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POHow can I get the roles of codec information in Android NDK?
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  1. POHow can I get the roles of codec information in Android NDK?
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    copied!<p>In Android 4.0(API level 15), there is no API to get the codec list. <a href="http://developer.android.com/reference/android/media/MediaCodecList.html" rel="nofollow">New API</a> only support API level 16 and later. But I have to support API level 15. So I have to use JNI to write some native code referring <a href="http://androidxref.com/4.0.4/xref/frameworks/base/media/libstagefright/omx/OMXMaster.cpp" rel="nofollow">here</a>.</p> <pre><code>struct OMXPluginBase { OMXPluginBase() {} virtual ~OMXPluginBase() {} virtual void dummy1() = 0; virtual void dummy2() = 0; virtual OMX_ERRORTYPE enumerateComponents( OMX_STRING name, size_t size, OMX_U32 index) = 0; virtual OMX_ERRORTYPE getRolesOfComponent( const char *name, Vector&lt;String8&gt; *roles) = 0; private: OMXPluginBase(const OMXPluginBase &amp;); OMXPluginBase &amp;operator=(const OMXPluginBase &amp;); }; </code></pre> <p>The code to get the name of the codec information:</p> <pre><code>void *handle = dlopen("libstagefrighthw.so", RTLD_NOW); if (handle == NULL) { return -1; } typedef OMXPluginBase *(*CreateOMXPluginFunc)(); CreateOMXPluginFunc createOMXPlugin = (CreateOMXPluginFunc)dlsym(handle, "createOMXPlugin"); if (!createOMXPlugin) { createOMXPlugin = (CreateOMXPluginFunc)dlsym( handle, "_ZN7android15createOMXPluginEv"); } OMXPluginBase *plugin = (*createOMXPlugin)(); if (plugin) { OMX_U32 index = -1; char name[128]; OMX_ERRORTYPE err; while ((err = plugin-&gt;enumerateComponents(name, sizeof(name), ++index)) == OMX_ErrorNone) { printf("%s\n", name); } if (err != OMX_ErrorNoMore) { printf("0x%x\n", err); } } </code></pre> <p>I can get the name of the codec information since the name is just of type <code>char *</code>. However, now I want to get the roles of the codec information using the function <code>OMX_ERRORTYPE getRolesOfComponent(const char *name, Vector&lt;String8&gt; *roles)</code> but I cannot do that because <code>roles</code> is of type <code>Vector&lt;String8&gt;</code> and I don't have this two class. More seriously, Android seems not provide the implementation of this two class in some shared library like <code>libutils.so</code>. So how can I call this function and get the information I want? Please help me. I have got headache for this for a whole day!</p> <p><strong>Update</strong></p> <p>Thanks to @Alex, finally I solved my problem. I put the code <a href="https://gist.github.com/itlodge/7652195" rel="nofollow">here</a>. Hope this will help those who met the same problem.</p>
 

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