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|
{MP3 file process}
unit fmt_MP3;
{$include compilers.inc}
interface
uses wat_api;
function ReadMP3(var Info:tSongInfo):boolean; cdecl;
function ReadMPG(var Info:tSongInfo):boolean; cdecl;
implementation
uses windows,common,io,tags,srv_format;
const
ScanSize = 16*1024; // block size to search header
type
tMP3FrameHdr = record
Version :integer;
Layer :cardinal;
Bitrate :cardinal;
Samplerate:cardinal;
Channel :cardinal; //Stereo, Joint, Dual, Mono
Length :cardinal;
CRC :boolean;
_Private :boolean;
Copyright :boolean;
Original :boolean;
isVBR :boolean;
end;
// ........ ........ 111..... 11111111 syncword
// ........ ........ ...xx... ........ version (11=1, 10=2, 00=2.5)
// ........ ........ .....xx. ........ layer (01=III, 10=II, 11=I)
// ........ ........ .......x ........ crc (0=yes, 1=no)
// xx...... ........ ........ ........ mode (00=stereo, 10=joint, 01=dual, 11=mono)
// ..xx.... ........ ........ ........ mode ext (only for joint stereo)
// ....x... ........ ........ ........ copyright (0=no, 1=yes)
// .....x.. ........ ........ ........ original (0=orig, 1=copy)
// ......xx ........ ........ ........ emphasis (not 10)
// ........ xxxx.... ........ ........ bitrate (not 0000 nor 1111)
// ........ ....xx.. ........ ........ sampling rate (not 11)
// ........ ......x. ........ ........ padded (0=no, 1=yes)
// ........ .......x ........ ........ private bit
const
btable:array [0..1,0..2,0..15] of word = (
( //MPEG 2 & 2.5
(0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0), //Layer III
(0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0), //Layer II
(0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256,0) //Layer I
),( //MPEG 1
(0, 32, 40, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,0), //Layer III
(0, 32, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,384,0), //Layer II
(0, 32, 64, 96,128,160,192,224,256,288,320,352,384,416,448,0) //Layer I
)
);
stable: array [0..3,0..2] of word = (
(32000, 16000, 8000), //MPEG 2.5
( 0, 0, 0), //reserved
(22050, 24000, 16000), //MPEG 2
(44100, 48000, 32000) //MPEG 1
);
procedure TranslateFrameHdr(const block:array of byte;var MP3FrameHdr:tMP3FrameHdr);
begin
FillChar(MP3FrameHdr,SizeOf(MP3FrameHdr),0);
if block[0]=$FF then
begin
with MP3FrameHdr do
begin
Version :=(block[1] and $18) shr 3;
Layer :=(block[1] and $06) shr 1;
CRC :=not Odd(block[1]);
Bitrate :=btable[Version and 1][Layer-1][block[2] shr 4];
Samplerate:=stable[Version][(block[2] and $0C) shr 2];
_Private :=odd(block[2]);
Channel :=block[3] shr 6;
Copyright :=((block[3] and $08) shr 3)<>0;
Original :=((block[3] and $04) shr 2)<>0;
end;
end;
end;
procedure CheckVBR(f:THANDLE; var hdr:tMP3FrameHdr);
var
pos,apos:cardinal;
sign:longint;
frames:longint;
begin
pos:=FilePos(f);
hdr.Length:=0;
if hdr.Version=3 then
begin
if hdr.Channel=3 then
apos:=17
else
apos:=32;
end
else if hdr.Channel=3 then
apos:=9
else
apos:=17;
Skip(f,apos);
BlockRead(f,sign,4);
hdr.isVBR:=sign=$676E6958; //Xing
//calculate length
if hdr.isVBR then
begin
if hdr.Samplerate<>0 then
begin
// Seek(f,pos+36);
BlockRead(f,sign,4);
if (sign and $01000000)<>0 then
begin
BlockRead(f,frames,4);
frames:=BSwap(frames);
hdr.Length:=Round((1152/hdr.Samplerate)*frames/(4-hdr.Version)); //!
