Changed ffmpeg verbosity semantics

[chrisdonahue]

The tf.contrib.ffmpeg.decode_* and tf.contrib.ffmpeg.encode_* functions are extremely verbose and make it nearly impossible to see other printed messages.

Corresponding methods for image such as tf.image.decode_png produce no output under normal conditions, and it would be nice for audio/video methods to align with this.

FFmpeg on valid MP3 file with -loglevel info and without -hide_banner (old semantics)

$ ffmpeg -loglevel info -nostats -i in.mp3 -acodec pcm_s16le -ar 44100 out.wav
ffmpeg version N-79546-g13406b6 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmfx --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 22.100 / 55. 22.100
  libavcodec     57. 35.100 / 57. 35.100
  libavformat    57. 34.102 / 57. 34.102
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 44.100 /  6. 44.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[mp3 @ 00000000010771e0] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'in.mp3':
  Metadata:
    title           : jet-60-low
    artist          : Jon Dattorro
    album           : Tinnitus
    date            : 2003
    comment         : 105 Hz Q 1
    track           : 2
    genre           : Noise
  Duration: 01:00:00.11, start: 0.000000, bitrate: 64 kb/s
    Stream #0:0: Audio: mp3, 22050 Hz, stereo, s16p, 64 kb/s
[wav @ 0000000000edb020] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
Output #0, wav, to 'out.wav':
  Metadata:
    INAM            : jet-60-low
    IART            : Jon Dattorro
    IPRD            : Tinnitus
    ICRD            : 2003
    ICMT            : 105 Hz Q 1
    IPRT            : 2
    IGNR            : Noise
    ISFT            : Lavf57.34.102
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
    Metadata:
      encoder         : Lavc57.35.100 pcm_s16le
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
size=  620172kB time=01:00:00.09 bitrate=1411.2kbits/s speed= 225x

FFmpeg on valid MP3 file with -loglevel error and with -hide_banner (new semantics)

$ ffmpeg -loglevel error -nostats -i in.mp3 -acodec pcm_s16le -ar 44100 out.wav -hide_banner

FFmpeg on text file (invalid) with -loglevel error and with -hide_banner (new semantics)

$ ffmpeg -loglevel error -nostats -i in.txt -acodec pcm_s16le -ar 44100 out.wav -hide_banner
Output file #0 does not contain any stream

[tensorflow-jenkins]

Can one of the admins verify this patch?

[yongtang]

The PR will fix issue #14733 I think.

[gibiansky]

Please merge this!

[chrisdonahue]

Are any of these check failures related to my changes? Having trouble parsing