用ACM控件进行语音通信，在回放中遇到问题，帮帮忙。(50分)

我用indy控件接收后，用acmout进行回放，但是它提示说“stream read error”
下面是接收部分代码，我是初学者，请帮忙。。。。
procedure TUDPMainForm.UDPServerUDPRead(Sender: TObject;
AData: TStream;
ABinding: TIdSocketHandle);
var
DataStringStream: TStringStream;
s: string;
begin

with GSM610do
begin

wFormatTag := $31;
nChannels := 1;
wBitsPerSample := 0;
nSamplesPerSec := 8000;
nBlockAlign := 65;
nAvgBytesPerSec := 1625;
cbSize := 2;
wSamplesPerBlock := $140;
end;

ACMFormat := @GSM610;
ACMWaveOut1.Open(ACMFormat);
ss:= TMemoryStream.Create;
try
ss.CopyFrom(AData,AData.Size) ;
ACMWaveOut1.PlayBack(ss.Memory, ss.Size);
finally
ss.Free;
end;

end;