[FFmpeg-devel] [PATCH] avfilter/xstack: Add support for fixed size grid
Vignesh Venkatasubramanian
vigneshv at google.com
Tue Jun 28 22:01:29 EEST 2022
Add a short hand parameter for making a fixed size grid. The existing
xstack layout parameter syntax gets tedious if all one wants is a
matrix like grid of the input streams. Add a grid option to the xstack
filter that simplifies this use case by simply specifying the number of
rows and columns instead of specific x/y co-ordinate for each stream.
Also updating the filter documentation to explain the new option.
Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
---
doc/filters.texi | 19 +++++++++--
libavfilter/vf_stack.c | 73 ++++++++++++++++++++++++++++++++++++------
2 files changed, 81 insertions(+), 11 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index e525e87b3c..9d800a0fd6 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -24381,8 +24381,23 @@ the output video frame will be filled. Similarly, videos can overlap each
other if their position doesn't leave enough space for the full frame of
adjoining videos.
-For 2 inputs, a default layout of @code{0_0|w0_0} is set. In all other cases,
-a layout must be set by the user.
+For 2 inputs, a default layout of @code{0_0|w0_0} is set. In all other cases, a
+layout or a grid must be set by the user. Either grid or layout option can be
+specified at a time. Specifying both will result in an error.
+
+ at item grid
+Specify a fixed size grid of inputs.
+This option is used to create a fixed size grid of the input streams. The
+option is of the form <rows>x<columns> (e.g. 2x4). There must be <rows> *
+<columns> input streams and they will be arranged as a grid with <rows> rows and
+<columns> columns. When using this option, all the input streams must have the
+same width and height.
+
+Either grid or layout option can be specified at a time. Specifying both will
+result in an error.
+
+If grid is set, then inputs option is ignored and is implicitly set to
+<rows>*<columns>.
@item shortest
If set to 1, force the output to terminate when the shortest input
diff --git a/libavfilter/vf_stack.c b/libavfilter/vf_stack.c
index aa32a1bf5e..b38a193355 100644
--- a/libavfilter/vf_stack.c
+++ b/libavfilter/vf_stack.c
@@ -48,6 +48,9 @@ typedef struct StackContext {
int is_vertical;
int is_horizontal;
int nb_planes;
+ char *grid;
+ int nb_grid_rows;
+ int nb_grid_columns;
uint8_t fillcolor[4];
char *fillcolor_str;
int fillcolor_enable;
@@ -85,14 +88,6 @@ static av_cold int init(AVFilterContext *ctx)
if (!strcmp(ctx->filter->name, "hstack"))
s->is_horizontal = 1;
- s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
- if (!s->frames)
- return AVERROR(ENOMEM);
-
- s->items = av_calloc(s->nb_inputs, sizeof(*s->items));
- if (!s->items)
- return AVERROR(ENOMEM);
-
if (!strcmp(ctx->filter->name, "xstack")) {
if (strcmp(s->fillcolor_str, "none") &&
av_parse_color(s->fillcolor, s->fillcolor_str, -1, ctx) >= 0) {
@@ -100,7 +95,21 @@ static av_cold int init(AVFilterContext *ctx)
} else {
s->fillcolor_enable = 0;
}
- if (!s->layout) {
+ if (s->grid && s->layout) {
+ av_log(ctx, AV_LOG_ERROR, "Both layout and grid were specified. Only one is allowed.\n");
+ return AVERROR(EINVAL);
+ }
+ if (s->grid) {
+ if (sscanf(s->grid, "%dx%d", &s->nb_grid_rows, &s->nb_grid_columns) != 2) {
+ av_log(ctx, AV_LOG_ERROR, "grid string is not of the form rowsxcolumns.\n");
+ return AVERROR(EINVAL);
+ }
+ s->nb_inputs = s->nb_grid_rows * s->nb_grid_columns;
+ } else {
+ s->nb_grid_rows = 0;
+ s->nb_grid_columns = 0;
+ }
+ if (!s->layout && !s->grid) {
if (s->nb_inputs == 2) {
s->layout = av_strdup("0_0|w0_0");
if (!s->layout)
@@ -112,6 +121,15 @@ static av_cold int init(AVFilterContext *ctx)
}
}
+ s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
+ if (!s->frames)
+ return AVERROR(ENOMEM);
+
+ s->items = av_calloc(s->nb_inputs, sizeof(*s->items));
+ if (!s->items)
+ return AVERROR(ENOMEM);
+
+
for (i = 0; i < s->nb_inputs; i++) {
AVFilterPad pad = { 0 };
@@ -244,6 +262,42 @@ static int config_output(AVFilterLink *outlink)
width += ctx->inputs[i]->w;
}
}
+ } else if (s->nb_grid_rows > 0 && s->nb_grid_columns > 0) {
+ int inw = 0, inh = 0;
+ int k = 0;
+ for (i = 0; i < s->nb_grid_rows; i++, inh += height) {
+ inw = 0;
+ for (int j = 0; j < s->nb_grid_columns; j++, k++, inw += width) {
+ AVFilterLink *inlink = ctx->inputs[k];
+ StackItem *item = &s->items[k];
+
+ if (ctx->inputs[k]->w != width) {
+ av_log(ctx, AV_LOG_ERROR, "Input %d width %d does not match input %d width %d.\n", k, ctx->inputs[k]->w, 0, width);
+ return AVERROR(EINVAL);
+ }
+
+ if (ctx->inputs[k]->h != height) {
+ av_log(ctx, AV_LOG_ERROR, "Input %d height %d does not match input %d height %d.\n", k, ctx->inputs[k]->h, 0, height);
+ return AVERROR(EINVAL);
+ }
+
+ if ((ret = av_image_fill_linesizes(item->linesize, inlink->format, inlink->w)) < 0) {
+ return ret;
+ }
+
+ item->height[1] = item->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
+ item->height[0] = item->height[3] = inlink->h;
+
+ if ((ret = av_image_fill_linesizes(item->x, inlink->format, inw)) < 0) {
+ return ret;
+ }
+
+ item->y[1] = item->y[2] = AV_CEIL_RSHIFT(inh, s->desc->log2_chroma_h);
+ item->y[0] = item->y[3] = inh;
+ }
+ }
+ width *= s->nb_grid_columns;
+ height *= s->nb_grid_rows;
} else {
char *arg, *p = s->layout, *saveptr = NULL;
char *arg2, *p2, *saveptr2 = NULL;
@@ -436,6 +490,7 @@ const AVFilter ff_vf_vstack = {
static const AVOption xstack_options[] = {
{ "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=2}, 2, INT_MAX, .flags = FLAGS },
{ "layout", "set custom layout", OFFSET(layout), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, .flags = FLAGS },
+ { "grid", "set fixed size grid layout", OFFSET(grid), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, .flags = FLAGS },
{ "shortest", "force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, .flags = FLAGS },
{ "fill", "set the color for unused pixels", OFFSET(fillcolor_str), AV_OPT_TYPE_STRING, {.str = "none"}, .flags = FLAGS },
{ NULL },
--
2.37.0.rc0.161.g10f37bed90-goog
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