Notes on Teletext in FFMPEG

Posted on | 174 words | ~1mins

Raw .TS recordings from DVB sources like DVB-S2 tuners contain all kind of data along the video, audio and subtitle tracks (like EPG information, SCTE-35 cue tones, program and service provider information as well as unspecified other binary data.

  • *.TS is usually MPEG-2

  • DVB_Teletext not supported in Matroska (incompatible with output codec id '94215')

  • Copying data like SCTE-35 cue tones from MPEG-2 TS into Matroska also doesn’t work

  • h264 ffmpeg flags for encoding interlaced and not progressive: -flags +ilme+ildct -x264opts tff=1

  • use -sn -map -0:s to don’t copy subtitles at all or alternatively use a script beforehand to find out stream id of teletext to remove it.

  • -ignore_unknown can be handy

  • use zvbi to convert DVB_Subtitles and subtitles inside DVB_Teletext to SRT

  • ffmpeg needs to be compiled with zvbi support --enable-libzvbi

  • Teletext subtitles zvbi needs to know on which page the subtitles are displayed -txt_page 777 -txt_format text

  • possible need to fix subtitle duration: -fix_sub_duration

  • for faster viewing in browser: -movflags +faststart

  • use -tune film for lower deblocking (better looking image of camera footage)