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ffmpeg/libavfilter/vf_overlay.c
Stefano Sabatini bde1e8bf06 lavfi/overlay: make use of av_opt_set_from_string() 
Simplify.
2012-12-22 16:14:23 +01:00

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/*
* Copyright (c) 2010 Stefano Sabatini
* Copyright (c) 2010 Baptiste Coudurier
* Copyright (c) 2007 Bobby Bingham
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* overlay one video on top of another
*/
/* #define DEBUG */
#include "avfilter.h"
#include "formats.h"
#include "libavutil/common.h"
#include "libavutil/eval.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/mathematics.h"
#include "libavutil/timestamp.h"
#include "internal.h"
#include "bufferqueue.h"
#include "drawutils.h"
#include "video.h"
static const char *const var_names[] = {
"main_w", "W", ///< width of the main video
"main_h", "H", ///< height of the main video
"overlay_w", "w", ///< width of the overlay video
"overlay_h", "h", ///< height of the overlay video
NULL
};
enum var_name {
VAR_MAIN_W, VAR_MW,
VAR_MAIN_H, VAR_MH,
VAR_OVERLAY_W, VAR_OW,
VAR_OVERLAY_H, VAR_OH,
VAR_VARS_NB
};
#define MAIN 0
#define OVERLAY 1
#define R 0
#define G 1
#define B 2
#define A 3
#define Y 0
#define U 1
#define V 2
typedef struct {
const AVClass *class;
int x, y; ///< position of overlayed picture
int allow_packed_rgb;
uint8_t frame_requested;
uint8_t overlay_eof;
uint8_t main_is_packed_rgb;
uint8_t main_rgba_map[4];
uint8_t main_has_alpha;
uint8_t overlay_is_packed_rgb;
uint8_t overlay_rgba_map[4];
uint8_t overlay_has_alpha;
AVFilterBufferRef *overpicref;
struct FFBufQueue queue_main;
struct FFBufQueue queue_over;
int main_pix_step[4]; ///< steps per pixel for each plane of the main output
int overlay_pix_step[4]; ///< steps per pixel for each plane of the overlay
int hsub, vsub; ///< chroma subsampling values
char *x_expr, *y_expr;
} OverlayContext;
#define OFFSET(x) offsetof(OverlayContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption overlay_options[] = {
{ "x", "set the x expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "y", "set the y expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX, FLAGS },
{"rgb", "force packed RGB in input and output", OFFSET(allow_packed_rgb), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{NULL},
};
AVFILTER_DEFINE_CLASS(overlay);
static av_cold int init(AVFilterContext *ctx, const char *args)
{
OverlayContext *over = ctx->priv;
static const char *shorthand[] = { "x", "y", NULL };
over->class = &overlay_class;
av_opt_set_defaults(over);
return av_opt_set_from_string(over, args, shorthand, "=", ":");
}
static av_cold void uninit(AVFilterContext *ctx)
{
OverlayContext *over = ctx->priv;
av_opt_free(over);
avfilter_unref_bufferp(&over->overpicref);
ff_bufqueue_discard_all(&over->queue_main);
ff_bufqueue_discard_all(&over->queue_over);
}
static int query_formats(AVFilterContext *ctx)
{
OverlayContext *over = ctx->priv;
/* overlay formats contains alpha, for avoiding conversion with alpha information loss */
static const enum AVPixelFormat main_pix_fmts_yuv[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_NONE };
static const enum AVPixelFormat overlay_pix_fmts_yuv[] = { AV_PIX_FMT_YUVA420P, AV_PIX_FMT_NONE };
static const enum AVPixelFormat main_pix_fmts_rgb[] = {
AV_PIX_FMT_ARGB, AV_PIX_FMT_RGBA,
