[FFmpeg-trac] #1408(undetermined:new): Encoding to mp3 produces a file with audio and video by default

[FFmpeg]

#1408: Encoding to mp3 produces a file with audio and video by default
-------------------------------------+-------------------------------------
               Reporter:  cehoyos    |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  important  |              Component:
                Version:  git-       |  undetermined
  master                             |               Keywords:  mp3
             Blocked By:             |  regression
Reproduced by developer:  0          |               Blocking:
                                     |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 http://thread.gmane.org/gmane.comp.video.ffmpeg.user/37424
 Since 2dfea12, FFmpeg by default creates a video (png) stream when
 encoding mp3, this causes a severe performance regression because video
 has to be decoded.
 {{{
 $ ffmpeg -i fate-suite/svq3/Vertical400kbit.sorenson3.mov out.mp3
 ffmpeg version N-41284-ge00b2d2 Copyright (c) 2000-2012 the FFmpeg
 developers
   built on Jun  4 2012 08:52:52 with gcc 4.3.2
   configuration: --cc=/usr/local/gcc-4.3.2/bin/gcc --enable-gpl --enable-
 libopenjpeg --enable-libvorbis --enable-libspeex --enable-libmp3lame
 --enable-libtheora --extra-ldflags=-lm --enable-libvpx --enable-libxavs
   libavutil      51. 56.100 / 51. 56.100
   libavcodec     54. 23.100 / 54. 23.100
   libavformat    54.  6.101 / 54.  6.101
   libavdevice    54.  0.100 / 54.  0.100
   libavfilter     2. 78.100 /  2. 78.100
   libswscale      2.  1.100 /  2.  1.100
   libswresample   0. 15.100 /  0. 15.100
   libpostproc    52.  0.100 / 52.  0.100
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x90123c0] max_analyze_duration 5000000 reached
 at 5000998
 Guessed Channel Layout for  Input Stream #0.1 : mono
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'fate-
 suite/svq3/Vertical400kbit.sorenson3.mov':
   Metadata:
     creation_time   : 2001-03-20 16:17:18
     title           : Vertical Online SV3 Demo
     title-eng       : Vertical Online SV3 Demo
     artist          : Logan Kelsey
     artist-eng      : Logan Kelsey
     copyright       : © Vertical Online 2001
     copyright-eng   : © Vertical Online 2001
     encoder         : Sorenson Video 3
     encoder-eng     : Sorenson Video 3
   Duration: 00:00:43.57, start: 0.000000, bitrate: 580 kb/s
     Stream #0:0(eng): Video: svq3 (SVQ3 / 0x33515653), yuvj420p, 320x240,
 391 kb/s, 30.02 fps, 30 tbr, 600 tbn, 600 tbc
     Metadata:
       creation_time   : 2001-03-20 16:17:18
       handler_name    : Apple Alias Data Handler
     Stream #0:1(eng): Audio: adpcm_ima_qt (ima4 / 0x34616D69), 44100 Hz,
 mono, s16, 176 kb/s
     Metadata:
       creation_time   : 2001-03-20 16:17:18
       handler_name    : Apple Alias Data Handler
 [buffer @ 0x900fa20] w:320 h:240 pixfmt:yuvj420p tb:1/600 sar:0/1
 sws_param:flags=2
 [ffmpeg_buffersink @ 0x900f8e0] No opaque field provided
 [format @ 0x900f9e0] auto-inserting filter 'auto-inserted scaler 0'
 between the filter 'Parsed_null_0' and the filter 'format'
 [auto-inserted scaler 0 @ 0x9012280] w:320 h:240 fmt:yuvj420p sar:0/1 ->
 w:320 h:240 fmt:rgb24 sar:0/1 flags:0x4
 Output #0, mp3, to 'out.mp3':
   Metadata:
     TDEN            : 2001-03-20 16:17:18
     TIT2            : Vertical Online SV3 Demo
     title-eng       : Vertical Online SV3 Demo
     TPE1            : Logan Kelsey
     artist-eng      : Logan Kelsey
     TCOP            : © Vertical Online 2001
     copyright-eng   : © Vertical Online 2001
     encoder-eng     : Sorenson Video 3
     TSSE            : Lavf54.6.101
     Stream #0:0(eng): Video: png, rgb24, 320x240, q=2-31, 200 kb/s, 90k
 tbn, 30 tbc
     Metadata:
       creation_time   : 2001-03-20 16:17:18
       handler_name    : Apple Alias Data Handler
     Stream #0:1(eng): Audio: mp3, 44100 Hz, mono, s16
     Metadata:
       creation_time   : 2001-03-20 16:17:18
       handler_name    : Apple Alias Data Handler
 Stream mapping:
   Stream #0:0 -> #0:0 (svq3 -> png)
   Stream #0:1 -> #0:1 (adpcm_ima_qt -> libmp3lame)
 Press [q] to stop, [?] for help
 Multiple frames in a packet from stream 1
 [mp3 @ 0x9018fa0] Got more than one picture in stream 0, ignoring.
 frame= 1308 fps= 49 q=0.0 Lsize=     341kB time=00:00:43.57 bitrate=
 64.2kbits/s
 video:86771kB audio:341kB global headers:0kB muxing overhead -99.608084%
 [libmp3lame @ 0x9011780] 1 frames left in que on closing
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1408>
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