Java 为什么我的libVLC程序在尝试绑定捕获设备时会死锁？

这是我最初在VideoLan论坛（）上发布的一个问题，但VideoLan支持工作过度，无论如何，我无法判断这是libVLC、JNA还是VLCj实现的问题，所以我想我会询问StackOverflow，看看是否有人有任何线索

大家好

我正在用Groovy在WindowsXP上用VLCj编写一个自动转码器。我的捕获设备是Epiphan VGA2USB LR framegrabber设备，我通过DirectShow连接到该设备。在这一点上，我只是试图记录任何数据从这个设备到一个文件，但到目前为止，我没有运气。我知道该设备与VLC兼容-我可以使用VLC GUI打开该设备并在屏幕上查看其输出

修复了以前困扰我的各种配置问题后，我现在发现当我尝试开始录制时，VLC似乎挂起。这是我得到的输出，用什么时间发生的事情注释：

[00384d30] main libvlc debug: VLC media player - 2.0.2 Twoflower
[00384d30] main libvlc debug: Copyright � 1996-2012 VLC authors and VideoLAN
[00384d30] main libvlc debug: revision 2.0.2-14-gbc2c368
[00384d30] main libvlc debug: configured with ../extras/package/win32/../../../configure  '--enable-update-check' '--enable-lua' '--enable-faad' '--enable-flac' '--enable-theora' '--enable-twolame' '--enable-quicktime' '--enable-avcodec' '--enable-merge-ffmpeg' '--enable-dca' '--enable-mpc' '--enable-libass' '--enable-x264' '--enable-schroedinger' '--enable-realrtsp' '--enable-live555' '--enable-dvdread' '--enable-shout' '--enable-goom' '--enable-caca' '--disable-portaudio' '--disable-sdl' '--enable-qt4' '--enable-skins2' '--enable-sse' '--enable-mmx' '--enable-libcddb' '--enable-zvbi' '--disable-telx' '--enable-sqlite' '--disable-dirac' '--host=i586-mingw32msvc' '--enable-crystalhd' 'host_alias=i586-mingw32msvc'
[00384d30] main libvlc debug: searching plug-in modules
[00384d30] main libvlc debug: loading plugins cache file C:\Documents and Settings\Administrator\digitizer\lib\libvlc-2.0.2\plugins\plugins.dat
[00384d30] main libvlc debug: recursively browsing `C:\Documents and Settings\Administrator\digitizer\lib\libvlc-2.0.2\plugins'
[00384d30] main libvlc debug: saving plugins cache C:\Documents and Settings\Administrator\digitizer\lib\libvlc-2.0.2\plugins\plugins.dat
[00384d30] main libvlc debug: plug-ins loaded: 388 modules
[00384d30] main libvlc debug: translation test: code is "C"
[00384d30] main libvlc debug: CPU has capabilities MMX MMXEXT SSE SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 FPU 
[00384d30] main libvlc debug: looking for memcpy module: 4 candidates
[00384d30] main libvlc debug: using memcpy module "memcpymmxext"
[0038c568] main interface debug: looking for interface module: 1 candidate
[0038c568] main interface debug: using interface module "hotkeys"
[0038c568] main interface debug: TIMER module_need() : 0.033 ms - Total 0.033 ms / 1 intvls (Avg 0.033 ms)

[这是代码中调用play（）的地方]

