Editing Header/Payload Demux

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Say our synchronization algorithm can be off by up to two samples, and the header length is 20 samples. So we set <code>header_len</code> to 20, and <code>header_padding</code> to 2. Now assume a trigger arrives on sample of index 100. We copy a total of 24 samples to the header port <code>out_hdr</code>, starting at sample of index 98.
 
Say our synchronization algorithm can be off by up to two samples, and the header length is 20 samples. So we set <code>header_len</code> to 20, and <code>header_padding</code> to 2. Now assume a trigger arrives on sample of index 100. We copy a total of 24 samples to the header port <code>out_hdr</code>, starting at sample of index 98.
  
====Payload and padding====
+
===Padding===
 
The payload is not padded. Let's say the header demod reports a payload length of 100. In the previous examples, we would copy 100 samples to the payload port, starting at sample index 120 (this means the padded samples appended to the header are copied to both ports!). However, the header demodulator has the option to specify a payload offset, which cannot exceed the padding value. To do this, include a key <code>payload_offset</code> in the message sent back to the HPD. A negative value means the payload starts earlier than otherwise. (If you wanted to always pad the payload, you could set payload_offset to -header_padding and increase the reported length of the payload).
 
The payload is not padded. Let's say the header demod reports a payload length of 100. In the previous examples, we would copy 100 samples to the payload port, starting at sample index 120 (this means the padded samples appended to the header are copied to both ports!). However, the header demodulator has the option to specify a payload offset, which cannot exceed the padding value. To do this, include a key <code>payload_offset</code> in the message sent back to the HPD. A negative value means the payload starts earlier than otherwise. (If you wanted to always pad the payload, you could set payload_offset to -header_padding and increase the reported length of the payload).
  

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