[FFmpeg-user] Transcode live mp3 stream to CBR aac+ with ffmpeg

Moritz Barsnick barsnick at gmx.net
Tue May 12 13:32:43 CEST 2015

Hi Chip,

On Tue, May 12, 2015 at 12:02:54 +0100, Chip wrote:

> ffmpeg version 1.0.10 Copyright (c) 2000-2014 the FFmpeg developers
>   built on Jul 25 2014 07:50:40 with gcc 4.7 (Debian 4.7.2-5)

Apart from Carl Eugen's comment that this version is way too old to try
to analyze and fix any issues with it:

> /usr/bin/ffmpeg -re -user-agent 42 -i
> http://example1.com:8002/stream.mp3 -c:a libfaac -ar 44100 -ab 48k
> -acodec copy http://username:password@example2.com:8099/stream.aac -v
> debug

Please do pay close attention to the construction of your command line.
What to you expect ffmpeg to do if you give
"-c:a libfaac -ar 44100 -ab 48k -acodec copy"?
ffmpeg can only fulfil one of the two (either aac or copy).

Note what happened:
> Output #0, adts, to
> 'http://username:password@example2.com:8099/stream.aac -v debug':
>   Metadata:
>     encoder         : Lavf54.29.104
>     Stream #0:0, 0, 1/90000: Audio: mp3, 44100 Hz, stereo, 128 kb/s
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)

You're actually streaming unchanged MP3 into an ADTS stream named with
the suffix "aac". It may work - i don't know - but this is not close to
what you're trying to achieve.


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