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| Rev | Author | Line No. | Line |
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| 2 | daniel-mar | 1 | { |
| 2 | MJPEG Decoder Class |
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| 3 | Copyright 2006, Steve Blinch |
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| 4 | http://code.blitzaffe.com |
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| 5 | |||
| 6 | This script is free software; you can redistribute it and/or modify it under the |
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| 7 | terms of the GNU General Public License as published by the Free Software |
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| 8 | Foundation; either version 2 of the License, or (at your option) any later |
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| 9 | version. |
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| 10 | |||
| 11 | This script is distributed in the hope that it will be useful, but WITHOUT ANY |
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| 12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
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| 13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for more |
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| 14 | details. |
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| 15 | |||
| 16 | You should have received a copy of the GNU General Public License along |
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| 17 | with this script; if not, write to the Free Software Foundation, Inc., |
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| 18 | 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 19 | } |
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| 20 | |||
| 21 | unit MJPEGDecoderThread; |
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| 22 | |||
| 23 | {$M+} // Added VTS 06.05.2019 to supress compiler warning |
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| 24 | |||
| 25 | interface |
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| 26 | |||
| 27 | uses Classes,IdTCPClient; |
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| 28 | |||
| 29 | const |
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| 30 | MSG_MJPEG_FRAME = 1; |
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| 31 | MSG_MJPEG_ERROR = 2; |
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| 32 | MSG_MJPEG_MESSAGE = 3; |
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| 33 | |||
| 34 | ERROR_MJPEG_BADFRAME = 1; |
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| 35 | ERROR_MJPEG_EXCEPT = 2; |
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| 36 | ERROR_MJPEG_DISCONNECT = 3; |
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| 37 | |||
| 38 | Type |
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| 39 | TMJPEGDecoderMsg = class(TObject) |
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| 40 | public |
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| 41 | Msg: String; |
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| 42 | end; |
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| 43 | |||
| 44 | TMJPEGDecoderThread = class(TThread) |
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| 45 | private |
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| 46 | FClient: TIdTCPClient; |
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| 47 | FActive: Boolean; |
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| 48 | FNotifyWindow: THandle; |
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| 49 | |||
| 50 | procedure Info(S: String); |
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| 51 | function CheckConnected: Boolean; |
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| 52 | public |
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| 53 | constructor Create(TCPClient: TIdTCPClient; NotifyWindow: THandle); |
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| 54 | procedure Execute; override; |
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| 55 | published |
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| 56 | property Active: Boolean read FActive; |
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| 57 | end; |
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| 58 | |||
| 59 | implementation |
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| 60 | |||
| 61 | uses SysUtils,Windows,Messages; |
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| 62 | |||
| 63 | constructor TMJPEGDecoderThread.Create(TCPClient: TIdTCPClient; NotifyWindow: THandle); |
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| 64 | begin |
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| 65 | FActive:=False; |
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| 66 | FClient:=TCPClient; |
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| 67 | FNotifyWindow:=NotifyWindow; |
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| 68 | |||
| 69 | inherited Create(True); |
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| 70 | FreeOnTerminate:=True; |
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| 71 | end; |
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| 72 | |||
| 73 | function TMJPEGDecoderThread.CheckConnected: Boolean; |
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| 74 | begin |
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| 75 | if not FClient.Connected then |
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| 76 | begin |
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| 77 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_ERROR,ERROR_MJPEG_DISCONNECT); |
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| 78 | Terminate; |
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| 79 | end; |
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| 80 | Result:=FClient.Connected; |
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| 81 | end; |
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| 82 | |||
| 83 | procedure TMJPEGDecoderThread.Execute; |
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| 84 | var |
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| 85 | S: String; |
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| 86 | CLength: Integer; |
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| 87 | JPEG: TMemoryStream; |
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| 88 | begin |
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| 89 | FActive:=True; |
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| 90 | try |
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| 91 | try |
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| 92 | |||
| 93 | CLength:=0; |
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| 94 | Info('Decoder thread starting execution loop'); |
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| 95 | while (not Terminated) do |
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| 96 | begin |
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| 97 | if not CheckConnected then break; |
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| 98 | |||
| 99 | // grab a header |
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| 100 | Info('Waiting for data...'); |
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| 101 | try |
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| 102 | S:=Trim(LowerCase(FClient.IOHandler.ReadLn)); |
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| 103 | except |
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| 104 | if (not CheckConnected) then break; |
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| 105 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_ERROR,ERROR_MJPEG_EXCEPT); |
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| 106 | Terminate; |
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| 107 | break; |
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| 108 | end; |
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| 109 | Info('Data: '+S); |
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| 110 | |||
| 111 | if not CheckConnected then break; |
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| 112 | |||
| 113 | // if it's a content-length line, record the content length |
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| 114 | if (Copy(S,1,15)='content-length:') then |
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| 115 | begin |
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| 116 | Delete(S,1,15); |
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| 117 | S:=Trim(S); |
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| 118 | CLength:=StrToIntDef(S,0); |
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| 119 | Info('Next frame content length: '+IntToStr(CLength)); |
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| 120 | end; |
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| 121 | |||
| 122 | // if it's a blank line and we have a content-length, then we're good to receive the stream |
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| 123 | if (Length(S)=0) and (CLength>0) then |
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| 124 | begin |
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| 125 | Info('Receiving frame'); |
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| 126 | JPEG:=TMemoryStream.Create; |
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| 127 | JPEG.SetSize(CLength); |
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| 128 | try |
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| 129 | FClient.IOHandler.ReadStream(JPEG,CLength); |
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| 130 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_FRAME,Integer(JPEG)); |
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| 131 | except |
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| 132 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_ERROR,ERROR_MJPEG_BADFRAME); |
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| 133 | Terminate; |
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| 134 | break; |
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| 135 | end; |
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| 136 | Info('Frame received'); |
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| 137 | CLength:=0; |
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| 138 | end; |
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| 139 | |||
| 140 | end; |
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| 141 | Info('Decoder thread execution loop complete'); |
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| 142 | except |
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| 143 | on E: Exception do |
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| 144 | begin |
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| 145 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_ERROR,ERROR_MJPEG_EXCEPT); |
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| 146 | end; |
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| 147 | end; |
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| 148 | finally |
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| 149 | FActive:=False; |
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| 150 | end; |
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| 151 | |||
| 152 | end; |
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| 153 | |||
| 154 | procedure TMJPEGDecoderThread.Info(S: String); |
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| 155 | var Msg: TMJPEGDecoderMsg; |
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| 156 | begin |
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| 157 | exit; |
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| 158 | Msg:=TMJPEGDecoderMsg.Create; |
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| 159 | Msg.Msg:=S; |
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| 160 | PostMessage(FNotifyWindow,WM_USER,MSG_MJPEG_MESSAGE,Integer(Msg)); |
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| 161 | end; |
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| 162 | |||
| 163 | end. |
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| 164 |