Removed incomplete encoder
James Taylor
parent
3b7fec89a5
commit
afdb2e1a82
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@ -2,4 +2,3 @@
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from .command import SSTVCommand
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from .decode import SSTVDecoder
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from .encode import SSTVEncoder
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221
sstv/encode.py
221
sstv/encode.py
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@ -1,221 +0,0 @@
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"""Class and methods to encode SSTV signal"""
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import numpy as np
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from . import spec
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from .common import log_message, progress_bar
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def calc_freq(lum):
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"""Converts 0-255 luminance byte into SSTV pixel frequency range"""
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freq = (lum * 3.1372549) + 1500
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return min(max(freq, 1500), 2300)
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class SSTVEncoder(object):
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"""Create an SSTV encoder that will encode a PIL image"""
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def __init__(self, image, mode=spec.S2):
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self.mode = mode
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self._sample_rate = 44100
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self._orig_image = image
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self._sig_phase = 0
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def encode(self):
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"""Encodes image data into SSTV audio signal"""
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log_message("Encoding SSTV image with mode {}".format(self.mode.NAME))
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header = np.append(self.encode_header(), self.encode_vis())
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image_data = self.create_image_data()
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full_audio = np.append(header, self.encode_image_data(image_data))
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log_message("Done!")
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return full_audio, self._sample_rate
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def freq_to_samples(self, freq, length):
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"""Creates an array of samples using a sine wave of given frequency"""
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sample_count = round(length * self._sample_rate)
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time_space = np.linspace(0, length, sample_count, endpoint=False)
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mult = freq * 2 * np.pi
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data = np.array(np.sin(time_space * mult + self._sig_phase),
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dtype=np.float64)
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self._sig_phase += length * mult
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return data
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def add_tone_data(self, data, point, freq, length):
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"""Adds sample data of given freq to array at specified point"""
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sig = self.freq_to_samples(freq, length)
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data[point:point+len(sig)] = sig
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def encode_header(self):
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"""Returns audio data of the SSTV header"""
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return np.concatenate((self.freq_to_samples(1900, 0.300),
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self.freq_to_samples(1200, 0.010),
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self.freq_to_samples(1900, 0.300)))
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def encode_vis(self):
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"""Encodes the VIS code into the correct frequencies"""
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vis_value = None
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for vis, mode in spec.VIS_MAP.items():
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if mode == self.mode:
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vis_value = vis
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if vis_value is None:
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raise ValueError("No vis code for mode: {}".format(self.mode.NAME))
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vis_bits = []
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for bit_idx in range(7):
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vis_bits.append((vis_value >> bit_idx) & 0x01)
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# Add even parity bit
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parity = sum(vis_bits) % 2
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vis_bits.append(parity)
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data = self.freq_to_samples(1200, 0.030)
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for bit in vis_bits:
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freq = 1100 if bit else 1300
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data = np.append(data, self.freq_to_samples(freq, 0.030))
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data = np.append(data, self.freq_to_samples(1200, 0.030))
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return data
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def create_image_data(self):
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"""Transforms image data into correct format to be encoded"""
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log_message("Formatting image")
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width = self.mode.LINE_WIDTH
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height = self.mode.LINE_COUNT
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channels = self.mode.CHAN_COUNT
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image = self._orig_image.resize((width, height))
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if self.mode.COLOR == spec.COL_FMT.YUV:
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image = image.convert("YCbCr")
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elif image.mode != "RGB":
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image = image.convert("RGB")
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pixel_data = image.load()
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image_data = []
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for y in range(height):
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image_data.append([])
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for x in range(width):
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if channels == 2:
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if self.mode.HAS_ALT_SCAN:
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if self.mode.COLOR == spec.COL_FMT.YUV:
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if y % 2 == 0:
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ry = round((pixel_data[x, y][2]
