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>
' g) ]  a9 I, k- J. ^" B<>TSuperPlayerform *SuperPlayerform;
typedef struct
# ^& F* c8 w% h {
  B% m3 O* t* r& d) G# r5 d2 Z    DWORD dwCallback;
3 D" Y" p; \5 L! E7 _5 ^; ?    DWORD dwItem;
8 I" B# E: W, k1 `+ U& m8 y    DWORD dwValue;
) E: S0 `! h7 b% k3 z    DWORD dwOver;
    LPSTR lpstrAlgorithm;
    LPSTR lpstrQuality;
; S" Y9 g* R7 x/ h8 b } MCI_DGV_SETAUDIO_PARMS;
5 q6 @5 Y1 I0 ^& l) ]: r8 m   
const MCI_SETAUDIO = 0x873;
const MCI_SETVIDEO = 0x0876;
$ S9 Q; [9 L; T3 M9 ?5 m; K4 _ const MCI_DGV_SETAUDIO_SOURCE_LEFT=1;
% ]* q/ a' Q- x  R, O5 y const MCI_DGV_SETAUDIO_SOURCE_STEREO=0;
. g5 l* U& x/ Y4 k" p5 ? const MCI_DGV_SETAUDIO_SOURCE_RIGHT=2;
const MCI_DGV_SETAUDIO_SOURCE=0x4004;
const MCI_DGV_SETAUDIO_VOLUME=0x4002;
const MAX_VOLUME=65535;
) U0 q9 n2 h# W const MIN_VOLUME=0;</P>
<>void __fastcall TSuperPlayerform:RC(char &amp;S)
& d4 \" R# [; }1 @2 H {
9 C9 d0 ^, o% o0 t& G  //char str;
& _! M; W; L# n9 ]7 B  MCI_DGV_SETAUDIO_PARMS s;
& w% X) c1 j0 b0 ]+ p6 p  int err;
  char buf[1001];
+ H$ c/ Q& y& C5 V' M  //str=''L'';
  if (MediaPlayer1-&gt;DeviceID&gt;0)
/ Q7 \) z# i- Y3 j7 P+ B  {
9 m/ \! w: @% I" j0 V    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO,MCI_SET_OFF,int(&amp;s));
1 O2 Q$ S+ m+ q2 D3 ~& ^- Y    if (err!=0)
       mciGetErrorString(err,buf,sizeof(buf) );
    if (S=='C')
       s.dwValue=MCI_DGV_SETAUDIO_SOURCE_STEREO;
    if (S=='L')
& ~# k; b- a) I* z8 U       s.dwValue=MCI_DGV_SETAUDIO_SOURCE_LEFT;
  a6 J" [  @8 x4 s  d    if (S=='R') s.dwValue=MCI_DGV_SETAUDIO_SOURCE_RIGHT;
5 V+ H0 [6 }. Z$ v       s.dwItem=MCI_DGV_SETAUDIO_SOURCE;
    const MCI_DGV_SETAUDIO_VALUE=0x01000000L;
    const MCI_DGV_SETAUDIO_ITEM=0x00800000L;
* G6 d+ l/ X+ {1 @, K. E    //(MCI_DGV_SETAUDIO_VALUE||MCI_DGV_SETAUDIO_ITEM)=0x01800000
- W" o+ W8 F3 ~2 m2 P& o8 u) Y' w" d, Q    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO,0x01800000,int(&amp;s));
    if (err!=0)
8 w7 r& }) ?% P  u       mciGetErrorString(err,buf,sizeof(buf) );
# T4 Z* N- l- }; X    err=mciSendCommand(MediaPlayer1-&gt;DeviceID,MCI_SETAUDIO, MCI_SET_ON ,int(&amp;s));
    if (err!=0)
* k0 {. g+ Y1 N: p6 N      mciGetErrorString(err,buf,sizeof(buf) );
   }
3 u' l& R& H6 o0 N9 ?( @ }</P>
<> void __fastcall TSuperPlayerform::popnosoundClick(TObject *Sender)
) F+ m- P' o' s: Q' _$ j {
/ J. S" d$ y, M  M) P, ?+ R     LRC('L');
0 V5 H/ Q  E/ `% ]: j     Label3-&gt;Caption=“左声道 ";
     tempchannel='L';
}
* s3 g' ~: J. z+ j; j3 R- I//---------------------------------------------------------------------------</P>
<> void __fastcall TSuperPlayerform::popsoundClick(TObject *Sender)
{
     LRC('R');
     Label3-&gt;Caption="右声道 ";
% Z7 g. ?$ s( M     tempchannel='R';
9 _' V  Z7 _6 O: g4 P# U }
//---------------------------------------------------------------------------</P>
<> void __fastcall TSuperPlayerform::steroClick(TObject *Sender)
{
     LRC('C');
     Label3-&gt;Caption="立体声 ";
     tempchannel='C';
8 n3 z7 [4 f$ O! j5 s3 ~ }</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)
3 b+ u/ }& ^  LlReturn=mciSendString("set right off",sReturn,32,0)
) v' d3 }- V! t2 ]- d' y4 M7 S3 @+ blReturn=mciSendString("setaudio left off",sReturn,32,0)
lReturn=mciSendString("setaudio right off",sReturn,32,0)
; |: ^2 k, Y7 D2 q7 P2 y  C1 t# x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。
' l4 U' Y; ?, K  D$ ?要想关闭左右声道可以这样：
lReturn=mciSendString("setaudio source to left",sReturn,32,0) '仅开左声道
; e+ [. w" _! llReturn=mciSendString("setaudio source to right",sReturn,32,0) '仅开右声道
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>