1 files changed, 220 insertions, 55 deletions

diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
index 39b2375..638da2d 100644
--- a/libavfilter/vf_overlay.c
+++ b/libavfilter/vf_overlay.c
@@ -3,20 +3,20 @@
  * Copyright (c) 2010 Baptiste Coudurier
  * Copyright (c) 2007 Bobby Bingham
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * 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.
  *
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -25,18 +25,20 @@
  * overlay one video on top of another
  */
 
+/* #define DEBUG */
+
 #include "avfilter.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 "drawutils.h"
 
-static const char *var_names[] = {
-    "E",
-    "PHI",
-    "PI",
+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
@@ -45,9 +47,6 @@ static const char *var_names[] = {
 };
 
 enum var_name {
-    VAR_E,
-    VAR_PHI,
-    VAR_PI,
     VAR_MAIN_W,    VAR_MW,
     VAR_MAIN_H,    VAR_MH,
     VAR_OVERLAY_W, VAR_OW,
@@ -58,61 +57,157 @@ enum var_name {
 #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
 
-    AVFilterBufferRef *overpicref;
+    int allow_packed_rgb;
+    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;
 
-    int max_plane_step[4];      ///< steps per pixel for each plane
+    AVFilterBufferRef *overpicref, *overpicref_next;
+
+    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[256], y_expr[256];
+    char *x_expr, *y_expr;
 } OverlayContext;
 
+#define OFFSET(x) offsetof(OverlayContext, x)
+
+static const AVOption overlay_options[] = {
+    { "x", "set the x expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX },
+    { "y", "set the y expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "0"}, CHAR_MIN, CHAR_MAX },
+    {"rgb", "force packed RGB in input and output", OFFSET(allow_packed_rgb), AV_OPT_TYPE_INT, {.dbl=0}, 0, 1 },
+    {NULL},
+};
+
+static const char *overlay_get_name(void *ctx)
+{
+    return "overlay";
+}
+
+static const AVClass overlay_class = {
+    "OverlayContext",
+    overlay_get_name,
+    overlay_options
+};
+
 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
 {
     OverlayContext *over = ctx->priv;
+    char *args1 = av_strdup(args);
+    char *expr, *bufptr = NULL;
+    int ret = 0;
+
+    over->class = &overlay_class;
+    av_opt_set_defaults(over);
+
+    if (expr = av_strtok(args1, ":", &bufptr)) {
+        av_free(over->x_expr);
+        if (!(over->x_expr = av_strdup(expr))) {
+            ret = AVERROR(ENOMEM);
+            goto end;
+        }
+    }
+    if (expr = av_strtok(NULL, ":", &bufptr)) {
+        av_free(over->y_expr);
+        if (!(over->y_expr = av_strdup(expr))) {
+            ret = AVERROR(ENOMEM);
+            goto end;
+        }
+    }
 
-    av_strlcpy(over->x_expr, "0", sizeof(over->x_expr));
-    av_strlcpy(over->y_expr, "0", sizeof(over->y_expr));
-
-    if (args)
-        sscanf(args, "%255[^:]:%255[^:]", over->x_expr, over->y_expr);
+    if (bufptr && (ret = av_set_options_string(over, bufptr, "=", ":")) < 0)
+        goto end;
 
-    return 0;
+end:
+    av_free(args1);
+    return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     OverlayContext *over = ctx->priv;
 
+    av_freep(&over->x_expr);
+    av_freep(&over->y_expr);
+
     if (over->overpicref)
         avfilter_unref_buffer(over->overpicref);
+    if (over->overpicref_next)
+        avfilter_unref_buffer(over->overpicref_next);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
-    const enum PixelFormat inout_pix_fmts[] = { PIX_FMT_YUV420P,  PIX_FMT_NONE };
-    const enum PixelFormat blend_pix_fmts[] = { PIX_FMT_YUVA420P, PIX_FMT_NONE };
-    AVFilterFormats *inout_formats = avfilter_make_format_list(inout_pix_fmts);
-    AVFilterFormats *blend_formats = avfilter_make_format_list(blend_pix_fmts);
+    OverlayContext *over = ctx->priv;
 
