ffplay regression with multithreaded audio decoding

[Carl Eugen Hoyos]

The sample from ticket #2552 by default only plays for a moment here:

$ time ffplay flac-file-with-valid-header-in-last-block.flac -autoexit
ffplay version N-54249-gfc736a9 Copyright (c) 2003-2013 the FFmpeg developers
  built on Jun 29 2013 01:27:18 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --disable-indev=jack
  libavutil      52. 37.101 / 52. 37.101
  libavcodec     55. 17.100 / 55. 17.100
  libavformat    55. 10.100 / 55. 10.100
  libavdevice    55.  2.100 / 55.  2.100
  libavfilter     3. 77.101 /  3. 77.101
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
Input #0, flac, from 'flac-file-with-valid-header-in-last-block.flac':
  Duration: 00:00:07.40, bitrate: 626 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
   6.80 M-A:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

real    0m0.105s
user    0m0.039s
sys     0m0.013s

Works fine without multi-threading:

$ time ffplay -threads 1 flac-file-with-valid-header-in-last-block.flac -autoexit
ffplay version N-54249-gfc736a9 Copyright (c) 2003-2013 the FFmpeg developers
  built on Jun 29 2013 01:27:18 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --disable-indev=jack
  libavutil      52. 37.101 / 52. 37.101
  libavcodec     55. 17.100 / 55. 17.100
  libavformat    55. 10.100 / 55. 10.100
  libavdevice    55.  2.100 / 55.  2.100
  libavfilter     3. 77.101 /  3. 77.101
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
Input #0, flac, from 'flac-file-with-valid-header-in-last-block.flac':
  Duration: 00:00:07.40, bitrate: 626 kb/s
    Stream #0:0: Audio: flac, 44100 Hz, stereo, s16
   6.78 M-A:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

real    0m6.819s
user    0m0.128s
sys     0m0.127s

[Marton Balint]

Duplicate of #1936.