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+ pixel_data[x, y + 1][2]) / 2)
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pixel = (pixel_data[x, y][0],
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ry)
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else:
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by = round((pixel_data[x, y][1]
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+ pixel_data[x, y - 1][1]) / 2)
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pixel = (pixel_data[x, y][0],
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by)
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elif channels == 3:
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if self.mode.COLOR == spec.COL_FMT.GBR:
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pixel = (pixel_data[x, y][1],
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pixel_data[x, y][2],
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pixel_data[x, y][0])
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elif self.mode.COLOR == spec.COL_FMT.YUV:
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pixel = (pixel_data[x, y][0],
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pixel_data[x, y][2],
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pixel_data[x, y][1])
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elif self.mode.COLOR == spec.COL_FMT.RGB:
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pixel = pixel_data[x, y]
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image_data[y].append(pixel)
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return image_data
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def encode_image_data(self, image_data):
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"""Encodes the actual image data into array of samples"""
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sync_length = round(self.mode.SYNC_PULSE * self._sample_rate)
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porch_length = round(self.mode.SYNC_PORCH * self._sample_rate)
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sep_length = round(self.mode.SEP_PULSE * self._sample_rate)
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total_time = round(self.mode.LINE_TIME * self.mode.LINE_COUNT
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* self._sample_rate * 1.05)
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total_time += sync_length if self.mode.HAS_START_SYNC else 0
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data = np.zeros(total_time)
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height = self.mode.LINE_COUNT
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channels = self.mode.CHAN_COUNT
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width = self.mode.LINE_WIDTH
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data_ptr = 0
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if self.mode.HAS_START_SYNC:
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self.add_tone_data(data, data_ptr, 1200,
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self.mode.SYNC_PULSE)
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data_ptr += sync_length
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for line in range(height):
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for chan in range(channels):
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if chan == self.mode.CHAN_SYNC:
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self.add_tone_data(data, data_ptr, 1200,
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self.mode.SYNC_PULSE)
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data_ptr += sync_length
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SYNC_PORCH)
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data_ptr += porch_length
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elif self.mode.CHAN_SYNC > 0:
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SEP_PULSE)
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data_ptr += sep_length
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pixel_time = self.mode.PIXEL_TIME
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if self.mode.HAS_HALF_SCAN and chan > 0:
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pixel_time = self.mode.HALF_PIXEL_TIME
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last_px_end = data_ptr
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for px in range(width):
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px_pos = last_px_end
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last_px_end = data_ptr + round((px + 1) * pixel_time
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* self._sample_rate)
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px_size = (last_px_end - px_pos) / self._sample_rate
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freq = calc_freq(image_data[line][px][chan])
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self.add_tone_data(data, px_pos, freq, px_size)
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data_ptr = last_px_end # end of last pixel
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if self.mode.CHAN_SYNC == 0:
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if self.mode.HAS_ALT_SCAN and chan == 0:
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if line % 2 == 0:
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SEP_PULSE)
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else:
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self.add_tone_data(data, data_ptr, 2300,
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self.mode.SEP_PULSE)
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data_ptr += sep_length
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self.add_tone_data(data, data_ptr, 1900,
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self.mode.SEP_PORCH)
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data_ptr += round(self.mode.SEP_PORCH *
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self._sample_rate)
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elif self.mode.HAS_HALF_SCAN:
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if chan == 0:
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SEP_PULSE)
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data_ptr += sep_length
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self.add_tone_data(data, data_ptr, 1900,
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self.mode.SEP_PORCH)
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data_ptr += round(self.mode.SEP_PORCH *
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self._sample_rate)
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elif chan == 1:
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self.add_tone_data(data, data_ptr, 2300,
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self.mode.SEP_PULSE)
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data_ptr += sep_length
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SEP_PORCH)
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data_ptr += round(self.mode.SEP_PORCH *
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self._sample_rate)
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else:
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self.add_tone_data(data, data_ptr, 1500,
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self.mode.SEP_PULSE)
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data_ptr += sep_length
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progress_bar(line, height - 1, "Encoding image data...")
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return data
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