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• How to manually reset the offset of an mp4 video created from m4s files ?

  12 août 2020, par natdev

  I'm building a service that combine .m4s files (from a dash stream) to a mp4 video.
  
I have some sample m4s files from a random point in time of a stream,
  
using ffmpeg on those file + the init file does the job.

  


  cat init.mp4 032.m4s 033.m4s 034.m4s > output.mp4


  


  I have tried concating the m4s files to the mp4 init file and I manage to play the video,
  
but there is an offset from the encoded video segments.

  


  I guess ffmpeg does reset that somehow, and I was wondering how can I reset that offset as well ?
  
Having a little bit of experience with dash, I know that there is a field name presentationTimeOffset that is responsible to set the offset.

  


• Execute mp4box cmd via java got error

  6 novembre 2015, par Ducthien

  sorry when I tag ffmpeg because I couldn’t tag MP4Box.But I have proplem with excuted with ffmpeg via javacode too.
  I read at How to execute cmd commands via Java but i can’t find my proplem.

  I’m tested commands in cmd, it was ok :

  MP4Box -dash 10000 -dash-profile live -segment-name output- seg -rap
  -bs-switching no input.mp4

  but when i executed cmd via java code , i get error :

  Error - only one input file found as argument, please check usage

  Below is my code, has something wrong ?

  package com.uit.reformatvideo;
  
  
  
  import java.io.BufferedReader;
  
  import java.io.IOException;
  
  import java.io.InputStreamReader;
  
  import java.util.logging.Logger;
  
  
  
  public class ExecuteComandToFormatVideo {
  
  
  
      public final static String LINK_MP4BOX = "C:/MP4Box/Tools/MP4Box.exe";
  
      public final static String CREATE_MPD_ECLIPSE = "mp4box -dash 10000 -frag 1000 -rap -bs-switching no";
  
      public final static String CREATE_MPD_IE = "MP4Box -dash 10000 -dash-profile live -segment-name output-seg -rap -bs-switching no";
  
      private static final Logger log = Logger.getLogger(ExecuteComandToFormatVideo.class.getName());
  
  
  
  
  
      public static void main(String[] args) throws IOException, InterruptedException {
  
            String s = null;
  
  
  
              try {
  
  
  
              // run the Unix "ps -ef" command
  
                  // using the Runtime exec method:
  
                  String lsCmd[] = new String [2];
  
                  lsCmd[0] = LINK_MP4BOX;
  
                  lsCmd[1] = "MP4Box -dash 10000 -dash-profile live -segment-name output-seg -rap -bs-switching no input.mp4";
  
                  Process p = Runtime.getRuntime().exec(lsCmd);
  
                  p.waitFor();
  
                  BufferedReader stdInput = new BufferedReader(new
  
                       InputStreamReader(p.getInputStream()));
  
  
  
                  BufferedReader stdError = new BufferedReader(new
  
                       InputStreamReader(p.getErrorStream()));
  
  
  
                  // read the output from the command
  
                  System.out.println("Here is the standard output of the command:\n");
  
                  while ((s = stdInput.readLine()) != null) {
  
                      System.out.println(s);
  
                  }
  
  
  
                  // read any errors from the attempted command
  
                  System.out.println("Here is the standard error of the command (if any):\n");
  
                  while ((s = stdError.readLine()) != null) {
  
                      System.out.println(s);
  
                  }
  
  
  
                  System.exit(0);
  
              }
  
              catch (IOException e) {
  
                  System.out.println("exception happened - here's what I know: ");
  
                  e.printStackTrace();
  
                  System.exit(-1);
  
              }
  
      }
  
  
  
  }

  Here was out put :

  Here is the standard output of the command :

  Here is the standarderror of the command (if any) : Error - only one
  input file found as argument, please check usage

• ffmpeg creates empty mpd-file

  1er avril 2021, par Macster

  I'm trying to live stream a webm file using ffmpeg and Dash.js as a Player. Creating chunks with ffmpeg seems to work fine, but when want to create the manifest it says Could not find codec parameters for stream 0 (Video: vp9, none, 640x480): unspecified pixel format Consider increasing the value for the 'analyzeduration' and 'probesize' options and at the end Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used).

