[mdlug] Ffmpeg Problem

[Carl T. Miller]

Or try using mplayer, since it can decode the file.

<http://www.mikealeonetti.com/wiki/index.php?title=Using_mplayer_to_extract_audio_from_a_video_file>

c


Tony Bemus wrote:
> 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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