Source code for timeside.plugins.grapher.spectrogram_log

# -*- coding: utf-8 -*-
#
# Copyright (c) 2007-2010 Guillaume Pellerin <yomguy@parisson.com>
# Copyright (c) 2010 Olivier Guilyardi <olivier@samalyse.com>

# This file is part of TimeSide.

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


from timeside.core import implements, interfacedoc
from timeside.core.api import IGrapher
from timeside.core.grapher import Grapher, Image
from timeside.plugins.grapher.color_schemes import default_color_schemes
from . utils import interpolate_colors
import math


class SpectrogramLog(Grapher):

    """Logarithmic scaled spectrogram (level vs. frequency vs. time).

    Adds pixels iteratively thanks to the adapter providing
    fixed size frame buffers."""

    implements(IGrapher)

    @interfacedoc
    def __init__(self, width=1024, height=256, bg_color=(0, 0, 0),
                 color_scheme='default'):
        super(SpectrogramLog, self).__init__(
            width, height, bg_color, color_scheme)
        self.lower_freq = 100
        self.colors = default_color_schemes[color_scheme]['spectrogram']
        self.pixels = []
        self.y_to_bin = []

    @staticmethod
    @interfacedoc
    def id():
        return "spectrogram_log"

    @staticmethod
    @interfacedoc
    def name():
        return "Spectrogram Log"

    @interfacedoc
    def setup(self, channels=None, samplerate=None, blocksize=None,
              totalframes=None):
        super(SpectrogramLog, self).setup(
            channels, samplerate, blocksize, totalframes)
        self.image = self.image.convert("P")
        self.image = self.image.transpose(Image.ROTATE_90)
        self.image.putpalette(interpolate_colors(self.colors, True))
        self.set_scale()

    def set_scale(self):
        """generate the lookup which translates y-coordinate to fft-bin"""

        f_min = float(self.lower_freq)
        f_max = float(self.higher_freq)
        y_min = math.log10(f_min)
        y_max = math.log10(f_max)
        for y in range(self.image_height):
            freq = math.pow(
                10.0, y_min + y / (self.image_height - 1.0) * (y_max - y_min))
            fft_bin = freq / f_max * (self.fft_size / 2 + 1)
            if fft_bin < self.fft_size / 2:
                alpha = fft_bin - int(fft_bin)
                self.y_to_bin.append((int(fft_bin), alpha * 255))

    def draw_spectrum(self, x, spectrum):
        for (index, alpha) in self.y_to_bin:
            self.pixels.append(
                int(((255.0 - alpha) * spectrum[index] + alpha * spectrum[index + 1])))
        for y in range(len(self.y_to_bin), self.image_height):
            self.pixels.append(0)

    @interfacedoc
    def process(self, frames, eod=False):
        if len(frames) != 1:
            chunk = frames[:, 0].copy()
            chunk.shape = (len(chunk), 1)
            for samples, end in self.pixels_adapter.process(chunk, eod):
                if self.pixel_cursor < self.image_width:
                    (spectral_centroid, db_spectrum) = self.spectrum.process(
                        samples, True)
                    self.draw_spectrum(self.pixel_cursor, db_spectrum)
                    self.pixel_cursor += 1
        return frames, eod

    @interfacedoc
    def post_process(self):
        """ Apply last 2D transforms"""
        self.image.putdata(self.pixels)
        self.image = self.image.transpose(Image.ROTATE_90)