[Spice-devel] [spice v10 08/27] server: Add VP8 support to the GStreamer video encoder
Francois Gouget
fgouget at codeweavers.com
Tue Mar 1 15:52:53 UTC 2016
Signed-off-by: Francois Gouget <fgouget at codeweavers.com>
---
Changed the VP8 encoder parameters based on the realtime profile to
improve performance. The patch does not use the realtime profile
directly because profiles don't seem to be supported from 'gst-launch'
pipeline strings yet.
Furthermore it turns out that it is important to get the number of
physical cores right, and that's something the encoder does not know how
to do itself.
configure.ac | 4 ++
server/gstreamer-encoder.c | 98 ++++++++++++++++++++++++++++++++++++++++++----
server/reds.c | 2 +-
3 files changed, 95 insertions(+), 9 deletions(-)
diff --git a/configure.ac b/configure.ac
index d9aa073..9865240 100644
--- a/configure.ac
+++ b/configure.ac
@@ -130,6 +130,10 @@ AC_SUBST([SPICE_PROTOCOL_MIN_VER])
PKG_CHECK_MODULES([GLIB2], [glib-2.0 >= 2.22])
AS_VAR_APPEND([SPICE_REQUIRES], [" glib-2.0 >= 2.22"])
+AC_CHECK_LIB(glib-2.0, g_get_num_processors,
+ AC_DEFINE([HAVE_G_GET_NUMPROCESSORS], 1, [Defined if we have g_get_num_processors()]),,
+ $GLIB2_LIBS)
+
PKG_CHECK_MODULES([GOBJECT2], [gobject-2.0 >= 2.22])
AS_VAR_APPEND([SPICE_REQUIRES], [" gobject-2.0 >= 2.22"])
diff --git a/server/gstreamer-encoder.c b/server/gstreamer-encoder.c
index aae47c7..3dfbdfb 100644
--- a/server/gstreamer-encoder.c
+++ b/server/gstreamer-encoder.c
@@ -188,14 +188,70 @@ static void set_appsrc_caps(SpiceGstEncoder *encoder)
g_object_set(G_OBJECT(encoder->appsrc), "caps", encoder->src_caps, NULL);
}
+static int physical_core_count = 0;
+static int get_physical_core_count(void)
+{
+ if (!physical_core_count) {
+#ifdef HAVE_G_GET_NUMPROCESSORS
+ physical_core_count = g_get_num_processors();
+#endif
+ if (system("egrep -l '^flags\\b.*: .*\\bht\\b' /proc/cpuinfo >/dev/null 2>&1") == 0) {
+ /* Hyperthreading is enabled so divide by two to get the number
+ * of physical cores.
+ */
+ physical_core_count = physical_core_count / 2;
+ }
+ if (physical_core_count == 0)
+ physical_core_count = 1;
+ }
+ return physical_core_count;
+}
+
/* A helper for spice_gst_encoder_encode_frame() */
static gboolean create_pipeline(SpiceGstEncoder *encoder)
{
+ gchar *gstenc;
+ switch (encoder->base.codec_type)
+ {
+ case SPICE_VIDEO_CODEC_TYPE_MJPEG:
+ /* Set max-threads to ensure zero-frame latency */
+ gstenc = g_strdup("avenc_mjpeg max-threads=1");
+ break;
+ case SPICE_VIDEO_CODEC_TYPE_VP8: {
+ /* See http://www.webmproject.org/docs/encoder-parameters/
+ * - Set end-usage to get a constant bitrate to help with streaming.
+ * - resize-allowed allows trading resolution for low bitrates while
+ * min-quantizer ensures the bitrate does not get needlessly high.
+ * - error-resilient minimises artifacts in case the client drops a
+ * frame.
+ * - Set lag-in-frames, deadline and cpu-used to match
+ * "Profile Realtime". lag-in-frames ensures zero-frame latency,
+ * deadline turns on realtime behavior, and cpu-used targets a 75%
+ * CPU usage.
+ * - deadline is supposed to be set in microseconds but in practice
+ * it behaves like a boolean.
+ * - At least up to GStreamer 1.6.2, vp8enc cannot be trusted to pick
+ * the optimal number of threads. Also exceeding the number of
+ * physical core really degrades image quality.
+ * - token-partitions parallelizes more operations.
