[Spice-devel] [PATCH spice-streaming-agent 1/1] Adding gstreamer based plugin

Jonathon Jongsma jjongsma at redhat.com
Wed Feb 28 21:34:09 UTC 2018


On Thu, 2018-02-22 at 11:40 -0500, Frediano Ziglio wrote:
> > 
> > Gstreamer based plugin utilizing gstreamer elements to capture
> > screen from X, convert and encode into h264 stream using x264enc
> > gstreamer plugin.
> > Configure with --with-gst, will be built as a separate plugin.
> > 
> > Signed-off-by: Snir Sheriber <ssheribe at redhat.com>
> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> 
> I can say it works.

I just got around to testing this, and it seemed like it may have
worked once, but now I can't get it to work properly. I get debug
output like this:


spice-streaming-agent[32712]: GOT START_STOP message -- request to
START streaming
spice-streaming-agent[32712]: streaming starts now
spice-streaming-agent[32712]: fps = 25
spice-streaming-agent[32712]: Elements were linked successfully
spice-streaming-agent[32712]: No sample- EOS or state change
spice-streaming-agent[32712]: got a frame -- size is 0 (116 ms)
(1519853449483 ms from last frame)(1519853449366907 us)
spice-streaming-agent[32712]: write_all -- 8 bytes written
spice-streaming-agent[32712]: wrote 8 bytes of header of data msg with
frame of size 0 bytes
spice-streaming-agent[32712]: write_all -- 0 bytes written
spice-streaming-agent[32712]: wrote data msg body of size 0
spice-streaming-agent[32712]: No sample- EOS or state change
spice-streaming-agent[32712]: got a frame -- size is 0 (0 ms) (0 ms
from last frame)(107 us)
spice-streaming-agent[32712]: write_all -- 8 bytes written
spice-streaming-agent[32712]: wrote 8 bytes of header of data msg with
frame of size 0 bytes
spice-streaming-agent[32712]: write_all -- 0 bytes written
spice-streaming-agent[32712]: wrote data msg body of size 0
spice-streaming-agent[32712]: No sample- EOS or state change
spice-streaming-agent[32712]: got a frame -- size is 0 (0 ms) (0 ms
from last frame)(50 us)
spice-streaming-agent[32712]: write_all -- 8 bytes written
spice-streaming-agent[32712]: wrote 8 bytes of header of data msg with
frame of size 0 bytes
spice-streaming-agent[32712]: write_all -- 0 bytes written
spice-streaming-agent[32712]: wrote data msg body of size 0
spice-streaming-agent[32712]: No sample- EOS or state change
spice-streaming-agent[32712]: got a frame -- size is 0 (0 ms) (0 ms
from last frame)(29 us)
spice-streaming-agent[32712]: write_all -- 8 bytes written
spice-streaming-agent[32712]: wrote 8 bytes of header of data msg with
frame of size 0 bytes
spice-streaming-agent[32712]: write_all -- 0 bytes written
spice-streaming-agent[32712]: wrote data msg body of size 0

.....


And it seems to do this in a tight loop so you get massive amounts of
this output.