24-07-2012 14:05:45 Digitizer: [DEBUG] Recording test-capture.mp4 start
[03f59340] main input debug: Creating an input for 'dshow://'
[03f5d578] main stream output debug: using sout chain=`transcode{vcodec=mp4v,vb=1024,scale=1}:standard{access=file,mux=mp4,dst="test-capture.mp4"}'
[03f5d578] main stream output debug: stream=`standard'
[03f4eb60] main stream out debug: looking for sout stream module: 1 candidate
[03f4eb60] main stream out debug: set config option: sout-standard-access to file
[03f4eb60] main stream out debug: set config option: sout-standard-mux to mp4
[03f4eb60] main stream out debug: set config option: sout-standard-dst to test-capture.mp4
[03f47c48] main access out debug: looking for sout access module: 1 candidate
[03f61ab8] main playlist debug: playlist threads correctly activated
[03f47c48] access_output_file access out debug: file access output opened (test-capture.mp4)
[03f47c48] main access out debug: using sout access module "access_output_file"
[03f47c48] main access out debug: TIMER module_need() : 1.176 ms - Total 1.176 ms / 1 intvls (Avg 1.176 ms)
[0038cbd8] main mux debug: looking for sout mux module: 1 candidate
[0038cbd8] mux_mp4 mux debug: Mp4 muxer opened
[0038cbd8] main mux debug: using sout mux module "mux_mp4"
[0038cbd8] main mux debug: TIMER module_need() : 0.907 ms - Total 0.907 ms / 1 intvls (Avg 0.907 ms)
[03f4eb60] stream_out_standard stream out debug: using `file/mp4://test-capture.mp4'
[03f4eb60] main stream out debug: using sout stream module "stream_out_standard"
[03f4eb60] main stream out debug: TIMER module_need() : 4.965 ms - Total 4.965 ms / 1 intvls (Avg 4.965 ms)
[03f5d578] main stream output debug: stream=`transcode'
[03f4ad70] main stream out debug: looking for sout stream module: 1 candidate
[03f4ad70] main stream out debug: set config option: sout-transcode-vcodec to mp4v
[03f4ad70] main stream out debug: set config option: sout-transcode-vb to 1024
[03f4ad70] main stream out debug: set config option: sout-transcode-scale to 1
[03f4ad70] stream_out_transcode stream out debug: codec video=mp4v 0x0 scaling: 1.000000 1024kb/s
[03f4ad70] main stream out debug: using sout stream module "stream_out_transcode"
[03f4ad70] main stream out debug: TIMER module_need() : 0.976 ms - Total 0.976 ms / 1 intvls (Avg 0.976 ms)
[03f59340] main input debug: using timeshift granularity of 50 MiB, in path 'C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp'
24-07-2012 14:05:45 Digitizer: [DEBUG] Recording started
[03f59340] main input debug: `dshow://' gives access `dshow' demux `' path `'
[03f59340] main input debug: creating demux: access='dshow' demux='' location='' file='(null)'
[03f4a898] main demux debug: looking for access_demux module: 1 candidate
[03f4a898] dshow demux debug: dshow-vdev: VGA2USB LR V3U48015
[03f4a898] dshow demux debug: dshow-adev: 
[03f61ab8] main playlist debug: rebuilding array of current - root Playlist
[03f61ab8] main playlist debug: rebuild done - 0 items, index -1
[03f4a898] dshow demux debug: found device: VGA2USB LR V3U48015
[03f4a898] dshow demux debug: found device: VGA2USB LR V4U120503
[03f4a898] dshow demux debug: asking for device: VGA2USB LR V3U48015
[03f4a898] dshow demux debug: asked for VGA2USB LR V3U48015, binding to VGA2USB LR V3U48015

[此时，执行停止。从不同线程调用player.stop（）将无限期阻塞。]

[以下是从其他线程调用运行时关闭过程后的输出：]