+ */
+ int threads = get_physical_core_count();
+ int parts = threads < 2 ? 0 : threads < 4 ? 1 : threads < 8 ? 2 : 3;
+ gstenc = g_strdup_printf("vp8enc end-usage=cbr min-quantizer=10 resize-allowed=true error-resilient=true lag-in-frames=0 deadline=1 cpu-used=4 threads=%d token-partitions=%d", threads, parts);
+ break;
+ }
+ default:
+ /* gstreamer_encoder_new() should have rejected this codec type */
+ spice_warning("unsupported codec type %d", encoder->base.codec_type);
+ return FALSE;
+ }
+
GError *err = NULL;
- /* Set max-threads to ensure zero-frame latency */
- const gchar *desc = "appsrc is-live=true format=time do-timestamp=true name=src ! videoconvert ! avenc_mjpeg max-threads=1 name=encoder ! appsink name=sink";
+ gchar *desc = g_strdup_printf("appsrc is-live=true format=time do-timestamp=true name=src ! videoconvert ! %s name=encoder ! appsink name=sink", gstenc);
spice_debug("GStreamer pipeline: %s", desc);
encoder->pipeline = gst_parse_launch_full(desc, NULL, GST_PARSE_FLAG_FATAL_ERRORS, &err);
+ g_free(gstenc);
+ g_free(desc);
if (!encoder->pipeline || err) {
spice_warning("GStreamer error: %s", err->message);
g_clear_error(&err);
@@ -221,11 +277,27 @@ static gboolean configure_pipeline(SpiceGstEncoder *encoder,
/* Configure the encoder bitrate */
adjust_bit_rate(encoder);
- g_object_set(G_OBJECT(encoder->gstenc), "bitrate", encoder->bit_rate, NULL);
-
- /* See https://bugzilla.gnome.org/show_bug.cgi?id=753257 */
- spice_debug("removing the pipeline clock");
- gst_pipeline_use_clock(GST_PIPELINE(encoder->pipeline), NULL);
+ switch (encoder->base.codec_type)
+ {
+ case SPICE_VIDEO_CODEC_TYPE_MJPEG:
+ g_object_set(G_OBJECT(encoder->gstenc),
+ "bitrate", encoder->bit_rate,
+ NULL);
+ /* See https://bugzilla.gnome.org/show_bug.cgi?id=753257 */
+ spice_debug("removing the pipeline clock");
+ gst_pipeline_use_clock(GST_PIPELINE(encoder->pipeline), NULL);
+ break;
+ case SPICE_VIDEO_CODEC_TYPE_VP8:
+ g_object_set(G_OBJECT(encoder->gstenc),
+ "target-bitrate", encoder->bit_rate,
+ NULL);
+ break;
+ default:
+ /* gstreamer_encoder_new() should have rejected this codec type */
+ spice_warning("unsupported codec type %d", encoder->base.codec_type);
+ free_pipeline(encoder);
+ return FALSE;
+ }
/* Set the source caps */
set_appsrc_caps(encoder);
@@ -247,6 +319,15 @@ static void reconfigure_pipeline(SpiceGstEncoder *encoder)
if (!is_pipeline_configured(encoder)) {
return;
}
+ if (encoder->base.codec_type == SPICE_VIDEO_CODEC_TYPE_VP8) {
+ /* vp8enc fails to account for caps changes that modify the frame
+ * size and complains about the buffer size.
+ * So recreate the pipeline from scratch.
+ */
+ free_pipeline(encoder);
+ return;
+ }
+
if (gst_element_set_state(encoder->pipeline, GST_STATE_PAUSED) == GST_STATE_CHANGE_FAILURE) {
spice_debug("GStreamer error: could not pause the pipeline, rebuilding it instead");
free_pipeline(encoder);
@@ -501,7 +582,8 @@ VideoEncoder *gstreamer_encoder_new(SpiceVideoCodecType codec_type,
uint64_t starting_bit_rate,
VideoEncoderRateControlCbs *cbs)
{
- spice_return_val_if_fail(codec_type == SPICE_VIDEO_CODEC_TYPE_MJPEG, NULL);
+ spice_return_val_if_fail(codec_type == SPICE_VIDEO_CODEC_TYPE_MJPEG ||
+ codec_type == SPICE_VIDEO_CODEC_TYPE_VP8, NULL);
GError *err = NULL;
if (!gst_init_check(NULL, NULL, &err)) {
diff --git a/server/reds.c b/server/reds.c
index e97038b..de98509 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -3427,7 +3427,7 @@ err:
static const char default_renderer[] = "sw";
#define RED_MAX_VIDEO_CODECS 8
-static const char default_video_codecs[] = "spice:mjpeg;gstreamer:mjpeg";
+static const char default_video_codecs[] = "spice:mjpeg;gstreamer:mjpeg;gstreamer:vp8";
/* new interface */
SPICE_GNUC_VISIBLE SpiceServer *spice_server_new(void)
--
2.7.0
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