DVD Subtitles

• ffmpeg

The MPG will need to be probed deeper than normal to check for VobSub streams because they only are detected once they show up in the video.

An example:

ffprobe -probesize 67108864 -analyzeduration 60000000 dvd_video.mpg

Input #0, mpeg, from '1.665.2138.17690.TNTGO.mpg':
  Duration: 00:11:09.02, start: 0.045500, bitrate: 5708 kb/s
    Stream #0:0[0x1bf]: Data: dvd_nav_packet
    Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, progressive), 720x480 [SAR 32:27 DAR 16:9], 29.92 fps, 59.94 tbr, 90k tbn, 59.94 tbc
    Stream #0:2[0x82]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
    Stream #0:3[0x81]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
    Stream #0:4[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
    Stream #0:5[0x21]: Subtitle: dvd_subtitle
    Stream #0:6[0x20]: Subtitle: dvd_subtitle
    Stream #0:7[0x23]: Subtitle: dvd_subtitle
    Stream #0:8[0x22]: Subtitle: dvd_subtitle

For a DVD directly:

dvd_copy -o - | ffprobe -probesize 67108864 -analyzeduration 60000000 -

For DVDs, closed captioning streams are embedded in the video stream.

The fastest way is to see if it has closed captioning is using ffprobe and looking for Closed Captions in the output:

ffprobe dvd_copy.mpg

Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, top first), 720x480 [SAR 32:27 DAR 16:9], Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc

Use ffprobe's INI style output to look for it as well:

ffprobe -v 0 -show_streams -show_entries stream=start_pts -select_streams s -f lavfi -i movie=dvd_copy.mpg[out+subcc]

See if a DVD has closed captioning:

dvd_copy -o - | ffprobe -v 0 -show_streams -show_entries stream=start_pts -select_streams s -f lavfi -i movie=pipe\\\\:0[out+subcc]

When splitting the streams using lavfi device, ffmpeg will “create” a subtitle stream, even if one is not present. To make sure one exists or not, a closer look at the stream itself is actually needed.

This one has a starting presentation timestamp (PTS) that's a positive value, so it's safe to say that one exists.

[STREAM]
start_pts=25257
DISPOSITION:default=0
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0
[/STREAM]

Here's one without it present:

[STREAM]
start_pts=N/A
DISPOSITION:default=0
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0
[/STREAM]

Use ffmpeg to extract the closed captioning stream from a DVD using dvd_copy:

dvd_copy -o - | ffmpeg -f lavfi -i movie=pipe\\\\:0[out+subcc] -map 0:s subtitles.srt

Extract CC subtitles from an MPG:

dvd_copy -o dvd_copy.mpg
ffmpeg -f lavfi -i move=dvd_copy.mpg[out+subcc] -map 0:s subtitles.srt

Since the closed captioning is embedded in the video stream, you can re-encode that at the same time. It won't see any other streams though (audio, vobsub).

ffmpeg -f lavfi -i move=dvd_copy.mpg[out+subcc] -map 0:v -map 0:s video.mkv