AV_PIX_FMT_ABGR, AV_PIX_FMT_BGRA,
AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
AV_PIX_FMT_NONE
};
static const enum AVPixelFormat overlay_pix_fmts_rgb[] = {
AV_PIX_FMT_ARGB, AV_PIX_FMT_RGBA,
AV_PIX_FMT_ABGR, AV_PIX_FMT_BGRA,
AV_PIX_FMT_NONE
};
AVFilterFormats *main_formats;
AVFilterFormats *overlay_formats;
if (over->allow_packed_rgb) {
main_formats = ff_make_format_list(main_pix_fmts_rgb);
overlay_formats = ff_make_format_list(overlay_pix_fmts_rgb);
} else {
main_formats = ff_make_format_list(main_pix_fmts_yuv);
overlay_formats = ff_make_format_list(overlay_pix_fmts_yuv);
}
ff_formats_ref(main_formats, &ctx->inputs [MAIN ]->out_formats);
ff_formats_ref(overlay_formats, &ctx->inputs [OVERLAY]->out_formats);
ff_formats_ref(main_formats, &ctx->outputs[MAIN ]->in_formats );
return 0;
}
static const enum AVPixelFormat alpha_pix_fmts[] = {
AV_PIX_FMT_YUVA420P, AV_PIX_FMT_ARGB, AV_PIX_FMT_ABGR, AV_PIX_FMT_RGBA,
AV_PIX_FMT_BGRA, AV_PIX_FMT_NONE
};
static int config_input_main(AVFilterLink *inlink)
{
OverlayContext *over = inlink->dst->priv;
const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
av_image_fill_max_pixsteps(over->main_pix_step, NULL, pix_desc);
over->hsub = pix_desc->log2_chroma_w;
over->vsub = pix_desc->log2_chroma_h;
over->main_is_packed_rgb =
ff_fill_rgba_map(over->main_rgba_map, inlink->format) >= 0;
over->main_has_alpha = ff_fmt_is_in(inlink->format, alpha_pix_fmts);
return 0;
}
static int config_input_overlay(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
OverlayContext *over = inlink->dst->priv;
char *expr;
double var_values[VAR_VARS_NB], res;
int ret;
const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
av_image_fill_max_pixsteps(over->overlay_pix_step, NULL, pix_desc);
/* Finish the configuration by evaluating the expressions
now when both inputs are configured. */
var_values[VAR_MAIN_W ] = var_values[VAR_MW] = ctx->inputs[MAIN ]->w;
var_values[VAR_MAIN_H ] = var_values[VAR_MH] = ctx->inputs[MAIN ]->h;
var_values[VAR_OVERLAY_W] = var_values[VAR_OW] = ctx->inputs[OVERLAY]->w;
var_values[VAR_OVERLAY_H] = var_values[VAR_OH] = ctx->inputs[OVERLAY]->h;
if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->x = res;
if ((ret = av_expr_parse_and_eval(&res, (expr = over->y_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)))
goto fail;
over->y = res;
/* x may depend on y */
if ((ret = av_expr_parse_and_eval(&res, (expr = over->x_expr), var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail;
over->x = res;
over->overlay_is_packed_rgb =
ff_fill_rgba_map(over->overlay_rgba_map, inlink->format) >= 0;
over->overlay_has_alpha = ff_fmt_is_in(inlink->format, alpha_pix_fmts);
av_log(ctx, AV_LOG_VERBOSE,
"main w:%d h:%d fmt:%s overlay x:%d y:%d w:%d h:%d fmt:%s\n",
ctx->inputs[MAIN]->w, ctx->inputs[MAIN]->h,
av_get_pix_fmt_name(ctx->inputs[MAIN]->format),
over->x, over->y,
ctx->inputs[OVERLAY]->w, ctx->inputs[OVERLAY]->h,
av_get_pix_fmt_name(ctx->inputs[OVERLAY]->format));
if (over->x < 0 || over->y < 0 ||
over->x + var_values[VAR_OVERLAY_W] > var_values[VAR_MAIN_W] ||
over->y + var_values[VAR_OVERLAY_H] > var_values[VAR_MAIN_H]) {
av_log(ctx, AV_LOG_ERROR,
"Overlay area (%d,%d)<->(%d,%d) not within the main area (0,0)<->(%d,%d) or zero-sized\n",
over->x, over->y,
(int)(over->x + var_values[VAR_OVERLAY_W]),
(int)(over->y + var_values[VAR_OVERLAY_H]),
