MP3s with cover-art are listed as video

[adamlwgriffiths]

MP3 cover art is listed in ffprobe as a motion jpeg stream with 0 frames.
This causes isVideo to return true for mp3s.
My current work around is to call frames() instead.
I'm not sure if checking TAG:title=cover would work, it may not be consistent across encoders / taggers?

Output of ffprobe is below

ffprobe -show_streams Garoad\ -\ VA-11\ HALL-A\ Prologue\ OST\ -\ Sounds\ From\ The\ Future\ -\ 14\ Follow\ The\ Trail.mp3
ffprobe version 1.2.6-7:1.2.6-1~trusty1 Copyright (c) 2007-2014 the FFmpeg developers
  built on Apr 26 2014 18:52:58 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  configuration: --arch=amd64 --disable-stripping --enable-avresample --enable-pthreads --enable-runtime-cpudetect --extra-version='7:1.2.6-1~trusty1' --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis --enable-libvpx --enable-zlib --enable-gpl --enable-postproc --enable-libcdio --enable-x11grab --enable-libx264 --shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static
  libavutil      52. 18.100 / 52. 18.100
  libavcodec     54. 92.100 / 54. 92.100
  libavformat    54. 63.104 / 54. 63.104
  libavdevice    53.  5.103 / 53.  5.103
  libavfilter     3. 42.103 /  3. 42.103
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[mp3 @ 0x130f020] max_analyze_duration 5000000 reached at 5015510 microseconds
Input #0, mp3, from 'Garoad - VA-11 HALL-A Prologue OST - Sounds From The Future - 14 Follow The Trail.mp3':
  Metadata:
    title           : Follow The Trail
    artist          : Garoad
    track           : 14
    album           : VA-11 HALL-A Prologue OST - Sounds From The Future
    album_artist    : Garoad
    date            : 2014
  Duration: 00:02:50.81, start: 0.000000, bitrate: 262 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 254 kb/s
    Stream #0:1: Video: mjpeg, yuvj444p, 700x700 [SAR 72:72 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
    Metadata:
      title           : cover
      comment         : Cover (front)
[STREAM]
index=0
codec_name=mp3
codec_long_name=MP3 (MPEG audio layer 3)
profile=unknown
codec_type=audio
codec_time_base=1/44100
codec_tag_string=[0][0][0][0]
codec_tag=0x0000
sample_fmt=s16p
sample_rate=44100
channels=2
bits_per_sample=0
id=N/A
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/14112000
start_pts=0
start_time=0.000000
duration_ts=2410536960
duration=170.814694
bit_rate=254883
nb_frames=N/A
nb_read_frames=N/A
nb_read_packets=N/A
DISPOSITION:default=0
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
[/STREAM]
[STREAM]
index=1
codec_name=mjpeg
codec_long_name=MJPEG (Motion JPEG)
profile=unknown
codec_type=video
codec_time_base=1/90000
codec_tag_string=[0][0][0][0]
codec_tag=0x0000
width=700
height=700
has_b_frames=0
sample_aspect_ratio=1:1
display_aspect_ratio=1:1
pix_fmt=yuvj444p
level=-99
timecode=N/A
id=N/A
r_frame_rate=90000/1
avg_frame_rate=0/0
time_base=1/90000
start_pts=0
start_time=0.000000
duration_ts=15373322
duration=170.814689
bit_rate=N/A
nb_frames=N/A
nb_read_frames=N/A
nb_read_packets=N/A
DISPOSITION:default=0
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=1
TAG:title=cover
TAG:comment=Cover (front)
[/STREAM]