[Spice-devel,v7,03/23] server: Add a GStreamer 1.0 MJPEG video encoder and use it by default

Submitted by Francois Gouget on Dec. 16, 2015, 3:16 p.m.

Details

Message ID alpine.DEB.2.20.1512161121050.16981@amboise
State New
Headers show
Series "Add GStreamer support for video streaming" ( rev: 1 ) in Spice

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Commit Message

Francois Gouget Dec. 16, 2015, 3:16 p.m.
This introduces a pared down GStreamer-based video encoder to serve as
the basis for later enhancements.
In this form the new encoder supports both regular and sized streams
but lacks any rate control. It should still work fine if bandwidth is
sufficient such as on LANs.

Signed-off-by: Francois Gouget <fgouget@codeweavers.com>
---
 configure.ac               |  25 +++
 server/Makefile.am         |   8 +
 server/gstreamer-encoder.c | 530 +++++++++++++++++++++++++++++++++++++++++++++
 server/stream.c            |  19 +-
 server/video-encoder.h     |   5 +
 5 files changed, 585 insertions(+), 2 deletions(-)
 create mode 100644 server/gstreamer-encoder.c

Changes:
 * Renamed the GSTE_ macros to SPICE_GST.
 * Split off part of push_raw_frame() to chunk_copy().
 * Uses spice_return_if_fail() instead of spice_assert().

Patch hide | download patch | download mbox

diff --git a/configure.ac b/configure.ac
index 2eb8128..141d874 100644
--- a/configure.ac
+++ b/configure.ac
@@ -69,6 +69,30 @@  dnl =========================================================================
 dnl Check optional features
 SPICE_CHECK_SMARTCARD
 
+AC_ARG_ENABLE(gstreamer,
+              AS_HELP_STRING([--enable-gstreamer=@<:@auto/yes/no@:>@],
+                             [Enable GStreamer 1.0 support]),,
+              [enable_gstreamer="auto"])
+
+if test "x$enable_gstreamer" != "xno"; then
+    SPICE_CHECK_GSTREAMER(GSTREAMER_1_0, 1.0, [gstreamer-1.0 gstreamer-base-1.0 gstreamer-app-1.0 gstreamer-video-1.0],
+        [enable_gstreamer="yes"
+         SPICE_CHECK_GSTREAMER_ELEMENTS($GST_INSPECT_1_0, [gst-plugins-base 1.0], [appsrc videoconvert appsink])
+         SPICE_CHECK_GSTREAMER_ELEMENTS($GST_INSPECT_1_0, [gstreamer-libav 1.0], [avenc_mjpeg])
+         SPICE_CHECK_GSTREAMER_ELEMENTS($GST_INSPECT_1_0, [gst-plugins-good 1.0], [vp8enc])
+         SPICE_CHECK_GSTREAMER_ELEMENTS($GST_INSPECT_1_0, [gst-plugins-ugly 1.0], [x264enc])
+         ],
+         [if test "x$enable_gstreamer" = "xyes"; then
+              AC_MSG_ERROR([GStreamer 1.0 support requested but not found. You may set GSTREAMER_1_0_CFLAGS and GSTREAMER_1_0_LIBS to avoid the need to call pkg-config.])
+          fi
+    ])
+fi
+AM_CONDITIONAL(HAVE_GSTREAMER_1_0, test "x$have_gstreamer_1_0" = "xyes")
+
+if test x"$gstreamer_missing" != x; then
+    SPICE_WARNING([The following GStreamer $enable_gstreamer tools/elements are missing:$gstreamer_missing. The GStreamer video encoder can be built but may not work.])
+fi
+
 AC_ARG_ENABLE([automated_tests],
               AS_HELP_STRING([--enable-automated-tests], [Enable automated tests using spicy-screenshot (part of spice--gtk)]),,
               [enable_automated_tests="no"])
@@ -290,6 +314,7 @@  AC_MSG_NOTICE([
 
