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Alessio
2013-03-26
2014-03-17
  • Alessio

    Alessio - 2013-03-26

    Hi,
    I  m using gpac tool to create dash content. The version that i installed is the 0.5.0, the last one that is stable. When i run the command mp4box -dash 10000 -rap -segment-name seg_%s -out test.mpd input1.mp4 input2.mp4 … InputN.mp4 where the input files are coded as h264 mp4 with different bit rates and resolutions, the final mpd is correct with the standard mpeg-dash and osmo4 runs correctly if the content is stored in local. When the content is stored in a server the video doesn t work correctly, the images are often blocked and the quality is bad. Do you know why? and how do the input files have to be coded?( the network is not congestioned and the bandwidth is conpletly available).
    Thanks
    Alessio

     
  • Milos

    Milos - 2013-03-26

    Hi,
    I have similar problem. In my case that happened couse video GOP was higher then segment length so player didnt have I frame for reference when changing to different representation, or use last one with different resolution. Try alignment of video gop and dash duration, it solved problem for me.

     
  • Satti

    Satti - 2014-03-17

    Hi, when i create dash representations using different resolutions, it recognizes them as separate adaptation sets in the mpd file, and there are multiple initialization files. Can anyone tell me why it is so? I made sure that the IDR frames in input mp4 files are happening at the same instants.

    S

     
  • Romain Bouqueau

    Romain Bouqueau - 2014-03-17

    Can you give more info? GPAC version, MP4Box command-line, output, etc.

    there are multiple initialization files. Can anyone tell me why it is so?

    Look at the '-bs-switching' option.

     
  • Satti

    Satti - 2014-03-17

    Thanks for a quick reply Romain

    The GPAC version is
    MP4Box - GPAC version 0.5.1-DEV-rev5158
    GPAC Copyright (c) Telecom ParisTech 2000-2012
    GPAC Configuration: (static configuration file)
    Features: GPAC_HAS_SSL GPAC_HAS_SPIDERMONKEY GPAC_HAS_JPEG GPAC_HAS_PNG

    I am using the command line

    mp4box -dash 2000 -frag 2000 -rap -segment-name seg_%s -bs-switching yes -out AV.mp4 AV1.mp4 AV2.mp4

    The output I get is
    DASH-ing files: 2.00s segments 2.00s fragments single sidx per segment
    Spliting segments at GOP boundaries
    [DASH] Generating MPD at time 2014-03-17T15:26:37Z
    DASHing file AV1.mp4
    DASHing file AV2.mp4

    The resulting mpd file is attached

     

    Last edit: Satti 2014-03-17
  • Satti

    Satti - 2014-03-17

    Hi Romain,

    I figured it out I think, the reason is that I was coding resolutions with different aspect ratios. Once I switched to the same aspect ratio resolutions, it yields different representations in a single adaptation set. logical, great.

    regards

    S