ffprobe to report DVD subtitles frame size

[Thierry Lelegard]

This is an enhancement request about ffprobe.

The context of this request can be found on the archive of FFmpeg-user mailing list at
​http://ffmpeg-users.933282.n4.nabble.com/Burning-DVD-subtitles-into-video-using-overlay-filter-not-working-td4660976.html

FFprobe reports the frame width and height of video streams. But it does not report the same information on DVD subtitles streams.

DVD subtitles are bitmaps with a frame size. In the above mentioned thread in FFmpeg-user, the debug output of a transcoding session reports:

[graph 0 input from stream 0:0 @ 00000000022412a0] w:1280 h:536 pixfmt:yuv420p tb:1/1000 fr:13978/583 sar:1/1 sws_param:flags=2
[graph 0 input from stream 0:2 @ 0000000002240e20] w:1920 h:1080 pixfmt:bgra tb:1/1000 fr:0/1 sar:0/1 sws_param:flags=2

We see that the video frame size is 1280x536 and the dvdsub frame size is 1920x1080. But ffprobe reports only the video frame size:

$ ffprobe file.mkv -loglevel warning -show_streams -print_format flat | grep -e codec_name -e width -e height
streams.stream.0.codec_name="h264"
streams.stream.0.width=1280
streams.stream.0.height=536
streams.stream.1.codec_name="dca"
streams.stream.2.codec_name="dvdsub"

For automated tools, it would be extremely useful to obtain the dvdsub frame size from ffprobe output.

It may be possible that such enhancement also applies to DVB subtitles since they are bitmaps too.

[Carl Eugen Hoyos]

Related to ticket #679

For future tickets: Please always add ffmpeg -i console output.

$ ffmpeg -i gg.mkv
ffmpeg version N-55962-gec8a484 Copyright (c) 2000-2013 the FFmpeg developers
  built on Sep  2 2013 10:17:48 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --enable-libzvbi --disable-indev=jack
  libavutil      52. 43.100 / 52. 43.100
  libavcodec     55. 31.100 / 55. 31.100
  libavformat    55. 15.100 / 55. 15.100
  libavdevice    55.  3.100 / 55.  3.100
  libavfilter     3. 82.102 /  3. 82.102
  libswscale      2.  5.100 /  2.  5.100
  libswresample   0. 17.103 /  0. 17.103
  libpostproc    52.  3.100 / 52.  3.100
Input #0, matroska,webm, from 'gg.mkv':
  Metadata:
    ENCODER         : Lavf55.14.102
  Duration: 00:00:23.00, start: 0.000000, bitrate: 5539 kb/s
    Chapter #0.0: start 0.000000, end 20.000000
    Stream #0:0: Video: h264 (High), yuv420p, 1280x536 [SAR 1:1 DAR 160:67], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
    Stream #0:1: Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s (default)
    Stream #0:2: Subtitle: dvd_subtitle (default)
At least one output file must be specified

[Stefano Sabatini]

Fixed in:

commit 83635ac67bc3429c147e214f0f44325b63832384
Author: Nicolas George <nicolas.george@normalesup.org>
Date:   Tue Sep 3 16:39:02 2013 +0200

    ffprobe: show bitmap subtitles size.
    
    Fix trac ticket #2930.

Sample command:

$ ffprobe gg.mkv -show_entries stream=width,height -select_streams s -of flat
[...]
streams.stream.0.width=1920
streams.stream.0.height=1080