#11470: get_eia608_packet misparses well formed files and corrupts Close
Captions
since 2020
-------------------------------------+-------------------------------------
Reporter: Pavel | Type: defect
Koshevoy |
Status: new | Priority: critical
Component: avformat | Version: git-
Keywords: lavf mov | master
captions | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
How to reproduce:
{{{
$ ./ffmpeg -i 'Test for Quicktime 608 CC file.mov' -map 0 -c copy -y
/tmp/remuxed.mov
ffmpeg version N-118471-ga50d36b5fd Copyright (c) 2000-2025 the FFmpeg
developers
built with gcc 7 (SUSE Linux)
configuration: --prefix=/Developer/x86_64 --prefix=/Developer/x86_64
--enable-runtime-cpudetect --enable-libzimg --enable-libx264 --enable-
libass --enable-libmodplug --enable-libxml2 --enable-libvmaf --enable-
shared --enable-pthreads --enable-gpl --enable-version3 --enable-gnutls
--enable-libfreetype --enable-pic --disable-static --enable-shared
--enable-rpath --enable-ffnvcodec --enable-debug --disable-stripping
--disable-optimizations --disable-mmx
libavutil 59. 56.100 / 59. 56.100
libavcodec 61. 33.102 / 61. 33.102
libavformat 61. 9.107 / 61. 9.107
libavdevice 61. 4.100 / 61. 4.100
libavfilter 10. 9.100 / 10. 9.100
libswscale 8. 13.100 / 8. 13.100
libswresample 5. 4.100 / 5. 4.100
libpostproc 58. 4.100 / 58. 4.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Test for Quicktime 608 CC
file.mov':
Metadata:
major_brand : qt
minor_version : 537199360
compatible_brands: qt
creation_time : 2010-11-04T17:28:46.000000Z
Duration: 00:00:28.40, start: 0.000000, bitrate: 1603 kb/s
Stream #0:0[0x1](eng): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709, progressive), 640x360,
1485 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn (default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Video Media Handler
vendor_id : [0][0][0][0]
Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
stereo, fltp, 109 kb/s (default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Sound Media Handler
vendor_id : [0][0][0][0]
Stream #0:2[0x3](eng): Subtitle: eia_608 (cc_dec) (c608 / 0x38303663),
640x360, 4 kb/s (default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Closed Caption Media Handler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Stream #0:2 -> #0:2 (copy)
Output #0, mov, to '/tmp/remuxed.mov':
Metadata:
major_brand : qt
minor_version : 537199360
compatible_brands: qt
encoder : Lavf61.9.107
Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709, progressive), 640x360,
q=2-31, 1485 kb/s, 29.97 fps, 29.97 tbr, 11988 tbn (default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Video Media Handler
vendor_id : [0][0][0][0]
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 109 kb/s (default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Sound Media Handler
vendor_id : [0][0][0][0]
Stream #0:2(eng): Subtitle: eia_608 (c608 / 0x38303663), 640x360, 4 kb/s
(default)
Metadata:
creation_time : 2010-11-04T17:28:46.000000Z
handler_name : Apple Closed Caption Media Handler
Press [q] to stop, [?] for help
[out#0/mov @ 0x17fb8420] video:5147KiB audio:379KiB subtitle:15KiB other
streams:0KiB global headers:0KiB muxing overhead: 0.546079%
frame= 851 fps=0.0 q=-1.0 Lsize= 5571KiB time=00:00:27.66
bitrate=1649.8kbits/s speed= 920x
}}}
The problem was introduced in commit
f91906973c62459f31beb5683a8e2105758af0bb in June 2020
The problem is reproducible with 'Test for Quicktime 608 CC file.mov' from
https://samples.ffmpeg.org/MPEG2/subcc/
A fix was provided in June 2023:
https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2023-June/310456.html
Two alternative fixes were provided in February 2025:
https://ffmpeg.org//pipermail/ffmpeg-devel/2025-February/339780.html
https://ffmpeg.org//pipermail/ffmpeg-devel/2025-February/339790.html
Attached are screenshots demonstrating the problem with the closed
captions corruption caused in get_eia608_packet, and what the captions are
supposed to look like when get_eia608_packet is fixed.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11470>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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