Manual
Table Of Contents
- Introduction
- Supported Codecs and Formats
- The Sonnox Fraunhofer Pro-Codec
- Additional Information on Workflows
- Lossless Codecs (mp3-HD and HD-AAC)
- Description of Controls
- Presets and Project/Session Data Handling
- Preset Manager Toolbar
- Pro-Codec Signal and Control Flow Diagram
- Specifications
- Copyright and Acknowledgements
- Manual Revision History
- Platform Specific Supplement
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15
3.4 Bitstream Level (TRIM tab)
Any form of filtering can, under certain circumstances, increase the level of the signal. If
your input is hot, this can potentially produce overloads when the signal is decoded. This
effect can be very easily demonstrated with this plug-in.
The BITSTREAM LEVELS TRIM tab (see above) can be used to monitor this potential for
overload. The post-decoder level is continually monitored, and a small meter indicates levels
over 0dB. There is a peak-hold text display (MAX dB) of the maximum post-decoder level
achieved, which is yellow if below 0dB and turns red on overload. Clicking on this display
resets the overload condition.
The TRIM dB control allows you to trim the input level to the codec to accommodate these
overloads. The gain reduction (headroom) is applied pre-encoding, and if non-zero the trim
value is displayed on a pink background. In order to allow like-for-like signal level
comparison and difference signal generation, the headroom is applied before encoding and
removed after the decoder output. This way the encoded bitstream is reduced in level, but the
auditioned signal remains at the input level.
In the screenshot above, the HE-AAC codec has generated an overload condition, and has
had its input trimmed down by 0.90dB to accommodate this overload. The TRIM dB
controls are automatable.