end;
end;
end
else if hdr.Bitrate<>0 then
hdr.Length:=((8*(FileSize(f)-(pos-4))) div 1000) div hdr.Bitrate;
end;
function SearchStart(f:THANDLE; var l:array of byte):Boolean;
var
CurPos:longint;
Buf:array [0..ScanSize] of byte;
i,j:integer;
begin
CurPos:=FilePos(f)-4;
Seek(f,CurPos);
j:=BlockRead(f,Buf,ScanSize);
i:=0;
while i<j do
begin
if (i<(j-2)) and (Buf[i]=$FF) and //FF FB E4
((Buf[i+1] and $E0)=$E0) and
((Buf[i+2] and $F0)<>$F0) then
begin
Seek(f,CurPos+i);
BlockRead(f,l,4);
result:=true;
Exit;
end;
inc(i);
end;
result:=false;
end;
function ReadMP3(var Info:tSongInfo):boolean; cdecl;
var
f:THANDLE;
l:array [0..3] of byte;
hdr:tMP3FrameHdr;
begin
result:=false;
f:=Reset(Info.mfile);
if f=THANDLE(INVALID_HANDLE_VALUE) then
exit;
ReadID3v2(f,Info);
BlockRead(f,l,4);
// if l[0]<>$FF then
if not SearchStart(f,l) then
begin
CloseHandle(f);
Exit;
end;
TranslateFrameHdr(l,hdr);
CheckVBR(f,hdr);
Info.kbps :=hdr.Bitrate;
Info.khz :=hdr.Samplerate div 1000;
Info.total:=hdr.Length;
if hdr.Channel=3 then
Info.channels:=1
else
Info.channels:=2;
Info.vbr:=ord(hdr.isVBR);
ReadAPEv2(f,Info);
ReadID3v1(f,Info);
CloseHandle(f);
result:=true;
end;
const
mpgAudio = 1;
mpgVideo = 2;
mpgVersion = 4;
type
l2b=array [0..3] of byte;
function ReadDWord(var p:pAnsiChar;endptr:pAnsiChar):integer;
begin
if (p+4)<endptr then
begin
result:=pDWord(p)^;
inc(p,4);
end
else
result:=-1;
end;
function ReadWord(var p:pAnsiChar;endptr:pAnsiChar):integer;
begin
if (p+2)<endptr then
begin
result:=pWord(p)^;
inc(p,2);
end
else
result:=-1;
end;
function ReadByte(var p:pAnsiChar;endptr:pAnsiChar):integer;
begin
if p<endptr then
begin
result:=pByte(p)^;
inc(p);
end
else
result:=-1;
end;
function ChunkRead(var p:pAnsiChar;endptr:pAnsiChar):integer;
var
i:integer;
begin
repeat
if ReadByte(p,endptr)=0 then
if ReadByte(p,endptr)=0 then
begin
repeat
i:=ReadByte(p,endptr);
until i<>0;
if i=1 then
begin
result:=ReadByte(p,endptr) or $100;
exit;
end;
end;
until p>=endptr;
result:=0;
end;
const
BufSize = 256*1024;
function ReadMPG(var Info:tSongInfo):boolean; cdecl;
var
endptr,buf,p:PAnsiChar;
f:THANDLE;
BlockType:integer;
l:dword;
w:word;
b:byte;
flag:integer;
version,layer:integer;
// vbitrate:integer;
// FrmCnt:integer;
begin
result:=false;
f:=Reset(Info.mfile);
if f=THANDLE(INVALID_HANDLE_VALUE) then
exit;
flag:=mpgAudio+mpgVideo+mpgVersion;
mGetMem(buf,BufSize);
endptr:=buf+BlockRead(f,buf^,BufSize);
CloseHandle(f);
p:=buf;
// FrmCnt:=0;
while (flag<>0) and (p<endptr) do
begin
BlockType:=ChunkRead(p,endptr);
case BlockType of
$1BA: begin // pack
if (flag and mpgVersion)<>0 then
begin
flag:=flag and not mpgVersion;
if (ReadByte(p,endptr) and $C0)=$40 then
Info.codec:=$3247504D // MPG2
else
Info.codec:=$4745504D; // MPEG
end;
end;
$1B3: begin // Video
if (flag and mpgVideo)<>0 then
begin
l:=ReadDWord(p,endptr);
flag:=flag and not mpgVideo;
Info.width :=((l2b(l)[1] and $F0) shr 4)+(l2b(l)[0] shl 4);
