Basic Options¶

-i name, --image-name=name

Compress the named images, not Standard Input. If name is -, read Standard Input. name has to be either an image filename or a template of the form:

prefix[start-end{+,-}step]suffix
    

Templates are useful when compressing video streams: e.g., if you specify the template img0[12-01-2].pgm, then pnmtofiasco compresses the images img012.pgm, img010.pgm, ..., img002.pgm.

If name is a relative path, pnmtofiasco searches for the image files in the current directory and in the (colon-separated) list of directories given by the environment variable FIASCO_IMAGES.

-o output-file, --output-name=name

Write FIASCO output to the named file, not to Standard Output.

If name is a relative path and the environment variable FIASCO_DATA is a (colon-separated) list of directories, then pnmtofiasco writes the output file to the first (writable) directory of this list. Otherwise, pnmtofiasco write it to the current directory.

-q N, --quality=N

Set quality of compression to N. Quality is 1 (worst) to 100 (best); default is 20.

-v, --version

Print pnmtofiasco version number, then exit.

-V N, --verbose N

Set level of verbosity to N. Level is 0 (no output at all), 1 (show progress meter), or 2 (show detailed compression statistics); default is 1.

-B N, --progress-meter N

Set type of progress-meter to N. The following types are available; default is 1:

0

no progress meter

1

RPM style progress bar using 50 hash marks

2

percentage meter

-f name, --config=name

Load parameter file name to initialize the options of pnmtofiasco. See file system.fiascorc for an example of the syntax. Options of pnmtofiasco are set by any of the following methods (in the specified order):

• Global resource file /etc/system.fiascorc
• $HOME/.fiascorc
• command line
• --config=name

-h, --info

Print brief help, then exit.

-H, --help

Print detailed help, then exit.

Options for Advanced Users¶

-b name, --basis-name=name

Preload compression basis name into FIASCO. The basis name provides the initial compression dictionary. Either use one of the files "small.fco", "medium.fco", or "large.fco" that come with pnmtofiasco or create a new ASCII basis file.

-z N, --optimize=N

Set optimization level to N. Level is 0 (fastest) to 3 (slowest); default is 1. Be warned, the encoding time dramatically increased when N=2 or N=3 while the compression performance only slightly improves.

-P, --prediction

Use additional predictive coding. If this optimization is enabled then the image is compressed in two steps. In the first step, a coarse approximation of the image is computed using large unichrome blocks. Finally, the delta image is computed and the prediction error is approximated using the standard FIASCO algorithm.

-D N, --dictionary-size=N

Set size of dictionary that is used when coding the luminance band to N; default is 10000, i.e., the dictionary is not restricted.

-C N, --chroma-dictionary=N

Set size of dictionary that is used when coding chroma bands to N; default is 40.

-Q N, --chroma-qfactor=N

Reduce the quality of chroma band compression N-times with respect to the user defined quality q of the luminance band compression (--quality=q); default is 2.

-t N, --tiling-exponent=N

Subdivide the image into 2^N tiles prior coding; default is 4, i.e. the image is subdivided into 16 tiles. The processing order of the individual tiles is defined by the option --tiling-method=name.

-T name, --tiling-method=name

Order the individual image tiles (the image is subdivided into; see option --tiling-exponent=N) by method name; default is desc-variance.

desc-variance

Tiles with small variances are processed first.

asc-variance

Tiles with large variances are processed first.

desc-spiral

Tiles are process in spiral order starting in the middle.

asc-spiral

Tiles are process in spiral order starting at the border.

--rpf-mantissa=N

Use N mantissa bits for quantized coefficients.

--dc-rpf-mantissa=N

Use N mantissa bits for quantized DC coefficients.

--rpf-range=N

Coefficients outside the quantization interval [-N,+N] are set to zero.

--dc-rpf-range=N

DC coefficients outside the quantization interval [-N,+N] are set to zero.

Additional Options for Video Compression¶

-s N, --smooth=N

Smooth decompressed reference frames along the partitioning borders by the given amount N. N is 0 (no smoothing) to 100; default is 70. This factor is stored in the FIASCO file.

-m N, --min-level=N

Start prediction (motion compensated prediction or additional prediction) on block level N; default is level 6. I.e., motion compensation is applied to all image blocks of at least 8x8 pixels (binary tree level N=6), 16x8 (N=7), 16x16 (N=8), etc.

-M N, --max-level=N

Stop prediction (motion compensated prediction or additional prediction) on block level N; default is level 10. I.e., motion compensation is applied to all image blocks of at most 16x16 pixels (N=8), 32x16 (N=9), 32x32 (N=10), etc.

-2, --half-pixel

Use half pixel precise motion compensation.

-F N, --fps=N

Set number of frames per second to N. This value is stored in the FIASCO output file and is used in the decoder fiascotopnm(1) to control the framerate.

-p type, --pattern=type

Defines the type of inter frame compression which should be applied to individual frames of a video stream. type is a sequence of characters; default is "IPPPPPPPPP". Element N defines the type of predicting which should be used for frame N; the frame type pattern is periodically extended. Valid characters are:

I

intra frame, i.e., no motion compensated prediction is used at all.

P

predicted frame, i.e., a previously encoded frame is used for prediction (forward prediction).

B

bidirectional predicted frame, i.e., not only a previously shown frame but also a frame of the future is used for prediction (forward, backward or interpolated prediction).

--cross-B-search

Instead of using exhaustive search the "Cross-B-Search" algorithm is used to find the best interpolated prediction of B-frames.

--B-as-past-ref

Also use previously encoded B-frames when prediction the current frame. If this option is not set, only I- and P-frames are used to predict the current frame.