(int)var_values[VAR_MAIN_W], (int)var_values[VAR_MAIN_H]);
return AVERROR(EINVAL);
}
return 0;
fail:
av_log(NULL, AV_LOG_ERROR,
"Error when evaluating the expression '%s'\n", expr);
return ret;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
outlink->w = ctx->inputs[MAIN]->w;
outlink->h = ctx->inputs[MAIN]->h;
outlink->time_base = ctx->inputs[MAIN]->time_base;
return 0;
}
// divide by 255 and round to nearest
// apply a fast variant: (X+127)/255 = ((X+127)*257+257)>>16 = ((X+128)*257)>>16
#define FAST_DIV255(x) ((((x) + 128) * 257) >> 16)
// calculate the unpremultiplied alpha, applying the general equation:
// alpha = alpha_overlay / ( (alpha_main + alpha_overlay) - (alpha_main * alpha_overlay) )
// (((x) << 16) - ((x) << 9) + (x)) is a faster version of: 255 * 255 * x
// ((((x) + (y)) << 8) - ((x) + (y)) - (y) * (x)) is a faster version of: 255 * (x + y)
#define UNPREMULTIPLY_ALPHA(x, y) ((((x) << 16) - ((x) << 9) + (x)) / ((((x) + (y)) << 8) - ((x) + (y)) - (y) * (x)))
/**
* Blend image in src to destination buffer dst at position (x, y).
*
* It is assumed that the src image at position (x, y) is contained in
* dst.
*/
static void blend_image(AVFilterContext *ctx,
AVFilterBufferRef *dst, AVFilterBufferRef *src,
int x, int y)
{
OverlayContext *over = ctx->priv;
int i, j, k;
int width = src->video->w;
int height = src->video->h;
if (over->main_is_packed_rgb) {
uint8_t *dp = dst->data[0] + x * over->main_pix_step[0] +
y * dst->linesize[0];
uint8_t *sp = src->data[0];
uint8_t alpha; ///< the amount of overlay to blend on to main
const int dr = over->main_rgba_map[R];
const int dg = over->main_rgba_map[G];
const int db = over->main_rgba_map[B];
const int da = over->main_rgba_map[A];
const int dstep = over->main_pix_step[0];
const int sr = over->overlay_rgba_map[R];
const int sg = over->overlay_rgba_map[G];
const int sb = over->overlay_rgba_map[B];
const int sa = over->overlay_rgba_map[A];
const int sstep = over->overlay_pix_step[0];
const int main_has_alpha = over->main_has_alpha;
for (i = 0; i < height; i++) {
uint8_t *d = dp, *s = sp;
for (j = 0; j < width; j++) {
alpha = s[sa];
// if the main channel has an alpha channel, alpha has to be calculated
// to create an un-premultiplied (straight) alpha value
if (main_has_alpha && alpha != 0 && alpha != 255) {
uint8_t alpha_d = d[da];
alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);
}
switch (alpha) {
case 0:
break;
case 255:
d[dr] = s[sr];
d[dg] = s[sg];
d[db] = s[sb];
break;
default:
// main_value = main_value * (1 - alpha) + overlay_value * alpha
// since alpha is in the range 0-255, the result must divided by 255
d[dr] = FAST_DIV255(d[dr] * (255 - alpha) + s[sr] * alpha);
d[dg] = FAST_DIV255(d[dg] * (255 - alpha) + s[sg] * alpha);
d[db] = FAST_DIV255(d[db] * (255 - alpha) + s[sb] * alpha);
}
if (main_has_alpha) {
switch (alpha) {
case 0:
break;
case 255:
d[da] = s[sa];
break;
default:
// apply alpha compositing: main_alpha += (1-main_alpha) * overlay_alpha
d[da] += FAST_DIV255((255 - d[da]) * s[sa]);
}
}
d += dstep;
s += sstep;
}
dp += dst->linesize[0];
sp += src->linesize[0];
}
} else {
const int main_has_alpha = over->main_has_alpha;
if (main_has_alpha) {
uint8_t *da = dst->data[3] + x * over->main_pix_step[3] +
y * dst->linesize[3];
uint8_t *sa = src->data[3];
uint8_t alpha; ///< the amount of overlay to blend on to main