Info.height:=((l2b(l)[1] and $0F) shl 8)+l2b(l)[2];
case l2b(l)[3] and $F of
1: Info.fps:=2397;
2: Info.fps:=2400;
3: Info.fps:=2500;
4: Info.fps:=2997;
5: Info.fps:=3000;
6: Info.fps:=5000;
7: Info.fps:=5994;
8: Info.fps:=6000;
end;
// BlockRead(f,l,4);
// vbitrate:=(l2b(l)[0] shl 10)+(l2b(l)[1] shl 2)+(l2b(l)[2] shr 6);
end;
end;
0,$1B7,$1B9: break;
{
$1E0: begin
BlockRead(f,w,2);
w:=swap(w);
mGetMem(buf,w);
BlockRead(f,buf^,w);
p:=buf;
for l:=0 to w-4 do
begin
if pdword(p)^=$00010000 then
begin
inc(FrmCnt);
inc(p,4);
end
else
inc(p);
end;
mFreeMem(buf);
end;
}
$1C0: begin // audio
w:=swap(ReadWord(p,endptr));
if flag and mpgAudio<>0 then
begin
flag:=flag and not mpgAudio;
b:=ReadByte(p,endptr);
dec(w);
if (b and $C0)=$80 then
begin
b:=ReadByte(p,endptr);
l:=ReadByte(p,endptr);
dec(w,2);
if (b and $80)<>0 then
begin
inc(p,5);
dec(w,5);
dec(l,5);
if (b and $40)<>0 then
begin
inc(p,5);
dec(w,5);
dec(l,5);
end;
end;
if l>0 then
begin
inc(p,l);
dec(w,l);
end;
end
else
begin
while (b and $80)<>0 do
begin
dec(w);
if w=0 then break;
b:=ReadByte(p,endptr);
end;
if (b and $40)<>0 then
begin
inc(p);
b:=ReadByte(p,endptr);
dec(w,2);
end;
if (b and $20)<>0 then
begin
inc(p,4);
dec(w,4);
if (b and $10)<>0 then
begin
inc(p,5);
dec(w,5);
end;
end;
end;
l:=ReadDWord(p,endptr);
version:=(l2b(l)[1] and $18) shr 3;
layer :=(l2b(l)[1] and $06) shr 1;
Info.kbps :=btable[version and 1][layer-1][l2b(l)[2] shr 4];
Info.khz :=(stable[version][(l2b(l)[2] and $0C) shr 2]) div 1000;
Info.channels:=l2b(l)[3] shr 6;
if Info.channels=3 then
Info.channels:=1
else
Info.channels:=2;
// if w>0 then inc(p,w);
end;
// else
inc(p,w);
end;
{
$1B5: begin
BlockRead(f,l,4);
if (l2b(l)[0] and $F0)=$10 then
begin
vbitrate:=vbitrate+
((((l2b(l)[2] and $1F) shl 7)+(l2b(l)[3] shr 1)) shl 18);
end;
end;
}
{
$1BD: begin
end;
}
$1C1..$1DF, // audio
//?? $1E0,
$1E1..$1EF, // video
$1BB{,$1BD},$1BE,$1BF: begin // system,private,padding,private
inc(p,swap(ReadWord(p,endptr)));
end;
end;
end;
// vbitrate:=(vbitrate*400) div 1000;
// Info.total:=(FrmCnt*100) div Info.fps;
mFreeMem(buf);
result:=true;
end;
var
LocalFormatLinkMP3,
LocalFormatLinkMPG,
LocalFormatLinkMPEG:twFormat;
procedure InitLink;
begin
LocalFormatLinkMP3.Next:=FormatLink;
LocalFormatLinkMP3.This.proc :=@ReadMP3;
LocalFormatLinkMP3.This.ext :='MP3';
LocalFormatLinkMP3.This.flags:=0;
FormatLink:=@LocalFormatLinkMP3;
LocalFormatLinkMPG.Next:=FormatLink;
LocalFormatLinkMPG.This.proc :=@ReadMPG;
LocalFormatLinkMPG.This.ext :='MPG';
LocalFormatLinkMPG.This.flags:=WAT_OPT_VIDEO;
FormatLink:=@LocalFormatLinkMPG;
LocalFormatLinkMPEG.Next:=FormatLink;
LocalFormatLinkMPEG.This.proc :=@ReadMPG;
LocalFormatLinkMPEG.This.ext :='MPEG';
LocalFormatLinkMPEG.This.flags:=WAT_OPT_VIDEO;
FormatLink:=@LocalFormatLinkMPEG;
end;
initialization
InitLink;
end.
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