On Fri, Apr 18, 2025 at 3:54 PM Dietmar Maurer <diet...@proxmox.com> wrote:
>
> The H264 implementation only sends frames when it detects changes in
> the server's framebuffer. This leads to artifacts when there are no
> further changes, as the internal H264 encoder may still contain data.
>
> This patch modifies the code to send a few additional frames in such
> situations to flush the H264 encoder data.
>
> Signed-off-by: Dietmar Maurer <diet...@proxmox.com>
(from v1)
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> ui/vnc.c | 25 ++++++++++++++++++++++++-
> ui/vnc.h | 3 +++
> 2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/ui/vnc.c b/ui/vnc.c
> index aed25b0183..badc7912c0 100644
> --- a/ui/vnc.c
> +++ b/ui/vnc.c
> @@ -3239,7 +3239,30 @@ static void vnc_refresh(DisplayChangeListener *dcl)
> vnc_unlock_display(vd);
>
> QTAILQ_FOREACH_SAFE(vs, &vd->clients, next, vn) {
> - rects += vnc_update_client(vs, has_dirty);
> + int client_dirty = has_dirty;
> + if (vs->h264) {
> + if (client_dirty) {
> + vs->h264->keep_dirty = VNC_H264_KEEP_DIRTY;
> + } else {
> + if (vs->h264->keep_dirty > 0) {
> + client_dirty = 1;
> + vs->h264->keep_dirty--;
> + }
> + }
> + }
> +
> + int count = vnc_update_client(vs, client_dirty);
> + rects += count;
> +
> + if (vs->h264 && !count && vs->h264->keep_dirty) {
> + VncJob *job = vnc_job_new(vs);
> + int height = pixman_image_get_height(vd->server);
> + int width = pixman_image_get_width(vd->server);
> + vs->job_update = vs->update;
> + vs->update = VNC_STATE_UPDATE_NONE;
> + vnc_job_add_rect(job, 0, 0, width, height);
> + vnc_job_push(job);
> + }
> /* vs might be free()ed here */
> }
>
> diff --git a/ui/vnc.h b/ui/vnc.h
> index a0d336738d..a5ea134de8 100644
> --- a/ui/vnc.h
> +++ b/ui/vnc.h
> @@ -236,10 +236,13 @@ typedef struct VncZywrle {
> } VncZywrle;
>
> #ifdef CONFIG_GSTREAMER
> +/* Number of frames we send after the display is clean. */
> +#define VNC_H264_KEEP_DIRTY 10
> typedef struct VncH264 {
> GstElement *pipeline, *source, *gst_encoder, *sink, *convert;
> size_t width;
> size_t height;
> + guint keep_dirty;
> } VncH264;
> #endif
>
> --
> 2.39.5
>
>
--
Marc-André Lureau