for (i = 0; i < height; i++) {
uint8_t *d = da, *s = sa;
for (j = 0; j < width; j++) {
alpha = *s;
if (alpha != 0 && alpha != 255) {
uint8_t alpha_d = *d;
alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);
}
switch (alpha) {
case 0:
break;
case 255:
*d = *s;
break;
default:
// apply alpha compositing: main_alpha += (1-main_alpha) * overlay_alpha
*d += FAST_DIV255((255 - *d) * *s);
}
d += 1;
s += 1;
}
da += dst->linesize[3];
sa += src->linesize[3];
}
}
for (i = 0; i < 3; i++) {
int hsub = i ? over->hsub : 0;
int vsub = i ? over->vsub : 0;
uint8_t *dp = dst->data[i] + (x >> hsub) +
(y >> vsub) * dst->linesize[i];
uint8_t *sp = src->data[i];
uint8_t *ap = src->data[3];
int wp = FFALIGN(width, 1<<hsub) >> hsub;
int hp = FFALIGN(height, 1<<vsub) >> vsub;
for (j = 0; j < hp; j++) {
uint8_t *d = dp, *s = sp, *a = ap;
for (k = 0; k < wp; k++) {
// average alpha for color components, improve quality
int alpha_v, alpha_h, alpha;
if (hsub && vsub && j+1 < hp && k+1 < wp) {
alpha = (a[0] + a[src->linesize[3]] +
a[1] + a[src->linesize[3]+1]) >> 2;
} else if (hsub || vsub) {
alpha_h = hsub && k+1 < wp ?
(a[0] + a[1]) >> 1 : a[0];
alpha_v = vsub && j+1 < hp ?
(a[0] + a[src->linesize[3]]) >> 1 : a[0];
alpha = (alpha_v + alpha_h) >> 1;
} else
alpha = a[0];
// if the main channel has an alpha channel, alpha has to be calculated
// to create an un-premultiplied (straight) alpha value
if (main_has_alpha && alpha != 0 && alpha != 255) {
// average alpha for color components, improve quality
uint8_t alpha_d;
if (hsub && vsub && j+1 < hp && k+1 < wp) {
alpha_d = (d[0] + d[src->linesize[3]] +
d[1] + d[src->linesize[3]+1]) >> 2;
} else if (hsub || vsub) {
alpha_h = hsub && k+1 < wp ?
(d[0] + d[1]) >> 1 : d[0];
alpha_v = vsub && j+1 < hp ?
(d[0] + d[src->linesize[3]]) >> 1 : d[0];
alpha_d = (alpha_v + alpha_h) >> 1;
} else
alpha_d = d[0];
alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);
}
*d = FAST_DIV255(*d * (255 - alpha) + *s * alpha);
s++;
d++;
a += 1 << hsub;
}
dp += dst->linesize[i];
sp += src->linesize[i];
ap += (1 << vsub) * src->linesize[3];
}
}
}
}
static int try_filter_frame(AVFilterContext *ctx, AVFilterBufferRef *mainpic)
{
OverlayContext *over = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
AVFilterBufferRef *next_overpic;
int ret;
/* Discard obsolete overlay frames: if there is a next overlay frame with pts
* before the main frame, we can drop the current overlay. */
while (1) {
next_overpic = ff_bufqueue_peek(&over->queue_over, 0);
if (!next_overpic || av_compare_ts(next_overpic->pts, ctx->inputs[OVERLAY]->time_base,
mainpic->pts , ctx->inputs[MAIN]->time_base) > 0)
break;
ff_bufqueue_get(&over->queue_over);
avfilter_unref_buffer(over->overpicref);
over->overpicref = next_overpic;
}
/* If there is no next frame and no EOF and the overlay frame is before
* the main frame, we can not know yet if it will be superseded. */
if (!over->queue_over.available && !over->overlay_eof &&
(!over->overpicref || av_compare_ts(over->overpicref->pts, ctx->inputs[OVERLAY]->time_base,
mainpic->pts , ctx->inputs[MAIN]->time_base) < 0))
return AVERROR(EAGAIN);
/* At this point, we know that the current overlay frame extends to the
* time of the main frame. */
av_dlog(ctx, "main_pts:%s main_pts_time:%s",
av_ts2str(mainpic->pts), av_ts2timestr(mainpic->pts, &outlink->time_base));
if (over->overpicref)
