omxil: Allow using IOMX on Android

This adds a fake OMX core implementation, relying the calls
via IOMX to the media server, which contains the actual
OMX core.

Building with IOMX requires private Android headers from the
Android source tree, namely the frameworks/base and
system/core repositories. (Either froyo or gingerbread
should work for building.) This API is not public, has no
ABI guarantees and isn't supported.

Linking also requires libraries extracted from a
froyo/gingerbread device or emulator.

Since there are no ABI guarantees, linking to this API might
make the .so fail to load on some devices, so for proper use
it should be in a dynamically loaded module, separate from the
rest of the VLC core and modules.

Since this can lead to crashes on unsupported devices, it should
only be used in production on whitelisted device/firmware
combinations that are known to work.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

configure.ac

@@ -2327,6 +2327,27 @@ then
   VLC_ADD_LIBS([omxil], [$LIBDL])
 fi
 
+dnl
+dnl iomx codec plugin
+dnl
+AC_ARG_ENABLE(iomx,
+  [  --enable-iomx           iomx codec module (default disabled)])
+if test "${enable_iomx}" = "yes"
+then
+  CPPFLAGS_save="${CPPFLAGS}"
+  CPPFLAGS="${CPPFLAGS} -I${srcdir}/modules/codec/omxil" # For the OMX headers
+  AC_LANG_PUSH([C++])
+  AC_CHECK_HEADER(media/stagefright/OMXClient.h, [
+    VLC_ADD_PLUGIN([iomx])
+    VLC_ADD_CXXFLAGS([iomx], [-fno-exceptions -fno-rtti])
+    VLC_ADD_LIBS([iomx], [-lstagefright -lmedia -lutils -lbinder])
+  ], [
+    AC_MSG_ERROR("Could not find IOMX headers")
+  ])
+  AC_LANG_POP([C++])
+  CPPFLAGS="${CPPFLAGS_save}"
+fi
+
 dnl
 dnl CrystalHD codec plugin
 dnl

modules/codec/omxil/Modules.am

 SOURCES_omxil = omxil.c utils.c omxil.h omxil_utils.h \
 	OMX_Component.h OMX_Core.h OMX_Image.h OMX_IVCommon.h OMX_Types.h \
         OMX_Audio.h OMX_Index.h OMX_Other.h OMX_Video.h
+
+CPPFLAGS_iomx = -DUSE_IOMX
+SOURCES_iomx = omxil.c utils.c iomx.cpp omxil.h omxil_utils.h iomx.h \
+	OMX_Component.h OMX_Core.h OMX_Image.h OMX_IVCommon.h OMX_Types.h \
+        OMX_Audio.h OMX_Index.h OMX_Other.h OMX_Video.h

modules/codec/omxil/iomx.h

+/*****************************************************************************
+ * iomx.h: Interface for the IOMX OpenMAX wrapper
+ *****************************************************************************
+ * Copyright (C) 2011 VLC authors and VideoLAN
+ *
+ * Authors: Martin Storsjo <martin@martin.st>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void* iomx_dlopen(const char *name);
+void iomx_dlclose(void *handle);
+void* iomx_dlsym(void *handle, const char *name);
+
+#ifdef __cplusplus
+}
+#endif

modules/codec/omxil/omxil.c

@@ -29,8 +29,15 @@
 #endif
 
 #include <dlfcn.h>
+#if defined(USE_IOMX)
+#include "iomx.h"
+#define dll_open(name) iomx_dlopen(name)
+#define dll_close(handle) iomx_dlclose(handle)
+#define dlsym(handle, name) iomx_dlsym(handle, name)
+#else
 #define dll_open(name) dlopen( name, RTLD_NOW )
 #define dll_close(handle) dlclose(handle)
+#endif
 
 #include <vlc_common.h>
 #include <vlc_plugin.h>