关于多媒体播放器VCD左右声道问题的BC代码

kmusttywyc

<>关于多媒体播放器在CB下声道转换的原代码！（DEPHI版的网上有）</P>
<>TSuperPlayerform *SuperPlayerform;
typedef struct
/ q3 t$ }+ |( ?* O2 O {
% w% x7 S; v  {+ X; H- L6 G1 Q( b( `    DWORD dwCallback;
    DWORD dwItem;
    DWORD dwValue;
7 e6 p- X) ]& [& r2 P* W    DWORD dwOver;
    LPSTR lpstrAlgorithm;
9 ]( h: k3 e+ V# J    LPSTR lpstrQuality;
} MCI_DGV_SETAUDIO_PARMS;
7 Z5 o# a4 [, H   
const MCI_SETAUDIO = 0x873;
# g% t$ s" m" W7 Z; f5 E const MCI_SETVIDEO = 0x0876;
# Y3 Z: a% w2 W' p const MCI_DGV_SETAUDIO_SOURCE_LEFT=1;
const MCI_DGV_SETAUDIO_SOURCE_STEREO=0;
const MCI_DGV_SETAUDIO_SOURCE_RIGHT=2;
# f6 {$ X# m! u+ v const MCI_DGV_SETAUDIO_SOURCE=0x4004;
* P4 p- |% s7 P/ L# Z- j5 b const MCI_DGV_SETAUDIO_VOLUME=0x4002;
4 R: P, x8 i7 w) h3 C+ j# _ const MAX_VOLUME=65535;
6 U1 C, E5 N8 F4 J const MIN_VOLUME=0;</P>
& W, o: M" M/ u0 V/ M<>void __fastcall TSuperPlayerform:RC(char &amp;S)
. |* Q/ C( b2 v* t1 u# S5 s {
  //char str;
7 a( ?+ N2 f! J4 L- k+ m% X; G; j  MCI_DGV_SETAUDIO_PARMS s;
  int err;
5 U. d- w9 Y2 m  F  char buf[1001];
  //str=''L'';
  if (MediaPlayer1-&gt;DeviceID&gt;0)
  {
% w# E+ e& @# S3 r/ |7 H% o    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO,MCI_SET_OFF,int(&amp;s));
    if (err!=0)
       mciGetErrorString(err,buf,sizeof(buf) );
; v- f  R- e" g  L    if (S=='C')
; {6 w1 q& }, I       s.dwValue=MCI_DGV_SETAUDIO_SOURCE_STEREO;
0 Q6 A% Z' f( P* m7 x& q* V    if (S=='L')
# Y9 o7 ]+ x1 S  K: V  l2 n       s.dwValue=MCI_DGV_SETAUDIO_SOURCE_LEFT;
0 h& ?0 g! G/ X    if (S=='R') s.dwValue=MCI_DGV_SETAUDIO_SOURCE_RIGHT;
7 L6 J4 S7 f; @' A; w$ Y       s.dwItem=MCI_DGV_SETAUDIO_SOURCE;
    const MCI_DGV_SETAUDIO_VALUE=0x01000000L;
0 g) K  g- v9 T; C5 L( q    const MCI_DGV_SETAUDIO_ITEM=0x00800000L;
    //(MCI_DGV_SETAUDIO_VALUE||MCI_DGV_SETAUDIO_ITEM)=0x01800000
+ P7 a# G! O% T" O$ X    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO,0x01800000,int(&amp;s));
    if (err!=0)
       mciGetErrorString(err,buf,sizeof(buf) );
* R$ b0 r8 M% B8 G5 u    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO, MCI_SET_ON ,int(&amp;s));
    if (err!=0)
7 q( d1 X4 B4 g. s+ H$ p/ g2 p9 s+ Y      mciGetErrorString(err,buf,sizeof(buf) );
   }
4 g  F7 H% L  k$ f6 M$ @, r) o5 i" v1 [ }</P>
# m" @3 Z( W. c+ O8 Y- f$ K<> void __fastcall TSuperPlayerform::popnosoundClick(TObject *Sender)
{
     LRC('L');
" V( R- ]: J* H5 z( G$ d6 a     Label3-&gt;Caption=“左声道 ";
- D- c, W( R- I* T1 F- L     tempchannel='L';
3 Z! q* ~1 O. \9 y9 k% ~" @ }
- n7 i+ ^0 M; V! x! t% _/ i//---------------------------------------------------------------------------</P>
<> void __fastcall TSuperPlayerform::popsoundClick(TObject *Sender)
{
# l. x4 Y  l- D7 l/ L2 x3 d  x     LRC('R');
  L4 I! w8 L" l+ T7 q9 M$ s) g4 j     Label3-&gt;Caption="右声道 ";
. q; U# u# \3 P' I: M" a     tempchannel='R';
}
2 {" V9 t' H& E) b% T//---------------------------------------------------------------------------</P>
<> void __fastcall TSuperPlayerform::steroClick(TObject *Sender)
{
     LRC('C');
+ K% @# Q6 ]. c" a6 K2 ?7 K     Label3-&gt;Caption="立体声 ";
: [/ f; y! B2 ]     tempchannel='C';
- L8 ]' i' y6 V, p# T9 Y }</P>

ilikenba

<>左右声道的设置代码！从网上找到的！</P><>lReturn=mciSendString("set left off",sReturn,32,0)
lReturn=mciSendString("set right off",sReturn,32,0)
lReturn=mciSendString("setaudio left off",sReturn,32,0)
3 B: D4 m9 R3 Q& r4 A. y& y  wlReturn=mciSendString("setaudio right off",sReturn,32,0)
确切地说，以上四句关闭的并不是左右声道，而是左右音箱。由于通常的多媒体音频流多是立体声的，并不是左音箱播放的完全是左声道的音频流，其中掺入轻微的右声道声音，以达到更好的立体效果。
要想关闭左右声道可以这样：
, h4 _9 w. o) @) dlReturn=mciSendString("setaudio source to left",sReturn,32,0) '仅开左声道
lReturn=mciSendString("setaudio source to right",sReturn,32,0) '仅开右声道
7 ?" h+ ~8 P, f; @lReturn=mciSendString("setaudio source to average",sReturn,32,0) '左右平均
lReturn=mciSendString("setaudio source to stereo",sReturn,32,0) '立体声，这是默认设置</P>