攻防世界_misc_funny_video

环境

funny_video，mkv音频隐写

flag{fun_v1d30_mu51c}

wp

查看mkv信息

ffmpeg -i d9cef34d84b14d72b99e3b1b3f1f0b97.mkv

得到一个视频轨和两个音频轨

Stream #0:0: Video: h264 (High), yuv420p(progressive), 852x480, SAR 1:1 DAR 71:40, 25 fps, 25 tbr, 1k tbn, 50 tbc (default)
  Metadata:
    BPS-eng         : 1837945
    DURATION-eng    : 00:00:36.800000000
    NUMBER_OF_FRAMES-eng: 920
    NUMBER_OF_BYTES-eng: 8454549
    _STATISTICS_WRITING_APP-eng: mkvmerge v24.0.0 ('Beyond The Pale') 64-bit
    _STATISTICS_WRITING_DATE_UTC-eng: 2018-10-19 04:02:25
    _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Stream #0:1: Audio: mp3, 44100 Hz, stereo, fltp, 192 kb/s (default)
  Metadata:
    BPS-eng         : 191710
    DURATION-eng    : 00:00:36.833000000
    NUMBER_OF_FRAMES-eng: 1410
    NUMBER_OF_BYTES-eng: 882660
    _STATISTICS_WRITING_APP-eng: mkvmerge v24.0.0 ('Beyond The Pale') 64-bit
    _STATISTICS_WRITING_DATE_UTC-eng: 2018-10-19 04:02:25
    _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Stream #0:2: Audio: mp3, 44100 Hz, stereo, fltp, 192 kb/s
  Metadata:
    BPS-eng         : 191710
    DURATION-eng    : 00:00:36.833000000
    NUMBER_OF_FRAMES-eng: 1410
    NUMBER_OF_BYTES-eng: 882660
    _STATISTICS_WRITING_APP-eng: mkvmerge v24.0.0 ('Beyond The Pale') 64-bit
    _STATISTICS_WRITING_DATE_UTC-eng: 2018-10-19 04:02:25
    _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES

第一个音频轨是默认的，二个音轨可疑，把第二个音轨的音频都提取出来

ffmpeg -i d9cef34d84b14d72b99e3b1b3f1f0b97.mkv -map 0:2 -c copy audio.mp3

查看频谱图即可