I'm trying to stream an IP webcam ASF live stream to a ffserver to output a webm video format. The server starts successfully but the ffserver commands used to feed the ffserver fails and generates a core dump.
Environment
Debian 7.5
ffmpeg 2.2
Input stream
$ ffprobe http://account:password@webcam/videostream.asf
Input #0, asf, from 'http://admin:alpha1237@webcam/videostream.asf':
  Duration: N/A, start: 0.000000, bitrate: 32 kb/s
    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj422p(pc), 640x480, 25 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: adpcm_ima_wav ([17][0][0][0] / 0x0011), 8000 Hz, 1 channels, s16p, 32 kb/s
ffserver configuration
my ffserver configuration is :
Port 8091
RTSPPort 554
BindAddress 192.168.1.62
MaxHTTPConnections 1000
MaxClients 100
MaxBandwidth 1000
CustomLog -
<Feed webcam.ffm>
        File /tmp/webcam.ffm
        FileMaxSize 500M
        ACL allow localhost
        ACL allow 192.168.0.0 192.168.255.255
</Feed>
<Stream webcam.webm>              # Output stream URL definition
   Feed webcam.ffm              # Feed from which to receive video
   Format webm
   # Audio settings
   AudioCodec vorbis
   AudioBitRate 64             # Audio bitrate
   # Video settings
   VideoCodec libvpx
   VideoSize 640x480           # Video resolution
   VideoFrameRate 25           # Video FPS
   AVOptionVideo flags +global_header  # Parameters passed to encoder
                                       # (same as ffmpeg command-line parameters)
   AVOptionVideo cpu-used 0
   AVOptionVideo qmin 10
   AVOptionVideo qmax 42
   AVOptionVideo quality good
   AVOptionAudio flags +global_header
   PreRoll 15
   StartSendOnKey
   # VideoBitRate 32            # Video bitrate
</Stream>
<Stream status.html>
        Format status
        # Only allow local people to get the status
        ACL allow localhost
        ACL allow 192.168.0.0 192.168.255.255
</Stream>
ffmpeg feed
I run the following command that fails
$ ffmpeg  -i http://account:password@webcam/videostream.asf http://192.168.1.62:8091/webcam.ffm
http://192.168.1.62:8091/webcam.ffm
Input #0, asf, from 'http://account:password@webcam/videostream.asf':
  Duration: N/A, start: 0.000000, bitrate: 32 kb/s
    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj422p(pc), 640x480, 25 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: adpcm_ima_wav ([17][0][0][0] / 0x0011), 8000 Hz, mono, s16p, 32 kb/s
[swscaler @ 0x36a80c0] deprecated pixel format used, make sure you did set range correctly
Segmentation fault
I tryed 
$ ffmpeg  -i http://account:password@webcam/videostream.asf -pix_fmt yuv420p  http://192.168.1.62:8091/webcam.ffm
But it raises the same error.
Thanks for your help 
Edit
For an easy testing (I thought), I tried to publish the whole ASF stream as is, meaning connecting the ASF webcam output stream to the ffserver that outputs ASF format too.
And thus with mirrored encoding so I changed the ffserver configuration to
...
<Stream webcam.asf>
    Feed webcam.ffm
    Format asf
    VideoFrameRate 25
    VideoSize 640X480
    VideoBitRate 256
    VideoBufferSize 1000
    VideoGopSize 30
    AudioBitRate 32
    StartSendOnKey
</Stream>
...
And the output is now :
Input #0, asf, from 'http://admin:alpha1237@webcam/videostream.asf':
  Duration: N/A, start: 0.000000, bitrate: 32 kb/s
    Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj422p(pc), 640x480, 1k tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: adpcm_ima_wav ([17][0][0][0] / 0x0011), 8000 Hz, mono, s16p, 32 kb/s
[swscaler @ 0x3d620c0] deprecated pixel format used, make sure you did set range correctly
Output #0, ffm, to 'http://192.168.1.62:8091/webcam.ffm':
  Metadata:
    creation_time   : now
    encoder         : Lavf55.40.100
    Stream #0:0: Audio: wmav2, 22050 Hz, mono, fltp, 32 kb/s
    Metadata:
      encoder         : Lavc55.64.100 wmav2
    Stream #0:1: Video: msmpeg4v3 (msmpeg4), yuv420p, 640x480, q=2-31, 256 kb/s, 1k fps, 1000k tbn, 1k tbc
    Metadata:
Stream mapping:
  Stream #0:1 -> #0:0 (adpcm_ima_wav -> wmav2)
  Stream #0:0 -> #0:1 (mjpeg -> msmpeg4)
Press [q] to stop, [?] for help
Segmentation fault
I can't even forward the stream.