-    avfilter_formats_ref(inout_formats, &ctx->inputs [MAIN   ]->out_formats);
-    avfilter_formats_ref(blend_formats, &ctx->inputs [OVERLAY]->out_formats);
-    avfilter_formats_ref(inout_formats, &ctx->outputs[MAIN   ]->in_formats );
+    /* overlay formats contains alpha, for avoiding conversion with alpha information loss */
+    const enum PixelFormat main_pix_fmts_yuv[] = { PIX_FMT_YUV420P,  PIX_FMT_NONE };
+    const enum PixelFormat overlay_pix_fmts_yuv[] = { PIX_FMT_YUVA420P, PIX_FMT_NONE };
+    const enum PixelFormat main_pix_fmts_rgb[] = {
+        PIX_FMT_ARGB,  PIX_FMT_RGBA,
+        PIX_FMT_ABGR,  PIX_FMT_BGRA,
+        PIX_FMT_RGB24, PIX_FMT_BGR24,
+        PIX_FMT_NONE
+    };
+    const enum PixelFormat overlay_pix_fmts_rgb[] = {
+        PIX_FMT_ARGB,  PIX_FMT_RGBA,
+        PIX_FMT_ABGR,  PIX_FMT_BGRA,
+        PIX_FMT_NONE
+    };
+
+    AVFilterFormats *main_formats;
+    AVFilterFormats *overlay_formats;
+
+    if (over->allow_packed_rgb) {
+        main_formats    = avfilter_make_format_list(main_pix_fmts_rgb);
+        overlay_formats = avfilter_make_format_list(overlay_pix_fmts_rgb);
+    } else {
+        main_formats    = avfilter_make_format_list(main_pix_fmts_yuv);
+        overlay_formats = avfilter_make_format_list(overlay_pix_fmts_yuv);
+    }
+
+    avfilter_formats_ref(main_formats,    &ctx->inputs [MAIN   ]->out_formats);
+    avfilter_formats_ref(overlay_formats, &ctx->inputs [OVERLAY]->out_formats);
+    avfilter_formats_ref(main_formats,    &ctx->outputs[MAIN   ]->in_formats );
 
     return 0;
 }
 
+static const enum PixelFormat alpha_pix_fmts[] = {
+    PIX_FMT_YUVA420P, PIX_FMT_ARGB, PIX_FMT_ABGR, PIX_FMT_RGBA,
+    PIX_FMT_BGRA, PIX_FMT_NONE
+};
+
 static int config_input_main(AVFilterLink *inlink)
 {
     OverlayContext *over = inlink->dst->priv;
     const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
 
-    av_image_fill_max_pixsteps(over->max_plane_step, NULL, pix_desc);
+    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;
 }
 
@@ -123,13 +218,12 @@ static int config_input_overlay(AVFilterLink *inlink)
     char *expr;
     double var_values[VAR_VARS_NB], res;
     int ret;
+    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[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_E  ] = M_E;
-    var_values[VAR_PHI] = M_PHI;
-    var_values[VAR_PI ] = M_PI;
-
     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;
@@ -149,6 +243,10 @@ static int config_input_overlay(AVFilterLink *inlink)
         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_INFO,
            "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,
@@ -211,22 +309,31 @@ static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
     AVFilterContext *ctx = inlink->dst;
     OverlayContext *over = ctx->priv;
+    av_unused AVFilterLink *outlink = ctx->outputs[0];
 
     inlink->dst->outputs[0]->out_buf = outpicref;
     outpicref->pts = av_rescale_q(outpicref->pts, ctx->inputs[MAIN]->time_base,
                                   ctx->outputs[0]->time_base);
 
     if (!over->overpicref || over->overpicref->pts < outpicref->pts) {
-        AVFilterBufferRef *old = over->overpicref;
-        over->overpicref = NULL;
-        avfilter_request_frame(ctx->inputs[OVERLAY]);
-        if (over->overpicref) {
-            if (old)
-                avfilter_unref_buffer(old);
-        } else
-            over->overpicref = old;
+        if (!over->overpicref_next)
+            avfilter_request_frame(ctx->inputs[OVERLAY]);
+
+        if (over->overpicref && over->overpicref_next &&
+            over->overpicref_next->pts <= outpicref->pts) {
+            avfilter_unref_buffer(over->overpicref);
+            over->overpicref = over->overpicref_next;
+            over->overpicref_next = NULL;
+        }
     }
 