  


  Commands I use

  


  ffmpeg -re -r 25 -i Dash/strm.webm
 -map 0:v:0
 -pix_fmt yuv420p
 -c:v libvpx-vp9
 -s 640x480 -keyint_min 25 -g 25 
 -speed 6 -threads 8 -static-thresh 0 -max-intra-rate 300 
 -deadline realtime -lag-in-frames 0 -error-resilient 1
 -f webm_chunk 
 -header "Dash/glass_360.hdr"
 -chunk_start_index 1
 Dash\glass_360_%d.chk


  


  Manifest

  


  ffmpeg ^
 -f webm_dash_manifest -live 1
 -r 25
 -i Dash/glass_360.hdr
 -c copy
 -map 0
 -r 25
 -framerate 25
 -f webm_dash_manifest -live 1
 -adaptation_sets "id=0,streams=0"
 -chunk_start_index 1
 -chunk_duration_ms 1000
 -time_shift_buffer_depth 7200
 -minimum_update_period 7200
 Dash/glass_live_manifest.mpd


  


  Manifest Output

  


   libavutil      56. 49.100 / 56. 49.100
  libavcodec     58. 87.101 / 58. 87.101
  libavformat    58. 43.100 / 58. 43.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 83.100 /  7. 83.100
  libswscale      5.  6.101 /  5.  6.101
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
[webm_dash_manifest @ 0000015f19f2ea40] Could not find codec parameters for stream 0 (Video: vp9, none, 640x480): unspecified pixel format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, webm_dash_manifest, from 'Dash/glass_360.hdr':
  Metadata:
    ENCODER         : Lavf58.43.100
  Duration: N/A, bitrate: N/A
    Stream #0:0(eng): Video: vp9, none, 640x480, SAR 1:1 DAR 4:3, 1k tbr, 1k tbn, 1k tbc (default)
    Metadata:
      ALPHA_MODE      : 1
      ENCODER         : Lavc58.87.101 libvpx-vp9
      webm_dash_manifest_file_name: glass_360.hdr
      webm_dash_manifest_track_number: 1
Output #0, webm_dash_manifest, to 'stream_manifest.mpd':
  Metadata:
    encoder         : Lavf58.43.100
    Stream #0:0(eng): Video: vp9, none, 640x480 [SAR 1:1 DAR 4:3], q=2-31, 1k tbr, 1k tbn, 1k tbc (default)
    Metadata:
      ALPHA_MODE      : 1
      ENCODER         : Lavc58.87.101 libvpx-vp9
      webm_dash_manifest_file_name: glass_360.hdr
      webm_dash_manifest_track_number: 1
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=    0 fps=0.0 q=-1.0 Lsize=       1kB time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)


  


  glass_live_manifest.mpd

  


  &lt;?xml version="1.0" encoding="UTF-8"?>&#xA;&#xA;<period start="PT0S">&#xA;<adaptationset mimetype="video/webm" codecs="vp9" lang="eng" bitstreamswitching="true" subsegmentalignment="true" subsegmentstartswithsap="1">&#xA;<contentcomponent type="video"></contentcomponent>&#xA;<segmenttemplate timescale="1000" duration="1000" media="glass_$RepresentationID$_$Number$.chk" startnumber="1" initialization="glass_$RepresentationID$.hdr"></segmenttemplate>&#xA;<representation bandwidth="1000000" width="640" height="480" codecs="vp9" mimetype="video/webm" startswithsap="1"></representation>&#xA;</adaptationset>&#xA;</period>&#xA;&#xA;

  


  UPDATE

  


  I fixed the "warnings" by changing the comands like this :

  


  ffmpeg -re -r 25 -i Dash/strm.webm
-map 0:v:0
-pix_fmt yuv420p
-c:v libvpx
-s 640x480 -keyint_min 60 -g 60 -speed 6 -tile-columns 4 -frame-parallel 1 -threads 8 -static-thresh 0 -max-intra-rate 300 -deadline realtime -lag-in-frames 0 -error-resilient 1
-b:v 3000k
-f webm_chunk
-header "Dash/glass_360.hdr"
-chunk_start_index 1 Dash/glass_360_%d.chk
-map 0:a:0
-c:a libvorbis
-b:a 128k -ar 44100
-f webm_chunk
-audio_chunk_duration 2000
-header Dash/glass_171.hdr
-chunk_start_index 1 Dash/glass_171_%d.chk

ffmpeg
-f webm_dash_manifest -live 1
-i Dash/glass_360.hdr
-f webm_dash_manifest -live 1
-i Dash/glass_171.hdr
-c copy
-map 0 -map 1
-f webm_dash_manifest -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 Dash/glass_video_manifest.mpd


  


  However, it's still not working.