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@@ -1,4 +1,91 @@ ODR-PadEnc ========== -ODR-PadEnc is an encoder for Programme Associated Data. +ODR-PadEnc is an encoder for Programme Associated Data, and includes support +for DAB MOT Slideshow and DLS. + +To encode DLS and Slideshow data, the *odr-padenc* tool reads images +from a folder and DLS text from a file, and generates the PAD data +for the encoder. + +For detailed usage, see the usage screen of the tool with the *-h* option. + +More information is available on the +[Opendigitalradio wiki](http://opendigitalradio.org) + +How to build +============= + +Requirements: + +* A C++11 compiler +* ImageMagick magickwand (optional, for MOT slideshow) + +This package: + + ./bootstrap + ./configure + make + sudo make install + +Usage of MOT Slideshow and DLS +============================== + +*odr-padenc* reads images from the specified folder, and generates the PAD +data for the encoder. This is communicated through a fifo to the encoder. It +also reads DLS from a file, and includes this information in the PAD. + +If ImageMagick is available +--------------------------- +It can read all file formats supported by ImageMagick, and by default resizes +them to 320x240 pixels, and compresses them as JPEG. If the input file is already +a JPEG file of the correct size, and smaller than 50kB, it is sent without further +compression. If the input file is a PNG that satisfies the same criteria, it is +transmitted as PNG without any recompression. + +RAW Format +---------- +If ImageMagick is not compiled in, or when enabled with the -R option, the images +are not modified, and are transmitted as-is. Use this if you can guarantee that +the generated files are smaller than 50kB and not larger than 320x240 pixels. + +Supported Encoders +------------------ +*odr-audioenc* can insert the PAD data from *odr-padenc* into the bitstream. +The mp2 encoder [Toolame-DAB](https://github.com/Opendigitalradio/toolame-dab) +can also read *odr-padenc* data. + +This is an ongoing development. Make sure you use the same pad length option +for *odr-padenc* and the audio encoder. Only some pad lengths are supported, +please see *odr-padenc*'s help. + +Character Sets +-------------- +When *odr-padenc* is launched with the default character set options, it assumes +that the DLS text in the file is encoded in UTF-8, and will convert it according to +the DAB standard to the *Complete EBU Latin based repertoire* character set encoding. + +If you set the character set encoding to any other setting (except +*Complete EBU Latin based repertoire* which needs no conversion), +*odr-padenc* will abort, as it does not support any other conversion than from +UTF-8 to *Complete EBU Latin based repertoire*. + +You can however use the -C option to transmit the untouched DLS text. In this +case, it is your responsibility to ensure the encoding is valid. For instance, +if your data is already encoded in *Complete EBU Latin based repertoire*, you +must specify both --charset=0 and --raw-dls. + +Known Limitations +================= +*odr-padenc* encodes slides in a 10 second interval, which is not linked +to the rate at which the encoder reads the PAD data. It also doesn't prioritise +DLS transmission over Slides. + +Some receivers are unable to decode slides larger than some size, even within the allowed +size limit given in the specification. + +Thanks +====== + +This encoder was initially called *mot-encoder* and has been contributed by +[CSP](http://rd.csp.it). |