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• AudioContext HTML5 Player

  15 février 2015, par Plyto

  So I’ve been playing with the Web Audio API and have the following issue.

  I am making a project in which I call an external library’s API with Ajax and get audio back (arraybuffer).

  • I send them the text and get audio back.
  • This is not necessarily a GET request (can be POST, etc.)
  • If text is too large, I split it into smaller chunks and send multiple requests

  So far so good, now comes the issue of how to play the multiple audios that I got back.

  Since users do not care that I have split the text and actually have multiple audio tracks, I need somehow to make it look like a single track or as a playlist.

  So I have tried to :

  • merge arraybuffer (apparently it does not work like that and most likely I need ffmpeg or simiar tools to do the merging, which is hard to do on client-side ? (like there is ffmpeg for browsers, but I don’t know how good is it to burden a client with it). If it’s not so, maybe you can suggest something here)
  • load it as a playlist, but so far cannot find a library that accepts multiple audiobuffers/audiocontexts and/or gives a playlist with it back.

  The easiest solution that I see so far is to create my own small library that accepts AudioBuffers/arraybuffers and go either with the playlist approach or play the ’chunked’ audios one by one and make scrubber that jumps between audio contexts.

  Is there a library/easier approach ?

  Will be thankful for any suggestions :]

• Play video files in a row without delay

  13 février 2015, par Ara Deonas

  I am looking for a way to play 2 video in a row without any delay (or
  very tiny delay) when changing files.
  I had 1 mp4 file and with ffmpeg I split it into 2 file and now I want
  to add them in playlist and play them but I don’t want user feel
  changing video but when I test it because of loading file there is a
  delay.
  I think about stream second file into memory before first file end.
  How can I do this ?
  I tested LibVLC and read Play a Video from MemoryStream, Using FFMpeg but still no luck.
  PS : Any library in any language is good for me.

  EDIT : I added a demo that play second file after first one but there is a delay beetwen changing.How can I minimize this ?(for example feeding VLC from memory and load second file into memory).
  EDIT : Files are small (less than 5mb).

  unit Unit1;
  
  
  
  {$mode objfpc}{$H+}
  
  
  
  interface
  
  
  
  uses
  
    Classes, SysUtils, FileUtil, PasLibVlcPlayerUnit, Forms, Controls, Graphics,LCLIntf,LCLType,
  
    Dialogs, ExtCtrls, StdCtrls, PasLibVlcPlayer, PasLibVlcUnit, PasLibVlcClassUnit;
  
  
  
  type
  
  
  
    { TForm1 }
  
  
  
    TForm1 = class(TForm)
  
      Button2: TButton;
  
      Panel2: TPanel;
  
      procedure Button1Click(Sender: TObject);
  
      procedure Button2Click(Sender: TObject);
  
      procedure FormCreate(Sender: TObject);
  
    private
  
      function GetVlcInstance(): TPasLibVlc;
  
      procedure WmMediaPlayerEndReached(var m: TVlcMessage); message WM_MEDIA_PLAYER_END_REACHED;
  
    public
  
      FVLC: TPasLibVlc;
  
      media_t_ptr:libvlc_media_t_ptr;
  
      media_t_ptr2:libvlc_media_t_ptr;
  
      FVideoOutput: TVideoOutput;
  
      FAudioOutput: TAudioOutput;
  
      p_mi: libvlc_media_player_t_ptr;
  
      p_instance: libvlc_instance_t_ptr;
  
      p_mi_ev_mgr: libvlc_event_manager_t_ptr;
  
      property VLC: TPasLibVlc read GetVlcInstance;
  
  
  
    end;
  
  
  
  var
  
    Form1: TForm1;
  
  
  
  procedure lib_vlc_player_event_hdlr(p_event: libvlc_event_t_ptr; Data: Pointer); cdecl;
  
  
  
  implementation
  
  
  
  procedure lib_vlc_player_event_hdlr(p_event: libvlc_event_t_ptr; Data: Pointer); cdecl;
  
  var
  
    Form: TForm1;
  
  begin
  
    if (Data = nil) then
  
      exit;
  
    Form := TForm1(Data);
  
    if not Assigned(Form) then
  
      exit;
  
    case p_event^.event_type of
  
      libvlc_MediaPlayerEndReached:
  
        PostMessage(Form.Handle, WM_MEDIA_PLAYER_END_REACHED, WPARAM(0), LPARAM(0));
  
    end;
  
  end;
  
  
  
  {$R *.lfm}
  
  
  
  { TForm1 }
  
  
  
  procedure TForm1.Button1Click(Sender: TObject);
  
  begin
  
  
  
  end;
  
  
  
  procedure TForm1.Button2Click(Sender: TObject);
  
  var
  
    mrl: string;
  
  begin
  
    mrl := 'C:\ffmpeg\bin\tmp\OUTPUT0.mp4';
  
  
  
   media_t_ptr:=libvlc_media_new_path(VLC.Handle, PAnsiChar(UTF8Encode(mrl)));
  
    p_instance := VLC.Handle;
  
    p_mi := libvlc_media_player_new(p_instance);
  
    p_mi_ev_mgr := libvlc_media_player_event_manager(p_mi);
  
    libvlc_event_attach(p_mi_ev_mgr, libvlc_MediaPlayerEndReached, @lib_vlc_player_event_hdlr, SELF);
  
    libvlc_media_player_set_media(p_mi, media_t_ptr);
  
    libvlc_media_release(media_t_ptr);
  
    libvlc_media_player_set_display_window(p_mi, Panel2.Handle);
  
    libvlc_media_player_play(p_mi);
  
  
  
     mrl := 'C:\ffmpeg\bin\tmp\OUTPUT1.mp4';
  
  
  
    media_t_ptr2:=libvlc_media_new_path(VLC.Handle, PAnsiChar(UTF8Encode(mrl)));
  
  end;
  
  
  
  procedure TForm1.FormCreate(Sender: TObject);
  
  begin
  
    Button2.Click;
  
  end;
  
  
  
  function TForm1.GetVlcInstance: TPasLibVlc;
  
  begin
  
    if not Assigned(FVLC) then
  
    begin
  
      FVLC := TPasLibVlc.Create;
  
    end;
  
    Result := FVLC;
  
  end;
  
  
  
  procedure TForm1.WmMediaPlayerEndReached(var m: TVlcMessage);
  
  begin
  
    libvlc_media_player_set_media(p_mi, media_t_ptr2);
  
    libvlc_media_player_play(p_mi);
  
  end;
  
  
  
  end.

• FFmpeg : Continuously download X minutes video from livestream ?

  16 février 2017, par Dorin Pleava

  I want to download X minutes from a livestream continuously and overwrite the same file, meaning the file will always have the latest X minutes from the livestream.

  Is there a way without calling the following command over and over again in a batch file ? Something that runs continuously from FFMPEG ?

  -i http://iphone-streaming.ustream.tv/uhls/17074538/streams/live/iphone/playlist.m3u8 -t 60 -y -c:a copy MyVideo.mp4