Source code for imaging.images2avi

#   Copyright (C) 2012, Almar Klein
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#   This code is subject to the (new) BSD license:
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# changes of this file GRASS (PNG instead of JPG) by Anna Petrasova 2013

""" 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

"""

import os
import time
import subprocess
import shutil
from grass.imaging import images2ims


def _cleanDir(tempDir):
    for i in range(3):
        try:
            shutil.rmtree(tempDir)
        except Exception:
            time.sleep(0.2)  # Give OS time to free sources
        else:
            break
    else:
        print("Oops, could not fully clean up temporary files.")


def writeAvi(filename, images, duration=0.1, encoding='mpeg4',
             inputOptions='', outputOptions=''):
    """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.

    Requires the "ffmpeg" application:
      * Most linux users can install using their package manager
      * There is a windows installer on the visvis website

    :param str filename: output filename
    :param images:
    :param float duration:
    :param str encoding: the encoding type
    :param inputOptions:
    :param outputOptions:
    """

    # Get fps
    try:
        fps = float(1.0/duration)
    except Exception:
        raise ValueError("Invalid duration parameter for writeAvi.")

    # Determine temp dir and create images
    tempDir = os.path.join(os.path.expanduser('~'), '.tempIms')
    images2ims.writeIms(os.path.join(tempDir, 'im*.png'), images)

    # Determine formatter
    N = len(images)
    formatter = '%04d'
    if N < 10:
        formatter = '%d'
    elif N < 100:
        formatter = '%02d'
    elif N < 1000:
        formatter = '%03d'

    # Compile command to create avi
    command = "ffmpeg -r %i %s " % (int(fps), inputOptions)
    command += "-i im%s.png " % (formatter,)
    command += "-g 1 -vcodec %s %s " % (encoding, outputOptions)
    command += "output.avi"

    # Run ffmpeg
    S = subprocess.Popen(command, shell=True, cwd=tempDir,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    # Show what ffmpeg has to say
    outPut = S.stdout.read()

    if S.wait():
        # An error occurred, show
        print(outPut)
        print(S.stderr.read())
        # Clean up
        _cleanDir(tempDir)
        raise RuntimeError("Could not write avi.")
    else:
        # Copy avi
        shutil.copy(os.path.join(tempDir, 'output.avi'), filename)
        # Clean up
        _cleanDir(tempDir)


def readAvi(filename, asNumpy=True):
    """Read images from an AVI (or MPG) movie.

    Requires the "ffmpeg" application:
      * Most linux users can install using their package manager
      * There is a windows installer on the visvis website

    :param str filename: name of input movie file
    :param bool asNumpy:
    """

    # Check whether it exists
    if not os.path.isfile(filename):
        raise IOError('File not found: '+str(filename))

    # Determine temp dir, make sure it exists
    tempDir = os.path.join(os.path.expanduser('~'), '.tempIms')
    if not os.path.isdir(tempDir):
        os.makedirs(tempDir)

    # Copy movie there
    shutil.copy(filename, os.path.join(tempDir, 'input.avi'))

    # Run ffmpeg
    command = "ffmpeg -i input.avi im%d.jpg"
    S = subprocess.Popen(command, shell=True, cwd=tempDir,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    # Show what mencodec has to say
    outPut = S.stdout.read()

    if S.wait():
        # An error occurred, show
        print(outPut)
        print(S.stderr.read())
        # Clean up
        _cleanDir(tempDir)
        raise RuntimeError("Could not read avi.")
    else:
        # Read images
        images = images2ims.readIms(os.path.join(tempDir, 'im*.jpg'), asNumpy)
        # Clean up
        _cleanDir(tempDir)

    # Done
    return images