+    av_dlog(ctx, "main_pts:%s main_pts_time:%s",
+            av_ts2str(outpicref->pts), av_ts2timestr(outpicref->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");
+
     avfilter_start_frame(inlink->dst->outputs[0], outpicref);
 }
 
@@ -235,11 +342,17 @@ static void start_frame_overlay(AVFilterLink *inlink, AVFilterBufferRef *inpicre
     AVFilterContext *ctx = inlink->dst;
     OverlayContext *over = ctx->priv;
 
-    over->overpicref = inpicref;
-    over->overpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[OVERLAY]->time_base,
-                                         ctx->outputs[0]->time_base);
+    inpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[OVERLAY]->time_base,
+                                 ctx->outputs[0]->time_base);
+
+    if (!over->overpicref) over->overpicref      = inpicref;
+    else                   over->overpicref_next = inpicref;
 }
 
+// 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)
+
 static void blend_slice(AVFilterContext *ctx,
                         AVFilterBufferRef *dst, AVFilterBufferRef *src,
                         int x, int y, int w, int h,
@@ -257,21 +370,72 @@ static void blend_slice(AVFilterContext *ctx,
     start_y = FFMAX(y, slice_y);
     height = end_y - start_y;
 
-    if (dst->format == PIX_FMT_BGR24 || dst->format == PIX_FMT_RGB24) {
-        uint8_t *dp = dst->data[0] + x * 3 + start_y * dst->linesize[0];
+    if (over->main_is_packed_rgb) {
+        uint8_t *dp = dst->data[0] + x * over->main_pix_step[0] +
+                      start_y * dst->linesize[0];
         uint8_t *sp = src->data[0];
-        int b = dst->format == PIX_FMT_BGR24 ? 2 : 0;
-        int r = dst->format == PIX_FMT_BGR24 ? 0 : 2;
+        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;
         if (slice_y > y)
             sp += (slice_y - y) * src->linesize[0];
         for (i = 0; i < height; i++) {
             uint8_t *d = dp, *s = sp;
             for (j = 0; j < width; j++) {
-                d[r] = (d[r] * (0xff - s[3]) + s[0] * s[3] + 128) >> 8;
-                d[1] = (d[1] * (0xff - s[3]) + s[1] * s[3] + 128) >> 8;
-                d[b] = (d[b] * (0xff - s[3]) + s[2] * s[3] + 128) >> 8;
-                d += 3;
-                s += 4;
+                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) {
+                    // apply the general equation:
+                    // alpha = alpha_overlay / ( (alpha_main + alpha_overlay) - (alpha_main * alpha_overlay) )
+                    alpha =
+                        // the next line is a faster version of: 255 * 255 * alpha
+                        ( (alpha << 16) - (alpha << 9) + alpha )
+                        /
+                        // the next line is a faster version of: 255 * (alpha + d[da])
+                        ( ((alpha + d[da]) << 8 ) - (alpha + d[da])
+                          - d[da] * alpha );
+                }
+
+                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];
@@ -306,7 +470,8 @@ static void blend_slice(AVFilterContext *ctx,
                         alpha = (alpha_v + alpha_h) >> 1;
                     } else
                         alpha = a[0];
-                    *d = (*d * (0xff - alpha) + *s++ * alpha + 128) >> 8;
+                    *d = FAST_DIV255(*d * (255 - alpha) + *s * alpha);
+                    s++;
                     d++;
                     a += 1 << hsub;
                 }
@@ -356,7 +521,7 @@ AVFilter avfilter_vf_overlay = {
 
     .query_formats = query_formats,
 
-    .inputs    = (AVFilterPad[]) {{ .name            = "main",
+    .inputs    = (const AVFilterPad[]) {{ .name      = "main",
                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .start_frame     = start_frame,
                                     .get_video_buffer= get_video_buffer,
@@ -374,7 +539,7 @@ AVFilter avfilter_vf_overlay = {
                                     .min_perms       = AV_PERM_READ,
                                     .rej_perms       = AV_PERM_REUSE2, },
                                   { .name = NULL}},
-    .outputs   = (AVFilterPad[]) {{ .name            = "default",
+    .outputs   = (const AVFilterPad[]) {{ .name      = "default",
                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .config_props    = config_output, },
                                   { .name = NULL}},