c++ - Yocto OpenCV w/GStreamer 安装问题

Question

我有一个通过 OpenCV VideoWriter 实例化的简单 GStreamer 管道

LOG_INFO("Opening VP8 GStreamer writer object at "
         << host << ":" << port << " with " << horizontal_resolution
         << "x" << vertical_resolution << "p@" << fps << "fps"
         << "(color=" << is_color << ")");

const std::string filename{
    " appsrc is-live=true ! videoconvert ! "
    " vp8enc cpu-used=2 threads=2 min_quantizer=5 max_quantizer=5 deadline=100000 ! "
    " rtpvp8pay ! application/x-rtp,media=video,encoding-name=VP8,payload=96 ! "
    " udpsink host= " + host + " port= " + port
};

writer.open(
    filename,
    cv::CAP_GSTREAMER,
    fps, 
    cv::Size{horizontal_resolution, vertical_resolution},
    is_color
);

在我的主机上它运行顺利，但是当我在目标上交叉编译和运行时，我得到以下信息:

Opening VP8 GStreamer writer object at 127.0.0.1:8004 with 160x120p@30fps(color=true)
0:00:00.003785000  3484      0xe7e0ac0 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "appsrc"!
0:00:00.003901750  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "appsrc"
0:00:00.003951125  3484      0xe7e0ac0 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "videoconvert"!
0:00:00.003972875  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "videoconvert"
0:00:00.003998375  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no source [sink=@(nil)]
0:00:00.004042250  3484      0xe7e0ac0 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "vp8enc"!
0:00:00.004070875  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "vp8enc"
0:00:00.004105500  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no source [sink=@(nil)]
0:00:00.004135750  3484      0xe7e0ac0 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "rtpvp8pay"!
0:00:00.004160250  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "rtpvp8pay"
0:00:00.004186875  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no source [sink=@(nil)]
0:00:00.004309875  3484      0xe7e0ac0 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "udpsink"!
0:00:00.004336375  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "udpsink"
0:00:00.004364125  3484      0xe7e0ac0 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no source [sink=@(nil)]

(EXE:3484): GStreamer-CRITICAL **: gst_debug_log_valist: assertion 'category != NULL' failed

** (EXE:3484): CRITICAL **: gst_app_src_end_of_stream: assertion 'GST_IS_APP_SRC (appsrc)' failed

我的 Yocto 配置文件如下，目标平台是 i.MX8M Mini。

require conf/distro/include/yocto-uninative.inc

MACHINE ??= "e0219"
UBOOT_CONFIG ??= "sd"
UBOOT_CONFIG[sd] ??= "e0219_config"


#MACHINE ??= 'imx8mmevk'
DISTRO ?= 'fsl-imx-xwayland'
PACKAGE_CLASSES ?= "package_rpm"
EXTRA_IMAGE_FEATURES ?= "debug-tweaks"
USER_CLASSES ?= "buildstats image-mklibs image-prelink"
PATCHRESOLVE = "noop"
BB_DISKMON_DIRS ??= "\
    STOPTASKS,${TMPDIR},1G,100K \
    STOPTASKS,${DL_DIR},1G,100K \
    STOPTASKS,${SSTATE_DIR},1G,100K \
    STOPTASKS,/tmp,100M,100K \
    ABORT,${TMPDIR},100M,1K \
    ABORT,${DL_DIR},100M,1K \
    ABORT,${SSTATE_DIR},100M,1K \
    ABORT,/tmp,10M,1K"
PACKAGECONFIG_append_pn-qemu-native = " sdl"
PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"
CONF_VERSION = "1"

DL_DIR ?= "${BSPDIR}/downloads/"

CORE_IMAGE_EXTRA_INSTALL += " net-tools iputils dhcpcd"
CORE_IMAGE_EXTRA_INSTALL += " openssh nano python3 ethtool i2c-tools strace spitools"
CORE_IMAGE_EXTRA_INSTALL += " tcpdump socat opencv libmicrohttpd libsrtp curl boost"
CORE_IMAGE_EXTRA_INSTALL += " nmap python-djangorestframework net-snmp"
CORE_IMAGE_EXTRA_INSTALL += " openmp llvm"
ACCEPT_FSL_EULA = "1"

