43 lines
1.4 KiB
Plaintext
43 lines
1.4 KiB
Plaintext
SSDV - simple command line app for encoding / decoding SSDV image data
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Created by Philip Heron <phil@sanslogic.co.uk>
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http://www.sanslogic.co.uk/ssdv/
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A robust packetised version of the JPEG image format.
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Uses the Reed-Solomon codec written by Phil Karn, KA9Q.
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ENCODING
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$ ssdv -e -c CALLSIGN -i ID input.jpeg output.bin
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This encodes the 'input.jpeg' image file into SSDV packets stored in the 'output.bin' file. CALLSIGN (an alphanumeric string up to 6 characters) and ID (a number from 0-255) are encoded into the header of each packet. The ID should be changed for each new image transmitted to allow the decoder to identify when a new image begins.
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The output file contains a series of SSDV packets, each packet always being 256 bytes in length. Additional data may be transmitted between each packet, the decoder will ignore this.
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DECODING
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$ ssdv -d input.bin output.jpeg
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This decodes a file 'input.bin' containing a series of SSDV packets into the JPEG file 'output.jpeg'.
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LIMITATIONS
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Only JPEG files are supported, with the following limitations:
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- YUV/YCbCr colour format
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- Width and height must be a multiple of 16 (up to a resolution of 4080 x 4080)
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- Baseline DCT only
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- The total number of MCU blocks must not exceed 65535
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INSTALLING
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make
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TODO
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* Allow the decoder to handle multiple images in the input stream.
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* Experiment with adaptive or multiple huffman tables.
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* Quality setting (4 bit / 16 quality levels).
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