[FFmpeg-trac] #4782(undetermined:new): Teletext subtitles are not automatically scaled

[FFmpeg]

#4782: Teletext subtitles are not automatically scaled
-------------------------------------+-------------------------------------
               Reporter:  cehoyos    |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:
                Version:  git-       |  undetermined
  master                             |               Keywords:  sub
             Blocked By:             |  dvb_teletext
Reproduced by developer:  0          |               Blocking:
                                     |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 http://streams.videolan.org/issues/10919/
 The subtitles on page 888 and page 889 are shown scaled with FFplay:
 {{{
 $ ffplay vlc-record-2014-03-13-03h01m41s-Arte.ts -txt_page 888
 }}}
 FFmpeg does not scale the subtitles:
 {{{
 $ ffmpeg -txt_page 888 -i vlc-record-2014-03-13-03h01m41s-Arte.ts
 -filter_complex [0:2][0:0]overlay -qscale 2 -t 50 out.avi
 ffmpeg version N-74483-gb807f7e Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-libzvbi --enable-gpl
   libavutil      54. 30.100 / 54. 30.100
   libavcodec     56. 57.100 / 56. 57.100
   libavformat    56. 40.101 / 56. 40.101
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 34.100 /  5. 34.100
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  2.101 /  1.  2.101
   libpostproc    53.  3.100 / 53.  3.100
 [mpegts @ 0x2101560] PES packet size mismatch
 Input #0, mpegts, from 'vlc-record-2014-03-13-03h01m41s-Arte.ts':
   Duration: 00:00:51.58, start: 40205.850389, bitrate: 1772 kb/s
   Program 1
     Stream #0:0[0x44](fra,fra): Subtitle: dvb_teletext ([6][0][0][0] /
 0x0006), 492x250
     Stream #0:1[0x45](???): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz,
 stereo, s16p, 128 kb/s
     Stream #0:2[0x46]: Video: h264 (Main) ([27][0][0][0] / 0x001B),
 yuv420p(tv, bt470bg), 720x576 [SAR 16:11 DAR 20:11], 25 fps, 25 tbr, 90k
 tbn, 50 tbc
 Please use -q:a or -q:v, -qscale is ambiguous
 Output #0, avi, to 'out.avi':
   Metadata:
     ISFT            : Lavf56.40.101
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 720x576 [SAR
 16:11 DAR 20:11], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc (default)
     Metadata:
       encoder         : Lavc56.57.100 mpeg4
     Stream #0:1(???): Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo,
 fltp, 192 kb/s
     Metadata:
       encoder         : Lavc56.57.100 ac3
 Stream mapping:
   Stream #0:0 (libzvbi_teletextdec) -> overlay:overlay (graph 0)
   Stream #0:2 (h264) -> overlay:main (graph 0)
   overlay (graph 0) -> Stream #0:0 (mpeg4)
   Stream #0:1 -> #0:1 (mp2 (native) -> ac3 (native))
 Press [q] to stop, [?] for help
 frame= 1238 fps=492 q=2.0 Lsize=   11230kB time=00:00:50.01
 bitrate=1839.4kbits/s
 video:9988kB audio:1166kB subtitle:0kB other streams:0kB global
 headers:0kB muxing overhead: 0.684026%
 }}}
 The following works as expected:
 {{{
 $ ffmpeg -txt_page 888 -i vlc-record-2014-03-13-03h01m41s-Arte.ts
 -filter_complex [0:0]scale=pal,[0:2]overlay -qscale 2 -t 50 out.avi
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4782>
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