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byte swapping 32-bit float and weird od results
Post 302317361 by GoDonkeys on Monday 18th of May 2009 08:57:09 PM
05-18-2009
byte swapping 32-bit float and weird od results
I'm attempting to read a file that is composed of complex 32-bit floating point values on Solaris 10 that came from a 64-bit Red Hat computer.
When I first tried reading the file, it looked like there was a byte-swapping problem and after running the od command on the file Solaris and Red Hat computers, I saw that they were indeed swapped (every other byte). So, I wrote a little Java program that would swap every other byte and the result was the at the byte-level, the files were the same on both computers. The following is the result of running 'od -x' on the file, showing the first 32-bits which represent the real portion of the first complex number:
f8a6 be03 cd76 bc99
What's weird is that when I run 'od -f' on both computers to see the 32-bit floating point value, I get different results! On the Red Hat computer I get: -1.288782e-01 and on the Solaris computer I get: -2.7055474e+34
. How can I have the same byte level file yet come up with completely different values when I try to print out the bytes as 32-bit floats?
This is really messing me up trying to write a C++ program to read this file on the Solaris computer. I'm getting the same value in my C++ code as what I see when I run 'od -f' on the Solaris computer. I've tried just about everything that I can think of and haven't been able to get past this.
Does anyone have any idea on what's going on with the od command between the Red Hat and Solaris computers? Any ideas on how to get my C++ code to give me the correct value for the 32-bit float?
When I first tried reading the file, it looked like there was a byte-swapping problem and after running the od command on the file Solaris and Red Hat computers, I saw that they were indeed swapped (every other byte). So, I wrote a little Java program that would swap every other byte and the result was the at the byte-level, the files were the same on both computers. The following is the result of running 'od -x' on the file, showing the first 32-bits which represent the real portion of the first complex number:
f8a6 be03 cd76 bc99
What's weird is that when I run 'od -f' on both computers to see the 32-bit floating point value, I get different results! On the Red Hat computer I get: -1.288782e-01 and on the Solaris computer I get: -2.7055474e+34
. How can I have the same byte level file yet come up with completely different values when I try to print out the bytes as 32-bit floats?This is really messing me up trying to write a C++ program to read this file on the Solaris computer. I'm getting the same value in my C++ code as what I see when I run 'od -f' on the Solaris computer. I've tried just about everything that I can think of and haven't been able to get past this.
Does anyone have any idea on what's going on with the od command between the Red Hat and Solaris computers? Any ideas on how to get my C++ code to give me the correct value for the 32-bit float?
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LEARN ABOUT DEBIAN
jack-stdout
JACK-STDOUT(1) General Commands Manual JACK-STDOUT(1) NAME
jack-stdout - write JACK audio data to stdout SYNOPSIS
jack-stdout [OPTIONS] port1 [ port2 ...] DESCRIPTION
jack-stdout captures audio from JACK and writes raw data to standard-output. The number of given ports detemine the number of audio channels that are used. If more than one channel is given, the audio-sample data will be interleaved. OPTIONS
-b, --bitdepth BITS Specify the bit-depth of each sample. For integer-encoding this can be 16 or 24. The default is 16. This setting is only used for integer encoding: Floating-point samples will always be 32 bit wide. -d, --duration SEC Specify the time for which jack-stdout should run in seconds. A value less than 1 means to run indefinitely. The default is 0. -e, --encoding FORMAT Set the output format of the data: signed-integer, unsigned-integer, floating-point (default: signed) -h, --help Print a brief usage information -L, --little-endian Write little-endian data or native-byte-order float (this is the default) -B, --big-endian Output big-endian data or swap the byte-order of floating-point -q, --quiet Inhibit usual output. This affects information and buffer-overflow warnings but not setup-errors. -S, --bufsize SAMPLES Choose the internal buffer-size in samples. The default size is 65536. The given value will be multiplied by the number of channels and bit-depth to get the size of the ring-buffer. EXAMPLES
jack-stdout xmms_0:out_1 xmms_0:out_2 | mono ~/Desktop/Downloads/JustePort.exe - 10.0.1.6 0 jack-stdout -b 24 -e unsigned -B system:capture_1 system:capture_2 | sox -t raw -r 48k -e unsigned -b 24 -B -c 2 - /tmp/recording.wav jack-stdout system:capture_1 system:capture_2 | oggenc -r -R 48000 -B 16 -C 2 - > /tmp/recording.ogg jack-stdout system:capture_1 | oggenc -r -R 48000 -B 16 -C 1 - | oggfwd -p -n "my live stream" localhost 5900 hackme live.ogg AUTHOR
Robin Gareus <robin@gareus.org>. SEE ALSO
http://jackaudio.org/, 29 March 2011 JACK-STDOUT(1)