dsf: no duration

[ami_stuff]

looks like regression

​http://www.bitperfectsound.com/public_files/Looking%20For%20A%20Home%20-%202.8MHz-DSD.dsf.zip

​http://dsdmaster.blogspot.com/p/blog-page.html

C:\>ffmpeg -i "Looking For A Home - 2.8MHz-DSD.dsf"
ffmpeg version N-79684-g55e6323 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.5.0 (GCC) 20100414 (Fedora MinGW 4.5.0-1.fc14)
  configuration: --prefix=/var/www/users/research/ffmpeg/snapshots/build --arch=
x86 --target-os=mingw32 --cross-prefix=i686-pc-mingw32- --cc='ccache i686-pc-min
gw32-gcc' --enable-pthreads --enable-memalign-hack --enable-runtime-cpudetect --
enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -lw
inmm -lpthread' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snapsh
ots/build/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/sna
pshots/build/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3 --
enable-nonfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-li
bvorbis --enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-li
bopencore-amrwb --enable-libmp3lame --enable-libfreetype --enable-libvpx --disab
le-decoder=libvpx
  libavutil      55. 23.100 / 55. 23.100
  libavcodec     57. 38.100 / 57. 38.100
  libavformat    57. 34.103 / 57. 34.103
  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
Input #0, dsf, from 'Looking For A Home- 2.8MHz-DSD.dsf':
  Metadata:
    album           : Blue Coast Collection
    title           : Looking For A Home
    artist          : Keith Greeninger & Dayan Kai
    TIME            :
    encoder         : KORG AudioGate ver.2.2.1 (Windows 7)
  Duration: N/A, bitrate: N/A
    Stream #0:0: Audio: dsd_lsbf_planar, 352800 Hz, stereo, fltp, 5644 kb/s
    Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 800x712 [S
AR 1:1 DAR 100:89], 90k tbr, 90k tbn
    Metadata:
      comment         : Other
At least one output file must be specified

C:\>ffmpeg -i "Looking For A Home - 2.8MHz-DSD.dsf"
ffmpeg version N-78758-g5156578 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enab
le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --en
able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --ena
ble-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --
enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-lib
x265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-d
ecklink --enable-zlib
  libavutil      55. 19.100 / 55. 19.100
  libavcodec     57. 27.100 / 57. 27.100
  libavformat    57. 26.100 / 57. 26.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 37.100 /  6. 37.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[mjpeg @ 03902a00] Changing bps to 8
[dsf @ 038de6e0] Estimating duration from bitrate, this may be inaccurate
Input #0, dsf, from 'Looking For A Home- 2.8MHz-DSD.dsf':
  Metadata:
    album           : Blue Coast Collection
    title           : Looking For A Home
    artist          : Keith Greeninger & Dayan Kai
    TIME            :
    encoder         : KORG AudioGate ver.2.2.1 (Windows 7)
  Duration: 00:05:53.79, bitrate: 5644 kb/s
    Stream #0:0: Audio: dsd_lsbf_planar, 352800 Hz, stereo, fltp, 5644 kb/s
    Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 800x712 [S
AR 1:1 DAR 100:89], 90k tbr, 90k tbn, 90k tbc
    Metadata:
      comment         : Other
At least one output file must be specified

[Carl Eugen Hoyos]

Regression since 6f69f7a8bf6a0d013985578df2ef42ee6b1c7994

[Elon Musk]

Fixed in 423a6a0993814e44fa8f34af23f5e9242cd0658a.