         LZ4 support:              ${enable_lz4}
         Smartcard:                ${have_smartcard}
+        GStreamer 1.0:            ${have_gstreamer_1_0}
         SASL support:             ${enable_sasl}
         Automated tests:          ${enable_automated_tests}
         Manual:                   ${have_asciidoc}
diff --git a/server/Makefile.am b/server/Makefile.am
index e2c4e55..c80378b 100644
--- a/server/Makefile.am
+++ b/server/Makefile.am
@@ -11,6 +11,7 @@  AM_CPPFLAGS =					\
 	$(SASL_CFLAGS)				\
 	$(SLIRP_CFLAGS)				\
 	$(SMARTCARD_CFLAGS)			\
+	$(GSTREAMER_1_0_CFLAGS)			\
 	$(SPICE_PROTOCOL_CFLAGS)		\
 	$(SSL_CFLAGS)				\
 	$(VISIBILITY_HIDDEN_CFLAGS)		\
@@ -42,6 +43,7 @@  libspice_server_la_LIBADD =						\
 	$(PIXMAN_LIBS)							\
 	$(SASL_LIBS)							\
 	$(SLIRP_LIBS)							\
+	$(GSTREAMER_1_0_LIBS)						\
 	$(SSL_LIBS)							\
 	$(Z_LIBS)							\
 	$(SPICE_NONPKGCONFIG_LIBS)					\
@@ -150,6 +152,12 @@  libspice_server_la_SOURCES +=	\
 	$(NULL)
 endif
 
