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

[Chip]

On 12 May 2015 at 13:29, Chip <chiapas at aktivix.org> wrote:
> Hi
>
> Many thanks Carl and Moritz.
>
> I'll go and recompile ffmpeg and have a think about the command line
> construction.
>
> I will return - no doubt with a new set of questions.
>
> Best regards for now
>
> Chip
>
> On 12 May 2015 at 12:32, Moritz Barsnick <barsnick at gmx.net> wrote:
>> 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.
>>
>> Moritz

Hi

I have moved forward quite a bit with this issue - trying to transcode
128kbps MP3 stream to 48kbps AAC.

I am streaming to an Icecast server and this is my command string:

user at machine:~# ~/bin/ffmpeg -user-agent 42 -i
http://example1.com:8002/stream.mp3 -c:a libfdk_aac -ar 44100 -ab 48k
icecast://username:password@example2.com:8099/stream.aac -v debug

Details amended to protect the innocent.

The command proceeds with no obvious error and completes with this:

icecast://username:password@example2.com:8099/stream.aac: End of file
[AVIOContext @ 0x3686240] Statistics: 131600 bytes read, 0 seeks

No AAC stream is generated.

Full output pasted here:

http://pastebin.com/tLmUGBtw

Version details below:

user at machine:~# ~/bin/ffmpeg -version
ffmpeg version 2.6.git Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.7 (Debian 4.7.2-5)
configuration: --prefix=/root/ffmpeg_build --pkg-config-flags=--static
--extra-cflags=-I/root/ffmpeg_build/include
--extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin
--enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype
--enable-libmp3lame --enable-libopus --enable-libtheora
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
libavutil      54. 23.101 / 54. 23.101
libavcodec     56. 38.100 / 56. 38.100
libavformat    56. 32.100 / 56. 32.100
libavdevice    56.  4.100 / 56.  4.100
libavfilter     5. 16.101 /  5. 16.101
libswscale      3.  1.101 /  3.  1.101
libswresample   1.  1.100 /  1.  1.100
libpostproc    53.  3.100 / 53.  3.100
user at machine:~#

Any suggestions?

Many thanks in advance

Chip Scooter