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[FFmpeg-devel,v4,2/6] vf_fps: properly preserve CEA-708 captions

Message ID 1682699871-22331-3-git-send-email-dheitmueller@ltnglobal.com
State New
Headers show
Series Add support for Closed Caption FIFO | expand


Context Check Description
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished

Commit Message

Devin Heitmueller April 28, 2023, 4:37 p.m. UTC
The existing implementation made an attempt to remove duplicate
captions if increasing the framerate, but made no attempt to
handle reducing the framerate, nor did it rewrite the caption
payloads to have the appropriate cc_count (e.g. the cc_count needs
to change from 20 to 10 when going from 1080i59 to 720p59 and

Make use of the new ccfifo mechanism to ensure that caption data
is properly preserved.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
 libavfilter/vf_fps.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
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diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index 051d278..19c727e 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -34,6 +34,7 @@ 
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "avfilter.h"
+#include "ccfifo.h"
 #include "filters.h"
 #include "internal.h"
@@ -85,6 +86,7 @@  typedef struct FPSContext {
     AVFrame *frames[2];     ///< buffered frames
     int      frames_count;  ///< number of buffered frames
+    AVCCFifo *cc_fifo;      ///< closed captions
     int64_t  next_pts;      ///< pts of the next frame to output
@@ -165,6 +167,7 @@  static av_cold void uninit(AVFilterContext *ctx)
         frame = shift_frame(ctx, s);
+    ff_ccfifo_freep(&s->cc_fifo);
     av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
            "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
@@ -210,6 +213,9 @@  static int config_props(AVFilterLink* outlink)
                s->in_pts_off, s->out_pts_off, s->start_time);
+    if (!(s->cc_fifo = ff_ccfifo_alloc(&outlink->frame_rate, ctx)))
+        av_log(ctx, AV_LOG_VERBOSE, "Failure to setup CC FIFO queue\n");
     av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", outlink->frame_rate.num, outlink->frame_rate.den);
     return 0;
@@ -242,6 +248,7 @@  static int read_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink,
     av_log(ctx, AV_LOG_DEBUG, "Read frame with in pts %"PRId64", out pts %"PRId64"\n",
            in_pts, frame->pts);
+    ff_ccfifo_extract(s->cc_fifo, frame);
     s->frames[s->frames_count++] = frame;
@@ -289,7 +296,7 @@  static int write_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlin
         if (!frame)
             return AVERROR(ENOMEM);
         // Make sure Closed Captions will not be duplicated
-        av_frame_remove_side_data(s->frames[0], AV_FRAME_DATA_A53_CC);
+        ff_ccfifo_inject(s->cc_fifo, frame);
         frame->pts = s->next_pts++;
         frame->duration = 1;