channel-display-gst: Use h/w based decoders with Intel GPUs if possible

We first try to detect if an Intel GPU is available (by looking into
udev's database) and then probe Gstreamer's registry cache to see
if there is h/w based decoder (element) available for the incoming
video codec format. If both these conditions are satisfied (i.e,
Intel Media SDK Gstreamer plugin (libgstmsdk.so) and associated
libraries are properly installed), we then create a simple decode
pipeline using appropriate h/w based decoder and post-processor
elements instead of relying on playbin -- which may not be able to
auto-select these elements.

For example, if the incoming codec format is h264, we then create
a pipeline using msdkh264dec and vaapipostproc elements instead of
avdec_h264 and videoconvert.

Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Hazwan Arif Mazlan <hazwan.arif.mazlan@intel.com>
Signed-off-by: Jin Chung Teng <jin.chung.teng@intel.com>
Acked-by: Frediano Ziglio <freddy77@gmail.com>

1 files changed, 211 insertions, 22 deletions

diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
index 923c7c4..3b372dc 100644
--- a/src/channel-display-gst.c
+++ b/src/channel-display-gst.c
@@ -20,6 +20,7 @@
 #include "spice-common.h"
 #include "spice-channel-priv.h"
 #include "common/recorder.h"
+#include "common/udev.h"
 
 #include "channel-display-priv.h"
 
@@ -492,13 +493,221 @@ deep_element_added_cb(GstBin *pipeline, GstBin *bin, GstElement *element,
     }
 }
 
-static gboolean create_pipeline(SpiceGstDecoder *decoder)
+static gchar *find_best_hw_plugin(const gchar *dec_name)
+{
+    static const char plugins[][8] = {"msdk", "va", "vaapi"};
+    GstRegistry *registry;
+    GstPluginFeature *feature;
+    gchar *feature_name;
+    int i;
+
+    registry = gst_registry_get();
+    if (!registry) {
+        return NULL;
+    }
+
+    for (i = 0; i < G_N_ELEMENTS(plugins); i++) {
+        feature_name = !dec_name ? g_strconcat(plugins[i], "postproc", NULL) :
+                       g_strconcat(plugins[i], dec_name, "dec", NULL);
+        feature = gst_registry_lookup_feature(registry, feature_name);
+        if (!feature) {
+            g_free(feature_name);
+            feature_name = NULL;
+            continue;
+        }
+        gst_object_unref(feature);
+        break;
+    }
+    return feature_name;
+}
+
+static bool launch_pipeline(SpiceGstDecoder *decoder)
 {
     GstBus *bus;
+
+    if (decoder->appsink) {
+        GstAppSinkCallbacks appsink_cbs = { NULL };
+        appsink_cbs.new_sample = new_sample;
+        gst_app_sink_set_callbacks(decoder->appsink, &appsink_cbs, decoder, NULL);
+        gst_app_sink_set_max_buffers(decoder->appsink, MAX_DECODED_FRAMES);
+        gst_app_sink_set_drop(decoder->appsink, FALSE);
+    }
+    bus = gst_pipeline_get_bus(GST_PIPELINE(decoder->pipeline));
+    gst_bus_add_watch(bus, handle_pipeline_message, decoder);
+    gst_object_unref(bus);
+
+    decoder->clock = gst_pipeline_get_clock(GST_PIPELINE(decoder->pipeline));
+
+    if (gst_element_set_state(decoder->pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+        SPICE_DEBUG("GStreamer error: Unable to set the pipeline to the playing state.");
+        free_pipeline(decoder);
+        return false;
+    }
+
+    return true;
+}
+
+static bool try_intel_hw_pipeline(SpiceGstDecoder *decoder)
+{
+    GstElement *pipeline = NULL, *src = NULL, *sink = NULL;
+    GstElement *parser = NULL, *hw_decoder = NULL, *vpp = NULL;
+    GstCaps *src_caps, *sink_caps;
+    int codec_type = decoder->base.codec_type;
+    const gchar *dec_name = gst_opts[codec_type].name;
+    gchar *hw_dec_name, *vpp_name, *parser_name;
+    bool use_parser;
+
+    use_parser = codec_type == SPICE_VIDEO_CODEC_TYPE_H264 ||
+                 codec_type == SPICE_VIDEO_CODEC_TYPE_H265;
+
+    src = gst_element_factory_make("appsrc", NULL);
+    if (!src) {
+        spice_warning("error upon creation of 'appsrc' element");
+        return false;
+    }
+    sink = gst_element_factory_make("appsink", NULL);
+    if (!sink) {
+        spice_warning("error upon creation of 'appsink' element");
+        goto err;
+    }
+
+    if (use_parser) {
+        parser_name = g_strconcat(dec_name, "parse", NULL);
+        parser = gst_element_factory_make(parser_name, NULL);
+        g_free(parser_name);
+        if (!parser) {
+            spice_warning("error upon creation of 'parser' element");
+            goto err;
+        }
+    }
+
+    hw_dec_name = find_best_hw_plugin(dec_name);
+    if (!hw_dec_name) {
+        spice_warning("error finding suitable plugin for decode");
+        goto err;
+    }
+    hw_decoder = gst_element_factory_make(hw_dec_name, NULL);
+    g_free(hw_dec_name);
+    if (!hw_decoder) {
+        spice_warning("error upon creation of 'decoder' element");
+        goto err;
+    }
+    vpp_name = find_best_hw_plugin(NULL);
+    if (!vpp_name) {
+        spice_warning("error finding suitable plugin for postproc");
+        goto err;
+    }
+    vpp = gst_element_factory_make(vpp_name, NULL);
+    g_free(vpp_name);
+    if (!vpp) {
+        spice_warning("error upon creation of 'vpp' element");
+        goto err;
+    }
+    g_object_set(vpp,
+                 "format", GST_VIDEO_FORMAT_BGRx,
+                 NULL);
+
+    pipeline = gst_pipeline_new(NULL);
+    if (!pipeline) {
+        spice_warning("error upon creation of 'pipeline' element");
+        goto err;
+    }
+
+    src_caps = gst_caps_from_string(gst_opts[codec_type].dec_caps);
+    g_object_set(src,
+                 "caps", src_caps,
+                 "is-live", TRUE,
+                 "format", GST_FORMAT_TIME,
+                 "max-bytes", G_GINT64_CONSTANT(0),
+                 "block", TRUE,
+                 NULL);
+    gst_caps_unref(src_caps);
+    decoder->appsrc = GST_APP_SRC(gst_object_ref(src));
+
+    sink_caps = gst_caps_from_string("video/x-raw,format=BGRx");
+    g_object_set(sink,
+                 "caps", sink_caps,
+                 "sync", FALSE,
+                 "drop", FALSE,
+                 NULL);
+    gst_caps_unref(sink_caps);
+    decoder->appsink = GST_APP_SINK(gst_object_ref(sink));
+
+    if (hand_pipeline_to_widget(decoder->base.stream,
+        GST_PIPELINE(pipeline))) {
+        spice_warning("error handing pipeline to widget");
+        goto err;
+    }
+
+    if (use_parser) {
+        gst_bin_add_many(GST_BIN(pipeline), src, parser, hw_decoder,
+                         vpp, sink, NULL);
+        if (!gst_element_link_many(src, parser, hw_decoder, vpp,
+                                   sink, NULL)) {
+            spice_warning("error linking elements");
+            /* No need to unref these elements anymore as their ownership
+             * would have transferred to the pipeline after gst_bin_add_many().
+             */
+            src = parser = hw_decoder = vpp = sink = NULL;
+            goto err;
+        }
+    } else {
+        gst_bin_add_many(GST_BIN(pipeline), src, hw_decoder,
+                         vpp, sink, NULL);
+        if (!gst_element_link_many(src, hw_decoder, vpp, sink, NULL)) {
+            spice_warning("error linking elements");
+            src = hw_decoder = vpp = sink = NULL;
+            goto err;
+        }
+    }
+
+    decoder->pipeline = pipeline;
+    return launch_pipeline(decoder);
+
+err:
+    if (decoder->appsink) {
+        gst_object_unref(decoder->appsink);
+        decoder->appsink = NULL;
+    }
+    if (decoder->appsrc) {
+        gst_object_unref(decoder->appsrc);
+        decoder->appsrc = NULL;
+    }
+    if (pipeline) {
+        gst_object_unref(pipeline);
+    }
+    if (vpp) {
+        gst_object_unref(vpp);
+    }
+    if (hw_decoder) {
+        gst_object_unref(hw_decoder);
+    }
+    if (parser) {
+        gst_object_unref(parser);
+    }
+    if (sink) {
+        gst_object_unref(sink);
+    }
+    if (src) {
+        gst_object_unref(src);
+    }
+    return false;
+}
+
+static gboolean create_pipeline(SpiceGstDecoder *decoder)
+{
     GstElement *playbin, *sink;
     SpiceGstPlayFlags flags;
     GstCaps *caps;
     static bool playbin3_supported = true;
+    GpuVendor vendor = spice_udev_detect_gpu(INTEL_VENDOR_ID);
+
+    if (vendor == VENDOR_GPU_DETECTED ||
+        vendor == VENDOR_GPU_UNKNOWN) {
+        if (try_intel_hw_pipeline(decoder)) {
+            return TRUE;
+        }
+    }
 
