从代码协商gstreamer管道时出错

如何解决从代码协商gstreamer管道时出错

只需几步即可从代码构建此管道。

使用了Gstreamermm。

• 创建appsrc_1：

appsrc = Gst::ElementFactory::create_element("appsrc",name);
appsrc->set_property("block",false);
appsrc->set_property("min-latency",0);
appsrc->set_property("max-latency",100);
appsrc->set_property("do-timestamp",false);
appsrc->set_property("format",3);

const char * format = nullptr;
switch (m_type)
{
    case CV_8UC1: format = "GRAY8"; break;
    case CV_8UC3: format = "BGR"; break;
    default:
        assert(false);
        return;
}

appsrcCaps = Gst::Caps::create_simple("video/x-raw","format",format,"framerate",Gst::Fraction(m_fps,1),"width",m_frameSize.width,"height",m_frameSize.height);
appsrc->set_property("caps",appsrcCaps);

• 创建bin0：

bin = Glib::RefPtr<Gst::Bin>::cast_dynamic(Gst::Parse::create_bin("queue ! videoconvert",false));

binSinkPad = bin->add_ghost_pad(bin->get_element("queue0"),"sink");
binSrcPad = bin->add_ghost_pad(bin->get_element("videoconvert0"),"src");

• 创建tee：

tee = Gst::ElementFactory::create_element("tee");
tee->set_property("allow-not-linked",true);

然后，创建了新管道并添加了现有元素：

pipeline = Gst::Pipeline::create("webrtc_pipeline");
pipeline->add(appsrc);
pipeline->add(tee)->add(bin);

• 链接步骤：

appsrc->link(bin)->link(tee);

然后，有时，当新客户端连接时，bin1会生成伪造的ximagesink：

pipeline->set_state(Gst::STATE_READY);

bin1 = Glib::RefPtr<Gst::Bin>::cast_dynamic(Gst::Parse::create_bin("queue name=q ! ximagesink",false));
videoSinkPad = bin1->add_ghost_pad(bin1->get_element("q"),"sink","videosinkpad");
bin1->set_state(Gst::STATE_PAUSED);

pipeline->add(bin1);

tee->link(bin1);

pipeline->set_state(Gst::STATE_PLAYING);

完成这些步骤后，我得到了这个奇怪的日志和错误：

0:01:13.399425680 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:405:gst_video_convert_transform_caps:<videoconvert0> transformed video/x-raw,format=(string)GRAY8,framerate=(fraction)8/1,width=(int)640,height=(int)480 into video/x-raw,format=(string){ I420,YV12,YUY2,UYVY,AYUV,VUYA,RGBx,BGRx,xRGB,xBGR,RGBA,BGRA,ARGB,ABGR,RGB,BGR,Y41B,Y42B,YVYU,Y444,v210,v216,Y210,Y410,NV12,NV21,GRAY8,GRAY16_BE,GRAY16_LE,v308,RGB16,BGR16,RGB15,BGR15,UYVP,A420,RGB8P,YUV9,YVU9,IYU1,ARGB64,AYUV64,r210,I420_10BE,I420_10LE,I422_10BE,I422_10LE,Y444_10BE,Y444_10LE,GBR,GBR_10BE,GBR_10LE,NV16,NV24,NV12_64Z32,A420_10BE,A420_10LE,A422_10BE,A422_10LE,A444_10BE,A444_10LE,NV61,P010_10BE,P010_10LE,IYU2,VYUY,GBRA,GBRA_10BE,GBRA_10LE,BGR10A2_LE,GBR_12BE,GBR_12LE,GBRA_12BE,GBRA_12LE,I420_12BE,I420_12LE,I422_12BE,I422_12LE,Y444_12BE,Y444_12LE,GRAY10_LE32,NV12_10LE32,NV16_10LE32,NV12_10LE40 },height=(int)480,framerate=(fraction)8/1
0:01:13.399443298 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:405:gst_video_convert_transform_caps:<videoconvert0> transformed video/x-raw,height=(int)480
0:01:13.399507923 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:342:gst_video_convert_fixate_caps:<videoconvert0> trying to fixate othercaps video/x-raw,format=(string)BGRx,pixel-aspect-ratio=(fraction)5/3 based on caps video/x-raw,height=(int)480
0:01:13.399515137 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:353:gst_video_convert_fixate_caps:<videoconvert0> now fixating video/x-raw,pixel-aspect-ratio=(fraction)5/3
0:01:13.399519528 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:290:gst_video_convert_fixate_format:<videoconvert0> source format GRAY8
0:01:13.399524394 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:300:gst_video_convert_fixate_format:<videoconvert0> iterate 1 structures
0:01:13.399528710 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:264:score_value:<videoconvert0> score GRAY8 -> BGRx = 3
0:01:13.399532151 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:269:score_value:<videoconvert0> found new best 3
0:01:13.399550504 32822 0x7fd578002800 ERROR           videoconvert gstvideoconvert.c:490:gst_video_convert_set_info:<videoconvert0> input and output formats do not match
...
0:01:13.399741982 32822 0x7fd578002800 WARN           basetransform gstbasetransform.c:1370:gst_base_transform_setcaps:<videoconvert0> FAILED to configure incaps video/x-raw,height=(int)480 and outcaps video/x-raw,pixel-aspect-ratio=(fraction)5/3
0:01:13.399756085 32822 0x7fd578002800 INFO                    task gsttask.c:312:gst_task_func:<queue0:src> Task going to paused
0:01:13.524512587 32822 0x7fd578002360 WARN                 basesrc gstbasesrc.c:3072:gst_base_src_loop:<appsrc_1> error: Internal data stream error.
0:01:13.524526933 32822 0x7fd578002360 WARN                 basesrc gstbasesrc.c:3072:gst_base_src_loop:<appsrc_1> error: streaming stopped,reason not-negotiated (-4)

问题是：如何解决此问题？

PS ：如果上游限制为format=GRAY8？

0:01:13.399507923 32822 0x7fd578002800 DEBUG           videoconvert gstvideoconvert.c:342:gst_video_convert_fixate_caps:<videoconvert0> trying to fixate othercaps video/x-raw,pixel-aspect-ratio=(fraction)5/3

解决方法

我认为您的问题不是像素format=GRAY8，而是pixel-aspect-ratio=5/3，它与您的videoconvert元素的上下游不同。

videoconvert无法处理不同像素纵横比之间的转换。如here所示。

请检查您为ximagesink设置了正确的分辨率。 ximagesink docs