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• H264/MP4 live stream from ffmpeg gets delayed

  1er octobre 2018, par paunescuionica

  I’m transcoding a MJPEG stream to H264/MP4 using ffmpeg. As client I’m using VLC.

  I use this command line :

  ffmpeg \
  
    -use_wallclock_as_timestamps 1 \
  
    -f mjpeg \
  
    -i "http://127.0.0.1:4100/getMjpegStream=L" \
  
    -f mp4 \
  
    -vcodec libx264 \
  
    -movflags frag_keyframe+empty_moov+faststart \
  
    -tune zerolatency \
  
    -crf 30 \
  
    -preset ultrafast \
  
    -g 1 \
  
    -reset_timestamps 1 \
  
    -vsync 1 \
  
    -flags global_header \
  
    -r 15 \
  
    -listen 1 \
  
    -fflags flush_packets \
  
    -avioflags direct \
  
    -flush_packets 1 \
  
    *output_URL*

  If I set the output_URL to this :

  udp://127.0.0.1:5000?pkt_size=1316

  it works just fine. I start ffmpeg, then after some time I start VLC with this URL udp://@127.0.0.1:5000, and it plays (almost) real time. The delay is 1-2 seconds, which is acceptable. And this delay is constant, it does not depend on when I start VLC. I can stop and reopen VLC and it keeps going realtime.

  But I need this stream to also be viewed in browser (in a HTML5 video), so I normally use this for output_URL :

  http://127.0.0.1:5000

  In VLC I use this URL http://127.0.0.1:5000 and it also works fine, but only if I start VLC immediately after I start ffmpeg. If there is a significant delay between the start of ffmpeg and the start of VLC, then that delay will be noticeable in the playback. Let’s say that I start ffmpeg at time T then after 10 seconds (at T+10) I start VLC. I have this behavior in VLC :

  • It starts, and it displays the frame at time T and then the stream freezes
  • After 10 seconds, the streaming resumes in VLC and it starts playing, but the image is 10 second behind ‘realtime’
  • This delays is constant, it does not recover from it

  Is there a way to solve this ?

  • Instruct ffmpeg to start transcoding only when the client connects ?
  • Instruct ffmpeg to not buffer transcoded stream until the client connects ? (with current command line, it clearly buffers because when VLC starts at T+10, the first frame displayed is from time T) ?

  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.

• 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 !