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• FFMPEG - VP9 - Fail to create DASH manifest file

  18 mars 2019, par Lev Bein

  Can’t create manifest.mpd file with FFMPEG.

  It writes :

  Stream mapping:
  
  Stream #0:0 -> #0:0 (copy)
  
  Stream #1:0 -> #0:1 (copy)
  
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid data found when processing input

  My code to generate manifest is :

  ffmpeg \
  
      -f webm_dash_manifest -live 1 -i video720.hdr \
  
      -f webm_dash_manifest -live 1 -i audio128.hdr \
  
      -map 0 -map 1 -c copy \
  
      -f webm_dash_manifest -y -live 1 -adaptation_sets "id=0,streams=0 id=1,streams=1" \
  
          -chunk_start_index 1 -chunk_duration_ms 2000 -time_shift_buffer_depth 7200 -minimum_update_period 7200 manifest.mpd

• FFMPEG/DASH-LL creates audio and video chunks at different rates ; player is confused (404 errors)

  26 mai 2021, par Danny

  I'm trying to create a MPEG-DASH "live" stream from a static file to test various low latency modes. The DASH muxer in FFmpeg creates two AdaptationSets, one for video chunks and one for audio chunks.

  


  However, the audio and video chunk files are not created at the same rate (should they be ?). ie, here stream0 are the video chunks and stream1 are the audio chunks. After a few seconds of running, the webroot directory contains :

  


  chunk-stream0-00001.m4s  chunk-stream1-00001.m4s  
chunk-stream0-00002.m4s  chunk-stream1-00002.m4s  
chunk-stream0-00003.m4s  chunk-stream1-00003.m4s  
chunk-stream0-00004.m4s  chunk-stream1-00004.m4s  
                         chunk-stream1-00005.m4s  
                         chunk-stream1-00006.m4s  
                         chunk-stream1-00007.m4s  
                         chunk-stream1-00008.m4s  
                         chunk-stream1-00009.m4s  
master.mpd  
init-stream0.m4s  
init-stream1.m4s  


  


  The stream doesn't load (or play) on either dash.js or shaka-player and there are lots of 404 (Not Found) errors for the video chunks. The player is requesting chunks from both stream0 and stream1 in sequence, ie, stream0-001 + stream1-001, then stream0-002 + stream1-002 and so on.

  


  But since stream0 only goes from 001 to 004, there are lots of 404 errors as it tries to load stream0-005 through 009.

  


  The gap gets wider after letting FFmpeg run for a while. eg, stream0 is 62 to 75 but stream1 is 174 to 187. Reloading the player page at this point fails with dash.all.debug.js:15615 [2055][FragmentController] No video bytes to push or stream is inactive. and shows 404 errors stream0 chunk 188 (which doesn't exist yet !)

  


  

  


  The FFmpeg command was adopted from DASH streaming from the top-down :

  


  ffmpeg -re -i /mnt/swdevel/TestStreams/H264/ThreeHourMovie.mp4 \
-c:v libx264 -x264-params keyint=120:scenecut=0 -b:v 1M -c:a copy \
-f dash -dash_segment_type mp4 \
 -seg_duration 2 \
 -target_latency 3 \
 -frag_type duration \
 -frag_duration 0.2 \
 -window_size 10 \
 -extra_window_size 3 \
 -streaming 1 \
 -ldash 1 \
 -use_template 1 \
 -use_timeline 0 \
 -write_prft 1 \
 -fflags +nobuffer+flush_packets \
 -format_options "movflags=+cmaf" \
 -utc_timing_url "/pelican/testPlayers/time.php" \
 master.mpd


  


  And the dash.js player code is very simple :

  


  const srcUrl = "../ottWebRoot/playerTest/master.mpd"; 

var player = dashjs.MediaPlayer().create();

let autoPlay = false;
player.initialize(document.querySelector("#videoTagId"), srcUrl, autoPlay);

player.updateSettings(
{
    streaming :
    {
        lowLatencyEnabled : true,
        liveDelay : 2,
        jumpGaps : true,
        jumpLargeGaps : true,
        smallGapLimit : 1.5,
    }
});


  


  To provide the UTCTiming element in the manifest, the small time.php URL returns a UTC time from the web server :

  


  <?php
    print gmdate("Y-m-d\TH:i:s\Z");
?>


  


  (It also shows 404 errors for the latest stream1/audio chunk, that's likely a different problem)

  


  I'm not sure what to try next. Any and suggestions greatly appreciated.

  


  EDIT I

  


  The suggestion by @Anonymous Coward to change the key interval improved things a lot. The chunks for stream0 and stream1 are in lock-step and have identical sequence numbers.

  


  However, there are still many 404 errors, both on initial page load (without pressing play) and during playback.

  


  I ran watch -n 1 ls -lt code> and compared side-by-side to the errors in the browser console.  It&#x27;s hard to compare but it <em>looks</em> like the browser is trying to fetch files "on the play edge" which haven&#x27;t yet been created by FFmpeg.  See the pic below.

  


  How do I instruct the browser to wait just a bit more before fetching the edge chunks ?

