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

If any subtitles are copied from the DVD, ffmpeg will mark them all as enabled by default. This means that when playing it back with mpv or mplayer, it will display the subtitles automatically.

ffmpeg has the ability to toggle some off and some on, but not the ability to mark all of them as not default.

An example …

Encode a video file using defaults for audio and video codec, and copying the first subtitle stream:

dvd_copy -o - | ffmpeg -probesize 67108864 -analyzeduration 60000000 -i - -map 0:v -map i:0x80 -map i:0x20 -scodec copy dvd_copy.mkv

mediainfo dvd_copy.mkv

Here, Default is set to yes.

...
Text
ID                                       : 3
Format                                   : VobSub
Codec ID                                 : S_VOBSUB
Codec ID/Info                            : Picture based subtitle format used on DVDs
Duration                                 : 26 s 660 ms
Default                                  : Yes
Forced                                   : No

If you were to copy multiple VobSub streams, it will set them all to default:

Switching to using an MPG file in the example here for simplicity.

ffmpeg -probesize 67108864 -analyzeduration 60000000 -i dvd_copy.mpg -map 0:v -map i:0x80 -map i:0x20 -map i:0x21 -scodec copy dvd_copy.mkv

mediainfo dvd_copy.mkv

Both are set to default here:

Text #1
ID                                       : 3
Format                                   : VobSub
Codec ID                                 : S_VOBSUB
Codec ID/Info                            : Picture based subtitle format used on DVDs
Duration                                 : 26 s 660 ms
Default                                  : Yes
Forced                                   : No

Text #2
ID                                       : 4
Format                                   : VobSub
Codec ID                                 : S_VOBSUB
Codec ID/Info                            : Picture based subtitle format used on DVDs
Duration                                 : 26 s 660 ms
Default                                  : Yes
Forced                                   : No

ffmpeg *does* let you set the disposition off for one or more, but not all.

Here's an example with three subtitles illustrating the point, where the first two will be disabled as default, and switching the third to enabled:

ffmpeg -probesize 67108864 -analyzeduration 60000000 -i dvd_copy.mpg -map 0:v -map i:0x80 -map i:0x20 -map i:0x21 -map i:0x22 -scodec copy -disposition:s:0 0 -disposition:s:1 0 -disposition:s:2 default dvd_copy.mkv