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Module images2avi
Uses ffmpeg to read and write AVI files. Requires PIL
I found these sites useful: http://www.catswhocode.com/blog/19-ffmpeg-commands-for-all-needs http://linux.die.net/man/1/ffmpeg
Read images from an AVI (or MPG) movie.
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Export movie to a AVI file, which is encoded with the given encoding. Hint for Windows users: the ‘msmpeg4v2’ codec is natively supported on Windows.
Images should be a list consisting of PIL images or numpy arrays. The latter should be between 0 and 255 for integer types, and between 0 and 1 for float types.
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Module images2gif
Provides functionality for reading and writing animated GIF images. Use writeGif to write a series of numpy arrays or PIL images as an animated GIF. Use readGif to read an animated gif as a series of numpy arrays.
Note that since July 2004, all patents on the LZW compression patent have expired. Therefore the GIF format may now be used freely.
Acknowledgements:
Many thanks to Ant1 for:
Many thanks to Marius van Voorden for porting the NeuQuant quantization algorithm of Anthony Dekker to Python (See the NeuQuant class for its license).
Many thanks to Alex Robinson for implementing the concept of subrectangles, which (depening on image content) can give a very significant reduction in file size.
This code is based on gifmaker (in the scripts folder of the source distribution of PIL)
Useful links:
Class that contains methods for helping write the animated GIF file.
Convert images to Paletted PIL images, which can then be written to a single animaged GIF.
Application extension. This part specifies the amount of loops. If loops is 0 or inf, it goes on infinitely.
Parameters: | loops (float) – |
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Graphics Control Extension. A sort of header at the start of each image. Specifies duration and transparency.
Dispose:
- 0 - No disposal specified.
- 1 - Do not dispose. The graphic is to be left in place.
- 2 - Restore to background color. The area used by the graphic must be restored to the background color.
- 3 - Restore to previous. The decoder is required to restore the area overwritten by the graphic with what was there prior to rendering the graphic.
- 4-7 -To be defined.
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Used for the local color table properties per image. Otherwise global color table applies to all frames irrespective of whether additional colors comes in play that require a redefined palette. Still a maximum of 256 color per frame, obviously.
Written by Ant1 on 2010-08-22 Modified by Alex Robinson in Janurari 2011 to implement subrectangles.
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Calculate the minimal rectangles that need updating each frame. Returns a two-element tuple containing the cropped images and a list of x-y positions.
Calculating the subrectangles takes extra time, obviously. However, if the image sizes were reduced, the actual writing of the GIF goes faster. In some cases applying this method produces a GIF faster.
Handle the sub-rectangle stuff. If the rectangles are given by the user, the values are checked. Otherwise the subrectangles are calculated automatically.
Given a set of images writes the bytes to the specified stream. Requires different handling of palette for PIL and Pillow: based on https://github.com/rec/echomesh/blob/master/ code/python/external/images2gif.py
NeuQuant(image, samplefac=10, colors=256)
samplefac should be an integer number of 1 or higher, 1 being the highest quality, but the slowest performance. With avalue of 10, one tenth of all pixels are used during training. This value seems a nice tradeof between speed and quality.
colors is the amount of colors to reduce the image to. This should best be a power of two.
See also: http://members.ozemail.com.au/~dekker/NEUQUANT.HTML
License of the NeuQuant Neural-Net Quantization Algorithm
Copyright (c) 1994 Anthony Dekker Ported to python by Marius van Voorden in 2010
NEUQUANT Neural-Net quantization algorithm by Anthony Dekker, 1994. See “Kohonen neural networks for optimal colour quantization” in “network: Computation in Neural Systems” Vol. 5 (1994) pp 351-367. for a discussion of the algorithm. See also http://members.ozemail.com.au/~dekker/NEUQUANT.HTML
Any party obtaining a copy of these files from the author, directly or indirectly, is granted, free of charge, a full and unrestricted irrevocable, world-wide, paid up, royalty-free, nonexclusive right and license to deal in this software and documentation files (the “Software”), including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons who receive copies from any such party to do so, with the only requirement being that this copyright notice remain intact.
Search for biased BGR values Finds closest neuron (min dist) and updates self.freq finds best neuron (min dist-self.bias) and returns position for frequently chosen neurons, self.freq[i] is high and self.bias[i] is negative self.bias[i] = self.GAMMA * ((1/self.NETSIZE)-self.freq[i])
PIL weird interface for making a paletted image: create an image which already has the palette, and use that in Image.quantize. This function returns this palette image.
