avfilter/vf_fps: add eof_action filter option

Allows to specify the action to be performed when reading the last frame
from the internal FIFO buffer. By default the last frame is written to
filter output depending on the timestamp rounding method. When using
"pass" action the last frame is passed through if input duration
has not been reached yet.

Examples using an input file with 25Hz, 1.4sec duration:
 - "fps=fps=1:round=near" generates an output file of 1sec
 - "fps=fps=1:round=near:eof_action=pass" generates an output file of
   2sec

Signed-off-by: Tobias Rapp <t.rapp@noa-archive.com>

3 files changed, 26 insertions, 2 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 624e5cd01b..57189c77b0 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8695,6 +8695,18 @@ round to nearest
 @end table
 The default is @code{near}.
 
+@item eof_action
+Action performed when reading the last frame.
+
+Possible values are:
+@table @option
+@item round
+Use same timestamp rounding method as used for other frames.
+@item pass
+Pass through last frame if input duration has not been reached yet.
+@end table
+The default is @code{round}.
+
 @end table
 
 Alternatively, the options can be specified as a flat string:
diff --git a/libavfilter/version.h b/libavfilter/version.h
index fb382d4e25..8191c59a15 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR   6
 #define LIBAVFILTER_VERSION_MINOR 106
-#define LIBAVFILTER_VERSION_MICRO 100
+#define LIBAVFILTER_VERSION_MICRO 101
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \
diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index a5e51c3bbb..dbafd2c35a 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -40,6 +40,12 @@
 #include "internal.h"
 #include "video.h"
 
+enum EOFAction {
+    EOF_ACTION_ROUND,
+    EOF_ACTION_PASS,
+    EOF_ACTION_NB
+};
+
 typedef struct FPSContext {
     const AVClass *class;
 
@@ -52,6 +58,7 @@ typedef struct FPSContext {
 
     AVRational framerate;   ///< target framerate
     int rounding;           ///< AVRounding method for timestamps
+    int eof_action;         ///< action performed for last frame in FIFO
 
     /* statistics */
     int frames_in;             ///< number of frames on input
@@ -72,6 +79,9 @@ static const AVOption fps_options[] = {
         { "down", "round towards -infty",            0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN     }, 0, 0, V|F, "round" },
         { "up",   "round towards +infty",            0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP       }, 0, 0, V|F, "round" },
         { "near", "round to nearest",                0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 0, V|F, "round" },
+    { "eof_action", "action performed for last frame", OFFSET(eof_action), AV_OPT_TYPE_INT, { .i64 = EOF_ACTION_ROUND }, 0, EOF_ACTION_NB-1, V|F, "eof_action" },
+        { "round", "round similar to other frames",  0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_ROUND }, 0, 0, V|F, "eof_action" },
+        { "pass",  "pass through last frame",        0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_PASS  }, 0, 0, V|F, "eof_action" },
     { NULL }
 };
 
@@ -151,9 +161,11 @@ static int request_frame(AVFilterLink *outlink)
                 /* This is the last frame, we may have to duplicate it to match
                  * the last frame duration */
                 int j;
+                int eof_rounding = (s->eof_action == EOF_ACTION_PASS) ? AV_ROUND_UP : s->rounding;
                 int delta = av_rescale_q_rnd(ctx->inputs[0]->current_pts - s->first_pts,
                                              ctx->inputs[0]->time_base,
-                                             outlink->time_base, s->rounding) - s->frames_out ;
+                                             outlink->time_base, eof_rounding) - s->frames_out;
+                av_log(ctx, AV_LOG_DEBUG, "EOF frames_out:%d delta:%d\n", s->frames_out, delta);
                 /* if the delta is equal to 1, it means we just need to output
                  * the last frame. Greater than 1 means we will need duplicate
                  * delta-1 frames */