  


  

  


  EDIT II

  


  Using shaka-player instead of dash.js plays properly without 404 errors. Configured as :

  


      player.configure(
    {
        streaming: 
        {
            lowLatencyMode: true,
            inaccurateManifestTolerance: 0,
            rebufferingGoal: 0.1,
        }
        
    });


  


  Client

  


  

  • MacOS 10.12

  


  • dash.js latest 3.2.2

  


  • Chrome 79, Safari 12, FireFox v ?

  


  


  Server

  


  

  • Apache 2.4.37

  


  • PHP 7.2.4 (for time function only)

  


  • Centos 8

  


  


  (For reference, here is the mpd file generated by FFmpeg)

  


  &lt;?xml version="1.0" encoding="utf-8"?>&#xA;<mpd xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" type="dynamic" minimumupdateperiod="PT500S" availabilitystarttime="2021-05-24T14:50:00.263Z" publishtime="2021-05-24T15:22:45.335Z" timeshiftbufferdepth="PT50.0S" maxsegmentduration="PT2.0S" minbuffertime="PT5.0S">&#xA;    <programinformation>&#xA;    </programinformation>&#xA;    <servicedescription>&#xA;        <latency target="3000" referenceid="0"></latency>&#xA;    </servicedescription>&#xA;    <period start="PT0.0S">&#xA;        <adaptationset contenttype="video" startwithsap="1" segmentalignment="true" bitstreamswitching="true" framerate="24/1" maxwidth="1280" maxheight="682" par="15:8" lang="und">&#xA;            <resync dt="200000" type="0"></resync>&#xA;            <representation mimetype="video/mp4" codecs="avc1.64081f" bandwidth="1000000" width="1280" height="682" sar="1023:1024">&#xA;                <producerreferencetime inband="true" type="captured" wallclocktime="2021-05-24T14:50:00.263Z" presentationtime="0">&#xA;                    <utctiming schemeiduri="urn:mpeg:dash:utc:http-xsdate:2014" value="/pelican/testPlayers/time.php"></utctiming>&#xA;                </producerreferencetime>&#xA;                <resync dt="5000000" type="1"></resync>&#xA;                <segmenttemplate timescale="1000000" duration="2000000" availabilitytimeoffset="1.800" availabilitytimecomplete="false" initialization="init-stream$RepresentationID$.m4s" media="chunk-stream$RepresentationID$-$Number%05d$.m4s" startnumber="1">&#xA;                </segmenttemplate>&#xA;            </representation>&#xA;        </adaptationset>&#xA;        <adaptationset contenttype="audio" startwithsap="1" segmentalignment="true" bitstreamswitching="true" lang="und">&#xA;            <resync dt="200000" type="0"></resync>&#xA;            <representation mimetype="audio/mp4" codecs="mp4a.40.2" bandwidth="116317" audiosamplingrate="48000">&#xA;                <audiochannelconfiguration schemeiduri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"></audiochannelconfiguration>&#xA;                <producerreferencetime inband="true" type="captured" wallclocktime="2021-05-24T14:50:00.306Z" presentationtime="0">&#xA;                    <utctiming schemeiduri="urn:mpeg:dash:utc:http-xsdate:2014" value="/pelican/testPlayers/time.php"></utctiming>&#xA;                </producerreferencetime>&#xA;                <resync dt="21333" type="1"></resync>&#xA;                <segmenttemplate timescale="1000000" duration="2000000" availabilitytimeoffset="1.800" availabilitytimecomplete="false" initialization="init-stream$RepresentationID$.m4s" media="chunk-stream$RepresentationID$-$Number%05d$.m4s" startnumber="1">&#xA;                </segmenttemplate>&#xA;            </representation>&#xA;        </adaptationset>&#xA;    </period>&#xA;    <utctiming schemeiduri="urn:mpeg:dash:utc:http-xsdate:2014" value="/pelican/testPlayers/time.php"></utctiming>&#xA;</mpd>&#xA;

  


• mid-roll ads in HLS or mpeg-dash [on hold]

  15 août 2018, par evan

  I’m encoding my videos with ffmpeg and transcoding them into HLS videos. I want to add mid-roll ads to my converted videos.

  I was wondering what is the best way to do it ? should I just add the ads to my video and make a big video stream and then do the HLS thing ? or I should break the HLs video and put the ads in the middle while playing ?

  My content is live streaming and I want to add mid-roll ads in the middle of my video while playing.

  ffmpeg -i main720.MTS -movflags faststart -s 640*360 -r 24 -vcodec libx264 -preset slow -tune zerolatency -tune fastdecode -b:v 300k -maxrate 300k -bufsize 400k -g 96 -an hls3/main720_300.mp4 -s 1280*720 -r 24 -vcodec libx264 -preset slow -tune zerolatency -tune fastdecode -b:v 700k -maxrate 700k -bufsize 1000k -g 96 -an hls3/main720_700.mp4 -hls_time 4 -hls_segment_filename 'hls3/file%03d.ts' -hls_list_size 0 hls3/out.m3u8