Python works in progress: can currently locate the QR code through a very slow process. Audio is going to prove to be a challenge with the BMPCC onboard mic

.gitignore

@@ -1 +1,4 @@
 *.DS_Store
+py/env
+*.wav
+*.png

py/audio_detect.py

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+import numpy as np
+from scipy.io.wavfile import read, write
+from scipy.signal import butter, filtfilt
+from argparse import ArgumentParser
+import os
+import subprocess
+import tempfile
+from time import strftime, localtime
+
+parser = ArgumentParser(prog='python3 audio_detect.py', description='Example script that uses ffmpeg and bandpass filter to locate audio signature')
+parser.add_argument('video', type=str, help='Video file to analyze')
+args = parser.parse_args()
+
+if not os.path.exists(args.video) :
+    print(f'Video {args.video} does not exist')
+    exit(1)
+
+print(f'Detecting audio signature in {args.video}')
+
+def rm (file) :
+    if os.path.exists(file):
+        os.remove(file)
+
+def bandpass_filter(data, lowcut, highcut, fs, order=5):
+    """Apply a bandpass filter to the audio data."""
+    nyq = 0.5 * fs
+    low = lowcut / nyq
+    high = highcut / nyq
+    b, a = butter(order, [low, high], btype='band')
+    y = filtfilt(b, a, data)
+    return y
+
+def apply_bandpass_to_wav(input_file, output_file, lowcut, highcut, order=5):
+    """Read a WAV file, apply a bandpass filter, and write the result to a new WAV file."""
+    fs, data = read(input_file)
+
+    print(f'Applying {lowcut} -> {highcut} bandpass on {input_file}')
+    if data.ndim == 2:
+        filtered_data = np.zeros_like(data)
+        for channel in range(data.shape[1]):
+            filtered_data[:, channel] = bandpass_filter(data[:, channel], lowcut, highcut, fs, order)
+    else:
+        filtered_data = bandpass_filter(data, lowcut, highcut, fs, order)
+
+    write(output_file, fs, filtered_data.astype(np.int16))
+
+def export_audio (video) :
+    print(f'Exporting audio from {video}...')
+
+    tmp_file, filename = tempfile.mkstemp(suffix='.wav')
+
+    cmd = [
+        'ffmpeg',
+        '-hwaccel', 'auto',
+        '-y',
+        '-i', f'"{video}"',
+        '-vn',
+        '-acodec', 'pcm_s16le',
+        f'"{filename}"'
+    ]
+    
+    proc = subprocess.Popen(' '.join(cmd), stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, shell = True)
+    
+    for line in proc.stdout :
+        #print(line.decode('ascii').strip())
+        a=1
+
+    return filename
+
+audio_file = export_audio(args.video)
+print(audio_file)
+apply_bandpass_to_wav(audio_file, 'extracted.wav', 290, 310)
+
+#rm(audio_file)

py/requirements.txt

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+opencv-python
+numpy
+scipy

py/video_detect.py

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+from argparse import ArgumentParser
+import os
+import subprocess
+import tempfile
+import cv2
+from time import strftime, localtime
+import json
+
+qcd = cv2.QRCodeDetector()
+
+parser = ArgumentParser(prog='python3 video_detect.py', description='Example script that uses ffmpeg, ffprobe and qreader to detect start of slate')
+parser.add_argument('video', type=str, help='Video file to analyze')
+args = parser.parse_args()
+
+if not os.path.exists(args.video) :
+	print(f'Video {args.video} does not exist')
+	exit(1)
+
+print(f'Detecting QR in {args.video}')
+
+def rm (file) :
+	if os.path.exists(file):
+		os.remove(file)
+
+def getFrameCount (video) :
+	count = -1
+	cmd = [ 
+		'ffprobe',
+		'-v', 'error',
+		'-count_frames',
+		'-select_streams', 'v:0',
+		'-show_entries', 'stream=nb_read_frames',
+		'-of', 'default=nokey=1:noprint_wrappers=1', 
+		f'"{video}"'
+	]
+
+	proc = subprocess.Popen(' '.join(cmd), stdout=subprocess.PIPE, shell=True)
+
+	for line in proc.stdout :
+		count = int(line.decode('ascii').strip())
+		break
+
+	#print(' '.join(cmd))
+
+	return count
+
+def exportFrame (video, frame) :
+	epoch = None
+	success = False
+	tmp_file, filename = tempfile.mkstemp(suffix='.png')
+	cmd = [
+		'ffmpeg',
+		'-hwaccel', 'auto',
+		'-y',
+		'-i', f'"{video}"',
+		'-vf', f"select='gte(n\\,{frame})'",
+		'-vframes', '1',
+		'-compression_algo', 'raw',
+		'-pix_fmt', 'rgb24',
+		'-crf', '0',
+		f'"{filename}"'
+	]
+	
+	proc = subprocess.Popen(' '.join(cmd), stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, shell = True)
+	
+	for line in proc.stdout :
+		#print(line.decode('ascii').strip())
+		a=1
+
+	#print(filename)
+
+	img = cv2.cvtColor(cv2.imread(filename), cv2.COLOR_BGR2RGB)
+
+	retval, decoded_info, points, straight_qrcode = qcd.detectAndDecodeMulti(img)
+
+	if not retval or decoded_info == '()' :
+		print(f'[{frame}] No QR detected')
+	else :
+		for qr in decoded_info :
+			if len(qr) == len('9999999999') :
+				print(points)
+				epoch = int(qr)
+				success = True
+
+	rm(filename)
+
+	return success, epoch
+
+count = getFrameCount(args.video)
+
+print(f'Video has {count} frames')
+
+for i in range(1, count):
+	success, epoch = exportFrame(args.video, i)
+	if success :
+		obj = {
+			'frame' : i,
+			'frames' : count,
+			'start_time' : epoch,
+			'time_str' : strftime('%Y-%m-%d %H:%M:%S', localtime(epoch))
+		}
+
+		with open(f'{args.video}.meta.json', 'w') as f :
+			f.write(json.dumps(obj))
+
+		print(json.dumps(obj))
+		break
+
+#${this.bin} -hwaccel auto -y -i "${video}" -vf "select='gte(n\\,${frameNum})'${scale}" -vframes 1 -compression_algo raw -pix_fmt rgb24 -crf 0 "${tmpoutput}"
+
+#ffprobe -v error -count_frames -select_streams v:0 -show_entries stream=nb_read_frames -of default=nokey=1:noprint_wrappers=1 "${video}"
+
+#proc = subprocess.run(cmd, stdout=subprocess.PIPE)
+#for line in proc.stdout :
+#	print(f'[BUILD] {line}')
+