[FFmpeg-user] Couple of newbie questions

[Gilles]

On Wed, 7 Nov 2012 10:39:55 -0700, Roger Pack <rogerdpack2 at gmail.com>
wrote:
>> ffmpeg -ss 0 -i input.mpg -t 60 -c:v libx264 -c:a copy output.x264.mpg
>> => No video, no sound
>>
>> ffmpeg -ss 0 -i input.mpg -t 60 -c:v copy -c:a copy output.mpg
>> => No sound
>>
>
>What do you mean by "no sound"? If you do
>$ ffmpeg -i
>on the file, what is the output?

When playing the files in VLC, one (the libx264) is just black, with
no video or audio, while the other (the "copy") has video but no
sound.
When playing them with Splash Lite, the former crashes the app while
the latter plays fine.

Here's the output of "ffmpeg -i" on the two files, respectively:

====================
C:\>ffmpeg.exe -i output.joined.libx264.1.mpg

ffmpeg version N-46146-g11d695d Copyright (c) 2000-2012 the FFmpeg
developers
  built on Oct 29 2012 18:06:25 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads
--enable-runt
ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r
--enable-libass -
-enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libfreetype --enab
le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg
--enable-libo
pus --enable-librtmp --enable-libschroedinger --enable-libspeex
--enable-libtheo
ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-li
bvorbis --enable-libvpx --enable-libx264 --enable-libxavs
--enable-libxvid --ena
ble-zlib
  libavutil      52.  1.100 / 52.  1.100
  libavcodec     54. 69.100 / 54. 69.100
  libavformat    54. 35.100 / 54. 35.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 20.109 /  3. 20.109
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 16.100 /  0. 16.100
  libpostproc    52.  1.100 / 52.  1.100
[mpeg @ 0034abc0] max_analyze_duration 5000000 reached at 5000000
Input #0, mpeg, from 'output.joined.libx264.1.mpg':
  Duration: 00:00:59.98, start: 1.000000, bitrate: 1279 kb/s
    Stream #0:0[0x1e0]: Video: h264 (High), yuv420p, 720x576 [SAR
64:45 DAR 16:9
], 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
At least one output file must be specified
====================
C:\>ffmpeg -i output.joined.nochange.2.mpg

ffmpeg version N-46146-g11d695d Copyright (c) 2000-2012 the FFmpeg
developers
[...]
  libpostproc    52.  1.100 / 52.  1.100
Input #0, mpeg, from 'output.joined.nochange.2.mpg':
  Duration: 00:01:00.00, start: 1.000000, bitrate: 9333 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576
[SAR 64:45 DA
R 16:9], 9100 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
At least one output file must be specified
====================

Thank you.