On Thu, 1 Jan 2026, Raja Rathour via ffmpeg-devel wrote:
v8: Restored original struct comments (unrelated to threads) and updated height
comment to Doxygen style (///<) as requested.
Thank you for the detailed feedback on the patch structure and project style.
Signed-off-by: Raja Rathour <[email protected]>
---
libavfilter/vf_blackframe.c | 69 ++++++++++++++++++++++++++++++++-----
1 file changed, 60 insertions(+), 9 deletions(-)
diff --git a/libavfilter/vf_blackframe.c b/libavfilter/vf_blackframe.c
index f0aa53e133..5b198e6594 100644
--- a/libavfilter/vf_blackframe.c
+++ b/libavfilter/vf_blackframe.c
@@ -32,6 +32,7 @@
#include "libavutil/internal.h"
#include "libavutil/opt.h"
+#include "libavutil/mem.h"
#include "avfilter.h"
#include "filters.h"
#include "video.h"
@@ -45,6 +46,15 @@ typedef struct BlackFrameContext {
unsigned int last_keyframe; ///< frame number of the last received key-frame
} BlackFrameContext;
+typedef struct ThreadData {
+ const uint8_t *data;
+ int linesize;
+ int bthresh;
+ int width;
+ int height; ///< height for cleaner slice math
+ unsigned int *counts;
You can use a single stdatomic atomic int for this and avoid the
allocation.
Also I suggest you open a pull request at code.ffmpeg.org.
Regards,
Marton
+} ThreadData;
+
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
@@ -55,22 +65,60 @@ static const enum AVPixelFormat pix_fmts[] = {
snprintf(buf, sizeof(buf), format, value); \
av_dict_set(metadata, key, buf, 0)
+static int blackframe_slice(AVFilterContext *ctx, void *arg, int jobnr, int
nb_jobs)
+{
+ ThreadData *td = arg;
+ int slice_start = (td->height * jobnr) / nb_jobs;
+ int slice_end = (td->height * (jobnr+1)) / nb_jobs;
+ int x, y;
+ const uint8_t *p;
+ unsigned int black_pixels_count = 0;
+
+ p = td->data + slice_start * td->linesize;
+
+ for (y = slice_start; y < slice_end; y++) {
+ for (x = 0; x < td->width; x++)
+ black_pixels_count += p[x] < td->bthresh;
+ p += td->linesize;
+ }
+
+ td->counts[jobnr] = black_pixels_count;
+ return 0;
+}
+
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
BlackFrameContext *s = ctx->priv;
- int x, i;
int pblack = 0;
- uint8_t *p = frame->data[0];
AVDictionary **metadata;
char buf[32];
+ ThreadData td;
+ int nb_threads, nb_jobs, i;
+ unsigned int *nb_black_pixels_per_slice;
+
+ nb_threads = ff_filter_get_nb_threads(ctx);
+
+ nb_black_pixels_per_slice = av_calloc(nb_threads,
sizeof(*nb_black_pixels_per_slice));
+ if (!nb_black_pixels_per_slice)
+ return AVERROR(ENOMEM);
+
+ td.data = frame->data[0];
+ td.linesize = frame->linesize[0];
+ td.width = inlink->w;
+ td.height = inlink->h;
+ td.bthresh = s->bthresh;
+ td.counts = nb_black_pixels_per_slice;
+
+ nb_jobs = FFMIN(td.height, nb_threads);
+
+ ff_filter_execute(ctx, blackframe_slice, &td, NULL, nb_jobs);
- for (i = 0; i < frame->height; i++) {
- for (x = 0; x < inlink->w; x++)
- s->nblack += p[x] < s->bthresh;
- p += frame->linesize[0];
+ s->nblack = 0;
+ for (i = 0; i < nb_jobs; i++) {
+ s->nblack += nb_black_pixels_per_slice[i];
}
-
+
if (frame->flags & AV_FRAME_FLAG_KEY)
s->last_keyframe = s->frame;
@@ -89,6 +137,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
s->frame++;
s->nblack = 0;
+
+ av_free(nb_black_pixels_per_slice);
+
return ff_filter_frame(inlink->dst->outputs[0], frame);
}
@@ -118,9 +169,9 @@ const FFFilter ff_vf_blackframe = {
.p.name = "blackframe",
.p.description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost)
black."),
.p.priv_class = &blackframe_class,
- .p.flags = AVFILTER_FLAG_METADATA_ONLY,
+ .p.flags = AVFILTER_FLAG_METADATA_ONLY | AVFILTER_FLAG_SLICE_THREADS,
.priv_size = sizeof(BlackFrameContext),
FILTER_INPUTS(avfilter_vf_blackframe_inputs),
FILTER_OUTPUTS(ff_video_default_filterpad),
FILTER_PIXFMTS_ARRAY(pix_fmts),
-};
+};
\ No newline at end of file
--
2.48.1
_______________________________________________
ffmpeg-devel mailing list -- [email protected]
To unsubscribe send an email to [email protected]
_______________________________________________
ffmpeg-devel mailing list -- [email protected]
To unsubscribe send an email to [email protected]
