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avfilter/vf_fps: properly preserve CEA-708 captions 

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
vice-versa).

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

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
This commit is contained in:
Devin Heitmueller 2023-05-05 15:09:03 -04:00 committed by Limin Wang
parent 2b0e794ffc
commit 61a9f3c0ce
1 changed files with 10 additions and 1 deletions
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11
libavfilter/vf_fps.c
View File

@ -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);
av_frame_free(&frame);
}
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 +213,11 @@ 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_ERROR, "Failure to setup CC FIFO queue\n");
return AVERROR(ENOMEM);
}
av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", outlink->frame_rate.num, outlink->frame_rate.den);
return 0;
@ -242,6 +250,7 @@ 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;
s->frames_in++;
@ -289,7 +298,7 @@ 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;