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• Merge individual frame to video file using Opencv

  18 août 2022, par Rohit

  I am trying to stack a individual frame to a video file using Opencv. I want to combine two different code together to make the individual frame.
Following code help me extract the individual frame,

  


  fourcc = cv2.VideoWriter_fourcc(*'mp4v')
out = cv2.VideoWriter('file_data.mp4',fourcc,20 (1920,1080),False)
while True:
    ret, frame=cap.read()
    mask = object_detector.apply(frame)
    _, mask  = cv2.threshold(mask,254,255,cv2.THRESH_BINARY)       
    contours,_ = cv2.findContours(mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    res = cv2.bitwise_and(frame,frame,mask=mask)
    for cnt in contours:
        area = cv2.contourArea(cnt)
        if area>1000:   
            #print("Area of contour:", area)
            cv2.drawContours(frame, [cnt], -1, (0,255,0),2)
            cv2.imwrite("file%d.jpg"%count, frame)
            out.write(frame)
    if cv2.waitKey(1) and 0xFF == ord('q'):
        break


  


  I tried storing the individual frame in array, but it didn't work. It doesn't show any error, but pc crash.

  


  


  fps = 20,
,width = 1920
,height = 1080

  


  


• MPEG DASH - do I need to have audio and video tracks as seperate source file for creating DASH package using mp4box

  10 juillet 2016, par Tarun

  I have one source mp4, I tried to create MPEG DASH package using mp4box by GPAC.
  I am able to play output MPD files in OSMO4 player by GPAC.

  However I am not able to play the same in DASH JS player @ http://dashif.org/reference/players/javascript/0.2.3/index.html

  When I try to play the mpd in it I get error "Error creating source buffer"

  I tried reading their MPD files, and I found that those guys are using audio and video as separate source track.

  Ques1) Does DASH specs states that audio and video tracks should be seprate source tracks ?

  Ques2) Please find below the MPD file created by me, Let me know if anybody thinks that there is a problem in it

  <mpd type="static" xmlns="urn:mpeg:DASH:schema:MPD:2011" profiles="urn:mpeg:dash:profile:full:2011" minbuffertime="PT1.5S" mediapresentationduration="PT0H2M31.63S">
  
  <programinformation moreinformationurl="http://gpac.sourceforge.net">
  
  
  
  </programinformation>
  
   <period start="PT0S" duration="PT0H2M31.63S">
  
    <adaptationset>
  
  <contentcomponent contenttype="video"></contentcomponent>
  
  <contentcomponent contenttype="audio" lang="und"></contentcomponent>
  
  <segmenttemplate initialization="flight_init.mp4"></segmenttemplate>
  
  <representation mimetype="video/mp4" codecs="avc1.64001f,mp4a.40.02" width="1280" height="720" samplerate="44100" numchannels="2" lang="und" startwithsap="1" bandwidth="3096320">
  
  <segmenttemplate timescale="1000" duration="20164" media="flight_test_flight_3000$Number$.mp4" startnumber="1"></segmenttemplate>
  
  </representation>
  
  <representation mimetype="video/mp4" codecs="avc1.64001e,mp4a.40.02" width="640" height="360" samplerate="44100" numchannels="2" lang="und" startwithsap="1" bandwidth="1119428">
  
  <segmenttemplate timescale="1000" duration="20099" media="flight_test_flight_1000$Number$.mp4" startnumber="1"></segmenttemplate>
  
  </representation>
  
  <representation mimetype="video/mp4" codecs="avc1.640014,mp4a.40.02" width="320" height="180" samplerate="44100" numchannels="2" lang="und" startwithsap="1" bandwidth="722208">
  
  <segmenttemplate timescale="1000" duration="20164" media="flight_test_flight_600$Number$.mp4" startnumber="1"></segmenttemplate>
  
  </representation>
  
  </adaptationset>
  
  </period> 
  
  </mpd>

• 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 !