The search list is currently hardcoded to: ["x264enc", "openh264enc"]
x264enc: is probably the best available software encoder
openh264enc: lower quality, but available on more systems.
We restrict encoders to a known list because each encoder requires
fine tuning to get reasonable/usable results.
Signed-off-by: Dietmar Maurer <diet...@proxmox.com>
---
ui/vnc-enc-h264.c | 76 +++++++++++++++++++++++++++++++++++++++--------
ui/vnc.h | 1 +
2 files changed, 65 insertions(+), 12 deletions(-)
diff --git a/ui/vnc-enc-h264.c b/ui/vnc-enc-h264.c
index 9e01b8a548..3eabfc2cfe 100644
--- a/ui/vnc-enc-h264.c
+++ b/ui/vnc-enc-h264.c
@@ -3,6 +3,60 @@
#include <gst/gst.h>
+const char *encoder_list[] = { "x264enc", "openh264enc", NULL };
+
+static const char *get_available_encoder(void)
+{
+ int i = 0;
+ do {
+ const char *encoder_name = encoder_list[i];
+ if (encoder_name == NULL) {
+ break;
+ }
+ GstElement *element = gst_element_factory_make(
+ encoder_name, "video-encoder");
+ if (element != NULL) {
+ gst_object_unref(element);
+ return encoder_name;
+ }
+ i = i + 1;
+ } while (true);
+
+ return NULL;
+}
+
+static GstElement *create_encoder(const char *encoder_name)
+{
+ GstElement *encoder = gst_element_factory_make(
+ encoder_name, "video-encoder");
+ if (!encoder) {
+ VNC_DEBUG("Could not create gst '%s' video encoder\n", encoder_name);
+ return NULL;
+ }
+
+ if (!strcmp(encoder_name, "x264enc")) {
+ g_object_set(encoder, "tune", 4, NULL); /* zerolatency */
+ /*
+ * fix for zerolatency with novnc (without,
+ * noVNC displays green stripes)
+ */
+ g_object_set(encoder, "threads", 1, NULL);
+ g_object_set(encoder, "pass", 5, NULL); /* Constant Quality */
+ g_object_set(encoder, "quantizer", 26, NULL);
+ /* avoid access unit delimiters (Nal Unit Type 9) - not required */
+ g_object_set(encoder, "aud", false, NULL);
+ } else if (!strcmp(encoder_name, "openh264enc")) {
+ g_object_set(encoder, "usage-type", 1, NULL); /* screen content */
+ g_object_set(encoder, "complexity", 2, NULL); /* high */
+ g_object_set(encoder, "rate-control", 2, NULL); /* off (buffer) */
+ } else {
+ VNC_DEBUG("Unknown H264 encoder name '%s' - no setting any properties",
+ encoder_name);
+ }
+
+ return encoder;
+}
+
static void destroy_encoder_context(VncState *vs)
{
if (!vs->h264) {
@@ -66,23 +120,12 @@ static bool create_encoder_context(VncState *vs, int w,
int h)
return FALSE;
}
- vs->h264->gst_encoder = gst_element_factory_make("x264enc", "gst-encoder");
+ vs->h264->gst_encoder = create_encoder(vs->h264->encoder_name);
if (!vs->h264->gst_encoder) {
- VNC_DEBUG("Could not create gst x264 encoder\n");
destroy_encoder_context(vs);
return FALSE;
}
- g_object_set(vs->h264->gst_encoder, "tune", 4, NULL); /* zerolatency */
- /* fix for zerolatency with novnc (without, noVNC displays green stripes)
*/
- g_object_set(vs->h264->gst_encoder, "threads", 1, NULL);
-
- g_object_set(vs->h264->gst_encoder, "pass", 5, NULL); /* Constant Quality
*/
- g_object_set(vs->h264->gst_encoder, "quantizer", 26, NULL);
-
- /* avoid access unit delimiters (Nal Unit Type 9) - not required */
- g_object_set(vs->h264->gst_encoder, "aud", false, NULL);
-
vs->h264->sink = gst_element_factory_make("appsink", "sink");
if (!vs->h264->sink) {
VNC_DEBUG("Could not create gst sink\n");
@@ -173,7 +216,16 @@ int vnc_h264_encoder_init(VncState *vs)
{
g_assert(vs->h264 == NULL);
+ const char *encoder_name = get_available_encoder();
+ if (encoder_name == NULL) {
+ VNC_DEBUG("No H264 encoder available.\n");
+ return -1;
+ }
+
vs->h264 = g_malloc0(sizeof(VncH264));
+ vs->h264->encoder_name = encoder_name;
+
+ VNC_DEBUG("Allow H264 using encoder '%s`\n", encoder_name);
return 0;
}
diff --git a/ui/vnc.h b/ui/vnc.h
index e1b81d6bcc..f39dbe21aa 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -239,6 +239,7 @@ typedef struct VncZywrle {
/* Number of frames we send after the display is clean. */
#define VNC_H264_KEEP_DIRTY 10
typedef struct VncH264 {
+ const char *encoder_name;
GstElement *pipeline, *source, *gst_encoder, *sink, *convert;
size_t width;
size_t height;
--
2.39.5
