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• ffmpeg creating mpeg-dash chunk files too slowly resulting in 404 errors

  17 juillet 2021, par Danny

  I have a hardware encoder feeding FFmpeg to create a MPEG-DASH Low Latency stream. It works well for a while, but after letting FFmpeg run for a while and reloading the page there are many 404 errors.

  


  When that happens, the dash.js player tries to fetch the segment file on the "live edge" but the file has not been created yet by FFmpeg. For example, after running for 20-30 minutes and loading the web page player, debug code in the web server shows :

  


  2021-07-16 16:46:30.64 : GET REQUEST : /data/ott/chunk-stream0-00702.m4s
2021-07-16 16:46:30.67 : NOT FOUND. Latest files on filesystem:
    chunk-stream0-00699.m4s.tmp
    chunk-stream0-00698.m4s
    chunk-stream0-00697.m4s
    chunk-stream0-00696.m4s
    ...


  


  So you can see the browser requested chunk 702 but the latest on the server is (part of) 699. With 2 second chunks, that is 3-5 seconds of content not yet available.

  


  To analyze, I modified FFmpeg's dashenc.c to add a timestamp every time a file is opened which displays like :

  


  [dash @ 0x9b17c0] 21:48:52.935 1626443332.935  : dashenc_io_open() - opened /data/ott/chunk-stream0-00060.m4s.tmp


  


  And loaded the timestamps into Excel.

  


  Despite a segment duration of 2.000 seconds, the average time between file opens is 2.011 seconds. Over two hours this accumulated to a 45 second difference between the calculated live edge and the latest file on the server.

  


  The HW encoder is set to 25 fps and a GOP size of 5. I've confirmed both by analyzing the H.264 NALUs output by the HW encoder.

  


  My Question : Is this a bug in FFmpeg or can I avoid this problem by adjusting the settings of either the HW encoder and/or FFmpeg options ?

  


  REFERENCE

  


  FFmpeg: Version 4.4 
Centos 8 
Apache 2.4.37


  


  FFmpeg command line (pipe is fed by process reading HW encoder)

  


  ffmpeg -re -loglevel verbose -an -f h264 -i pipe:17 -c:v copy \
-f dash -dash_segment_type mp4 -b:v 1000000 -seg_duration 2.000000 \
-frag_type duration -frag_duration 0.200000 -target_latency 1 \
-window_size 10 -extra_window_size 5 -remove_at_exit 1 -streaming 1 \
-ldash 1 -use_template 1 -use_timeline 0 -write_prft 1 -avioflags direct \
-fflags +nobuffer+flush_packets -format_options movflags=+cmaf \
-utc_timing_url /web/be/time.php /data/ott/master.mpd


  


  Modified dash_io_open() from dashenc.c

  


  static int 
dashenc_io_open(AVFormatContext *s, AVIOContext **pb, char *filename, AVDictionary **options)
{
    DASHContext *c = s->priv_data;
    int http_base_proto = filename ? ff_is_http_proto(filename) : 0;
    int err = AVERROR_MUXER_NOT_FOUND;
    if (!*pb || !http_base_proto || !c->http_persistent)
    {
        err = s->io_open(s, pb, filename, AVIO_FLAG_WRITE, options);

        // My Debug
        {
            char buf[20], milli[60];
            struct timeb tp;

            ftime(&tp); // sec + ms
            struct tm *tmInfo = localtime(&tp.time);

            // 2020-05-15 21:15:12.123
            strftime(buf, sizeof(buf), "%H:%M:%S", tmInfo);
            snprintf(milli, 59, "%s.%03d %d.%03d ", buf, tp.millitm, tp.time, tp.millitm);

            av_log(s, AV_LOG_INFO, "%s : dashenc_io_open() - opened %s\n", milli, filename);
        }
    }
    return err;
}


  


• ASPSMS : a successful integration with Piwik

  3 octobre 2017, par Piwik Core Team — Development

  Have you ever wondered how an integration between a third party company and Piwik is possible ? What are the key factors for a good partnership ? This article describes our recent collaboration with a company for a mobile messaging integration.

  At Piwik, we are always looking for new functionalities to build and improve the work of our community members. ASPSMS, an innovative SMS Gateway & Messaging solutions provider got in contact with us in order to do just this.

  Why did we decide to partner with ASPSMS ?

  • Fast
  • Easy
  • Just works

  Those three words define the collaboration we had with ASPSMS and in the end everyone benefits.

  Stefan, one of our developers who did the integration into Piwik, says “Thanks to an easy to understand API the SMS integration was done in a couple of hours. We got SMS credits upfront for testing which helped a lot.”

  Using the ASPSMS integration, you can receive a daily or weekly SMS message listing the Key Performance Indicators of your website(s).

  ASPSMS is now part of Piwik through the Mobile messaging settings :

  

  As a company, how can I contribute to Piwik ?

  If, like ASPSMS, you are providing great services which can help Piwik final users take better decisions, do not hesitate to contact the Piwik core team.

  You can also start to develop your own, specific plugins, that you can freely publish on the Piwik marketplace.

  About ASPSMS

  VADIAN.NET AG is today one of the leading global providers of SMS solutions with more than 200,000 satisfied business clients. The product ASPSMS was launched in 2001. ASPSMS is a product of VADIAN.NET AG, a Swiss based Internet and Mobile Solutions provider.

  

  Learn more about ASPSMS.

• How to edit video (cut some scenes) without increasing the video's size

  18 février 2016, par 123iamking

  [Introduction]

  I have a video : Input.mp4 - length : 29 min 6 sec - size : 120 MB

  I use Microsoft Movie Maker 2012 (Movie Maker is included in the Windows Essentials 2012 program suite), to cut some boring scenes and keep the cool scenes and I get the video : Output.mp4 - length : 15 min 22 sec - size : 155 MB.

  And it’s take a long time to create the Output.mp4 and the size is ridiculously increased. I can’t use this kind of software anymore, I need to create a new software to serve my purpose.

  [Question]

  Is there anyway with C# .Net to simply cut and merge video without increasing the video’s size and have to be fast ?

  [What I have tried]

  I intend to use ffmpeg to cut the clip and merge the clip and I found something about cut video here , but the console said something about "Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future." - should I still use this ?

  Should I use ffmpeg or there’s better way to do this.