+if HAVE_GSTREAMER_1_0
+libspice_server_la_SOURCES +=			\
+	gstreamer-encoder.c			\
+	$(NULL)
+endif
+
 EXTRA_DIST =					\
 	spice-bitmap-utils.tmpl.c			\
 	cache-item.tmpl.c			\
diff --git a/server/gstreamer-encoder.c b/server/gstreamer-encoder.c
new file mode 100644
index 0000000..e934180
--- /dev/null
+++ b/server/gstreamer-encoder.c
@@ -0,0 +1,530 @@ 
+/* -*- Mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+   Copyright (C) 2015 Jeremy White
+   Copyright (C) 2015 Francois Gouget
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <<A HREF="http://www.gnu.org/licenses/">http://www.gnu.org/licenses/</A>>.
+*/
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <gst/gst.h>
+#include <gst/app/gstappsrc.h>
+#include <gst/app/gstappsink.h>
+
+#include "red-common.h"
+#include "video-encoder.h"
+
+
+#define SPICE_GST_DEFAULT_FPS 30
+
+
+typedef struct {
+    SpiceBitmapFmt spice_format;
+    const char *format;
+    uint32_t bpp;
+} SpiceFormatForGStreamer;
+
+typedef struct SpiceGstEncoder {
+    VideoEncoder base;
+
+    /* Rate control callbacks */
+    VideoEncoderRateControlCbs cbs;
+    void *cbs_opaque;
+
+    /* Spice's initial bit rate estimation in bits per second. */
+    uint64_t starting_bit_rate;
+
+    /* ---------- Video characteristics ---------- */
+
+    int width;
+    int height;
+    SpiceFormatForGStreamer *format;
+    SpiceBitmapFmt spice_format;
+
+    /* ---------- GStreamer pipeline ---------- */
+
+    /* Pointers to the GStreamer pipeline elements. If pipeline is NULL the
+     * other pointers are invalid.
+     */
+    GstElement *pipeline;
+    GstAppSrc *appsrc;
+    GstElement *gstenc;
+    GstAppSink *appsink;
+
+    /* If src_caps is NULL the pipeline has not been configured yet. */
+    GstCaps *src_caps;
+
+    /* The frame counter for GStreamer buffers */
+    uint32_t frame;
+
+    /* The bit rate target for the outgoing network stream. (bits per second) */
+    uint64_t bit_rate;
+
+    /* The minimum bit rate */
+#   define SPICE_GST_MIN_BITRATE (128 * 1024)
+
+    /* The default bit rate */
+#   define SPICE_GST_DEFAULT_BITRATE (8 * 1024 * 1024)
+} SpiceGstEncoder;
+
+
+/* ---------- Miscellaneous SpiceGstEncoder helpers ---------- */
+
+static inline double get_mbps(uint64_t bit_rate)
+{
+    return (double)bit_rate / 1024 / 1024;
+}
+
+/* Returns the source frame rate which may change at any time so don't store
+ * the result.
+ */
+static uint32_t get_source_fps(SpiceGstEncoder *encoder)
+{
+    return encoder->cbs.get_source_fps ?
+        encoder->cbs.get_source_fps(encoder->cbs_opaque) : SPICE_GST_DEFAULT_FPS;
+}
+
+static inline int is_pipeline_configured(SpiceGstEncoder *encoder)
+{
+    return encoder->src_caps != NULL;
+}
+
+static void free_pipeline(SpiceGstEncoder *encoder)
+{
+    if (encoder->src_caps) {
+        gst_caps_unref(encoder->src_caps);
+        encoder->src_caps = NULL;
+    }
+    if (encoder->pipeline) {
+        gst_element_set_state(encoder->pipeline, GST_STATE_NULL);
+        gst_object_unref(encoder->appsrc);
+        gst_object_unref(encoder->gstenc);
+        gst_object_unref(encoder->appsink);
+        gst_object_unref(encoder->pipeline);
+        encoder->pipeline = NULL;
+    }
+}
+
+/* The maximum bit rate we will use for the current video.
+ *
+ * This is based on a 10x compression ratio which should be more than enough
+ * for even MJPEG to provide good quality.
+ */
+static uint64_t get_bit_rate_cap(SpiceGstEncoder *encoder)
+{
+    uint32_t raw_frame_bits = encoder->width * encoder->height * encoder->format->bpp;
+    return raw_frame_bits * get_source_fps(encoder) / 10;
+}
+
+static void adjust_bit_rate(SpiceGstEncoder *encoder)
+{
+    if (encoder->bit_rate == 0) {
+        /* Use the default value, */
+        encoder->bit_rate = SPICE_GST_DEFAULT_BITRATE;
+    } else if (encoder->bit_rate < SPICE_GST_MIN_BITRATE) {
+        /* don't let the bit rate go too low */
+        encoder->bit_rate = SPICE_GST_MIN_BITRATE;
+    } else {
+        /* or too high */
+        encoder->bit_rate = MIN(encoder->bit_rate, get_bit_rate_cap(encoder));
+    }
+    spice_debug("adjust_bit_rate(%.3fMbps)", get_mbps(encoder->bit_rate));
+}
+
+
+/* ---------- GStreamer pipeline ---------- */
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static SpiceFormatForGStreamer *map_format(SpiceBitmapFmt format)
+{
+    /* See GStreamer's part-mediatype-video-raw.txt and
+     * section-types-definitions.html documents.
+     */
+    static SpiceFormatForGStreamer format_map[] =  {
+        {SPICE_BITMAP_FMT_RGBA, "BGRA", 32},
+        /* TODO: Test the other formats */
+        {SPICE_BITMAP_FMT_32BIT, "BGRx", 32},
+        {SPICE_BITMAP_FMT_24BIT, "BGR", 24},
+        {SPICE_BITMAP_FMT_16BIT, "BGR15", 16},
+    };
+
+    int i;
+    for (i = 0; i < G_N_ELEMENTS(format_map); i++) {
