[FFmpeg-devel] [PATCH v3] avformat/movenc: split empty text sample when duration overflow

Jun Li junli1026 at gmail.com
Wed Oct 2 03:20:37 EEST 2019


On Tue, Oct 1, 2019 at 4:19 AM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> Am Di., 10. Sept. 2019 um 21:12 Uhr schrieb Jun Li <junli1026 at gmail.com>:
> >
> > Fix #7637
> > One empty/end sample is created and inserted between two caption lines
> when there is a gap.
> > This patch is to split the sample into multiple ones when its duration
> is too long (>= INT_MAX).
> > ---
> >  libavformat/movenc.c                          | 24 ++++++++++++++-----
> >  tests/fate/subtitles.mak                      |  6 +++++
> >  tests/ref/fate/binsub-movtextenc-long-dur     |  1 +
> >  .../fate/binsub-movtextenc-long-dur-timebase  |  1 +
> >  4 files changed, 26 insertions(+), 6 deletions(-)
> >  create mode 100644 tests/ref/fate/binsub-movtextenc-long-dur
> >  create mode 100644 tests/ref/fate/binsub-movtextenc-long-dur-timebase
> >
> > diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> > index edddfeeb00..aeb7de351f 100644
> > --- a/libavformat/movenc.c
> > +++ b/libavformat/movenc.c
> > @@ -5746,7 +5746,8 @@ static int mov_write_packet(AVFormatContext *s,
> AVPacket *pkt)
> >           *
> >           * 2) For each subtitle track, check if the current packet's
> >           * dts is past the duration of the last subtitle sample. If
> > -         * so, we now need to write an end sample for that subtitle.
> > +         * so, we now need to write one or multiple end samples for
> > +         * that subtitle.
> >           *
> >           * This must be done conditionally to allow for subtitles that
> >           * immediately replace each other, in which case an end sample
> > @@ -5760,11 +5761,22 @@ static int mov_write_packet(AVFormatContext *s,
> AVPacket *pkt)
> >              int ret;
> >
> >              if (trk->par->codec_id == AV_CODEC_ID_MOV_TEXT &&
> > -                trk->track_duration < pkt->dts &&
> > -                (trk->entry == 0 || !trk->last_sample_is_subtitle_end))
> {
> > -                ret = mov_write_subtitle_end_packet(s, i,
> trk->track_duration);
> > -                if (ret < 0) return ret;
> > -                trk->last_sample_is_subtitle_end = 1;
> > +                trk->track_duration < pkt->dts) {
> > +                int max_duration = INT_MAX - 1;
> > +                if (trk->entry == 0 ||
> !trk->last_sample_is_subtitle_end) {
> > +                    ret = mov_write_subtitle_end_packet(s, i,
> trk->track_duration);
>
> > +                    if (ret < 0) return ret;
>
> > +                    trk->last_sample_is_subtitle_end = 1;
> > +                }
> > +                if (trk->last_sample_is_subtitle_end &&
> > +                    pkt->dts - trk->track_duration > max_duration) {
> > +                    int64_t dts = trk->track_duration;
> > +                    while(pkt->dts - dts > max_duration) {
> > +                        dts += max_duration;
> > +                        ret = mov_write_subtitle_end_packet(s, i, dts);
>
> > +                        if (ret < 0) return ret;
>
> Please add two CRLFs and I am threatening to push this.
>
> Carl Eugen
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Thanks Carl for review. Code is updated as follows.



Fix #7637
One empty/end sample is created and inserted between two caption lines when
there is a gap.
This patch is to split the sample into multiple ones when its duration is
too long (>= INT_MAX)
---
 libavformat/movenc.c                          | 26 ++++++++++++++-----
 tests/fate/subtitles.mak                      |  6 +++++
 tests/ref/fate/binsub-movtextenc-long-dur     |  1 +
 .../fate/binsub-movtextenc-long-dur-timebase  |  1 +
 4 files changed, 28 insertions(+), 6 deletions(-)
 create mode 100644 tests/ref/fate/binsub-movtextenc-long-dur
 create mode 100644 tests/ref/fate/binsub-movtextenc-long-dur-timebase

