1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,
System.DateUtils,
Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Label1: TLabel;
procedure Button1Click(Sender: TObject);
private
{ Déclarations privées }
function MP4Duration(const AFileName: string): string;
public
{ Déclarations publiques }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
function LSwap(C: Cardinal): Cardinal;
begin
Result := Swap(C) shl 16 + Swap(C shr 16);
end;
function LLSwap(L: UInt64): UInt64;
begin
Result := LSwap(L) shl 32 + LSwap(L shr 32);
end;
function GetMP4Duration(const AFileName: string; var Duration: Int64): Boolean;
type
TMP4Chunk = packed record
Size: Cardinal;
Tag : array[0..3] of AnsiChar;
end;
TMP4Mvhd = packed record
Ver: Byte;
Flags: array[0..2] of Byte;
case Boolean of
True: (
Creation1, Modified1: UInt64;
Timescale1: Cardinal;
Duration1: UInt64;
);
False: (
Creation2, Modified2: Cardinal;
Timescale2: Cardinal;
Duration2: Cardinal;
);
end;
var
S: TFileStream;
H: TMP4Chunk;
M: TMP4Mvhd;
begin
Result := False;
S := TfileStream.Create(AFileName, fmOpenRead or fmShareDenyNone);
try
S.ReadBuffer(H, SizeOf(H)); // lecture d'un entête MP4
if H.Tag <> 'ftyp' then // vérification du type
Exit(False);
repeat
H.Size := LSwap(H.Size);
S.Seek(H.Size - SizeOf(H), TSeekOrigin.soCurrent); // sauter la section
S.ReadBuffer(H, SizeOf(H)); // lire la suivante
until H.Tag = 'moov'; // jusqu'au "moov"
S.ReadBuffer(H, SizeOf(H)); // lire dans "moov"
while H.Tag <> 'mvhd' do // jusque "mvhd"
begin
H.Size := LSwap(H.Size);
S.Seek(H.Size - SizeOf(H), TSeekOrigin.soCurrent);
S.ReadBuffer(H, SizeOf(H));
end;
S.ReadBuffer(M, SizeOf(M)); // lire son contenu
if M.Ver = 1 then // en fonction de la version
begin
M.Duration2 := LLSwap(M.Duration2); // non testé !
M.Timescale1 := LSwap(M.Timescale1);
Duration := M.Duration1 div M.Timescale1;
end else begin
M.Duration2 := LSwap(M.Duration2);
M.Timescale2 := LSwap(M.Timescale2);
Duration := M.Duration2 div M.Timescale2; // calculé la durée en secondes
end;
Result := True;
finally
S.Free;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
Str: string;
begin
if PromptForFileName(Str, '*.mp4') then
Label1.Caption := MP4Duration(Str);
end;
function TForm1.MP4Duration(const AFileName: string): string;
var
Duration: Int64;
H,M,S : Word;
Date : TDateTime;
begin
if GetMP4Duration(AFileName, Duration) then
begin
M := Duration div 60;
S := Duration - 60 * M;
H := M div 60;
Dec(M, H * 60);
Date := Encodetime(H, M, S, 0); // durée en Time
Result := TimeToStr(Date); // pour faciliter le formatage
end else begin
Result := 'Unknown';
end;
end;
end. |
