Using decimate allows EIA-608 captions to pass through to MP4 files even when the -sn option is used
|Reported by:||navilor||Owned by:|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
Summary of the bug:
I am currently using FFmpeg build number N-89980-ge752da5464. This issue also reproduces using build number N-87130-g2b9fd15 which is much older.
I have some MPEG-PS content that is behind NTSC hard telecine. As such I am using both yadif and decimate to remove that. If I use decimate then EIA-608 captions pass through even when the -sn option is in place. If I do not use decimate then captions, as expected, do not pass through because the -sn option is in place.
Note that the size of the data stream reported by MediaInfo is zero in both the source media as well as the output MP4 file. The data stream plays back as expected in the VOB file but not in the MP4 file.
How to reproduce:
ffmpeg -t 00:01:00 -fpsprobesize 48 -i decimate-allows-EIA-608-captions-to-pass-through-S01E01.vob -vf yadif,decimate,crop=720:480:0:0,scale=720:480 -pix_fmt yuv420p -vsync 1 -sn -map 0:1 -r 23.976 -threads 0 -vcodec libx264 -b:v:0:1 803752 -bufsize 1410194 -maxrate 1004690 -an -preset medium -profile:v high -g 48 -tune film -x264opts no-scenecut -map_metadata -1 -f mp4 -y S01E01-decimate.mp4-video.mp4
Compare against the following command line that does not use the decimate option:
ffmpeg -t 00:01:00 -fpsprobesize 60 -i decimate-allows-EIA-608-captions-to-pass-through-S01E01.vob -vf yadif,crop=720:480:0:0,scale=720:480 -pix_fmt yuv420p -vsync 1 -sn -map 0:1 -r 29.970 -threads 0 -vcodec libx264 -b:v:0:1 818252 -bufsize 1428319 -maxrate 1022815 -an -preset medium -profile:v high -g 60 -tune film -x264opts no-scenecut -map_metadata -1 -f mp4 -y S01E01.mp4-video.mp4
It is important to either have full subtitles in a file or none at all especially when delivering streaming media compliant content. I always use a sidecar file for my VOD captions.
I am currently attempting to upload a copy of the sample media and the associated text file to ftp://upload.ffmpeg.org per your bug report documentation at https://ffmpeg.org/bugreports.html, however I am unable to connect to upload.ffmpeg.org via either WinSCP's FTP or Windows 7's command line FTP.
The names of the files I plan to upload for replication will be named as following provided I can establish communication with the server.
Change History (12)
comment:1 by , 4 years ago
|Summary:||Using decimate allows EIA-608 captions to pass through to MP4 file even when the -sn option is uses → Using decimate allows EIA-608 captions to pass through to MP4 files even when the -sn option is used|
comment:3 by , 4 years ago
|Component:||ffmpeg → undetermined|
|Keywords:||cc added; captions removed|
|Priority:||minor → normal|
|Version:||3.4 → unspecified|