     playbin = playbin3_supported ?
               gst_element_factory_make("playbin3", "playbin") : NULL;
@@ -574,29 +783,9 @@ static gboolean create_pipeline(SpiceGstDecoder *decoder)
     g_warn_if_fail(decoder->appsrc == NULL);
     decoder->pipeline = playbin;
 
-    if (decoder->appsink) {
-        GstAppSinkCallbacks appsink_cbs = { NULL };
-        appsink_cbs.new_sample = new_sample;
-        gst_app_sink_set_callbacks(decoder->appsink, &appsink_cbs, decoder, NULL);
-        gst_app_sink_set_max_buffers(decoder->appsink, MAX_DECODED_FRAMES);
-        gst_app_sink_set_drop(decoder->appsink, FALSE);
-    }
-    bus = gst_pipeline_get_bus(GST_PIPELINE(decoder->pipeline));
-    gst_bus_add_watch(bus, handle_pipeline_message, decoder);
-    gst_object_unref(bus);
-
-    decoder->clock = gst_pipeline_get_clock(GST_PIPELINE(decoder->pipeline));
-
-    if (gst_element_set_state(decoder->pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
-        SPICE_DEBUG("GStreamer error: Unable to set the pipeline to the playing state.");
-        free_pipeline(decoder);
-        return FALSE;
-    }
-
-    return TRUE;
+    return launch_pipeline(decoder);
 }
 
-
 /* ---------- VideoDecoder's public API ---------- */
 
 static void spice_gst_decoder_reschedule(VideoDecoder *video_decoder)