xml file header support (reading and writing)

[andimik]

As described in #861, some other DAB tools have introduced a 2048 or longer byte header which allows loading a file regardless of the used format, sampling rate and bit depth.

Description

https://qirx.softsyst.com/RawXmlHeader

Example

<?xml version="1.0" encoding="utf-8"?>
<SDR>
 <Recorder Name="AbracaDABra" Version="2.1.1+"/>
 <Device Name="rtl-sdr [R820T]" Model="Generic RTL2832U OEM"/>
 <Time Unit="UTC" Value="2023-09-10 05:56:52"/>
 <Sample>
  <Samplerate Unit="Hz" Value="2048000"/>
  <Channels Container="uint8" Ordering="LSB" Bits="8">
   <Channel Value="I"/>
   <Channel Value="Q"/>
  </Channels>
 </Sample>
 <Datablocks>
  <Datablock Unit="Channel" Number="1" Offset="2048" Count="91750400">
   <Frequency Unit="kHz" Value="213360"/>
   <Modulation Value="DAB"/>
  </Datablock>
 </Datablocks>
</SDR>

There are basically 3 extensions in use

• *.raw (not recommended)
• *.xml
• *.uff

2023-09-10_075649_10C.uff.zip