[03f4a898] dshow demux debug: using device: VGA2USB LR V3U48015
[03f4a898] dshow demux debug: EnumDeviceCaps: output pin: Capture
[03f4a898] dshow demux debug: EnumDeviceCaps: trying pin Capture
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin default format configured
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts chroma: RV24, width:1024, height:768, fps:59.900326
[03f4a898] dshow demux debug: CaptureFilter::JoinFilterGraph
[03f4a898] dshow demux debug: connecting filters
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::ConnectedTo [not connected]
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::QueryFilterInfo
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryAccept [OK] (width=1024, height=768, chroma=RV24, fps=59.900326)
[03f4a898] dshow demux debug: CapturePin::ReceiveConnection [OK]
[03f4a898] dshow demux debug: CapturePin::NotifyAllocator
[03f4a898] dshow demux debug: ConnectFilters: graph_builder2 available.
[03f4a898] dshow demux warning: ConnectFilters: No crossBar routes found (incompatible pin types)
[03f4a898] dshow demux debug: filters connected successfully !
[03f4a898] dshow demux debug: MEDIATYPE_Video
[03f4a898] dshow demux debug: selected video pin accepts format: RV24
[03f4a898] dshow demux debug: found device: Creative Sound Blaster PCI
[03f4a898] dshow demux debug: asking for default device: Creative Sound Blaster PCI
[03f4a898] dshow demux debug: asked for Creative Sound Blaster PCI, binding to Creative Sound Blaster PCI
[03f4a898] dshow demux debug: using device: Creative Sound Blaster PCI
[03f4a898] dshow demux debug: EnumDeviceCaps: output pin: Capture
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Stereo Mix
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Phone Line
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Aux Volume
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Video Volume
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Mic Volume
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: Line In
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin: CD Audio
[03f4a898] dshow demux debug: EnumDeviceCaps: trying pin Capture
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin default format configured
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:44100 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:44100 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:44100 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:32000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:32000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:22050 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:22050 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:11025 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:11025 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:8000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:8000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:44100 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:44100 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:22050 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:22050 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:11025 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:11025 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:8000 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:8000 bits/sample:8
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:48000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:48000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:2, samples/sec:96000 bits/sample:16
[03f4a898] dshow demux debug: EnumDeviceCaps: input pin accepts format: araw, channels:1, samples/sec:96000 bits/sample:16
[03f4a898] dshow demux debug: CaptureFilter::JoinFilterGraph
[03f4a898] dshow demux debug: connecting filters
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::ConnectedTo [not connected]
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::QueryFilterInfo
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryAccept [OK] (channels=2, samples/sec=44100, bits/samples=16, format=araw)
[03f4a898] dshow demux debug: CapturePin::ReceiveConnection [OK]
[03f4a898] dshow demux debug: CapturePin::NotifyAllocator
[03f4a898] dshow demux debug: filters connected successfully !
[03f4a898] dshow demux debug: MEDIATYPE_Audio
[03f4a898] dshow demux debug: selected audio pin accepts format: araw
[03f4a898] dshow demux debug: Playing...
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::QueryPinInfo
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::ConnectedTo [OK]
[03f4a898] dshow demux debug: CaptureFilter::EnumPins
[03f4a898] dshow demux debug: CapturePin::QueryDirection
[03f4a898] dshow demux debug: CapturePin::ConnectedTo [OK]
[03f4a898] dshow demux debug: CaptureFilter::SetSyncSource
[03f4a898] dshow demux debug: CaptureFilter::SetSyncSource
[03f4a898] dshow demux debug: CaptureFilter::Pause
[03f4a898] dshow demux debug: CaptureFilter::Pause
[03f4a898] dshow demux debug: CaptureFilter::Run
[03f4a898] dshow demux debug: CaptureFilter::Run
[03f59340] main input debug: selecting program id=0

Process finished with exit code 0

从源代码中可以看出，IMoniker->BindToObject（）似乎在等待一个只有在程序终止时才释放的资源——据我所知，阻塞的调用是dshow.cpp:1317

                hr = p_moniker->BindToObject( NULL, 0, IID_IBaseFilter,
                                              (void **)&p_base_filter );

这一行是VLC调用DirectShowAPI来注册设备的地方，所以我完全不明白为什么它不返回。在我看来，play（）操作似乎成功地完成了，但当然，由于这是在程序终止时发生的，因此如果我们想要实际录制任何内容，那么它是无用的

---

如果有人能向我建议一种解决这个问题的方法，或者告诉我我做错了什么导致了它，我将永远感激

这个调用被阻塞是因为在从playMedia调用返回后，我的程序的主线程立即等待标准输入（以实现“按enter键退出”类型的安排）-触发调用突然返回的不是VM关闭，而是控制台读取返回，因此，I/O等待不再阻止DirectShowAPI调用

我完全无法理解为什么控制台I/O调用会阻止DirectShow中的某些内容，但问题就在这里。通过在playMedia（）调用（easy）后让执行控制台I/O的任何线程休眠几秒钟，或者在从控制台读取之前检查VLC对象是否已完成播放操作的启动，可以轻松解决此问题（不太容易，更可靠）