Too verbose output using concat demuxer with wav files

[Carl Eugen Hoyos]

​http://thread.gmane.org/gmane.comp.video.ffmpeg.user/51553

When using the concat demuxer to concatenate wav files, ffmpeg prints many warnings starting from the second file.

$ ffmpeg -f lavfi -i sine -t 0.5 out.wav

$ echo "file out.wav" >concat.txt
$ echo "file out.wav" >>concat.txt

$ ffmpeg -f concat -i concat.txt -f null -
ffmpeg version N-62757-g18af0ce Copyright (c) 2000-2014 the FFmpeg developers
  built on Apr 28 2014 09:25:16 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl
  libavutil      52. 79.100 / 52. 79.100
  libavcodec     55. 59.100 / 55. 59.100
  libavformat    55. 37.101 / 55. 37.101
  libavdevice    55. 13.100 / 55. 13.100
  libavfilter     4.  4.100 /  4.  4.100
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 18.100 /  0. 18.100
  libpostproc    52.  3.100 / 52.  3.100
[concat @ 0x1a6cd00] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for  Input Stream #0.0 : mono
Input #0, concat, from 'concat.txt':
  Duration: 00:00:00.00, start: 0.000000, bitrate: 705 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, mono, s16, 705 kb/s
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf55.37.101
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le -> pcm_s16le)
Press [q] to stop, [?] for help
DTS -406750698235338944, next:499999 st:0 invalid dropping
PTS -406750698235338944, next:499999 invalid dropping st:0
DTS -406750698235336896, next:546438 st:0 invalid dropping
PTS -406750698235336896, next:546438 invalid dropping st:0
DTS -406750698235334848, next:592877 st:0 invalid dropping
PTS -406750698235334848, next:592877 invalid dropping st:0
DTS -406750698235332800, next:639316 st:0 invalid dropping
PTS -406750698235332800, next:639316 invalid dropping st:0
DTS -406750698235330752, next:685755 st:0 invalid dropping
PTS -406750698235330752, next:685755 invalid dropping st:0
DTS -406750698235328704, next:732194 st:0 invalid dropping
PTS -406750698235328704, next:732194 invalid dropping st:0
DTS -406750698235326656, next:778633 st:0 invalid dropping
PTS -406750698235326656, next:778633 invalid dropping st:0
DTS -406750698235324608, next:825072 st:0 invalid dropping
PTS -406750698235324608, next:825072 invalid dropping st:0
DTS -406750698235322560, next:871511 st:0 invalid dropping
PTS -406750698235322560, next:871511 invalid dropping st:0
DTS -406750698235320512, next:917950 st:0 invalid dropping
PTS -406750698235320512, next:917950 invalid dropping st:0
DTS -406750698235318464, next:964389 st:0 invalid dropping
PTS -406750698235318464, next:964389 invalid dropping st:0
size=N/A time=00:00:01.00 bitrate=N/A
video:0kB audio:86kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 20914676107837440.000000%

[Michael Niedermayer]

Fixed by nicolas in acbc2ed26ab6d1f3fbd0db3c594672561a692d99