root@test:/tmp# ffmpeg -i goofy.avi -i subtitles.srt -scodec mov_text -acodec copy -vcodec copy -f mp4 test.mp4
ffmpeg version 2.4.2 Copyright (c) 2000-2014 the FFmpeg developers
  built on Oct 18 2014 15:38:04 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  configuration: --prefix=/root/ffmpeg/target --extra-cflags='-I/root/ffmpeg/target/include -static' --extra-ldflags='-L/root/ffmpeg/target/lib -lm -static' --disable-debug --disable-shared --enable-static --extra-cflags=--static --disable-ffplay --disable-ffserver --disable-doc --enable-openssl --enable-gpl --enable-pthreads --enable-postproc --enable-libass --enable-gray --enable-runtime-cpudetect --enable-libfaac --enable-gnutls --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-bzlib --enable-zlib --enable-nonfree --enable-version3 --enable-libvpx --enable-libxavs --disable-devices --enable-librtmp --extra-libs='-lrtmp -lnettle -lhogweed -lgmp -lssl -lcrypto -lz -lc -ldl'
  libavutil      54.  7.100 / 54.  7.100
  libavcodec     56.  1.100 / 56.  1.100
  libavformat    56.  4.101 / 56.  4.101
  libavdevice    56.  0.100 / 56.  0.100
  libavfilter     5.  1.100 /  5.  1.100
  libswscale      3.  0.100 /  3.  0.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  0.100 / 53.  0.100
Input #0, avi, from 'goofy.avi':
  Metadata:
    title           : MIH-LP-1W1.1_DES.Title6.DVDRip
    album           : MIH-LP-1W1.1_DES
    encoder         : Lavf52.33.0
  Duration: 00:23:03.56, start: 0.000000, bitrate: 1992 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 1789 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, fltp, 192 kb/s
Input #1, srt, from 'subtitles.srt':
  Duration: N/A, bitrate: N/A
    Stream #1:0: Subtitle: subrip
[mp4 @ 0x2b63cc0] track 1: codec frame size is not set
Output #0, mp4, to 'test.mp4':
  Metadata:
    title           : MIH-LP-1W1.1_DES.Title6.DVDRip
    album           : MIH-LP-1W1.1_DES
    encoder         : Lavf56.4.101
    Stream #0:0: Video: mpeg4 ( [0][0][0] / 0x0020), yuv420p, 720x400 [SAR 1:1 DAR 9:5], q=2-31, 1789 kb/s, 25 fps, 12800 tbn, 25 tbc
    Stream #0:1: Audio: ac3 ([165][0][0][0] / 0x00A5), 48000 Hz, stereo, 192 kb/s
    Stream #0:2: Subtitle: mov_text ([8][0][0][0] / 0x0008)
    Metadata:
      encoder         : Lavc56.1.100 mov_text
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
  Stream #1:0 -> #0:2 (subrip (native) -> mov_text (native))
Press [q] to stop, [?] for help
frame=34589 fps=30396 q=-1.0 Lsize=  335488kB time=02:14:33.02 bitrate= 340.4kbits/s
video:302290kB audio:32427kB subtitle:120kB other streams:0kB global headers:0kB muxing overhead: 0.194507%