+        if (format_map[i].spice_format == format) {
+            if (i != 0) {
+                spice_warning("The %d format has not been tested yet", format);
+            }
+            return &format_map[i];
+        }
+    }
+
+    return NULL;
+}
+
+static void set_appsrc_caps(SpiceGstEncoder *encoder)
+{
+    if (encoder->src_caps) {
+        gst_caps_unref(encoder->src_caps);
+    }
+    encoder->src_caps = gst_caps_new_simple(
+        "video/x-raw",
+        "format", G_TYPE_STRING, encoder->format->format,
+        "width", G_TYPE_INT, encoder->width,
+        "height", G_TYPE_INT, encoder->height,
+        "framerate", GST_TYPE_FRACTION, get_source_fps(encoder), 1,
+        NULL);
+    g_object_set(G_OBJECT(encoder->appsrc), "caps", encoder->src_caps, NULL);
+}
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static gboolean create_pipeline(SpiceGstEncoder *encoder)
+{
+    GError *err = NULL;
+    const gchar *desc = "appsrc name=src format=2 do-timestamp=true ! videoconvert ! avenc_mjpeg name=encoder ! appsink name=sink";
+    spice_debug("GStreamer pipeline: %s", desc);
+    encoder->pipeline = gst_parse_launch_full(desc, NULL, GST_PARSE_FLAG_FATAL_ERRORS, &err);
+    if (!encoder->pipeline || err) {
+        spice_warning("GStreamer error: %s", err->message);
+        g_clear_error(&err);
+        if (encoder->pipeline) {
+            gst_object_unref(encoder->pipeline);
+            encoder->pipeline = NULL;
+        }
+        return FALSE;
+    }
+    encoder->appsrc = GST_APP_SRC(gst_bin_get_by_name(GST_BIN(encoder->pipeline), "src"));
+    encoder->gstenc = gst_bin_get_by_name(GST_BIN(encoder->pipeline), "encoder");
+    encoder->appsink = GST_APP_SINK(gst_bin_get_by_name(GST_BIN(encoder->pipeline), "sink"));
+    return TRUE;
+}
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static gboolean configure_pipeline(SpiceGstEncoder *encoder,
+                                   const SpiceBitmap *bitmap)
+{
+    if (!encoder->pipeline && !create_pipeline(encoder)) {
+        return FALSE;
+    }
+
+    /* Configure the encoder bitrate, frame latency, etc. */
+    adjust_bit_rate(encoder);
+    g_object_set(G_OBJECT(encoder->gstenc),
+                 "bitrate", encoder->bit_rate,
+                 "max-threads", 1, /* zero-frame latency */
+                 NULL);
+
+    /* Set the source caps */
+    set_appsrc_caps(encoder);
+
+    /* 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);
+
+    /* Start playing */
+    spice_debug("setting state to PLAYING");
+    if (gst_element_set_state(encoder->pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+        spice_warning("GStreamer error: unable to set the pipeline to the playing state");
+        free_pipeline(encoder);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static void reconfigure_pipeline(SpiceGstEncoder *encoder)
+{
+    if (!is_pipeline_configured(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);
+    }
+    set_appsrc_caps(encoder);
+    if (gst_element_set_state(encoder->pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+        spice_debug("GStreamer error: could not restart the pipeline, rebuilding it instead");
+        free_pipeline(encoder);
+    }
+}
+
+/* A helper for push_raw_frame() */
+static inline int line_copy(SpiceGstEncoder *encoder, const SpiceBitmap *bitmap,
+                            uint32_t chunk_offset, uint32_t stream_stride,
+                            uint32_t height, uint8_t *buffer)
+{
+     uint8_t *dst = buffer;
+     SpiceChunks *chunks = bitmap->data;
+     uint32_t chunk_index = 0;
+     for (int l = 0; l < height; l++) {
+         /* We may have to move forward by more than one chunk the first
+          * time around.
+          */
+         while (chunk_offset >= chunks->chunk[chunk_index].len) {
+             /* Make sure that the chunk is not padded */
+             if (chunks->chunk[chunk_index].len % bitmap->stride != 0) {
+                 spice_warning("chunk %d/%d is padded, cannot copy line %d/%d",
+                               chunk_index, chunks->num_chunks, l, height);
+                 return FALSE;
+             }
+             chunk_offset -= chunks->chunk[chunk_index].len;
+             chunk_index++;
+         }
+
+         /* Copy the line */
+         uint8_t *src = chunks->chunk[chunk_index].data + chunk_offset;
+         memcpy(dst, src, stream_stride);
+         dst += stream_stride;
+         chunk_offset += bitmap->stride;
+     }
+     spice_return_val_if_fail(dst - buffer == stream_stride * height, FALSE);
+     return TRUE;
+}
+
+/* A helper for push_raw_frame() */
+static inline int chunk_copy(SpiceGstEncoder *encoder, const SpiceBitmap *bitmap,
+                             uint32_t chunk_offset, uint32_t len, uint8_t *dst)
+{
+    SpiceChunks *chunks = bitmap->data;
+    uint32_t chunk_index = 0;
