http://samples.mplayerhq.hu/A-codecs/wavpcm/madbear.wav
C:\>ffmpeg -i madbear.wav -ac 1 -ar 300000 out.wv
ffmpeg version N-65672-g65f05ef Copyright (c) 2000-2014 the FFmpeg developers
built on Aug 15 2014 22:01:33 with gcc 4.8.3 (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-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-decklink --enable-zlib
libavutil 54. 3.100 / 54. 3.100
libavcodec 56. 0.101 / 56. 0.101
libavformat 56. 1.100 / 56. 1.100
libavdevice 56. 0.100 / 56. 0.100
libavfilter 5. 0.100 / 5. 0.100
libswscale 3. 0.100 / 3. 0.100
libswresample 1. 0.100 / 1. 0.100
libpostproc 53. 0.100 / 53. 0.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, wav, from 'madbear.wav':
Metadata:
encoder : File created by GoldWave. GoldWave copyright (C) Chris Cr
aig
Duration: 00:00:06.48, bitrate: 352 kb/s
Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 11025 Hz, 2 channels,
s16, 352 kb/s
Output #0, wv, to 'out.wv':
Metadata:
encoder : Lavf56.1.100
Stream #0:0: Audio: wavpack, 300000 Hz, mono, s16p, 128 kb/s
Metadata:
encoder : Lavc56.0.101 wavpack
Stream mapping:
Stream #0:0 -> #0:0 (pcm_s16le (native) -> wavpack (native))
Press [q] to stop, [?] for help
size= 1504kB time=00:00:06.50 bitrate=1896.0kbits/s
video:0kB audio:1504kB subtitle:0kB other streams:0kB global headers:0kB muxing
overhead: 0.005973%
C:\>ffmpeg -i out.wv -f null -
ffmpeg version N-65672-g65f05ef Copyright (c) 2000-2014 the FFmpeg developers
built on Aug 15 2014 22:01:33 with gcc 4.8.3 (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-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-decklink --enable-zlib
libavutil 54. 3.100 / 54. 3.100
libavcodec 56. 0.101 / 56. 0.101
libavformat 56. 1.100 / 56. 1.100
libavdevice 56. 0.100 / 56. 0.100
libavfilter 5. 0.100 / 5. 0.100
libswscale 3. 0.100 / 3. 0.100
libswresample 1. 0.100 / 1. 0.100
libpostproc 53. 0.100 / 53. 0.100
[wavpack @ 02e1c700] Invalid number of samples: 150000
Last message repeated 11 times
[wv @ 02e1c020] decoding for stream 0 failed
[wv @ 02e1c020] Could not find codec parameters for stream 0 (Audio: wavpack, 30
0000 Hz, mono): unspecified sample format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
out.wv: could not find codec parameters
Input #0, wv, from 'out.wv':
Metadata:
encoder : Lavf56.1.100
Duration: 00:00:06.48, start: 0.000000, bitrate: 1901 kb/s
Stream #0:0: Audio: wavpack, 300000 Hz, mono
[abuffer @ 02e1a2c0] Unable to parse option value "(null)" as sample format
Last message repeated 1 times
[abuffer @ 02e1a2c0] Error setting option sample_fmt to value (null).
[graph 0 input from stream 0:0 @ 02ef6da0] Error applying options to the filter.
Error opening filters!
Thank you for filing this bug separately. Will soon send a patch for it. For the record, the encoder only tries to reduce the blocksize down to 150000, and the decoder has another limit.