[FFmpeg-devel] [PATCH 2/2] avfilter/vf_fps: add eof_action filter option

[Tobias Rapp]

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 at noa-archive.com>
---
 doc/filters.texi      | 12 ++++++++++++
 libavfilter/version.h |  2 +-
 libavfilter/vf_fps.c  | 14 +++++++++++++-
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 96b3dfd..0dc6ba5 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8695,6 +8695,18 @@ For example, this could be set to 0 to pad the beginning with duplicates of
 the first frame if a video stream starts after the audio stream or to trim any
 frames with a negative PTS.
 
+ at item eof_action
+Action performed when reading the last frame.
+
+Possible values are:
+ at table @option
+ at item round
+Use same timestamp rounding method as used for other frames.
+ at item pass
+Pass through last frame if input duration has not been reached yet.
+ at 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 5d6aa5f..0366a66 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR   6
 #define LIBAVFILTER_VERSION_MINOR 105
-#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 0db2b48..3fcb584 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[] = {
         { "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" },
     { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX}, -DBL_MAX, DBL_MAX, V|F },
+    { "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 */
-- 
2.7.4