+    /* We can copy the bitmap chunk by chunk */
+    while (len && chunk_index < chunks->num_chunks) {
+        /* Make sure that the chunk is not padded */
+        if (chunks->chunk[chunk_index].len % bitmap->stride != 0) {
+            spice_warning("chunk %d/%d is padded, cannot copy it",
+                          chunk_index, chunks->num_chunks);
+            return FALSE;
+        }
+        if (chunk_offset >= chunks->chunk[chunk_index].len) {
+            chunk_offset -= chunks->chunk[chunk_index].len;
+            chunk_index++;
+            continue;
+        }
+
+        uint8_t *src = chunks->chunk[chunk_index].data + chunk_offset;
+        uint32_t thislen = MIN(chunks->chunk[chunk_index].len - chunk_offset, len);
+        memcpy(dst, src, thislen);
+        dst += thislen;
+        len -= thislen;
+        chunk_offset = 0;
+        chunk_index++;
+    }
+    spice_return_val_if_fail(len == 0, FALSE);
+    return TRUE;
+}
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static int push_raw_frame(SpiceGstEncoder *encoder, const SpiceBitmap *bitmap,
+                          const SpiceRect *src, int top_down)
+{
+    const uint32_t height = src->bottom - src->top;
+    const uint32_t stream_stride = (src->right - src->left) * encoder->format->bpp / 8;
+    uint32_t len = stream_stride * height;
+    GstBuffer *buffer = gst_buffer_new_and_alloc(len);
+    GstMapInfo map;
+    gst_buffer_map(buffer, &map, GST_MAP_WRITE);
+    uint8_t *dst = map.data;
+
+    /* Note that we should not reorder the lines, even if top_down is false.
+     * It just changes the number of lines to skip at the start of the bitmap.
+     */
+    const uint32_t skip_lines = top_down ? src->top : bitmap->y - (src->bottom - 0);
+    uint32_t chunk_offset = bitmap->stride * skip_lines;
+
+    if (stream_stride != bitmap->stride) {
+        /* We have to do a line-by-line copy because for each we have to leave
+         * out pixels on the left or right.
+         */
+        chunk_offset += src->left * encoder->format->bpp / 8;
+        if (!line_copy(encoder, bitmap, chunk_offset, stream_stride, height, dst)) {
+            gst_buffer_unmap(buffer, &map);
+            gst_buffer_unref(buffer);
+            return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+        }
+    } else {
+        if (!chunk_copy(encoder, bitmap, chunk_offset, len, dst)) {
+            gst_buffer_unmap(buffer, &map);
+            gst_buffer_unref(buffer);
+            return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+        }
+    }
+    gst_buffer_unmap(buffer, &map);
+    GST_BUFFER_OFFSET(buffer) = encoder->frame++;
+
+    GstFlowReturn ret = gst_app_src_push_buffer(encoder->appsrc, buffer);
+    if (ret != GST_FLOW_OK) {
+        spice_debug("GStreamer error: unable to push source buffer (%d)", ret);
+        return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+    }
+
+    return VIDEO_ENCODER_FRAME_ENCODE_DONE;
+}
+
+/* A helper for spice_gst_encoder_encode_frame() */
+static int pull_compressed_buffer(SpiceGstEncoder *encoder,
+                                  uint8_t **outbuf, size_t *outbuf_size,
+                                  int *data_size)
+{
+    spice_return_val_if_fail(outbuf && outbuf_size, VIDEO_ENCODER_FRAME_UNSUPPORTED);
+
+    GstSample *sample = gst_app_sink_pull_sample(encoder->appsink);
+    if (sample) {
+        GstMapInfo map;
+        GstBuffer *buffer = gst_sample_get_buffer(sample);
+        if (buffer && gst_buffer_map(buffer, &map, GST_MAP_READ)) {
+            int size = gst_buffer_get_size(buffer);
+            if (!*outbuf || *outbuf_size < size) {
+                free(*outbuf);
+                *outbuf = spice_malloc(size);
+                *outbuf_size = size;
+            }
+            /* TODO Try to avoid this copy by changing the GstBuffer handling */
+            memcpy(*outbuf, map.data, size);
+            *data_size = size;
+            gst_buffer_unmap(buffer, &map);
+            gst_sample_unref(sample);
+            return VIDEO_ENCODER_FRAME_ENCODE_DONE;
+        }
+        gst_sample_unref(sample);
+    }
+    spice_debug("failed to pull the compressed buffer");
+    return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+}
+
+
+/* ---------- VideoEncoder's public API ---------- */
+
+static void spice_gst_encoder_destroy(VideoEncoder *video_encoder)
+{
+    SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
+    free_pipeline(encoder);
+    free(encoder);
+}
+
+static int spice_gst_encoder_encode_frame(VideoEncoder *video_encoder,
+                                          const SpiceBitmap *bitmap,
+                                          int width, int height,
+                                          const SpiceRect *src, int top_down,
+                                          uint32_t frame_mm_time,
