ui/spice: Add an option for users to provide a preferred video codec

Giving users an option to choose a particular codec will enable
them to make an appropriate decision based on their hardware and
use-case. Note that, the Spice server would use this codec with
Gstreamer encoder and only when gl=on is specified.

If no codec is provided, then the codec gstreamer:h264 would be used
as default. And, for the case where gl=off, the default codec to be
used is determined by the Spice server.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Michael Scherle <michael.scherle@rz.uni-freiburg.de>
Cc: Daniel P. Berrangé <berrange@redhat.com>
[ Marc-Andre - fix unused variables warnings ]
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Message-Id: <20250617043546.1022779-4-vivek.kasireddy@intel.com>

2 files changed, 24 insertions, 0 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index 1f862b1..8f6a228 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2281,6 +2281,7 @@ DEF("spice", HAS_ARG, QEMU_OPTION_spice,
     "       [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n"
     "       [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n"
     "       [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n"
+    "       [,video-codec=<codec>\n"
     "       [,gl=[on|off]][,rendernode=<file>]\n"
     "                enable spice\n"
     "                at least one of {port, tls-port} is mandatory\n",
@@ -2369,6 +2370,13 @@ SRST
     ``seamless-migration=[on|off]``
         Enable/disable spice seamless migration. Default is off.
 
+    ``video-codec=<codec>``
+        Provide the preferred codec the Spice server should use with the
+        Gstreamer encoder. This option is only relevant when gl=on is
+        specified. If no codec is provided, then the codec gstreamer:h264
+        would be used as default. And, for the case where gl=off, the
+        default codec to be used is determined by the Spice server.
+
     ``gl=[on|off]``
         Enable/disable OpenGL context. Default is off.
 
diff --git a/ui/spice-core.c b/ui/spice-core.c
index 5acbdd3..51bdcef 100644
--- a/ui/spice-core.c
+++ b/ui/spice-core.c
@@ -489,6 +489,9 @@ static QemuOptsList qemu_spice_opts = {
             .name = "streaming-video",
             .type = QEMU_OPT_STRING,
         },{
+            .name = "video-codec",
+            .type = QEMU_OPT_STRING,
+        },{
             .name = "agent-mouse",
             .type = QEMU_OPT_BOOL,
         },{
@@ -837,7 +840,20 @@ static void qemu_spice_init(void)
     if (qemu_opt_get_bool(opts, "gl", 0)) {
         if ((port != 0) || (tls_port != 0)) {
 #if SPICE_SERVER_VERSION >= 0x000f03 /* release 0.15.3 */
+            const char *video_codec = NULL;
+            g_autofree char *enc_codec = NULL;
+
             spice_remote_client = 1;
+
+            video_codec = qemu_opt_get(opts, "video-codec");
+            if (video_codec) {
+                enc_codec = g_strconcat("gstreamer:", video_codec, NULL);
+            }
+            if (spice_server_set_video_codecs(spice_server,
+                                              enc_codec ?: "gstreamer:h264")) {
+                error_report("invalid video codec");
+                exit(1);
+            }
 #else
             error_report("SPICE GL support is local-only for now and "
                          "incompatible with -spice port/tls-port");