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• How to make a MPEG-DASH MPD which starts the playback in the middle of the first segment ?

  18 septembre 2018, par ravin.wang

  Here are the reproduce steps :

  1. Normalize an H.264 video stream

     ffmpeg -i 2.h264 -c:v libx264 -intra -r 25 -vf scale=640x360,setdar=16:9 2@25fps@intra@640x360.h264

     (*) After that, I got an H.264 stream where all pictures are H.264 IDR frames, and fps is 25, resolution is 640x360, aspect-ratio is 16:9.

  2. Generate an MP4 file

     MP4Box -add 2@25fps@intra@640x360.h264:timescale=1000 -fps 25 2@25fps@intra@640x360.mp4

  3. Make dash MP4 fragmented content, including init mp4, .m4s files and one .mpd file

     MP4Box -dash 5000 -frag 5000 -dash-scale 1000 -frag-rap -segment-name ’seg_second$Number$’ -segment-timeline -profile live 2@25fps@intra@640x360.mp4

  4. Copy and publish all these files to a folder under one HTTPD server

  5. I want to play from 4s of the first segment, and don’t display any frames before 4s, so I changed the .MPD file to modify the fields "SegmentTemplate@presentationTimeOffset", "SegmentTimeline:S@d/t", like as :
     

     <?xml version="1.0"?>
<mpd xmlns="urn:mpeg:dash:schema:mpd:2011" minbuffertime="PT1.500S" type="static" mediapresentationduration="PT0H0M26.000S" maxsegmentduration="PT0H0M5.000S" profiles="urn:mpeg:dash:profile:isoff-live:2011">
<period duration="PT0H0M26.000S">
<adaptationset segmentalignment="true" maxwidth="640" maxheight="360" maxframerate="25" par="16:9" lang="und">
 <segmenttemplate presentationtimeoffset="4000" media="seg_second$Number$.m4s" timescale="1000" startnumber="1" initialization="seg_secondinit.mp4">
   <segmenttimeline>
       <s d="1000" t="4000"></s>
       <s d="5000" r="4"></s>
   </segmenttimeline>
  </segmenttemplate>
<representation mimetype="video/mp4" codecs="avc3.64101E" width="640" height="360" framerate="25" sar="1:1" startwithsap="1" bandwidth="2261831">
</representation>
</adaptationset>
</period>
</mpd>

     
     

  6. Play the MPD url from VLC player, or Edge browser, it always starts the the first frame of the first segment, the frames between 0s 4s are also displayed unexpectedly.

  What’s wrong with my steps ? Or any other options for it ?

• ultimate video player not working with one video (Uncaught in promise)

  29 octobre 2018, par completeidiothereDoh

  So I have a small website that I have yet to launch using PHP / MySQL. One section there is a video player, and I am using the Ultimate video player script beecause it easily allowed me to change some codes to insert ads, etc. So far I’ve only added about 20 videos, mostly downloaded from archive.org. The uploads are processed using FFMPEG, specifically this command :
  exec(’ffmpeg -i ’.$uploadfile.’ -f mp4 ’.$new_flv) ;

  I also do some other things with ffmpeg such as create an animated .gif and a video thumbnail. So far everything has worked. Prior to using the current video script I was using video.js and this issue didn’t happen. Once I switched over to the new script I noticed this one video won’t play. It acts like it wants to play (spinner spins for a few seconds) but ultimately goes back to the pre-play video thumbnail rather than playing the video.

  I am experiencing this in Google Chrome, though the same thing using Edge. The Chrome console messages reads as follows : Uncaught (in promise) DOMException : The play() request was interrupted by a call to pause().

  The video worked prior to switching to this video player. The file also works attempting to open in Windows. The file works opening directly in Chrome. Plus all other videos work except for this one. I contacted the author and was told that it sounds like an encoding issue and that he isn’t very good at that sort of thing.

  I won’t post the paid script’s js source file here, but I guess I am wondering if anything I’ve listed points to maybe he is correct (although then why did it work in video.js and not uvp ?) and my rudimentary ffmpeg mp4 conversion command needs some work, or else perhaps some of the research I’ve done on this google chrome console message can fix the issue. I don’t believe I can make the corrections myself but I’m curious if anyone suspects this is really an encoding issue.

  I’ve only managed to add about 20 videos, so so far 1/20, or 5% videos aren’t working. I am worried that ignoring a video that isn’t working now, once there are thousands of videos, then maybe 100 won’t work, etc. Furthermore, although probably mostly SERPS (since I haven’t technically launched yet), the video in question has the most views haha. So if it is attracting more organic traffic than the other videos I would obviously like to have it working again.

  I may need to move back to video.js, but the reason I switched was I was having a difficult time (not being an excellent coder) attempting to implement an ads system. Oh well, thanks if anyone has any suggestions or ideas.

• dxva2_h264 : add a workaround for old Intel GPUs

  22 avril 2014, par Hendrik Leppkes

  dxva2_h264 : add a workaround for old Intel GPUs
  Old Intel GPUs expect the reference frame index to the actual surface,
  
  instead of the index into RefFrameList as specified by the spec.
  This workaround should be set when using one of the "ClearVideo" decoder
  
  devices.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] doc/APIchanges
  • [DBH] libavcodec/dxva2.h
  • [DBH] libavcodec/dxva2_h264.c
  • [DBH] libavcodec/version.h