+                                          uint8_t **outbuf, size_t *outbuf_size,
+                                          int *data_size)
+{
+    SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
+    if (width != encoder->width || height != encoder->height ||
+        encoder->spice_format != bitmap->format) {
+        spice_debug("video format change: width %d -> %d, height %d -> %d, format %d -> %d",
+                    encoder->width, width, encoder->height, height,
+                    encoder->spice_format, bitmap->format);
+        encoder->format = map_format(bitmap->format);
+        if (!encoder->format) {
+            spice_debug("unable to map format type %d", bitmap->format);
+            return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+        }
+        encoder->spice_format = bitmap->format;
+        encoder->width = width;
+        encoder->height = height;
+        if (encoder->pipeline) {
+            reconfigure_pipeline(encoder);
+        }
+    }
+    if (!is_pipeline_configured(encoder) &&
+        !configure_pipeline(encoder, bitmap)) {
+        return VIDEO_ENCODER_FRAME_UNSUPPORTED;
+    }
+
+    int rc = push_raw_frame(encoder, bitmap, src, top_down);
+    if (rc == VIDEO_ENCODER_FRAME_ENCODE_DONE) {
+        rc = pull_compressed_buffer(encoder, outbuf, outbuf_size, data_size);
+    }
+    return rc;
+}
+
+static void spice_gst_encoder_client_stream_report(VideoEncoder *video_encoder,
+                                             uint32_t num_frames,
+                                             uint32_t num_drops,
+                                             uint32_t start_frame_mm_time,
+                                             uint32_t end_frame_mm_time,
+                                             int32_t end_frame_delay,
+                                             uint32_t audio_delay)
+{
+    spice_debug("client report: #frames %u, #drops %d, duration %u video-delay %d audio-delay %u",
+                num_frames, num_drops,
+                end_frame_mm_time - start_frame_mm_time,
+                end_frame_delay, audio_delay);
+}
+
+static void spice_gst_encoder_notify_server_frame_drop(VideoEncoder *video_encoder)
+{
+    spice_debug("server report: getting frame drops...");
+}
+
+static uint64_t spice_gst_encoder_get_bit_rate(VideoEncoder *video_encoder)
+{
+    SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
+    return encoder->bit_rate;
+}
+
+static void spice_gst_encoder_get_stats(VideoEncoder *video_encoder,
+                                        VideoEncoderStats *stats)
+{
+    SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
+    uint64_t raw_bit_rate = encoder->width * encoder->height * (encoder->format ? encoder->format->bpp : 0) * get_source_fps(encoder);
+
+    spice_return_if_fail(stats != NULL);
+    stats->starting_bit_rate = encoder->starting_bit_rate;
+    stats->cur_bit_rate = encoder->bit_rate;
+
+    /* Use the compression level as a proxy for the quality */
+    stats->avg_quality = stats->cur_bit_rate ? 100.0 - raw_bit_rate / stats->cur_bit_rate : 0;
+    if (stats->avg_quality < 0) {
+        stats->avg_quality = 0;
+    }
+}
+
+VideoEncoder *gstreamer_encoder_new(uint64_t starting_bit_rate,
+                                    VideoEncoderRateControlCbs *cbs,
+                                    void *cbs_opaque)
+{
+    GError *err = NULL;
+    if (!gst_init_check(NULL, NULL, &err)) {
+        spice_warning("GStreamer error: %s", err->message);
+        g_clear_error(&err);
+        return NULL;
+    }
+
+    SpiceGstEncoder *encoder = spice_new0(SpiceGstEncoder, 1);
+    encoder->base.destroy = &spice_gst_encoder_destroy;
+    encoder->base.encode_frame = &spice_gst_encoder_encode_frame;
+    encoder->base.client_stream_report = &spice_gst_encoder_client_stream_report;
+    encoder->base.notify_server_frame_drop = &spice_gst_encoder_notify_server_frame_drop;
+    encoder->base.get_bit_rate = &spice_gst_encoder_get_bit_rate;
+    encoder->base.get_stats = &spice_gst_encoder_get_stats;
+
+    if (cbs) {
+        encoder->cbs = *cbs;
+        encoder->cbs_opaque = cbs_opaque;
+    }
+    encoder->bit_rate = encoder->starting_bit_rate = starting_bit_rate;
+
+    /* All the other fields are initialized to zero by spice_new0(). */
+
+    if (!create_pipeline(encoder)) {
+        /* Some GStreamer dependency is probably missing */
+        free(encoder);
+        encoder = NULL;
+    }
+    return (VideoEncoder*)encoder;
+}
diff --git a/server/stream.c b/server/stream.c
index 2bfa3a5..9c335b6 100644
--- a/server/stream.c
+++ b/server/stream.c
@@ -694,6 +694,21 @@  static void update_client_playback_delay(void *opaque, uint32_t delay_ms)
     main_dispatcher_set_mm_time_latency(RED_CHANNEL_CLIENT(agent->dcc)->client, agent->dcc->streams_max_latency);
 }
 
