GStreamer 1.0 series序列示例
GStreamer 1.0 series序列示例
OpenEmbedded layer for GStreamer 1.0
这layer层为GStreamer 1.0框架提供了非官方的支持，用于OpenEmbedded/Yocto。它用于GStreamer recipe backports，为早期的OE版本提供对更新GStreamer版本的支持，同时也作为尚未进入OE核心的最新升级（最近发布了一个新的GStreamer版本）。
参考：https://github.com/OSSystems/meta-gstreamer1.0
Dependencies
- URI: git://git.openembedded.org/openembedded-core
- branch: master
- revision: HEAD
此外，the meta-multimedia and meta-oe layers of the meta-openembedded repo at git://git.openembedded.org/meta-openembedded是可选插件所必需的（见下文）。
Package names and coexistence with 0.10
由于1.0版本设计为能够在同一个系统中与0.10共存，GStreamer 1.0的配方命名反映了这一点。这些命名是：
- gstreamer1.0
- gstreamer1.0-plugins-base
- gstreamer1.0-plugins-good
- gstreamer1.0-plugins-bad
- gstreamer1.0-plugins-ugly
- gstreamer1.0-libav
- gstreamer1.0-omx
- gstreamer1.0-rtsp-server
- gstreamer1.0-vaapi
Building git versions
默认情况下，释放tarball是解包和构建的。但是，可以从GStreamer git存储库构建。一般来说，最好使用版本发布release，但是对于最前沿的特性，git版本可能是必要的。
要让Bitbake知道git版本的包是首选的，请添加到本地.conf:
PREFERRED_VERSION_<packagename> = "git"
For example, to use git versions of all packages, add to local.conf:
PREFERRED_VERSION_gstreamer1.0 = "git"
PREFERRED_VERSION_gstreamer1.0-plugins-base = "git"
PREFERRED_VERSION_gstreamer1.0-plugins-good = "git"
PREFERRED_VERSION_gstreamer1.0-plugins-bad = "git"
PREFERRED_VERSION_gstreamer1.0-plugins-ugly = "git"
PREFERRED_VERSION_gstreamer1.0-libav = "git"
PREFERRED_VERSION_gstreamer1.0-omx = "git"
Enabling plugins with dependencies
默认情况下，在base/good/bad/unicky recipes中，只有依赖关系较少的插件和OE core支持的具有依赖关系的插件（即OE core中存在这些插件的配方）始终处于使能状态。
These are:
- gstreamer1.0-plugins-base : gio-unix-2.0, ogg, pango, theora, vorbis
- gstreamer1.0-plugins-good : cairo, flac, gdk-pixbuf, gudev, jpeg, lame, libpng, mpg123, soup, speex, taglib, v4l2
- gstreamer1.0-plugins-bad : bz2, curl, dash, dtls, hls, neon, rsvg, sbc, smoothstreaming, sndfile, uvch264, webp
- gstreamer1.0-plugins-ugly : a52dec, mpeg2dec
- gstreamer1.0-libav : yasm
- gstreamer1.0-vaapi : drm
对于X11、Wayland、ALSA、BlueZ、DirectFB、OpenGL、Vulkan和PulseAudio插件，情况有所不同。它们是根据发行版特性值的内容构建的（换句话说，取决于OE发行版支持的内容）。
其余的默认情况下是禁用的，可以通过附加到相应的PACKAGECONFIG值来启用。例如，要在gstreamer1.0-plugins-good中启用vpx和wappack支持，请添加到本地.conf:
PACKAGECONFIG_append_pn-gstreamer1.0-plugins-good = "vpx wavpack"
注意，以这种方式启用插件后，必须确保插件依赖项的配方可用。在上面的例子中，vpx和wappack的配方必须存在。这通常意味着必须使用额外的additional OE layers层（通常是meta-OE或meta-multimedia）。
这也是内部启用Orc支持的方式。自版本1.6.0以来，Orc包含在该层中，并在默认情况下启用。（Orc存在于OE核心中，但是为了使gstreamre1.6可以用较旧的层构建，它的配方包含在内。）
下面列出了在包中启用附加插件和特性的所有配置值。
- gstreamer1.0
- check : build unit test libraries
- debug : enable debug build
- tests : build test applications
- valgrind : enable run-time valgrind detection
- gst-tracer-hooks : enable tracing subsystem hooks
- trace-historic : enable historic tracing subsystem
- unwind: enables libunwind-based stack trace generation
- dw: adds source lines and numbers to backtraces using the elfutils libdw library
