[FFmpeg-devel] [PATCH v4] avformat/movenc: split empty text sample when duration overflow

[Jun Li]

On Wed, Oct 9, 2019 at 3:42 PM Jun Li <junli1026 at gmail.com> wrote:

>
>
> On Mon, Oct 7, 2019 at 6:36 PM Jun Li <junli1026 at gmail.com> wrote:
>
>>
>>
>> On Mon, Oct 7, 2019 at 6:34 PM Jun Li <junli1026 at gmail.com> wrote:
>>
>>> 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)
>>>
>>> Signed-off-by: Jun Li <junli1026 at gmail.com>
>>> ---
>>>  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 715bec1c2f..5dc2a19c3c 100644
>>> --- a/libavformat/movenc.c
>>> +++ b/libavformat/movenc.c
>>> @@ -5750,7 +5750,8 @@ 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
>>> @@ -5764,11 +5765,24 @@ 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
>>>
>>>
>> Test file attached.
>>
>
> Ping
>

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