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• Redux : how to add subtitles to mp4 using ffmpeg ?

  25 novembre 2015, par stachyra

  I have a tiny little example mp4 video (which unfortunately stack overflow won’t allow me to embed directly inside my question). Following the advice previously offered in this answer, I’d like to add a subtitle to the video, which will flash on the screen for 2 seconds, using an .srt file that looks like this :

  1
  
  00:00:02,000 --> 00:00:04,000
  
  Test subtitle

  As provided in the link above, I issue a command that looks like this :

  ffmpeg -i small.mp4 -f srt -i small.srt -c:v copy -c:a copy -c:s mov_text small_subtitles.mp4 >& err.log

  And the err.log file looks like this :

  ffmpeg version N-76950-g401c93d-tessus Copyright (c) 2000-2015 the FFmpeg developers
  
  built with Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
  
  configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --as=yasm --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-version3 --disable-ffplay --disable-indev=qtkit --disable-indev=x11grab_xcb
  
    libavutil      55.  7.100 / 55.  7.100
  
    libavcodec     57. 15.100 / 57. 15.100
  
    libavformat    57. 17.100 / 57. 17.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 15.100 /  6. 15.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'small.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf56.40.101
  
    Duration: 00:00:10.02, start: 0.000000, bitrate: 23 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 188x112 [SAR 1:1 DAR 47:28], 17 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
  
  Metadata:
  
    handler_name    : VideoHandler
  
  Input #1, srt, from 'small.srt':
  
    Duration: N/A, bitrate: N/A
  
  Stream #1:0: Subtitle: subrip
  
  [mp4 @ 0x7f8492848000] Codec for stream 0 does not use global headers but container format requires global headers
  
  Output #0, mp4, to 'small_subtitles.mp4':
  
    Metadata:
  
  major_brand     : isom
  
  minor_version   : 512
  
  compatible_brands: isomiso2avc1mp41
  
  encoder         : Lavf57.17.100
  
  Stream #0:0(und): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 188x112 [SAR 1:1 DAR 47:28], q=2-31, 17 kb/s, 60 fps, 60 tbr, 15360 tbn, 15360 tbc (default)
  
  Metadata:
  
    handler_name    : VideoHandler
  
  Stream #0:1: Subtitle: mov_text ([8][0][0][0] / 0x0008) (default)
  
  Metadata:
  
    encoder         : Lavc57.15.100 mov_text
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #1:0 -> #0:1 (subrip (srt) -> mov_text (native))
  
  Press [q] to stop, [?] for help
  
  frame=  601 fps=0.0 q=-1.0 Lsize=      29kB time=00:00:09.96 bitrate=  24.0kbits/s    
  
  video:21kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 39.561928%

  The resulting output, small_subtitles.mp4, does not seem to have the expected subtitle present.

  Furthermore, the error message,

  [mp4 @ 0x7f8492848000] Codec for stream 0 does not use global headers but container format requires global headers

  is highlighted in bold colors when I run this at the command line without capturing the err.log file (which makes me think it must be a significant message), although I am unable to reproduce that special print formatting easily here.

  I’ve also tried this method, but with the .avi replaced by .mp4, and it seems to just fail silently—no obvious error message, but also no subtitle in the resulting video either.

  Anybody have an idea how to fix this ? In particular, what does the business about global headers mean ?

  I’m working on OS X and am open to hearing answers that would use other open source tools as well.

• avfilter/avf_showvolume : fix several issues

  29 novembre 2015, par Paul B Mahol

  avfilter/avf_showvolume : fix several issues
  Fix color fading : previously color could fade to red when
  
  volume level for red color was actually never reached.
  
  Display volume value on right side.
  
  Use red color only if clipping is needed.
  Signed-off-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/avf_showvolume.c

• aac_ltp : actually signal LTP as off during EIGHT_SHORT windows

  26 novembre 2015, par Rostislav Pehlivanov

  aac_ltp : actually signal LTP as off during EIGHT_SHORT windows
  This hugely reduces the echo which was introduced with the previous
  
  commit (though likely because previously everything was broken).
  
  Makes LTP actually worthwhile now.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/aacenc_ltp.c