[FFmpeg-trac] #1737(avcodec:new): ffmpeg detect aac stereo as mono

FFmpeg trac at avcodec.org
Sat Sep 15 14:05:13 CEST 2012

#1737: ffmpeg detect aac stereo as mono
             Reporter:  dmitry9     |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  aac         |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |

Comment (by dmitry9):

 * QuickTime detect audio stream as Mono, 48000 and when play sound

 * MEncoder detect stream as stereo(2ch) and successfully transcode to mp3.
 Play sound normal.
  mencoder /tmp/audio_aac_stereo_as_mono.mp4 -oac mp3lame -ovc x264 -o
 MEncoder SVN-r1.0~rc3+svn20090426-4.4.3 (C) 2000-2009 MPlayer Team

 success: format: 0  data: 0x0 - 0x11ef42
 libavformat file format detected.
 [lavf] Video stream found, -vid 0
 [lavf] Audio stream found, -aid 1
 VIDEO:  [avc1]  360x240  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
 [V] filefmt:44  fourcc:0x31637661  size:360x240  fps:25.000  ftime:=0.0400
 Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding)
 FAAD: compressed input bitrate missing, assuming 128kbit/s!
 AUDIO: 48000 Hz, 2 ch, s16le, 128.0 kbit/8.33% (ratio: 16000->192000)
 Selected audio codec: [faad] afm: faad (FAAD AAC (MPEG-2/MPEG-4 Audio))
 Opening video filter: [expand osd=1]
 Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
 Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
 Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
 MP3 audio selected.

 * cvlc
 VLC media player 1.0.6 Goldeneye when play detect:
 [0x7f2acc00e1e8] pulse audio output: No. of Audio Channels: 2

 * ffmpeg when try change rate 48000 -> 22050: sound output broken. Please
 see log file in attachment ffmpeg-20120914-161147.log

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1737#comment:2>
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