[FFmpeg-user] Problem capturing from 64ch SoundFlower on OSX

[Piers O'Hanlon]

Hi,

I've been trying to capture multiple audio channels using ffmpeg on OSX - specifically I've been trying to capture from the Soundflower 64 channel input device (kext: com.Cycling74.driver.Soundflower (1.6.6)) and stream to rtp. It works fine with 2ch Soundflower device but when I try to capture anything from the 64ch channel I get the errors below. This is using the latest git version of ffmpeg on OSX10.7.5 (I've also tested it on OSX10.9.5 and get the same error). It complains about "Setting 'sample_fmt' to value '(null)'" but I've tried adding a separate -sample_fmt argument to no avail.

Any suggestions welcome. 

Thanks,

Piers

./ffmpeg -loglevel debug  -f avfoundation   -i "none:1" -map_channel 0.0.0  -f mp2 -f rtp rtp://224.4.4.4:4444 -map_channel 0.0.1  -f mp2 -f rtp rtp://224.4.4.4:4448
ffmpeg version N-73454-g9174866 Copyright (c) 2000-2015 the FFmpeg developers
  built with Apple clang version 2.1 (tags/Apple/clang-163.7.1) (based on LLVM 3.0svn)
  configuration: --cc=clang
  libavutil      54. 28.100 / 54. 28.100
  libavcodec     56. 46.101 / 56. 46.101
  libavformat    56. 40.100 / 56. 40.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 21.100 /  5. 21.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.100 /  1.  2.100
Splitting the commandline.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'debug'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'avfoundation'.
Reading option '-i' ... matched as input file with argument 'none:1'.
Reading option '-map_channel' ... matched as option 'map_channel' (map an audio channel from one stream to another) with argument '0.0.0'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'mp2'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'rtp'.
Reading option 'rtp://224.4.4.4:4444' ... matched as output file.
Reading option '-map_channel' ... matched as option 'map_channel' (map an audio channel from one stream to another) with argument '0.0.1'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'mp2'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'rtp'.
Reading option 'rtp://224.4.4.4:4448' ... matched as output file.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option loglevel (set logging level) with argument debug.
Successfully parsed a group of options.
Parsing a group of options: input file none:1.
Applying option f (force format) with argument avfoundation.
Successfully parsed a group of options.
Opening an input file: none:1.
[avfoundation @ 0x7f8dfb83d800] audio device 'Soundflower (64ch)' opened
[avfoundation @ 0x7f8dfb83d800] Failed to open codec in av_find_stream_info
[avfoundation @ 0x7f8dfb83d800] All info found
Input #0, avfoundation, from 'none:1':
  Duration: N/A, start: 289287.941202, bitrate: N/A
    Stream #0:0, 1, 1/1000000: Audio: pcm_s32be, 44100 Hz, 64 channels, 90316 kb/s
Successfully opened the file.
Parsing a group of options: output file rtp://224.4.4.4:4444.
Applying option map_channel (map an audio channel from one stream to another) with argument 0.0.0.
Applying option f (force format) with argument mp2.
Applying option f (force format) with argument rtp.
Successfully parsed a group of options.
Opening an output file: rtp://224.4.4.4:4444.
Successfully opened the file.
Parsing a group of options: output file rtp://224.4.4.4:4448.
Applying option map_channel (map an audio channel from one stream to another) with argument 0.0.1.
Applying option f (force format) with argument mp2.
Applying option f (force format) with argument rtp.
Successfully parsed a group of options.
Opening an output file: rtp://224.4.4.4:4448.
Successfully opened the file.
detected 2 logical cores
[graph 0 input from stream 0:0 @ 0x10d11a580] Setting 'time_base' to value '1/44100'
[graph 0 input from stream 0:0 @ 0x10d11a580] Setting 'sample_rate' to value '44100'
[graph 0 input from stream 0:0 @ 0x10d11a580] Setting 'sample_fmt' to value '(null)'
[abuffer @ 0x10d119d40] Unable to parse option value "(null)" as sample format
[graph 0 input from stream 0:0 @ 0x10d11a580] Setting 'channels' to value '64'
[abuffer @ 0x10d119d40] Unable to parse option value "(null)" as sample format
[abuffer @ 0x10d119d40] Error setting option sample_fmt to value (null).
[graph 0 input from stream 0:0 @ 0x10d11a580] Error applying options to the filter.
Error opening filters!
[AVIOContext @ 0x10d17e600] Statistics: 0 seeks, 0 writeouts
[AVIOContext @ 0x10d17f0c0] Statistics: 0 seeks, 0 writeouts