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• How can I fix a audio delay caused by a batch trim of the start and end of a video file

  15 mai 2019, par trozz

  When using this ffmpeg batch trimmer I found on here - will be posted down below in "show code" Tried to format it correctly, but I’m new here so.

  It causes the audio to be delayed by 100 milliseconds. Is there a way to fix this in the same bat file, or maybe after with another edit ?

  Thanks

  @Echo Off
  
  SetLocal
  
  
  
  Set "ext=mp4"
  
  
  
  Set "opts=-v quiet"
  
  
  
  Set "opts=%opts% -print_format "compact=print_section=0:nokey=1:escape=csv"
  
  
  
  Set "opts=%opts% -show_entries "format=duration""
  
  
  
  If Exist *.%ext% (If Not Exist "Trimmed\" MD Trimmed)
  
  
  
  For %%a In (*.%ext%) Do Call :Sub "%%~a"
  
  
  
  Exit/B
  
  
  
  :Sub
  
  
  
  For /f "Tokens=1* Delims=." %%a In (
  
      'FFProbe %opts% %1') Do (Set/A "ws=%%a-7.85" & Set "ps=%%b")
  
  
  
  rem If %ws% Lss 20 GoTo :EOF
  
  
  
  Set/A hh=ws/(60*60), lo=ws%%(60*60), mm=lo/60, ss=lo%%60
  
  
  
  If %hh% Lss 10 Set hh=0%hh%
  
  
  
  If %mm% Lss 10 Set mm=0%mm%
  
  
  
  If %ss% Lss 10 Set ss=0%ss%
  
  
  
  FFMpeg -i %1 -ss 00:00:04.5000 -to %hh%:%mm%:%ss%.%ps:~,3% -c:v copy -c:a copy "Trimmed\%~1"

• Why aren't the videos in my S3 bucket buffering to html video tag ?

  2 juin 2019, par Michael Cain

  I have so far successfully programmed a node script on a Udoo x86 advanced plus that captures an Ethernet connected IP cam’s RTSP stream. I use ffmpeg to trans-code the stream into 5 second mp4 files. As soon as the files show up in the folder they are uploaded/synced to my AWS S3 Bucket. Next I have a Node server that GET’s the most recently created mp4 file from the S3 bucket and runs it through mediasource extension and finally to an html video tag.

  The videos are playing on the browser but not in any kind of synchronous manner. No buffering seems to be taking place. one video plays then another and so on. Video is skipping all over the place.

  I would really appreciate any guidance with this bug.

  export function startlivestream() {
  
    const videoElement = document.getElementById("my-video");
  
    const myMediaSource = new MediaSource();
  
    const url = URL.createObjectURL(myMediaSource);
  
    videoElement.src = url;
  
    myMediaSource.addEventListener("sourceopen", sourceOpen);
  
  }
  
  function sourceOpen() {
  
    if (window.MediaSource.isTypeSupported(
  
        'video/mp4; codecs="avc1.42E01E, mp4a.40.2"'
  
      )
  
    ) 
  
  {
  
         console.log("YES");
  
    }
  
  
  
  // 1. add source buffers
  
  
  
    const mediaCodec = 'video/mp4; codecs="avc1.4D601F"';
  
    var mediasource = this;
  
    const videoSourceBuffer = mediasource.addSourceBuffer(mediaCodec);
  
  
  
  // 2. download and add our audio/video to the SourceBuffers
  
  
  
  function checkVideo(url) {
  
    var oReq = new XMLHttpRequest();
  
      oReq.open("GET", url, true);
  
      oReq.responseType = "arraybuffer";
  
  
  
       oReq.onload = function(oEvent) {
  
        var arrayBuffer = oReq.response; // Note: not oReq.responseText
  
        if (arrayBuffer) {
  
           videoSourceBuffer.addEventListener("updateend", function(_) {
  
             mediasource.endOfStream();
  
             document.getElementById("my-video").play();
  
     });
  
             videoSourceBuffer.appendBuffer(arrayBuffer);
  
        }
  
      };
  
  
  
      oReq.send(null);
  
    }
  
  
  
    setInterval(function() {
  
      checkVideo("http://localhost:8080");
  
    }, 5000);

  My ffmpeg tags :

  const startRecording = () => {
  
    const args = [
  
      "-rtsp_transport",
  
      "tcp",
  
      "-i",
  
      inputURL,
  
      "-f",
  
      "segment",
  
      "-segment_time",
  
      "5",
  
      "-segment_format",
  
      "mp4",
  
      "-segment_format_options",
  
      "movflags=frag_keyframe+empty_moov+default_base_moof",
  
      "-segment_time",
  
      "5",
  
      "-segment_list_type",
  
      "m3u8",
  
      "-c:v",
  
      "copy",
  
      "-strftime",
  
      "1",
  
      `${path.join(savePath, "test-%Y-%m-%dT%H-%M-%S.mp4")}`
  
    ];

  From what I have learned about Mediasource extensions they allow multiple videos to be taken in and allow the client to buffer them so it looks like one longer video. In simple terms.

