[FFmpeg-devel] [PATCH v7 0/4] add ARIB caption decoder using libaribcaption

Ridley Combs rcombs at rcombs.me
Tue Feb 28 02:07:18 EET 2023


> On Feb 23, 2023, at 04:17, TADANO Tokumei <aimingoff at pc.nifty.jp> wrote:
> 
> Ping with rebased patch set.
> Some chages are added to reflect review results from outside of this ML.
> 
> ---
> This patch set add another ARIB caption decoder using libaribcaption
> external library: https://github.com/xqq/libaribcaption
> The library decodes subtitles of ISDB-based TV broadcasting.
> It is not only for Japanese ARIB STD-B24 caption, but also for
> Brazilian ABNT NBR 15606-1 and Philippines version of ISDB-T.
> 
> Unlike libaribb24, it supports 3 types of subtitle outputs:
> * text: plain text
> * ass: ASS formatted text
> * bitmap: bitmap image
> 
> Default subtitle type is ASS as same as libaribb24.
> Advantages compared with libaribb24 on ASS subtitle are:
> * Subtitle positioning.
> * Multi-rect subtitle: some captions are displayed at different
>  position at a time.
> * More stability and reproducibility.
> 
> Subtitle type can be changed by `-sub_type` option.
> You can see ARIB caption with ffplay tool:
>  ffplay -sub_type bitmap MPEG.TS
> 
> Sample files exist under:
>  https://streams.videolan.org/streams/ts/ARIB/
> Some of them are encrypted and some don't contain ARIB caption data.
> Good samples for ARIB caption are:
>  brazil/07-25_20-33-35_UCV - HD_.ts
>  japan/channel2[137]_clear.ts
>  japan/osaka_15.ts
> 
> ---
> v7: reflect review results from outside of this ML
>  - rename -ass_workaround option to -ass_single_rect and default to
>    false (latest mpv supports multiple ASS rectangle)
>  - add -canvas_size option to specify frame size to render bitmap subtitle
>  - add -caption_encoding option to specify encoding of subtitle text
>  - change behavior of profile C ARIB caption
>  - some cosmetic changes
> v6: reflect review results from outside of this ML
>  - check clut table overflow
>  - do not adjust vertical position of ruby for ASS format
> v5: reflect review comments from Mao Hata
>  - reset correct variable in aribcaption_close()
>  - add aribcaption_close() to some places in aribcaption_init()
>  - check if av_strdup() returns NULL in set_ass_header()
> v4: reflect review results from outside of this ML.
>  - resize bitmap subtitle image to display fonts with correct aspect ratio
>  - multiple font families can be specified by '-font' option
>  - remove 'rendering_backend' option
>  - add document
>  - minor bug fixes
> v3: combine former 1/4 and 2/4 due to the patchwork shows build error.
>  - fix help option content which incorrectly separated to 2 lines in 2/4.
>  - amend commit message of 4/4.
> 
> TADANO Tokumei (4):
>  lavc/libaribcaption.c: add ARIB caption decoder using libaribcaption
>  lavc/codec_desc.c: remove AV_CODEC_PROP_TEXT_SUB property
>  lavf/mpegts.c: set some properties for ARIB caption
>  doc/decoders.texi: add document of aribcaption decoder
> 
> configure                   |    4 +
> doc/decoders.texi           |  150 +++++
> libavcodec/Makefile         |    1 +
> libavcodec/allcodecs.c      |    1 +
> libavcodec/codec_desc.c     |    1 -
> libavcodec/libaribb24.c     |    1 +
> libavcodec/libaribcaption.c | 1171 +++++++++++++++++++++++++++++++++++
> libavformat/mpegts.c        |    6 +-
> 8 files changed, 1333 insertions(+), 2 deletions(-)
> create mode 100644 libavcodec/libaribcaption.c
> 
> -- 
> 2.30.2
> 
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This set looks reasonable to me at this point; the one thing blocking it is the issue with assenc.c muxing for AVSubtitles with multiple rects, which needs a decision on this question: http://ffmpeg.org/pipermail/ffmpeg-devel/2023-February/306850.html

Once that's resolved, I'm happy to merge this.



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