[FFmpeg-user] audio extraction for no sound at end of video

[Cliff R Wong]

Sorry. I'm quite new here. Here is the console output. The mp4 video is
2:58:41 long but the mp4 audio is only 2:55:33 long. I want the wav audio
output to also be 2:58:41 long.

./ffmpeg -i videoIN.mp4 -ar 8000 -ac 1 -acodec pcm_s16le audioOUT.wav
ffmpeg version N-63893-gc69defd Copyright (c) 2000-2014 the FFmpeg
developers
  built on Jul 16 2014 05:38:01 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. 89.100 / 52. 89.100
  libavcodec     55. 66.101 / 55. 66.101
  libavformat    55. 43.100 / 55. 43.100
  libavdevice    55. 13.101 / 55. 13.101
  libavfilter     4.  8.100 /  4.  8.100
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'videoIN.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 1
    compatible_brands: isomavc1
    creation_time   : 2013-01-03 17:20:49
  Duration: 02:58:41.67, start: 0.000000, bitrate: 1921 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
1920x816 [SAR 1:1 DAR 40:17], 1822 kb/s, 23.98 fps, 23.98 tbr, 96k tbn,
47.95 tbc (default)
    Metadata:
      creation_time   : 2013-01-03 17:20:49
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo,
fltp, 95 kb/s (default)
    Metadata:
      creation_time   : 2013-01-03 17:22:34
      handler_name    : GPAC ISO Audio Handler
File 'audioOUT.wav' already exists. Overwrite ? [y/N] y
Output #0, wav, to 'audioOUT.wav':
  Metadata:
    major_brand     : isom
    minor_version   : 1
    compatible_brands: isomavc1
    ISFT            : Lavf55.43.100
    Stream #0:0(und): Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz,
mono, s16, 128 kb/s (default)
    Metadata:
      creation_time   : 2013-01-03 17:22:34
      handler_name    : GPAC ISO Audio Handler
      encoder         : Lavc55.66.101 pcm_s16le
Stream mapping:
  Stream #0:1 -> #0:0 (aac (native) -> pcm_s16le (pcm_s16le))
Press [q] to stop, [?] for help
size=  164582kB time=02:55:33.26 bitrate= 128.0kbits/s
video:0kB audio:164582kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.000046%

On Sat, Jan 10, 2015 at 3:20 PM, Lou <lou at lrcd.com> wrote:

> On Sat, 10 Jan 2015 11:37:00 -0500
> Cliff R Wong <cliff.r.wong at gmail.com> wrote:
>
> > Hi. I am extracting the audio from a video file to a wav format
> >
> > ffmpeg -i {0} -ar 8000 -ac 1  -acodec pcm_s16le {1}.wav
> >
> > where {0} is the input file and {1} is the output filename.
> >
> > However, the last 3 minutes of the video has no sound and ffmpeg does not
> > convert that so the resulting audio file is 3 minutes shorter than the
> > video file. Is there an option that will keep those last 3 minutes of
> > silence in the audio file?
>
> You forgot to include the complete ffmpeg console output from your
> command.
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