X4

384 MPEG-4 encoder settings
http://pro.magix.com
settings provide a bit rate of 7.4 kbit/s. The highest bit rate for this format is
more suited for transferring conversations.
AAC
The AAC audio was developed by MPEG, the Moving Picture Experts Group
(Dolby, Fraunhofer Institut für Integrierte Schaltungen in Erlangen, AT&T, Nokia,
Sony) as an audio data compression process, that was specified as a further
development of MPEG-2 Multichannel in the MPEG-2 standard.
It's also a further development of MPEG-2 audio. This format is equally suitable
for encoding general audio information and not especially optimized for certain
types of audio material. As with video material, the audio format should be
considered for playback later.
AAC audio can be encoded with a sample rate of 8,000, 16,000, 24,000,
32,000 or 48,000 Hz and in mono and stereo sound, respectively. By default,
the sound is set to 48,000 Hz stereo. The higher the sample rate is, the larger
the resulting file and higher the audio quality.
The advanced AAC audio menu includes the following settings options:
 The bit rate can be set between 6 and 512 kbit/s. 160 kbits/s is active by
default. The higher the value is, the larger the resulting file and higher the audio
quality. After a certain limit, additional improvements to audio quality will not
be perceived. Bit rates under 64 kb/s are not recommended.
 As an MPEG version, set MPEG-4 or the older, proven MPEG-2 format.
 For the File Header Type, choose either RAW or ADTS. The "Header"
indicates an explanatory head for the beginning of the file segment, which in
fact takes up extra space, but is required for decoding under circumstances.
- RAW indicates material which does not include a file header in audio
format. The audio material is therefore transferred directly without any
special additional information (raw).
This requires that decoding routines are able to process the material
without the explanatory file header. Especially in case "exotic" sample
rates are set, this can lead to problems during RAW encoding.
- ADTS indicates a file header type which contains information for
encoded audio material. In case of doubt, select this file header type,
since fewer problems can be expected in this case.
Object type: This provides selection between "Main" and "Low complexity".