File Meta Sink: Difference between revisions

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[[Category:Block Docs]]
[[Category:Block Docs]]
[[Category:Stub Docs]]
Write stream to file with meta-data headers.
This is the template for the [[:Category:Block_Docs|"Page-per-block Docs"]].  This first section should describe what the block does and how to use it, using however many paragraphs necessary.  Note that the title of the wiki page should match the block's name in GRC, i.e. the one defined in the block's .grc file.  Look at the [[FFT]] Block for a good example.


As this is a basic template, it's also in the [[:Category:Stub_Docs|"Stub Docs category"]]. Please improve it.
These files represent data as binary information in between meta-data headers. The headers contain information about the type of data and properties of the data in the next segment of samples.
The information includes:
*  rx_rate (double): sample rate of data.
*  rx_time (uint64_t, double): time stamp of first sample in segment.
*  size (uint32_t): item size in bytes.
*  type (::gr_file_types as int32_t): data type.
*  cplx (bool): Is data complex?
*  strt (uint64_t): Starting byte of data in this segment.
*  bytes (uint64_t): Size in bytes of data in this segment.
 
Tags can be sent to the file to update the information, which will create a new header. Headers are found by searching from the first header (at position 0 in the file) and reading where the data segment starts plus the data segment size. Following will either be a new header or EOF.


== Parameters ==
== Parameters ==
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>


; Param 1 (''R'')
; File (''R'')
: Description of parameter, provide any tips or recommended values. Note that the name of the parameter above should match the param's label that shows up in grc (e.g. Sample Rate).
: Name of file to write data to.
 
; Sample Rate
: Sample rate of data. If sample rate will be set by a tag, such as rx_tag from a UHD source, this is basically ignored.
 
; Relative_rate
: Rate chance from source of sample rate tag to sink.
 
; Max Seg. size
: Length of a single segment before the header is repeated (in items).
 
; Extra dict.
: A PMT dictionary of extra information.
 
; Detached header
: Set to true to store the header info in a separate file (named filename.hdr)


; Param 2
; Unbuffered (''R'')
: blah blah blah
: If new samples are flushed to file at the end of each call to the work function


== Example Flowgraph ==
== Example Flowgraph ==
Line 21: Line 45:


; C++ files
; C++ files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/lib/file_sink_impl.cc]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/lib/file_sink_base.cc]


; Header files
; Header files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/lib/file_sink_impl.h]


; Public header files
; Public header files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/include/gnuradio/blocks/file_meta_sink.h]


; Block definition
; Block definition
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-blocks/grc/blocks_file_meta_sink.block.yml]

Revision as of 16:31, 20 August 2019

Write stream to file with meta-data headers.

These files represent data as binary information in between meta-data headers. The headers contain information about the type of data and properties of the data in the next segment of samples. The information includes:

  • rx_rate (double): sample rate of data.
  • rx_time (uint64_t, double): time stamp of first sample in segment.
  • size (uint32_t): item size in bytes.
  • type (::gr_file_types as int32_t): data type.
  • cplx (bool): Is data complex?
  • strt (uint64_t): Starting byte of data in this segment.
  • bytes (uint64_t): Size in bytes of data in this segment.

Tags can be sent to the file to update the information, which will create a new header. Headers are found by searching from the first header (at position 0 in the file) and reading where the data segment starts plus the data segment size. Following will either be a new header or EOF.

Parameters

(R): Run-time adjustable

File (R)
Name of file to write data to.
Sample Rate
Sample rate of data. If sample rate will be set by a tag, such as rx_tag from a UHD source, this is basically ignored.
Relative_rate
Rate chance from source of sample rate tag to sink.
Max Seg. size
Length of a single segment before the header is repeated (in items).
Extra dict.
A PMT dictionary of extra information.
Detached header
Set to true to store the header info in a separate file (named filename.hdr)
Unbuffered (R)
If new samples are flushed to file at the end of each call to the work function

Example Flowgraph

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

Source Files

C++ files
[1]
[2]
Header files
[3]
Public header files
[4]
Block definition
[5]
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