声卡过滤驱动问题

有人碰到过这个问题吗？我写了一个声卡的upper过滤驱动，在IOCTL_KS_WRITE_STREAM中获取到KSSTREAM_HEADER结构数据，可是根据这个结构获取到的数据长度和app播放的wave数据长度不一样，小很多，不知道为什么？
 

00000000    10:36:09.937    AudioFilter ->I am IRP_MJ_CREATE    
00000001    10:36:09.937    EmptyPacketList(), Count=0    
00000002    10:36:11.546    [1892] data size=171008, m_WaveLong=171008, 0xd40068    
00000014    10:36:11.734        
00000015    10:36:11.734    AudioFilter: nSamplesPerSec = 22050    
00000016    10:36:11.734    AudioFilter: nAvgBytesPerSec= 88200    
00000017    10:36:11.734    AudioFilter: nChannels      = 2    
00000018    10:36:11.734    AudioFilter: wBitsPerSample = 16    
00000019    10:36:11.734    AudioFilter: wFormatTag     = 1    
00000020    10:36:11.734        
00000021    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000022    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000023    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000024    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000025    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000026    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000027    10:36:11.734    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000028    10:36:11.734    [1892] nAvgBytesPerSec=88200    
00000029    10:36:11.750    [1892] nSamplesPerSec=22050    
00000030    10:36:11.750    [1892] nChannels=2    
00000031    10:36:11.750    [1892] wBitsPerSample=16    
00000032    10:36:11.750    [1892] wFormatTag=1    
00000033    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_RUN    
00000034    10:36:11.750    OutputBuffer=0x81a82000, Data=0x81a83000, OutputLength=48    
00000035    10:36:11.750    OutputBuffer=0x81a82030, Data=0x81a87000, OutputLength=48    
00000036    10:36:11.750    OutputBuffer=0x81a82060, Data=0x81a8b000, OutputLength=48    
00000037    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_RUN    
00000038    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_RUN    
00000039    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_RUN    
00000040    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000041    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000042    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000043    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000044    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000045    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_PAUSE    
00000046    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000047    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_ACQUIRE    
00000048    10:36:11.750    DataUsed=880, FrameExtent=16008, TypeSpecificFlags=0x0, OptionsFlags=0x10    
00000049    10:36:11.750    DataUsed=884, FrameExtent=16008, TypeSpecificFlags=0x0, OptionsFlags=0x10    
00000050    10:36:11.750    DataUsed=880, FrameExtent=16008, TypeSpecificFlags=0x0, OptionsFlags=0x10    
00000051    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_STOP    
00000052    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_STOP    
00000053    10:36:11.750    AudioFilter: return KSSTATE = KSSTATE_STOP    
00000054    10:36:14.046    AudioFilter: IOCTL_AUDIO_FORMAT    
00000055    10:36:14.046    AudioFilter: nSamplesPerSec = 22050    
00000056    10:36:14.046    AudioFilter: nAvgBytesPerSec= 88200    
00000057    10:36:14.046    AudioFilter: nChannels      = 2    
00000058    10:36:14.046    AudioFilter: wBitsPerSample = 16    
00000059    10:36:14.046    AudioFilter: wFormatTag     = 1    
00000060    10:36:14.046        
00000061    10:36:15.062    AudioFilter ->I am IRP_MJ_CLEANUP    
00000062    10:36:15.062    AudioFilter ->I am IRP_MJ_CLOSE