#11455(undetermined:new): Degradation in Closed Captions decoding
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Type: defect Status: new | Priority: normal Component: | Version: git- undetermined | master Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Summary of the bug: in some cases, FFmpeg fails to extract Closed Captions (A/53 Part 4 format). This is a degradation: same file can be processed correctly with FFmpeg 4.0, but also with VLC. How to reproduce: {{{ % ffmpeg.EXE" -f lavfi -report -i "movie=CC720p60_10sec.mp4[out+subcc]" -map 0:1 output_10sec.srt ffmpeg version N-118422-g1fbe9deee3-20250204 built on 2025-02-04 17:56 }}} Relevant error is: {{{ [Closed Captions Decoder @ 000002f8b063dec0] Data ignored due to columns exceeding screen width. }}} I will (try to) attach original file, and reports and output by latest master and by 4.0 -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by ValeryKot): * Attachment "master_ffmpeg-20250205-095901.log" added. FFmpeg report, latest master -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by ValeryKot): * Attachment "master_output_10sec.srt" added. output SRT file, latest master -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by ValeryKot): * Attachment "4.0_ffmpeg-20250205-100028.log" added. FFmpeg report, version 4.0 -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by ValeryKot): * Attachment "4.0_output_10sec.srt" added. output SRT file, version 4.0 -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by ValeryKot): I uploaded cropped (10 seconds) and longer (1 minute) video file which trigger the issue to https://streams.videolan.org/upload/ -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Description changed by ValeryKot: Old description:
Summary of the bug: in some cases, FFmpeg fails to extract Closed Captions (A/53 Part 4 format). This is a degradation: same file can be processed correctly with FFmpeg 4.0, but also with VLC. How to reproduce: {{{ % ffmpeg.EXE" -f lavfi -report -i "movie=CC720p60_10sec.mp4[out+subcc]" -map 0:1 output_10sec.srt ffmpeg version N-118422-g1fbe9deee3-20250204 built on 2025-02-04 17:56 }}} Relevant error is:
{{{ [Closed Captions Decoder @ 000002f8b063dec0] Data ignored due to columns exceeding screen width. }}} I will (try to) attach original file, and reports and output by latest master and by 4.0
New description: Summary of the bug: in some cases, FFmpeg fails to extract Closed Captions (A/53 Part 4 format). This is a degradation: same file can be processed correctly with FFmpeg 4.0, but also with VLC. How to reproduce: {{{ % ffmpeg.EXE -f lavfi -report -i "movie=CC720p60_10sec.mp4[out+subcc]" -map 0:1 output_10sec.srt ffmpeg version N-118422-g1fbe9deee3-20250204 built on 2025-02-04 17:56 }}} Relevant error is: {{{ [Closed Captions Decoder @ 000002f8b063dec0] Data ignored due to columns exceeding screen width. }}} I will (try to) attach original file, and reports and output by latest master and by 4.0 -- -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455#comment:2> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Marth64): Your sample has actual text on field 1 (odd) instead of field 2. But field 2 is transmitting bits before field 1, the CC decoder is choosing it as the default field to decode. This command works for your sample: {{{ ffmpeg -data_field first -f lavfi -i "movie=CC720p60_10sec.mp4[out+subcc]" -map 0:1 output_10sec.srt }}} This is similar to #11263 -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455#comment:3> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by ValeryKot): With explicit -data_field first it works indeed, thanks! So it is not a degradation, but change in functionality and default behaviour. Before 4.4, CC decoder was always processing first data field. Since 4.4 it has an option to select first or second, but default is "auto", which in 50% might get wrong and non-deterministic. In my view, "first" would be a better default. But of course it is now too late to discuss. Thanks for the explanation, ticket can be closed. -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455#comment:4> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11455: Degradation in Closed Captions decoding -------------------------------------+------------------------------------- Reporter: ValeryKot | Owner: (none) Type: defect | Status: closed Priority: normal | Component: avcodec Version: git-master | Resolution: duplicate Keywords: | Blocked By: ccaption_dec | Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by MasterQuestionable): * cc: MasterQuestionable (added) * component: undetermined => avcodec * keywords: => ccaption_dec * resolution: => duplicate * status: new => closed Comment: ͏ Exact duplicate? ͏ https://trac.ffmpeg.org/ticket/11263#comment:12 -- Ticket URL: <https://trac.ffmpeg.org/ticket/11455#comment:5> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
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