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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 ?

• H264/MP4 live stream from ffmpeg does not work in browser

  22 septembre 2018, par paunescuionica

  I cannot visualize a H264/MP4 stream generated by ffmpeg in Chrome, IE, Edge. It works only in Firefox.

  My testing environment is Windows 10, all updates done, all browsers up to date.

  I have a source MJPEG stream, which I need to transcode to H264/MP4 and show it in browser in a HTML5 element.
  In order to provide a working example, I use here this MJPEG stream : http://200.36.58.250/mjpg/video.mjpg?resolution=320x240. In my real case I have MJPEG input from different sources like IP cameras.
  I use the following command line :

  ffmpeg.exe -use_wallclock_as_timestamps 1 -f mjpeg -i "http://200.36.58.250/mjpg/video.mjpg?resolution=320x240" -f mp4 -c:v libx264 -an -preset ultrafast -tune zerolatency -movflags frag_keyframe+empty_moov+faststart -reset_timestamps 1 -vsync 1 -flags global_header -r 15 "tcp ://127.0.0.1:5000 ?listen"

  If I try to visualize the output in VLC, I use this link : tcp ://127.0.0.1:5000 and it works.
  Then I try to visualize the stream in browser, so I put this into a html document :

  <video autoplay="autoplay" controls="controls">
  
  <source src="http://127.0.0.1:5000" type="video/mp4">
  
  </source></video>

  If I open the document in Firefox it works just fine.
  But it does not work when trying to open in Chrome, IE or Edge. It seems that the browser tries to connect to the TCP server exposed by ffmpeg, but something happens because ffmpeg exits after few seconds.

  In ffmpeg console I can see this :

  av_interleaved_write_frame(): Unknown error
  
  Error writing trailer of tcp://127.0.0.1:5000?listen: Error number -10053 occurred

  If I inspect the video element in Chrome is can see this error :

  Failed to load resource: net::ERR_INVALID_HTTP_RESPONSE

  As far as I know all these browsers should support H264 encoded streams transported in MP4 containers. If in the element I replace the link http://127.0.0.1:5000 with a local link to a mp4/H264 encoded file, it is played just fine in each browser. The problem seems to be related to live streaming.

  Does anyone know why this happens and how it can be solved ?

  Thank you !

• Stream real-time video flux in HTML video tag

  26 septembre 2018, par c.censier

  I want to stream a real-time video flux that come from udp into a HTML video tag.
  I made some research but I got a lot of informations and I struggle to have a clear overview of what I can do and what I can’t.

  The video flux use H.264 and AAC codecs, MP4 container and has a 3840x2160 (4K) resolution. I’d like to play it on Chrome (latest version).

  As I understand from now, HTML video tag can natively read H.264/AAC videos. I made it work with the video direclty on my server (I’m using Meteor JS + React).

  I learnt to use FFmpeg to stream an udp flux read by VLC player, and then I used FFserver (I know it’s deprecated) to create an HTTP flux also read by VLC but not by the HTML video tag.

  So... my question is : is HTML video can natively read video stream from HTTP ?

  I’ve seen a lot of discussions about HLS and DASH, but I didn’t understand if (and why) they’re mandatory.

  I read a post about someone creating a HLS m3u8 using only FFmpeg, is it a viable solution ?

  FFserver configuration

  HTTPPort                        8090
  
  HTTPBindAddress                 0.0.0.0
  
  MaxHTTPConnections              20
  
  MaxClients                      10
  
  MaxBandwidth                    100000
  
  
  
  <feed>
  
    File                          /tmp/feed.ffm
  
    FileMaxSize                   1g
  
    ACL allow                     127.0.0.1
  
  </feed>
  
  
  
  <stream>
  
    Feed                          feed.ffm
  
    Format                        mpeg
  
    AudioCodec                    aac
  
    AudioBitRate                  256
  
    AudioChannels                 1
  
    VideoCodec                    libx264
  
    VideoBitRate                  10000      // Total random here
  
    VideoBitRateRange             5000-15000 // And here...
  
    VideoFrameRate                30
  
    VideoQMin                     1
  
    VideoQMax                     50
  
    VideoSize                     3840x2160
  
    VideoBufferSize               20000      // Not sure either
  
    AVOptionVideo                 flags +global_header
  
  </stream>

  I had to specify QMin and QMax to avoid error message but I don’t really understand what is it.

  FFmpeg command line

  ffmpeg -re -i bbb_sunflower_2160p_30fps_normal.mp4 -strict -2 -r 30 -vcodec libx264 http://localhost:8090/feed.ffm

  This work with VLC. I’m working with a file on my computer before moving to an udp stream.