Extract subtitle stream from AVI

Question

I have an AVI file (mpeg4 video) with 3 subtitle streams. I need to extract the second stream to SRT/txt in order to make some corrections to the translation. I'm currently on an Ubuntu machine.

I tried using avconv, but I was getting errors. Here is the result of 'avconv -i':

Stream #0.0: Video: mpeg4 (Advanced Simple Profile), yuv420p ...
Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Stream #0.2: Subtitle: srt
Stream #0.3: Subtitle: srt
Stream #0.4: Subtitle: srt

And here is the command I initially tried: 'avconv -i video.avi -map 0:3 subs.srt'

This gave me an error: 'Encoder (codec id 0) not found for output stream #0:0'

Any help? Forgive me if this seems like a simple problem -- I am a bit new to this.

Answer 1

avconv is a fork off the original ffmpeg and often has less features.

On my Ubuntu 13.04 (raring) I get this info in a terminal:

$ avconv -version
avconv version 0.8.9-6:0.8.9-0ubuntu0.13.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:09:48 with gcc 4.7.3
avconv 0.8.9-6:0.8.9-0ubuntu0.13.04.1

You can list the codecs for encoding any data know to avconv into an output file with avconv -codecs. That's a long list. To filter it down for encoding (E) and for subtitles (S) we can grep those lines:

$ avconv -codecs |grep ES
avconv version 0.8.9-6:0.8.9-0ubuntu0.13.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:09:48 with gcc 4.7.3
 DES    ass             Advanced SubStation Alpha subtitle
 DES    dvbsub          DVB subtitles
 DES    dvdsub          DVD subtitles
 DES    xsub            DivX subtitles (XSUB)

As you can see there's no entry for srt. Bummer.

The latest ffmpeg has it:

$ ~/bin/ffmpeg -codecs |grep ES
ffmpeg version N-60596-gabe3f79 Copyright (c) 2000-2014 the FFmpeg developers
  built on Feb 14 2014 05:31:07 with gcc 4.6 (Debian 4.6.3-1)
  configuration: --prefix=/root/ffmpeg-static/64bit --extra-cflags='-I/root/ffmpeg-static/64bit/include -static' --extra-ldflags='-L/root/ffmpeg-static/64bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx
  libavutil      52. 63.101 / 52. 63.101
  libavcodec     55. 52.101 / 55. 52.101
  libavformat    55. 32.101 / 55. 32.101
  libavdevice    55.  9.100 / 55.  9.100
  libavfilter     4.  1.102 /  4.  1.102
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
 DES... ass                  ASS (Advanced SSA) subtitle
 DES... dvb_subtitle         DVB subtitles (decoders: dvbsub ) (encoders: dvbsub )
 DES... dvd_subtitle         DVD subtitles (decoders: dvdsub ) (encoders: dvdsub )
 DES... mov_text             MOV text
 DES... srt                  SubRip subtitle with embedded timing
 DES... ssa                  SSA (SubStation Alpha) subtitle
 DES... subrip               SubRip subtitle
 DES... xsub                 XSUB

So if you use any reasonably current ffmpeg, you'll probably have it working with the command line which you already used. As both tools use the same code base, most of the command line options work the same.

Look at my answer here and the paragraph ffmpeg setup to see where to download it from. Very easy to do, and you don't even have to become root.