[FFmpeg-user] Why ffmpeg detect inside a mp3 file a video?

[Roger Pack]

> I'm not expert, but it looks ok to me. For example, just doing ffmpeg
> -i ~/MyTestJPEG.jpeg reports Stream #0:0: Video: mjpeg, yuvj420p,
> 384x256 [SAR 1:1 DAR 3:2], 25 tbr, 25 tbn, 25 tbc. A single, still
> image is treated as a "video" with only 1 frame.
>
> Is there something specific that looks wrong?

I guess the only worry I have with it is that it appears to attempt to
re-encode the (probably still image) as a video stream.  I suppose
ideally it would somehow treat it as metadata, and store it as such in
the output file.

ffmpeg111 -i a.mp3 -acodec libvorbis -y a123.ogg

ex:
ffmpeg111 -i a.mp3 -acodec libvorbis -y a123.ogg
ffmpeg version N-43206-gf857465 Copyright (c) 2000-2012 the FFmpeg developers
 built on Aug 4 2012 16:10:39 with gcc 4.7.1 (GCC)
 configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-runtime-cpudetect --enable-avisynth --enable-bzlib
--enable-frei0r --enable-libass --enable-libcelt
--enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libfreetype --enable-libgsm --enable-libmp3lame
--enable-libnut --enable-libopenjpeg --enable-librtmp
--enable-libschroedinger --enable-libspeex --enable-libtheora
--enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs
--enable-libxvid --enable-zlib
 libavutil 51. 66.100 / 51. 66.100
 libavcodec 54. 49.100 / 54. 49.100
 libavformat 54. 22.100 / 54. 22.100
 libavdevice 54. 2.100 / 54. 2.100
 libavfilter 3. 5.102 / 3. 5.102
 libswscale 2. 1.100 / 2. 1.100
 libswresample 0. 15.100 / 0. 15.100
 libpostproc 52. 0.100 / 52. 0.100
[mp3 @ 002fc500] max_analyze_duration 5000000 reached at 5015510
[mp3 @ 002fc500] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'a.mp3':
 Metadata:
 album : Loud
 composer : Mikkel S. Eriksen, Sandy Wilhelm, Tor Erik Hermansen & Esther Dean
 genre : R&B/Soul
 encoded_by : iTunes 10.3.1.55
 title : S&M
 artist : Rihanna
 album_artist : Rihanna
 track : 1/11
 date : 2010
 Duration: 00:04:08.49, start: 0.000000, bitrate: 256 kb/s
 Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 256 kb/s
 Stream #0:1: Video: mjpeg, yuvj444p, 600x600 [SAR 72:72 DAR 1:1], 90k
tbr, 90k tbn, 90k tbc
 Metadata:
 title :
 comment : Cover (front)
[ogg @ 002ff6c0] Frame rate very high for a muxer not efficiently supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
Output #0, ogg, to 'a123.ogg':
 Metadata:
 album : Loud
 composer : Mikkel S. Eriksen, Sandy Wilhelm, Tor Erik Hermansen & Esther Dean
 genre : R&B/Soul
 encoded_by : iTunes 10.3.1.55
 title : S&M
 artist : Rihanna
 ALBUMARTIST : Rihanna
 TRACKNUMBER : 1/11
 date : 2010
 encoder : Lavf54.22.100
 Stream #0:0: Video: theora, yuv444p, 600x600 [SAR 1:1 DAR 1:1],
q=2-31, 200 kb/s, 90k tbn, 90k tbc
 Metadata:
 title :
 comment : Cover (front)
 Stream #0:1: Audio: vorbis, 44100 Hz, stereo, flt
Stream mapping:
 Stream #0:1 -> #0:0 (mjpeg -> libtheora)
 Stream #0:0 -> #0:1 (mp3 -> libvorbis)