+/* A helper for dcc_create_stream(). */
+static VideoEncoder* dcc_create_video_encoder(uint64_t starting_bit_rate,
+                                              VideoEncoderRateControlCbs *cbs,
+                                              void *cbs_opaque)
+{
+#ifdef HAVE_GSTREAMER_1_0
+    VideoEncoder* video_encoder = gstreamer_encoder_new(starting_bit_rate, cbs, cbs_opaque);
+    if (video_encoder) {
+        return video_encoder;
+    }
+#endif
+    /* Use the builtin MJPEG video encoder as a fallback */
+    return mjpeg_encoder_new(starting_bit_rate, cbs, cbs_opaque);
+}
+
 void dcc_create_stream(DisplayChannelClient *dcc, Stream *stream)
 {
     StreamAgent *agent = &dcc->stream_agents[get_stream_id(DCC_TO_DC(dcc), stream)];
@@ -721,9 +736,9 @@  void dcc_create_stream(DisplayChannelClient *dcc, Stream *stream)
         video_cbs.update_client_playback_delay = update_client_playback_delay;
 
         initial_bit_rate = get_initial_bit_rate(dcc, stream);
-        agent->video_encoder = mjpeg_encoder_new(initial_bit_rate, &video_cbs, agent);
+        agent->video_encoder = dcc_create_video_encoder(initial_bit_rate, &video_cbs, agent);
     } else {
-        agent->video_encoder = mjpeg_encoder_new(0, NULL, NULL);
+        agent->video_encoder = dcc_create_video_encoder(0, NULL, NULL);
     }
     red_channel_client_pipe_add(RED_CHANNEL_CLIENT(dcc), &agent->create_item);
 
diff --git a/server/video-encoder.h b/server/video-encoder.h
index 3b1d541..1c6ceb3 100644
--- a/server/video-encoder.h
+++ b/server/video-encoder.h
@@ -156,5 +156,10 @@  typedef struct VideoEncoderRateControlCbs {
 VideoEncoder* mjpeg_encoder_new(uint64_t starting_bit_rate,
                                 VideoEncoderRateControlCbs *cbs,
                                 void *cbs_opaque);
+#ifdef HAVE_GSTREAMER_1_0
+VideoEncoder* gstreamer_encoder_new(uint64_t starting_bit_rate,
+                                    VideoEncoderRateControlCbs *cbs,
+                                    void *cbs_opaque);
+#endif
 
 #endif