如果我理解正确的话，opencv 配方应该需要 gstreamer 和它的一些插件，但在我看来，在构建之后，GStreamer 找不到运行管道所需的插件。这是 gst-inspect 的输出:

$ gst-inspect-1.0        
coreelements:  capsfilter: CapsFilter
coreelements:  concat: Concat
coreelements:  dataurisrc: data: URI source element
coreelements:  downloadbuffer: DownloadBuffer
coreelements:  fakesrc: Fake Source
coreelements:  fakesink: Fake Sink
coreelements:  fdsrc: Filedescriptor Source
coreelements:  fdsink: Filedescriptor Sink
coreelements:  filesrc: File Source
coreelements:  funnel: Funnel pipe fitting
coreelements:  identity: Identity
coreelements:  input-selector: Input selector
coreelements:  output-selector: Output selector
coreelements:  queue: Queue
coreelements:  queue2: Queue 2
coreelements:  filesink: File Sink
coreelements:  tee: Tee pipe fitting
coreelements:  typefind: TypeFind
coreelements:  multiqueue: MultiQueue
coreelements:  valve: Valve element
coreelements:  streamiddemux: Streamid Demux
staticelements:  bin: Generic bin
staticelements:  pipeline: Pipeline object

Total count: 2 plugins, 23 features

我该如何解决这个问题？

使用@Subrata 建议更新 2

我将@Subrata 建议的包添加到我的 local.conf 中，如下所示:

CORE_IMAGE_EXTRA_INSTALL += " gstreamer1.0 gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav"

现在可以通过 gst-inspect 查看 179 个插件。

启动我的应用程序时，我仍然缺少一个元素，但这是朝着正确方向迈出的一步。

Opening VP8 GStreamer writer object at 127.0.0.1:8004 with 160x120p@30fps(color=true)
0:00:00.053317750  3520     0x16290b00 WARN     GST_ELEMENT_FACTORY gstelementfactory.c:456:gst_element_factory_make: no such element factory "vp8enc"!
0:00:00.053537875  3520     0x16290b00 ERROR           GST_PIPELINE grammar.y:816:priv_gst_parse_yyparse: no element "vp8enc"
0:00:00.053606125  3520     0x16290b00 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no sink [source=@0x16293290]
0:00:00.057937500  3520     0x16290b00 ERROR           GST_PIPELINE grammar.y:901:priv_gst_parse_yyparse: link has no source [sink=@0x162a0250]
0:00:00.081852625  3520     0x1629f720 FIXME                default gstutils.c:3981:gst_pad_create_stream_id_internal:<appsrc0:src> Creating random stream-id, consider implementing a deterministic way of creating a stream-id

Answer 1

完成@Subrata 的回答:您需要安装与 gstreamer 所需元素对应的包。

我不知道您使用的是哪个 Yocto 版本，但您可以看到默认情况下在 gstreamer 上安装了哪些 gstreamer 元素。在 meta/recipes-multimedia/gstreamer/gstreamer1.0-plugins-good.inc 文件中:

PACKAGECONFIG ??= " \
    ${GSTREAMER_ORC} \
    ${@bb.utils.filter('DISTRO_FEATURES', 'pulseaudio x11', d)} \
    cairo flac gdk-pixbuf gudev jpeg libpng soup speex taglib v4l2 \
"

[...]

PACKAGECONFIG[vpx]        = "--enable-vpx,--disable-vpx,libvpx"

现在您需要 vp8enc，包含在 vpx 中库，但是，如您所见，PACKAGECONFIG 变量不包含此选项。

您需要添加一个 .bbappend 文件并添加此选项才能使用此插件，在您的 meta 中:your-meta/repices-multimedia/gstreamer/gstreamer1.0-plugins- good_%.bbappend

PACKAGECONFIG_append=" vpx"

如果您打算编写一个需要此 vpx 元素的食谱，您可以将其添加到 RDEPENDS 中:

DEPENDS=" gstreamer1.0 gstreamer1.0-plugins-good"

RDEPENDS_${PN}=" gstreamer1.0 \
                 gstreamer1.0-plugins-good-vpx "