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• Overlay video onto another video at multiple points in time

  22 décembre 2024, par kbcool

  I have a case where I want to have a background video and use a second video overlaying the first but at multiple points in time. The second video is shorter.

  



  So for example the main video is a minute long and the second video is 10 seconds. I want to overlay the second video once at 15seconds then again at 35 seconds and then again at 55 seconds (terminating when the main video does).

  



  I am able to get the second video to overlay successfully using overlay filter and between option but it only ever works for the first overlay. The second overlay seems to show the last or first frame of the video(??) but for the period I set in between. I am guessing it needs to be rewound and played somehow.

  



  Eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[out][1]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  I have also tried specifying the overlay as an input twice eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[out][2]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  The same thing happens.

  



  I'm sure the answer is simple and probably to do with how I'm using inputs but I'm not able to wrap my head around how to get the overlay video to play twice at different times on top of the original.

  



  I have also tried using the setpts filter to rewind the overlay but again the results are exactly the same.

  



  Eg :

  



  ffmpeg  -i background.mp4 -i overlay.mov -filter_complex "[0][1]overlay=0:0:enable='between(t,0,2)'[out];[1]setpts=PTS-STARTPTS,[out]overlay=-200:200:enable='between(t,4,8)'[out]" -map "[out]" -t 00:00:10 -y output.mp4


  



  There are a lot of similar questions involving overlaying multiple videos but I can't find anything about reusing the same video at multiple points in time.

  


• Using ffmpeg to generate dash manifest and it cannot be played by dash.js

  18 mars 2019, par Punkhead

  I’m using ffmpeg to encode incoming stream via rtmp protocol, the code as following :

  ffmpeg -re -i rtmp://localhost:1935${StreamPath} -use_timeline 1 /
  
  -use_template 1 -window_size 10 -min_seg_duration 5000 -f dash out.mpd

  The manifest looks like this :

  <?xml version="1.0" encoding="utf-8"?>
  
  <mpd xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" type="static" mediapresentationduration="PT1M36.4S" minbuffertime="PT8.3S">
  
      <programinformation>
  
      </programinformation>
  
      <period start="PT0.0S">
  
          <adaptationset contenttype="video" segmentalignment="true" bitstreamswitching="true" framerate="30/1">
  
          <representation mimetype="video/mp4" codecs="avc1.640028" width="1920" height="1080" framerate="30/1">
  
              <segmenttemplate timescale="15360" initialization="init-stream$RepresentationID$.m4s" media="chunk-stream$RepresentationID$-$Number%05d$.m4s" startnumber="4">
  
                  <segmenttimeline>
  
                      <s t="384000" d="128000"></s>
  
                      <s d="71680"></s>
  
                      <s d="128000" r="4"></s>
  
                      <s d="56832"></s>
  
                      <s d="128000"></s>
  
                      <s d="72704"></s>
  
                  </segmenttimeline>
  
              </segmenttemplate>
  
          </representation>
  
      </adaptationset>
  
      <adaptationset contenttype="audio" segmentalignment="true" bitstreamswitching="true">
  
          <representation mimetype="audio/mp4" codecs="mp4a.40.2" bandwidth="128000" audiosamplingrate="44100">
  
              <audiochannelconfiguration schemeiduri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"></audiochannelconfiguration>
  
              <segmenttemplate timescale="44100" initialization="init-stream$RepresentationID$.m4s" media="chunk-stream$RepresentationID$-$Number%05d$.m4s" startnumber="4">
  
                  <segmenttimeline>
  
                      <s t="1099755" d="367616"></s>
  
                      <s d="205824"></s>
  
                      <s d="367616" r="4"></s>
  
                      <s d="162816"></s>
  
                      <s d="367616"></s>
  
                      <s d="207872"></s>
  
                  </segmenttimeline>
  
              </segmenttemplate>
  
          </representation>
  
      </adaptationset>
  
  </period>
  
  </mpd>

  When I try to play it on dash.js player, a error occured :

  [112] Parsing complete: ( xml2json: 3.50ms, objectiron: 1.76ms, total: 0.00526s) Debug.js:127 
  
  [116] SegmentTimeline detected using calculated Live Edge Time Debug.js:127 
  
  [118] MediaSource attached to element.  Waiting on open... Debug.js:127 
  
  [119] Manifest has been refreshed at Tue Jan 02 2018 01:57:35 GMT+0800 [1514829455.1] Debug.js:127 
  
  [155] MediaSource is open! Debug.js:127 
  
  [156] Duration successfully set to: 96.4 Debug.js:127 
  
  [157] Added 0 inline events Debug.js:127 
  
  [158] video codec: video/mp4;codecs="avc1.640028" Stream.js:225 
  
  Uncaught TypeError: Cannot read property 'type' of null
  
      at z (Stream.js:225)
  
      at C (Stream.js:285)
  
      at D (Stream.js:373)
  
      at E (Stream.js:398)
  
      at Object.d [as activate] (Stream.js:107)
  
      at y (StreamController.js:363)
  
      at MediaSource.c (StreamController.js:342)

  then it fails to playback...

  Is it because I didn’t set the parameters right on ffmpeg or this is a bug in dash.js ?

  I really stuck here !

• avformat/hls : add http_multiple option

  13 décembre 2017, par Aman Gupta

  avformat/hls : add http_multiple option
  This improves network throughput of the hls demuxer by avoiding
  
  the latency introduced by downloading segments one at a time.
  The problem is particularly noticable over high-latency network
  
  connections : for instance, if RTT is 250ms, there will a 250ms idle
  
  period between when one segment response is read and the next one
  
  starts.
  The obvious solution to this is to use HTTP pipelining, where a
  
  second request can be sent (on the persistent http/1.1 connection)
  
  before the first response is fully read. Unfortunately the way the
  
  http protocol is implemented in avformat makes implementing pipleining
  
  very complex.
  Instead, this commit simulates pipelining using two separate persistent
  
  http connections. This has the advantage of working independently of
  
  the http_persistent option, and can be used with http/1.0 servers as
  
  well. The pair of connections is swapped every time a new segment starts
  
  downloading, and a request for the next segment is sent on the secondary
  
  connection right away. This means the second response will be ready and
  
  waiting by the time the current response is fully read.
  Signed-off-by : Aman Gupta <aman@tmm1.net>
  
  Signed-off-by : Anssi Hannula <anssi.hannula@iki.fi>
  

  • [DH] doc/demuxers.texi
  • [DH] libavformat/hls.c