[FFmpeg-devel] [PATCH 1/2] lavfi/framesync2: add dualinput helper functions.

[Nicolas George]

Signed-off-by: Nicolas George <george at nsup.org>
---
 libavfilter/framesync2.c | 78 +++++++++++++++++++++++++++++++++++++-----------
 libavfilter/framesync2.h | 20 +++++++++++++
 2 files changed, 80 insertions(+), 18 deletions(-)


Ok, this one actually works.

There was a bug in framesync2 triggered by certain time bases, fixed.

When pushing, I will add another commit to reorder the functions and get rid
of the forward declaration.

Next steps: update blend, libvmaf, lut3d, paletteuse, psnr, ssim;
make shortest ans cie. options of the framesync context and make it a child
context of the filters, so that all options are always available.


diff --git a/libavfilter/framesync2.c b/libavfilter/framesync2.c
index 0e9f6f210c..02c41e7203 100644
--- a/libavfilter/framesync2.c
+++ b/libavfilter/framesync2.c
@@ -46,6 +46,8 @@ enum {
     STATE_EOF,
 };
 
+static int consume_from_fifos(FFFrameSync *fs);
+
 int ff_framesync2_init(FFFrameSync *fs, AVFilterContext *parent, unsigned nb_in)
 {
     /* For filters with several outputs, we will not be able to assume which
@@ -127,26 +129,16 @@ int ff_framesync2_configure(FFFrameSync *fs)
     return 0;
 }
 
-static void framesync_advance(FFFrameSync *fs)
+static int framesync_advance(FFFrameSync *fs)
 {
-    int latest;
     unsigned i;
     int64_t pts;
+    int ret;
 
-    if (fs->eof)
-        return;
-    while (!fs->frame_ready) {
-        latest = -1;
-        for (i = 0; i < fs->nb_in; i++) {
-            if (!fs->in[i].have_next) {
-                if (latest < 0 || fs->in[i].pts < fs->in[latest].pts)
-                    latest = i;
-            }
-        }
-        if (latest >= 0) {
-            fs->in_request = latest;
-            break;
-        }
+    while (!(fs->frame_ready || fs->eof)) {
+        ret = consume_from_fifos(fs);
+        if (ret <= 0)
+            return ret;
 
         pts = fs->in[0].pts_next;
         for (i = 1; i < fs->nb_in; i++)
@@ -181,6 +173,7 @@ static void framesync_advance(FFFrameSync *fs)
                     fs->frame_ready = 0;
         fs->pts = pts;
     }
+    return 0;
 }
 
 static int64_t framesync_pts_extrapolate(FFFrameSync *fs, unsigned in,
@@ -264,7 +257,7 @@ void ff_framesync2_uninit(FFFrameSync *fs)
     av_freep(&fs->in);
 }
 
-int ff_framesync2_activate(FFFrameSync *fs)
+static int consume_from_fifos(FFFrameSync *fs)
 {
     AVFilterContext *ctx = fs->parent;
     AVFrame *frame = NULL;
@@ -300,8 +293,16 @@ int ff_framesync2_activate(FFFrameSync *fs)
                 ff_inlink_request_frame(ctx->inputs[i]);
         return 0;
     }
+    return 1;
+}
 
-    framesync_advance(fs);
+int ff_framesync2_activate(FFFrameSync *fs)
+{
+    int ret;
+
+    ret = framesync_advance(fs);
+    if (ret < 0)
+        return ret;
     if (fs->eof || !fs->frame_ready)
         return 0;
     ret = fs->on_event(fs);
@@ -311,3 +312,44 @@ int ff_framesync2_activate(FFFrameSync *fs)
 
     return 0;
 }
+
+int ff_framesync2_init_dualinput(FFFrameSync *fs, AVFilterContext *parent)
+{
+    int ret;
+
+    ret = ff_framesync2_init(fs, parent, 2);
+    if (ret < 0)
+        return ret;
+    fs->in[0].time_base = parent->inputs[0]->time_base;
+    fs->in[1].time_base = parent->inputs[1]->time_base;
+    fs->in[0].sync   = 2;
+    fs->in[0].before = EXT_STOP;
+    fs->in[0].after  = EXT_INFINITY;
+    fs->in[1].sync   = 1;
+    fs->in[1].before = EXT_NULL;
+    fs->in[1].after  = EXT_INFINITY;
+    return 0;
+}
+
+int ff_framesync2_dualinput_get(FFFrameSync *fs, AVFrame **f0, AVFrame **f1)
+{
+    AVFilterContext *ctx = fs->parent;
+    AVFrame *mainpic = NULL, *secondpic = NULL;
+    int ret = 0;
+
+    if ((ret = ff_framesync2_get_frame(fs, 0, &mainpic,   1)) < 0 ||
+        (ret = ff_framesync2_get_frame(fs, 1, &secondpic, 0)) < 0) {
+        av_frame_free(&mainpic);
+        return ret;
+    }
+    ret = ff_inlink_make_frame_writable(ctx->inputs[0], &mainpic);
+    if (ret < 0)
+        return ret;
+    av_assert0(mainpic);
+    mainpic->pts = av_rescale_q(fs->pts, fs->time_base, ctx->outputs[0]->time_base);
+    if (ctx->is_disabled)
+        secondpic = NULL;
+    *f0 = mainpic;
+    *f1 = secondpic;
+    return 0;
+}
diff --git a/libavfilter/framesync2.h b/libavfilter/framesync2.h
index 2b37636ebb..d24bd7abe8 100644
--- a/libavfilter/framesync2.h
+++ b/libavfilter/framesync2.h
@@ -245,4 +245,24 @@ int ff_framesync2_get_frame(FFFrameSync *fs, unsigned in, AVFrame **rframe,
  */
 int ff_framesync2_activate(FFFrameSync *fs);
 
+/**
+ * Initialize a frame sync structure for dualinput.
+ *
+ * Compared to generic framesync, dualinput assumes the first input is the
+ * main one and the filtering is performed on it. The first input will be
+ * the only one with sync set and generic timeline support will just pass it
+ * unchanged when disabled.
+ *
+ * Equivalent to ff_framesync2_init(fs, parent, 2) then setting the time
+ * base, sync and ext modes on the inputs.
+ */
+int ff_framesync2_init_dualinput(FFFrameSync *fs, AVFilterContext *parent);
+
+/**
+ * @param f0  used to return the main frame
+ * @param f1  used to return the second frame, or NULL if disabled
+ * @return  >=0 for success or AVERROR code
+ */
+int ff_framesync2_dualinput_get(FFFrameSync *fs, AVFrame **f0, AVFrame **f1);
+
 #endif /* AVFILTER_FRAMESYNC2_H */
-- 
2.13.2