> 
> > ---
> >  configure.ac       |   8 ++
> >  src/Makefile.am    |  26 +++++++
> >  src/gst-plugin.cpp | 222
> >  +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 256 insertions(+)
> >  create mode 100644 src/gst-plugin.cpp
> > 
> > diff --git a/configure.ac b/configure.ac
> > index 5aab662..ee2ef68 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -52,6 +52,13 @@ AC_SUBST(JPEG_LIBS)
> >  
> >  AC_CHECK_HEADER([catch/catch.hpp],,[AC_MSG_ERROR([Could not find
> > Catch
> >  dependency header (catch/catch.hpp)])])
> >  
> > +AC_ARG_WITH([gst], AS_HELP_STRING([--with-gst], [Build with the
> > gstreamer
> > plugin]))
> > +have_gst=no
> > +if test "x$with_gst" = "xyes"; then
> > +    PKG_CHECK_MODULES(GST, [gstreamer-1.0 gstreamer-app-1.0],
> > [have_gst=yes], [have_gst=no])
> > +fi
> > +AM_CONDITIONAL([HAVE_GST],[test "$have_gst" = "yes"])
> > +
> >  dnl
> 
> I was just checking spice-server, it uses --enable-gstreamer.
> Not that important.
> 
> >  ==================================================================
> > =========
> >  dnl check compiler flags
> >  
> > @@ -102,6 +109,7 @@ AC_MSG_NOTICE([
> >          prefix:                   ${prefix}
> >          C compiler:               ${CC}
> >          C++ compiler:             ${CXX}
> > +        Gstreamer plugin:         ${have_gst}
> >  
> >          Now type 'make' to build $PACKAGE
> >  ])
> > diff --git a/src/Makefile.am b/src/Makefile.am
> > index 3717b5c..c09a2d7 100644
> > --- a/src/Makefile.am
> > +++ b/src/Makefile.am
> > @@ -5,6 +5,8 @@
> >  
> >  NULL =
> >  SUBDIRS = . unittests
> > +plugin_LTLIBRARIES =
> > +plugindir = $(pkglibdir)/plugins
> >  
> >  AM_CPPFLAGS = \
> >  	-DSPICE_STREAMING_AGENT_PROGRAM \
> > @@ -56,3 +58,27 @@ spice_streaming_agent_SOURCES = \
> >  	jpeg.cpp \
> >  	jpeg.hpp \
> >  	$(NULL)
> > +
> > +if HAVE_GST
> > +plugin_LTLIBRARIES += gst-plugin.la
> > +
> > +gst_plugin_la_LDFLAGS = \
> > +	-module -avoid-version \
> > +	$(RELRO_LDFLAGS) \
> > +	$(NO_INDIRECT_LDFLAGS) \
> > +	$(NULL)
> > +
> > +gst_plugin_la_LIBADD = \
> > +	$(GST_LIBS) \
> > +	$(NULL)
> > +
> > +gst_plugin_la_SOURCES = \
> > +	gst-plugin.cpp \
> > +	$(NULL)
> > +
> > +gst_plugin_la_CPPFLAGS = \
> > +	-I$(top_srcdir)/include \
> > +	$(SPICE_PROTOCOL_CFLAGS) \
> > +	$(GST_CFLAGS) \
> > +	$(NULL)
> > +endif
> > diff --git a/src/gst-plugin.cpp b/src/gst-plugin.cpp
> > new file mode 100644
> > index 0000000..2d170a0
> > --- /dev/null
> > +++ b/src/gst-plugin.cpp
> > @@ -0,0 +1,222 @@
> 
> Oh, missing the copyright header.
> 
> > +#include <config.h>
> > +#include <cstring>
> > +#include <exception>
> > +#include <stdexcept>
> > +#include <sstream>
> > +#include <memory>
> > +#include <syslog.h>
> > +#include <unistd.h>
> > +#include <gst/gst.h>
> > +#include <gst/app/gstappsink.h>
> > +
> > +#include <spice-streaming-agent/plugin.hpp>
> > +#include <spice-streaming-agent/frame-capture.hpp>
> > +
> > +using namespace spice::streaming_agent;
> > +
> > +namespace {
> > +struct GstSettings
> > +{
> > +    int fps;
> > +    int encode_speed;
> > +};
> > +
> > +class GstFrameCapture final: public FrameCapture
> > +{
> > +public:
> > +    GstFrameCapture(const GstSettings &settings);
> > +    ~GstFrameCapture();
> > +    FrameInfo CaptureFrame() override;
> > +    void Reset() override;
> > +    SpiceVideoCodecType VideoCodecType() const override {
> > +        return SPICE_VIDEO_CODEC_TYPE_H264;
> > +    }
> > +private:
> > +    void free_buffer();
> > +
> > +    GstElement *pipeline, *capture, *sink;
> > +    GstSettings settings;
> > +    bool is_first = true;
> > +    int w, h;
> > +    GstSample *sample = nullptr;
> > +    GstBuffer *buffer = nullptr;
> > +    GstMapInfo map = {};
> > +};
> > +
> > +class GstreamerPlugin final: public Plugin
> > +{
> > +public:
> > +    FrameCapture *CreateCapture() override;
> > +    unsigned Rank() override;
> > +    void ParseOptions(const ConfigureOption *options);
> > +    SpiceVideoCodecType VideoCodecType() const override {
> > +        return SPICE_VIDEO_CODEC_TYPE_H264;
> > +    }
> > +private:
> > +    GstSettings settings = { 25, 1 };
> > +};
> > +}
> > +
> > +GstFrameCapture::GstFrameCapture(const GstSettings& settings):
> > +    settings(settings)
> > +{
> > +    GstElement *encoder, *convert;
> > +    GstCaps *caps;
> > +
> > +    pipeline = gst_pipeline_new("pipeline");
> > +    capture = gst_element_factory_make("ximagesrc", "capture");
> > +    convert = gst_element_factory_make("videoconvert", "convert");
> > +    encoder = gst_element_factory_make("x264enc", "encoder");
> > //TODO: move
> > to use encodebin and profiles - much more generic
> > +    sink = gst_element_factory_make("appsink", "sink");
> > +    if (!capture || !convert || !encoder || !sink) {
> > +        //TODO: check elements existence in build time (and\or
> > improve error
> > in runtime)
> > +        throw std::runtime_error("One or more gstreamr element
