[mdlug] Ffmpeg Problem

[Tony Bemus]

Frank
  I ran into a similar problem.   I ended up using VLC  to save the audio track.   I'm not at my computer now but Google it and there will be the directions. 
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

On June 17, 2014 9:51:30 PM EDT, Frank Peters <frank.peters at comcast.net> wrote:
>Hello,
>
>I downloaded a video from which I need to extract the audio portion.
>(The video is actually an audio track with some accompanying images
>so this operation is more like stripping the video from the audio.)
>
>Mplayer is able to play the video (and audio) without problem and it
>identifies the video stream as h264 and the audio stream as aac.
>Therefore, I thought, it should be a simple matter to extract the
>audio portion using ffmpeg:
>
>ffmpeg -i input.mp4 -vn -acodec copy output.aac
>
>However, the extracted audio file, which should be a bona fide AAC
>audio file, fails to play with mplayer.  (See below for full error
>output.)  
>
>I use the above ffmpeg command to extract AAC audio from other MP4
>files and have never had a problem before.
>
>Using the file command to determine the file type of output.aac
>gives this information:
>
>output.aac: MPEG ADTS, AAC, v4 LC, 44.1 kHz, stereo
>
>This is the same information I get using a ffmpeg extracted AAC
>audio file that *does* play with mplayer.
>
>If anyone can shed some light on this problem or offer a different
>way to extract the AAC audio, I would be extremely grateful.
>
>Because the mplayer error message is so long, I include it at the
>end.
>
>F Peters
>
>mplayer output.aac
>
>Playing output.aac.
>libavformat version 55.33.100 (external)
>MPEG-PES file format detected.
>MPEG: FATAL: EOF while searching for sequence header.
>Video: Cannot read properties.
>Load subtitles in ./
>==========================================================================
>Opening audio decoder: [mpg123] MPEG 1.0/2.0/2.5 layers I, II, III
>mpg123 init error: Error reading the stream. (code 18)
>ADecoder init failed :(
>ADecoder init failed :(
>Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
>libavcodec version 55.52.102 (external)
>Unknown/missing audio format -> no sound
>ADecoder init failed :(
>Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
>Unknown/missing audio format -> no sound
>ADecoder init failed :(
>Opening audio decoder: [libmad] libmad mpeg audio decoder
>Cannot sync MAD frame
>ADecoder init failed :(
>ADecoder init failed :(
>Opening audio decoder: [hwmpa] MPEG audio pass-through (fake decoder)
>Cannot sync MPA frame: 0
>ADecoder init failed :(
>ADecoder init failed :(
>Opening audio decoder: [spdif] libavformat/spdifenc audio pass-through
>decoder.
>AUDIO: 48000 Hz, 2 ch, mpeg2, 768.0 kbit/50.00% (ratio: 96000->192000)
>Selected audio codec: [spdifmpa] afm: spdif (libavformat/spdifenc MPEG
>AUDIO BC pass-through decoder)
>==========================================================================
>[AO_ALSA] Format mpeg2 is not supported by hardware, trying default.
>AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
>[format] Sample format big-endian MPEG-2 not yet supported 
>[libaf] Reinitialization did not work, audio filter 'format' returned
>error code -2
>[libaf] Unable to setup filter system can not meet sound-card demands,
>please send a bug report. 
>Couldn't find matching filter/ao format!
>Audio: no sound
>Video: no video
>
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