the packet to the frame in the read_frame_internal method :

    static int read_frame_internal(AVFormatContext *s, AVPacket *pkt)
    
{
    
    ...
    
    uint64_t rtp_ntp_time_stamp = 0;
    
...
    
    while (!got_packet &amp;&amp; !s->internal->parse_queue) {
    
          ...
    
          //COPY OVER the RTP time stamp TODO: just create a local copy
    
          rtp_ntp_time_stamp = cur_pkt.rtp_ntp_time_stamp;
    

    

    
          ...
    

    

    
  #if FF_API_LAVF_AVCTX
    
    update_stream_avctx(s);
    
  #endif
    

    
  if (s->debug &amp; FF_FDEBUG_TS)
    
      av_log(s, AV_LOG_DEBUG,
    
           "read_frame_internal stream=%d, pts=%s, dts=%s, "
    
           "size=%d, duration=%"PRId64", flags=%d\n",
    
           pkt->stream_index,
    
           av_ts2str(pkt->pts),
    
           av_ts2str(pkt->dts),
    
           pkt->size, pkt->duration, pkt->flags);
    
pkt->rtp_ntp_time_stamp = rtp_ntp_time_stamp; #Just added this line in the if statement.
    
return ret;

    My python code to utilise these changes :

    import cv2
    

    
uri = 'rtsp://admin:password@192.168.1.67:554'
    
cap = cv2.VideoCapture(uri)
    

    
while True:
    
    frame_exists, curr_frame = cap.read()
    
    # if frame_exists:
    
    k = cap.getRTPTimeStampSeconds()
    
    l = cap.getRTPTimeStampFraction()
    
    time_shift = 0x100000000
    
    #because in the getRTPTimeStampSeconds() 
    
    #function, seconds was multiplied by 0x10000000 
    
    seconds = time_shift * k
    
    m = (time_shift * k) + l
    
    print("Imagetimestamp: %i" % m)
    
cap.release()

    What I am getting as my output :

        Imagetimestamp: 0
    
    Imagetimestamp: 212041451700224
    
    Imagetimestamp: 212041687629824
    
    Imagetimestamp: 212041923559424
    
    Imagetimestamp: 212042159489024
    
    Imagetimestamp: 212042395418624
    
    Imagetimestamp: 212042631348224
    
    ...

    What astounded me the most was that when i powered off the ip camera and powered it back on, timestamp would start from 0 then quickly increments. I read NTP time format is relative to January 1, 1900 00:00. Even when I tried calculating the offset, and accounting between now and 01-01-1900, I still ended up getting a crazy high number for the date.

    Don’t know if I calculated it wrong. I have a feeling it’s very off or what I am getting is not the timestamp.

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