[FFmpeg-devel] [PATCH v2] avformat/movenc: split empty text sample when duration overflow
Jun Li
junli1026 at gmail.com
Mon Sep 9 03:59:47 EEST 2019
On Sun, Sep 8, 2019 at 5:51 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).
> ---
> 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;
> + }
> + }
> }
> }
>
> diff --git a/tests/fate/subtitles.mak b/tests/fate/subtitles.mak
> index 0042902161..59055e975c 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
> $(TARGET_SAMPLES)/sub/WebVTT_movtext_long_dur.vtt -map 0 -scodec mov_text
> -f mp4 -flags +bitexact -fflags +bitexact -movflags empty_moov
> +
> +FATE_SUBTITLES-$(call ENCDEC, MOVTEXT, MOV) +=
> fate-binsub-movtextenc-long-dur-timebase
> +fate-binsub-movtextenc-long-dur-timebase: CMD = md5 -i
> $(TARGET_SAMPLES)/sub/WebVTT_movtext_long_dur.vtt -map 0 -scodec mov_text
> -time_base 1000 -f mp4 -flags +bitexact -fflags +bitexact -movflags
> empty_moov
> +
> FATE_SUBTITLES_ASS-$(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..4db0be514b
> --- /dev/null
> +++ b/tests/ref/fate/binsub-movtextenc-long-dur
> @@ -0,0 +1 @@
> +043848a72c3ae75744115fe8d06c8bf1
> 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..14b2f0167b
> --- /dev/null
> +++ b/tests/ref/fate/binsub-movtextenc-long-dur-timebase
> @@ -0,0 +1 @@
> +043848a72c3ae75744115fe8d06c8bf1
> \ No newline at end of file
> --
> 2.17.1
>
>
Version 2 addressed the feedback from Jan, adding fate test.
The attachment is the sample file for the tests. I will send it to
samples-request at ffmpeg.org if this patch is approved.
-Jun
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