AN1250 STMicroelectronics, AN1250 Datasheet - Page 18

• Manufacturer Part Number: AN1250
• Description: STA014/STA015 MPEG LAYER III DECODER AND ADPCM CODEC
• Manufacturer: STMicroelectronics

AN1250 APPLICATION NOTE
8.6 Codec page
Figure 17. Codec page
§ 1 : The 'Audio Control' section offers a duplicate set of the audio controls available on the main page.
§ 2 : This section can be used to select the encoding/decoding ADPCM algorithm. User selected settings
§ 3 : This is the memory selection bank. As explained at the previous point every time a memory is select-
§ 4 : Record/Play button are used to start/stop the encoding or decoding operation. The green filling-bar
§ 5 : This controls are not enabled in the current release of the software.
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The only difference is that the 'Tone Attenuation' register is automatically set to the maximum value
of the desired tones enhancement. Of course this controls can be used when decoding an MP3 file as
well: infact they just rely on the same set of I2C registers.
are automatically stored in the 'STA014/STA015T.ini' file located in the Windows system directory and
are linked with each memory button: selecting a different memory will retrieve codec parameters used
to store that memory. After the memory has been selected anyway, it's possible, to change the decod-
ing parameters (increasing, for instance, the sampling frequency it's possible to make a fast playback
of the message). This feature will not work if the message was recorded using the 'frame mode': in
this case, infact, the decoding parameters comes from the header information inside the bitstream it-
self instead of coming from the I2C register settings. Some problem could arise when encoding/de-
coding the higher bitrates message (for instace, using the 32KHz Stereo mode with G723_40
algorithm), especially on slow machines: due to the PC parallel port speed limitation, infact, some
communication problem could affect the encoded/decoded message. In any case the full set of option
is still available in order to show all the device features and capabilities and to allow an exhaustive
evaluation of the product. Again, in order to make the communication link between the PC and the
STA014/STA015 board more robust it's stronly adviced to always enable the 'frame mode' operation.
ed the ADPCM codec parameters are retrieved from the 'STA014/STA015T.ini' file (if exist). Each
memory can store up to 500 Kbytes.
show the status of the memory or, when decoding, the current playback position.