From: Limin Wang <lance.lmw...@gmail.com>
It's useful to compare two 4K videos quality side by side on 4K TV.
Signed-off-by: Limin Wang <lance.lmw...@gmail.com>
---
doc/filters.texi | 6 ++++++
libavfilter/vf_stack.c | 31 ++++++++++++++++++++++++++-----
2 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index ee6a93ffbf..675b02fc34 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -11280,6 +11280,9 @@ The filter accept the following option:
@item inputs
Set number of input streams. Default is 2.
+@item keep_dar
+stack with 1/nb_inputs of each inputs screen to keep the same DAR, Default is
0.
+
@item shortest
If set to 1, force the output to terminate when the shortest input
terminates. Default value is 0.
@@ -18333,6 +18336,9 @@ The filter accept the following option:
@item inputs
Set number of input streams. Default is 2.
+@item keep_dar
+stack with 1/nb_inputs of each inputs screen to keep the same DAR, Default is
0.
+
@item shortest
If set to 1, force the output to terminate when the shortest input
terminates. Default value is 0.
diff --git a/libavfilter/vf_stack.c b/libavfilter/vf_stack.c
index 4d254e0013..9196b5b0b7 100644
--- a/libavfilter/vf_stack.c
+++ b/libavfilter/vf_stack.c
@@ -44,6 +44,7 @@ typedef struct StackContext {
int is_vertical;
int is_horizontal;
int nb_planes;
+ int keep_dar;
StackItem *items;
AVFrame **frames;
@@ -123,7 +124,7 @@ static int process_frame(FFFrameSync *fs)
StackContext *s = fs->opaque;
AVFrame **in = s->frames;
AVFrame *out;
- int i, p, ret, offset[4] = { 0 };
+ int i, p, ret, offset[4] = { 0 }, in_offset[4] = { 0 };
for (i = 0; i < s->nb_inputs; i++) {
if ((ret = ff_framesync_get_frame(&s->fs, i, &in[i], 0)) < 0)
@@ -153,16 +154,25 @@ static int process_frame(FFFrameSync *fs)
for (p = 0; p < s->nb_planes; p++) {
if (s->is_vertical) {
+ if (s->keep_dar) {
+ height[p] /= s->nb_inputs;
+ in_offset[p] = i * height[p] * in[i]->linesize[p];
+ }
+
av_image_copy_plane(out->data[p] + offset[p] *
out->linesize[p],
out->linesize[p],
- in[i]->data[p],
+ in[i]->data[p] + in_offset[p],
in[i]->linesize[p],
linesize[p], height[p]);
offset[p] += height[p];
} else if (s->is_horizontal) {
+ if (s->keep_dar) {
+ linesize[p] /= s->nb_inputs;
+ in_offset[p] = i * in[i]->linesize[p] / s->nb_inputs;
+ }
av_image_copy_plane(out->data[p] + offset[p],
out->linesize[p],
- in[i]->data[p],
+ in[i]->data[p] + in_offset[p],
in[i]->linesize[p],
linesize[p], height[p]);
offset[p] += linesize[p];
@@ -197,20 +207,30 @@ static int config_output(AVFilterLink *outlink)
return AVERROR_BUG;
if (s->is_vertical) {
+ if (s->keep_dar)
+ height /= s->nb_inputs;
for (i = 1; i < s->nb_inputs; i++) {
if (ctx->inputs[i]->w != width) {
av_log(ctx, AV_LOG_ERROR, "Input %d width %d does not match input %d
width %d.\n", i, ctx->inputs[i]->w, 0, width);
return AVERROR(EINVAL);
}
- height += ctx->inputs[i]->h;
+ if (!s->keep_dar)
+ height += ctx->inputs[i]->h;
+ else
+ height += ctx->inputs[i]->h / s->nb_inputs;
}
} else if (s->is_horizontal) {
+ if (s->keep_dar)
+ width /= s->nb_inputs;
for (i = 1; i < s->nb_inputs; i++) {
if (ctx->inputs[i]->h != height) {
av_log(ctx, AV_LOG_ERROR, "Input %d height %d does not match input %d
height %d.\n", i, ctx->inputs[i]->h, 0, height);
return AVERROR(EINVAL);
}
- width += ctx->inputs[i]->w;
+ if (!s->keep_dar)
+ width += ctx->inputs[i]->w;
+ else
+ width += ctx->inputs[i]->w / s->nb_inputs;
}
} else {
char *arg, *p = s->layout, *saveptr = NULL;
@@ -339,6 +359,7 @@ static int activate(AVFilterContext *ctx)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
static const AVOption stack_options[] = {
{ "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT,
{.i64=2}, 2, INT_MAX, .flags = FLAGS },
+ { "keep_dar", "stack with 1/nb_inputs of each inputs screen to keep the same
DAR", OFFSET(keep_dar), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, .flags = FLAGS },
{ "shortest", "force termination when the shortest input terminates",
OFFSET(shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, .flags = FLAGS },
{ NULL },
};