Use a kdtree to quickly find the closest palette colors for the pixels
Parameters: | image – |
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” This function can be used if no scipy is available. It’s 7 times slower though.
Parameters: | image – |
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Check numpy images and correct intensity range etc. The same for all movie formats.
Parameters: | images – |
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Read images from an animated GIF file. Returns a list of numpy arrays, or, if asNumpy is false, a list if PIL images.
Write an animated gif from the specified images. Depending on which PIL library is used, either writeGifVisvis or writeGifPillow is used here.
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Write an animated gif from the specified images. Uses native Pillow implementation, which is available since Pillow 3.4.0.
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Write an animated gif from the specified images. Uses VisVis implementation. Unfortunately it produces corrupted GIF with Pillow >= 3.4.0.
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Module images2ims
Use PIL to create a series of images.
Check numpy images and correct intensity range etc. The same for all movie formats.
Parameters: | images – |
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Read images from a series of images in a single directory. Returns a list of numpy arrays, or, if asNumpy is false, a list if PIL images.
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Export movie to a series of image files. If the filenenumber contains an asterix, a sequence number is introduced at its location. Otherwise the sequence number is introduced right before the final dot.
To enable easy creation of a new directory with image files, it is made sure that the full path exists.
Images should be a list consisting of PIL images or numpy arrays. The latter should be between 0 and 255 for integer types, and between 0 and 1 for float types.
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Module images2swf
Provides a function (writeSwf) to store a series of PIL images or numpy arrays in an SWF movie, that can be played on a wide range of OS’s.
This module came into being because I wanted to store a series of images in a movie that can be viewed by other people, and which I can embed in flash presentations. For writing AVI or MPEG you really need a c/c++ library, and although the filesize is then very small, the quality is sometimes not adequate. Besides I’d like to be independent of yet another package. I tried writing animated gif using PIL (which is widely available), but the quality is so poor because it only allows for 256 different colors. [EDIT: thanks to Ant1, now the quality of animated gif isn’t so bad!] I also looked into MNG and APNG, two standards similar to the PNG stanard. Both standards promise exactly what I need. However, hardly any application can read those formats, and I cannot import them in flash.
Therefore I decided to check out the swf file format, which is very well documented. This is the result: a pure python module to create an SWF file that shows a series of images. The images are stored using the DEFLATE algorithm (same as PNG and ZIP and which is included in the standard Python distribution). As this compression algorithm is much more effective than that used in GIF images, we obtain better quality (24 bit colors + alpha channel) while still producesing smaller files (a test showed ~75%). Although SWF also allows for JPEG compression, doing so would probably require a third party library (because encoding JPEG is much harder).
This module requires Python 2.x and numpy.
sources and tools:
Dynamic array of bits that automatically resizes with factors of two. Append bits using .Append() or += You can reverse bits using .Reverse()
Bases: imaging.images2swf.Tag
Bases: imaging.images2swf.Tag
Bases: imaging.images2swf.Tag
Bases: imaging.images2swf.ControlTag
Set the color in 0-255, or 0-1 (if floats given).
Give the given file (as bytes) a header.
Check numpy images and correct intensity range etc. The same for all movie formats.
Given a few (signed) numbers, convert them to bits, stored as FB (float bit values). We always use 16.16. Negative numbers are not (yet) possible, because I don’t know how the’re implemented (ambiguity).
bb should be 6 bytes at least Return (type, length, length_of_full_tag)
convert int to a string of bits (0’s and 1’s in a string), pad to n elements. Convert back using int(ss,2).
Read all images from an SWF (shockwave flash) file. Returns a list of numpy arrays, or, if asNumpy is false, a list if PIL images.
Limitation: only read the PNG encoded images (not the JPG encoded ones).
convert signed int to a string of bits (0’s and 1’s in a string), pad to n elements. Negative numbers are stored in 2’s complement bit patterns, thus positive numbers always start with a 0.
Given a few (signed) numbers, store them as compactly as possible in the wat specifief by the swf format. The numbers are multiplied by 20, assuming they are twits. Can be used to make the RECT record.
Write an swf-file from the specified images. If repeat is False, the movie is finished with a stop action. Duration may also be a list with durations for each frame (note that the duration for each frame is always an integer amount of the minimum duration.)
Images should be a list consisting of PIL images or numpy arrays. The latter should be between 0 and 255 for integer types, and between 0 and 1 for float types.
Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8. Go directly to the new manual page here
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