av_dlog(ctx, " over_pts:%s over_pts_time:%s",
av_ts2str(over->overpicref->pts), av_ts2timestr(over->overpicref->pts, &outlink->time_base));
av_dlog(ctx, "\n");
if (over->overpicref)
blend_image(ctx, mainpic, over->overpicref, over->x, over->y);
ret = ff_filter_frame(ctx->outputs[0], mainpic);
over->frame_requested = 0;
return ret;
}
static int try_filter_next_frame(AVFilterContext *ctx)
{
OverlayContext *over = ctx->priv;
AVFilterBufferRef *next_mainpic = ff_bufqueue_peek(&over->queue_main, 0);
int ret;
if (!next_mainpic)
return AVERROR(EAGAIN);
if ((ret = try_filter_frame(ctx, next_mainpic)) == AVERROR(EAGAIN))
return ret;
ff_bufqueue_get(&over->queue_main);
return ret;
}
static int flush_frames(AVFilterContext *ctx)
{
int ret;
while (!(ret = try_filter_next_frame(ctx)));
return ret == AVERROR(EAGAIN) ? 0 : ret;
}
static int filter_frame_main(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
AVFilterContext *ctx = inlink->dst;
OverlayContext *over = ctx->priv;
int ret;
if ((ret = flush_frames(ctx)) < 0)
return ret;
if ((ret = try_filter_frame(ctx, inpicref)) < 0) {
if (ret != AVERROR(EAGAIN))
return ret;
ff_bufqueue_add(ctx, &over->queue_main, inpicref);
}
if (!over->overpicref)
return 0;
flush_frames(ctx);
return 0;
}
static int filter_frame_over(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
AVFilterContext *ctx = inlink->dst;
OverlayContext *over = ctx->priv;
int ret;
if ((ret = flush_frames(ctx)) < 0)
return ret;
ff_bufqueue_add(ctx, &over->queue_over, inpicref);
ret = try_filter_next_frame(ctx);
return ret == AVERROR(EAGAIN) ? 0 : ret;
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
OverlayContext *over = ctx->priv;
int input, ret;
if (!try_filter_next_frame(ctx))
return 0;
over->frame_requested = 1;
while (over->frame_requested) {
/* TODO if we had a frame duration, we could guess more accurately */
input = !over->overlay_eof && (over->queue_main.available ||
over->queue_over.available < 2) ?
OVERLAY : MAIN;
ret = ff_request_frame(ctx->inputs[input]);
/* EOF on main is reported immediately */
if (ret == AVERROR_EOF && input == OVERLAY) {
over->overlay_eof = 1;
if ((ret = try_filter_next_frame(ctx)) != AVERROR(EAGAIN))
return ret;
ret = 0; /* continue requesting frames on main */
}
if (ret < 0)
return ret;
}
return 0;
}
static const AVFilterPad avfilter_vf_overlay_inputs[] = {
{
.name = "main",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.config_props = config_input_main,
.filter_frame = filter_frame_main,
.min_perms = AV_PERM_READ | AV_PERM_WRITE | AV_PERM_PRESERVE,
},
{
.name = "overlay",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input_overlay,
.filter_frame = filter_frame_over,
.min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
},
{ NULL }
};
static const AVFilterPad avfilter_vf_overlay_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.rej_perms = AV_PERM_WRITE,
.config_props = config_output,
.request_frame = request_frame,
},
{ NULL }
};
AVFilter avfilter_vf_overlay = {
.name = "overlay",
.description = NULL_IF_CONFIG_SMALL("Overlay a video source on top of the input."),
.init = init,
.uninit = uninit,
.priv_size = sizeof(OverlayContext),
.query_formats = query_formats,
.inputs = avfilter_vf_overlay_inputs,
.outputs = avfilter_vf_overlay_outputs,
.priv_class = &overlay_class,
};
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