> > cannot be
> > created");
> > +    }
> > +
> > +    syslog(LOG_INFO, "fps = %d\n", settings.fps);
> > +    std::string str =
> > "video/x-h264,stream-format=(string)byte-stream,framerate=" +
> > std::to_string(settings.fps) + "/1";
> > +    caps = gst_caps_from_string(str.c_str());
> > +    g_object_set(sink,
> > +                 "caps", caps,
> > +                 "sync", FALSE,
> > +                 "drop", TRUE,
> > +                 "max-buffers", 1,
> > +                 NULL);
> > +    gst_caps_unref(caps);
> > +
> > +    g_object_set(capture,
> > +                 "use-damage", 0,
> > +                 NULL);
> > +
> > +    gst_util_set_object_arg(G_OBJECT(encoder), "tune",
> > "zerolatency");//stillimage,fastdecode,zerolatency
> > +    g_object_set(encoder,
> > +                 "bframes", 0,
> > +                 "speed-preset", 1, //1-ultrafast,6-med, 9-
> > veryslow
> > +                  NULL);
> > +
> > +    gst_bin_add_many(GST_BIN(pipeline), capture, convert, encoder,
> > sink,
> > NULL);
> > +
> > +    caps = gst_caps_from_string("video/x-
> > raw,format=(string)I420");
> > +    if (gst_element_link(capture, convert) &&
> > +        gst_element_link_filtered(convert, encoder, caps) &&
> > +        gst_element_link(encoder, sink)) {
> > +        syslog(LOG_INFO, "Elements were linked successfully\n");
> > +    } else {
> > +        throw std::runtime_error("Link failed");
> > +    }
> > +
> > +    gst_caps_unref(caps);
> > +    gst_element_set_state(pipeline, GST_STATE_PLAYING);//TODO: Not
> > sure
> > playing state is ideal for this case (timing wise)
> > +}
> > +
> > +void GstFrameCapture::free_buffer()
> > +{
> > +    if (buffer) {
> > +        gst_buffer_unmap(buffer, &map);
> > +        // don't unref buffer, will be unref when sample is unref
> > +        buffer = nullptr;
> > +    }
> > +    if (sample) {
> > +        gst_sample_unref(sample);
> > +        sample = nullptr;
> > +    }
> > +}
> > +
> > +GstFrameCapture::~GstFrameCapture()
> > +{
> > +    free_buffer();
> > +    gst_element_set_state(pipeline, GST_STATE_NULL);
> > +    gst_object_unref(pipeline);
> > +}
> > +
> > +void GstFrameCapture::Reset()
> > +{
> > +    //TODO
> > +}
> > +
> > +FrameInfo GstFrameCapture::CaptureFrame()
> > +{
> > +    free_buffer();
> > +
> > +    sample = gst_app_sink_pull_sample(GST_APP_SINK(sink));//block,
> > timeout
> > needed?
> > +
> > +    FrameInfo info{};
> > +    if (sample) {
> > +        buffer = gst_sample_get_buffer(sample);
> > +        gst_buffer_map(buffer, &map, GST_MAP_READ);
> > +
> > +        info.stream_start = is_first;
> > +        if (is_first) {
> > +            int sx,sy,ex,ey;
> > +            g_object_get(capture,
> > +                         "endx", &ex,
> > +                         "endy", &ey,
> > +                         "startx", &sx ,
> > +                         "starty", &sy,
> > +                         NULL);
> > +            w = ex - sx;
> > +            h = ey - sy;
> > +            syslog(LOG_INFO, "%d x %d \n", w, h);
> > +            if ( h <= 0 || w <= 0 ) { // <=16?
> > +                throw std::runtime_error("Invalid stream size");
> > +            }
> > +            is_first = false;
> > +        }
> > +        info.size.width = w;
> > +        info.size.height = h;
> > +        info.buffer = map.data;
> > +        info.buffer_size = map.size;
> > +    } else {
> > +        syslog(LOG_ERR, "No sample- EOS or state change\n");
> > +    }
> > +
> > +    return info;
> > +}
> > +
> > +FrameCapture *GstreamerPlugin::CreateCapture()
> > +{
> > +    return new GstFrameCapture(settings);
> > +}
> > +
> > +unsigned GstreamerPlugin::Rank()
> > +{
> > +    return SoftwareMin;
> > +}
> > +
> > +void GstreamerPlugin::ParseOptions(const ConfigureOption *options)
> > +{
> > +#define arg_error(...) syslog(LOG_ERR, ## __VA_ARGS__);
> > +
> > +    for (; options->name; ++options) {
> > +        const char *name = options->name;
> > +        const char *value = options->value;
> > +
> > +        if (strcmp(name, "framerate") == 0) {
> > +            int val = atoi(value);
> > +            if (val > 0) {
> > +                settings.fps = val;
> > +            }
> > +            else {
> > +                arg_error("wrong framerate arg %s\n", value);
> > +            }
> > +        }
> > +    }
> > +}
> > +
> > +__attribute__ ((visibility ("default")))
> > +bool spice_streaming_agent_plugin_init(Agent* agent)
> > +{
> > +    if (agent->Version() != PluginVersion) {
> > +        return false;
> > +    }
> > +
> > +    gst_init(NULL, NULL);
> > +
> > +    std::unique_ptr<GstreamerPlugin> plugin(new
> > GstreamerPlugin());
> > +
> > +    plugin->ParseOptions(agent->Options());
> > +
> > +    agent->Register(*plugin.release());
> > +
> > +    return true;
> > +}
> 
> Not perfect but surely helpful.
> 
> Fine for me.
> 
> Frediano
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