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index edddfeeb00..db6f5afefc 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -5746,7 +5746,8 @@ static int mov_write_packet(AVFormatContext *s,
AVPacket *pkt)
          *
          * 2) For each subtitle track, check if the current packet's
          * dts is past the duration of the last subtitle sample. If
-         * so, we now need to write an end sample for that subtitle.
+         * so, we now need to write one or multiple end samples for
+         * that subtitle.
          *
          * This must be done conditionally to allow for subtitles that
          * immediately replace each other, in which case an end sample
@@ -5760,11 +5761,24 @@ static int mov_write_packet(AVFormatContext *s,
AVPacket *pkt)
             int ret;

             if (trk->par->codec_id == AV_CODEC_ID_MOV_TEXT &&
-                trk->track_duration < pkt->dts &&
-                (trk->entry == 0 || !trk->last_sample_is_subtitle_end)) {
-                ret = mov_write_subtitle_end_packet(s, i,
trk->track_duration);
-                if (ret < 0) return ret;
-                trk->last_sample_is_subtitle_end = 1;
+                trk->track_duration < pkt->dts) {
+                int max_duration = INT_MAX - 1;
+                if (trk->entry == 0 || !trk->last_sample_is_subtitle_end) {
+                    ret = mov_write_subtitle_end_packet(s, i,
trk->track_duration);
+                    if (ret < 0)
+                        return ret;
+                    trk->last_sample_is_subtitle_end = 1;
+                }
+                if (trk->last_sample_is_subtitle_end &&
+                    pkt->dts - trk->track_duration > max_duration) {
+                    int64_t dts = trk->track_duration;
+                    while(pkt->dts - dts > max_duration) {
+                        dts += max_duration;
+                        ret = mov_write_subtitle_end_packet(s, i, dts);
+                        if (ret < 0)
+                            return ret;
+                    }
+                }
             }
         }

diff --git a/tests/fate/subtitles.mak b/tests/fate/subtitles.mak
index 0042902161..4c2b34c431 100644
--- a/tests/fate/subtitles.mak
+++ b/tests/fate/subtitles.mak
@@ -34,6 +34,12 @@ fate-sub-movtext: CMD = fmtstdout ass -i
$(TARGET_SAMPLES)/sub/MovText_capabilit
 FATE_SUBTITLES-$(call ENCDEC, MOVTEXT, MOV) += fate-binsub-movtextenc
 fate-binsub-movtextenc: CMD = md5 -i
$(TARGET_SAMPLES)/sub/MovText_capability_tester.mp4 -map 0 -scodec mov_text
-f mp4 -flags +bitexact -fflags +bitexact -movflags frag_keyframe+empty_moov

+FATE_SUBTITLES-$(call ENCDEC, MOVTEXT, MOV) +=
fate-binsub-movtextenc-long-dur
+fate-binsub-movtextenc-long-dur: CMD = md5 -i
$(TARGET_SAMPLES)/sub/WebVTT_movtext_long_dur.vtt -map 0 -scodec mov_text
-f mp4 -flags +bitexact -fflags +bitexact -movflags frag_keyframe+empty_moov
+
+FATE_SUBTITLES-$(call ENCDEC, MOVTEXT, MOV) +=
fate-binsub-movtextenc-long-dur-timebase
+fate-binsub-movtextenc-long-dur-timebase: CMD = md5 -i
$(TARGET_SAMPLES)/sub/WebVTT_movtext_long_dur.vtt -map 0 -scodec mov_text
-time_base 1000 -f mp4 -flags +bitexact -fflags +bitexact -movflags
frag_keyframe+empty_moov
+
 FATE_SUBTITLES_ASS-$(call DEMDEC, MPL2, MPL2) += fate-sub-mpl2
 fate-sub-mpl2: CMD = fmtstdout ass -i
$(TARGET_SAMPLES)/sub/MPL2_capability_tester.txt

diff --git a/tests/ref/fate/binsub-movtextenc-long-dur
b/tests/ref/fate/binsub-movtextenc-long-dur
new file mode 100644
index 0000000000..eb8a3f8fc7
--- /dev/null
+++ b/tests/ref/fate/binsub-movtextenc-long-dur
@@ -0,0 +1 @@
+7f78c11bb4a6b16335540ef31ba10219
diff --git a/tests/ref/fate/binsub-movtextenc-long-dur-timebase
b/tests/ref/fate/binsub-movtextenc-long-dur-timebase
new file mode 100644
index 0000000000..185dcc0aab
--- /dev/null
+++ b/tests/ref/fate/binsub-movtextenc-long-dur-timebase
@@ -0,0 +1 @@
+349d78698cc1226d33d4e6699dbf46d9
-- 
2.17.1


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