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Merge branch 'master' into 'master' 

Do not read every single float to locate last fully pixeled line

See merge request librespacefoundation/satnogs/gr-satnogs!112
This commit is contained in:
Manolis Surligas 2017-10-01 19:48:47 +00:00
parent ae1e331228 d3186fcad2
commit 5a9e479add
1 changed files with 6 additions and 10 deletions
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16
apps/scripts/satnogs_waterfall.gp
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@ -38,19 +38,15 @@ if (!exists("outfile")) outfile='/tmp/waterfall.png'
set terminal unknown
# Read the first float to get the FFT size
# Then, read until the last float to get the number of floats written in the file.
# For strange reasons the STATS_records returns inconcistent size (always the half)
plot inputfile binary format='%float32' index 0 every 1:1:0:0:0:0 u (fft_size=$1):1, "" binary format='%float32' using (float_num=$0+1)
# The file contains a float specifying the FFT size the x-axis scale
# and then each each pixel line
# starts with the time in seconds from the beginning of the capture.
# Based on this info the exact number of the fully filled pixel lines can
# be retrieved.
pixel_lines=int((float_num - fft_size - 1)/(fft_size + 1))
new_size=(4 + fft_size*4 + ( (fft_size+1)*pixel_lines)*4)
cmd = sprintf("truncate -s %u %s", new_size, inputfile)
# Then, read until the last float of a fully filled pixel line to get the number
# of floats that should be in the file.
# For strange reasons the STATS_records returns inconcistent size (always the half)
plot inputfile binary format='%float32' index 0 every ::0:0:0:0 using (fft_size = $1), \
"" binary format='%float32' every fft_size + 1::fft_size using (float_num = $0 + 1)
cmd = sprintf("truncate -s %u %s", float_num * 4, inputfile)
# Truncate properly the file
system(cmd)