$ ffprobe stream.asf
avprobe version 0.8.5-4:0.8.5-0ubuntu0.12.04.1, Copyright (c) 2007-2012 the Libav developers
  built on Jan 24 2013 18:03:14 with gcc 4.6.3
[wmv3 @ 0x8b66d00] Extra data: 8 bits left, value: 0
[asf @ 0x8b62aa0] max_analyze_duration reached
[asf @ 0x8b62aa0] Estimating duration from bitrate, this may be inaccurate
Input #0, asf, from 'stream.asf':
  Metadata:
    WMFSDKVersion   : 11.0.6002.18049
    WMFSDKNeeded    : 0.0.0.0000
    IsVBR           : 0
  Duration: 00:05:07.55, start: 0.000000, bitrate: 592 kb/s
    Stream #0.0(eng): Audio: wmav2, 32000 Hz, 2 channels, s16, 32 kb/s
    Stream #0.1(eng): Video: wmv3 (Main), yuv420p, 480x360, 551 kb/s, PAR 4:3 DAR 16:9, 59.92 tbr, 1k tbn, 1k tbc
    Stream #0.2(eng): Data: [0][0][0][0] / 0x0000, 10 kb/s
[wmv3 @ 0x8b66d00] Extra data: 8 bits left, value: 0
Unsupported codec with id 0 for input stream 2