• Adaptive part in MPD using MP4box

  28 janvier 2019, par enigmaVada

  I have used ffmpeg to encode audio and video files of my video sample.mp4 for the dash player. The commands are as follows :

  ffmpeg -i sample.mp4 -s 426x240 -c:v libx264 -b:v 640k -g 90 -an sample_video_240.mp4
  
  ffmpeg -i sample.mp4 -s 480x360 -c:v libx264 -b:v 960k -g 90 -an sample_video_360.mp4
  
  ffmpeg -i sample.mp4 -s 640x480 -c:v libx264 -b:v 1280k -g 90 -an sample_video_480.mp4
  
  ffmpeg -i sample.mp4 -s 1280x720 -c:v libx264 -b:v 2560k -g 90 -an sample_video_720.mp4
  
  
  
  ffmpeg -i sample.mp4 -c:a aac -b:a 128k -vn sample_audio.mp4

  I have generated 240p,360p,480p and 720p videos and audio file.

  Then I have used mp4box to generate the mpd file using the following command :

  mp4box -dash 10000 -rap -profile dashavc264:onDemand -mpd-title BBB -out sample.mpd -frag 5000 sample_audio.mp4 sample_video_240.mp4 sample_video_360.mp4 sample_video_480.mp4 sample_video_720.mp4 

  I am using the dash.js player to play the video. The problem is, the adaptive part of DASH isn’t working. The player is just using the 240p video and not switching to a better format even if proper bandwidth is available. I am checking using the network tab of chrome dev tools.

  What am i doing wrong ? Please help.

  Here is the mpd file for reference :

  <?xml version="1.0"?>
  
  
  
  <mpd xmlns="urn:mpeg:dash:schema:mpd:2011" minbuffertime="PT1.500S" type="static" mediapresentationduration="PT0H1M9.869S" maxsegmentduration="PT0H0M9.985S" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011,http://dashif.org/guidelines/dash264">
  
   <programinformation moreinformationurl="http://gpac.io">
  
    
  
   </programinformation>
  
  
  
   <period duration="PT0H1M9.869S">
  
    <adaptationset segmentalignment="true" lang="und" subsegmentalignment="true" subsegmentstartswithsap="1">
  
     <representation mimetype="audio/mp4" codecs="mp4a.40.2" audiosamplingrate="44100" startwithsap="1" bandwidth="130920">
  
      <audiochannelconfiguration schemeiduri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"></audiochannelconfiguration>
  
      <baseurl>sample_audio_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="902-1017">
  
        <initialization range="0-901"></initialization>
  
      </segmentbase>
  
     </representation>
  
    </adaptationset>
  
    <adaptationset segmentalignment="true" group="1" maxwidth="426" maxheight="240" maxframerate="30" par="426:240" lang="und" subsegmentalignment="true" subsegmentstartswithsap="1">
  
     <representation mimetype="video/mp4" codecs="avc1.640015" width="426" height="240" framerate="30" sar="1:1" startwithsap="1" bandwidth="590708">
  
      <baseurl>sample_video_240_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="914-1053">
  
        <initialization range="0-913"></initialization>
  
      </segmentbase>
  
     </representation>
  
    </adaptationset>
  
    <adaptationset segmentalignment="true" group="1" maxwidth="640" maxheight="480" maxframerate="30" par="4:3" lang="und" subsegmentalignment="true" subsegmentstartswithsap="1">
  
     <representation mimetype="video/mp4" codecs="avc1.64001E" width="480" height="360" framerate="30" sar="1:1" startwithsap="1" bandwidth="883873">
  
      <baseurl>sample_video_360_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="914-1053">
  
        <initialization range="0-913"></initialization>
  
      </segmentbase>
  
     </representation>
  
     <representation mimetype="video/mp4" codecs="avc1.64001E" width="640" height="480" framerate="30" sar="1:1" startwithsap="1" bandwidth="1188712">
  
      <baseurl>sample_video_480_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="913-1052">
  
        <initialization range="0-912"></initialization>
  
      </segmentbase>
  
     </representation>
  
    </adaptationset>
  
    <adaptationset segmentalignment="true" group="1" maxwidth="1280" maxheight="720" maxframerate="30" par="16:9" lang="und" subsegmentalignment="true" subsegmentstartswithsap="1">
  
     <representation mimetype="video/mp4" codecs="avc1.64001F" width="1280" height="720" framerate="30" sar="1:1" startwithsap="1" bandwidth="2365717">
  
      <baseurl>sample_video_720_dashinit.mp4</baseurl>
  
      <segmentbase indexrangeexact="true" indexrange="914-1053">
  
        <initialization range="0-913"></initialization>
  
      </segmentbase>
  
     </representation>
  
    </adaptationset>
  
   </period>
  
  </mpd>