- gstreamer1.0-plugins-base
- cdparanoia : cdparanoia audio CD ripping plugin
- ivorbis: Integer-only Vorbis decoding using the Tremor library
- opus : Opus audio decoder plugin
- gstreamer1.0-plugins-good
- `dv1394' : IEEE 1394 raw video source plugins
- gtk : GTK+3 plugins
- jack : JACK audio system plugins
- libv4l2 : additional v4l2 plugins based on libv4l2
- vpx : plugins for en- and decoding VP8 video streams, using Google's libvpx
- wavpack : WavPack plugins
- gstreamer1.0-plugins-bad
- assrender : ASS/SSA subtitle renderer plugins
- dc1394 : libdc1394 based video source plugin for IIDC cameras
- faac : AAC encoding plugins using the FAAC library
- faad : AAC decoding plugins using the FAAD library
- flite : Flite speech synthesizer plugins
- fluidsynth : FluidSynth plugins
- kms : Video sink plugin using the Linux kernel mode setting API
- libmms : Microsoft Multimedia Stream plugins
- libssh2 : Enable libssh2 support in cURL plugins
- lcms2 : Little CMS open source color management engine plugins
- modplug : Decoder plugins for module files (MOD/S3M/XM/IT/..) using the ModPlug library
- openal : OpenAL audio plugins
- opencv : OpenCV image processing plugins
- openjpeg : OpenJPEG-based JPEG2000 image decoder/encoder plugin
- opusparse : Opus bitstream parser plugin
- resindvd : DVD navigation and playback plugin
- rtmp : Real Time Messaging Protocol (RTMP) plugins
- sctp : Stream Control Transmission Protocol (SCTP) plugin
- srtp : RFC 3711 SRTP plugin
- ttml : Timed Text Markup Language plugins
- voaacenc : OpenCORE based AAC encoder plugin
- voamrwbenc : OpenCORE based AMR wideband encoder plugin
- webp : WebP plugins
- gstreamer1.0-plugins-ugly
- amrnb : OpenCORE based AMR narrowband decoder plugin
- amrwb : OpenCORE based AMR wideband decoder plugin
- cdio : Compact Disc audio plugins using libcdio
- dvdread : DVD source plugins using libdvdread
- x264 : h.264/AVC encoder plugin using libx264
- gstreamer1.0-libav
- libav : builds the package using the system's libav instead of the included one (not recommended unless you really know what you are doing!)
- gpl : build the package in GPL mode (enables GPL elements)
- valgrind : enable run-time valgrind detection
- gstreamer1.0-vaapi
- egl : use the EGL backend
- glx : use the GLX backend
- wayland : enable Wayland output sinks
- X11 : enable X11 output sinks
OpenMAX IL support
gstreamer1.0-omx包增加了对OpenMAX-IL的支持。默认情况下，配方配置为使用OE Core附带的bellagio OpenMAX IL实现。BSP激励层添加.bbappend文件，这些文件设置GSTREAMER_1_0_OMX_目标变量，以使gstreamer1.0-OMX使用特定于设备的OpenMAX IL支持。目前，支持这些特定于设备的对象：
rpi : Raspberry Pi OpenMAX IL implementation
如果.bbappend文件将GSTREAMER_1_0_OMX_TARGET的值更改为特定set的值，则配置会自动将gstreamer1.0-OMX的PACKAGE_ARCH设置为MACHINE_ARCH。
此外，如果写入了特定set的.bbappend文件，建议也在其中设置GSTREAMER_1_0_OMX_CORE_NAME的值。此值指定需要使用的OpenMAX核心（共享库）的文件名。对于Bellagio OpenMAX实现，它的值是：${libdir}/libomxil-bellagio.so.0。gstreamer1.0-omx配方需要此值来调整gstomx.conf文件配置文件。
