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decklink-output-ui: Pipeline GPU data for preview

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Mapping a GPU resource for CPU read immediately after GPU write creates
a large stall on the graphics thread. Use a small circular buffer, and
read the oldest frame instead.
This commit is contained in:
jpark37 2022-09-05 16:36:13 -07:00 committed by Jim
parent 1adb984bd9
commit 4a108a6935
1 changed files with 50 additions and 27 deletions
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77
UI/frontend-plugins/decklink-output-ui/decklink-ui-main.cpp
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@ -21,6 +21,8 @@ bool preview_output_running = false;
obs_output_t *output;
constexpr size_t STAGE_BUFFER_COUNT = 3;
struct preview_output {
bool enabled;
obs_source_t *current_source;
@ -28,7 +30,9 @@ struct preview_output {
video_t *video_queue;
gs_texrender_t *texrender;
gs_stagesurf_t *stagesurface;
gs_stagesurf_t *stagesurfaces[STAGE_BUFFER_COUNT];
bool surf_written[STAGE_BUFFER_COUNT];
size_t stage_index;
uint8_t *video_data;
uint32_t video_linesize;
@ -131,7 +135,8 @@ void preview_output_stop()
obs_source_release(context.current_source);
obs_enter_graphics();
gs_stagesurface_destroy(context.stagesurface);
for (gs_stagesurf_t *surf : context.stagesurfaces)
gs_stagesurface_destroy(surf);
gs_texrender_destroy(context.texrender);
obs_leave_graphics();
@ -161,10 +166,15 @@ void preview_output_start()
obs_enter_graphics();
context.texrender = gs_texrender_create(GS_BGRA, GS_ZS_NONE);
context.stagesurface =
gs_stagesurface_create(width, height, GS_BGRA);
for (gs_stagesurf_t *&surf : context.stagesurfaces)
surf = gs_stagesurface_create(width, height, GS_BGRA);
obs_leave_graphics();
for (bool &written : context.surf_written)
written = false;
context.stage_index = 0;
const video_output_info *mainVOI =
video_output_get_info(obs_get_video());
@ -266,34 +276,47 @@ void render_preview_source(void *param, uint32_t cx, uint32_t cy)
gs_blend_state_pop();
gs_texrender_end(ctx->texrender);
struct video_frame output_frame;
if (video_output_lock_frame(ctx->video_queue, &output_frame, 1,
os_gettime_ns())) {
gs_stage_texture(
ctx->stagesurface,
gs_texrender_get_texture(ctx->texrender));
const size_t write_stage_index = ctx->stage_index;
gs_stage_texture(ctx->stagesurfaces[write_stage_index],
gs_texrender_get_texture(ctx->texrender));
ctx->surf_written[write_stage_index] = true;
if (gs_stagesurface_map(ctx->stagesurface,
&ctx->video_data,
&ctx->video_linesize)) {
uint32_t linesize = output_frame.linesize[0];
for (uint32_t i = 0; i < ctx->ovi.base_height;
i++) {
uint32_t dst_offset = linesize * i;
uint32_t src_offset =
ctx->video_linesize * i;
memcpy(output_frame.data[0] +
dst_offset,
ctx->video_data + src_offset,
linesize);
const size_t read_stage_index =
(write_stage_index + 1) % STAGE_BUFFER_COUNT;
if (ctx->surf_written[read_stage_index]) {
struct video_frame output_frame;
if (video_output_lock_frame(ctx->video_queue,
&output_frame, 1,
os_gettime_ns())) {
gs_stagesurf_t *const read_surf =
ctx->stagesurfaces[read_stage_index];
if (gs_stagesurface_map(read_surf,
&ctx->video_data,
&ctx->video_linesize)) {
uint32_t linesize =
output_frame.linesize[0];
for (uint32_t i = 0;
i < ctx->ovi.base_height; i++) {
uint32_t dst_offset =
linesize * i;
uint32_t src_offset =
ctx->video_linesize * i;
memcpy(output_frame.data[0] +
dst_offset,
ctx->video_data +
src_offset,
linesize);
}
gs_stagesurface_unmap(read_surf);
ctx->video_data = nullptr;
}
gs_stagesurface_unmap(ctx->stagesurface);
ctx->video_data = nullptr;
video_output_unlock_frame(ctx->video_queue);
}
video_output_unlock_frame(ctx->video_queue);
}
ctx->stage_index = read_stage_index;
}
}