[FFmpeg-devel] [PATCH] avfilter/xstack: Add support for fixed size grid
Paul B Mahol
onemda at gmail.com
Wed Jun 29 10:21:20 EEST 2022
On Tue, Jun 28, 2022 at 9:01 PM Vignesh Venkatasubramanian <
vigneshv-at-google.com at ffmpeg.org> wrote:
> 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.
>
Use SIZE AVOption for grid size option.
As already done in tile filter.
>
> 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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