Add a small time range around the timestamp when extracting a frame

This should hopefully result in frames on the edge of timestamps being extracted
from a combination of the neighboring segment and the naive one,
so that we don't get errors extracting a frame.

common/common/segments.py

@@ -101,6 +101,13 @@ class ContainsHoles(Exception):
 	"""Raised by get_best_segments() when a hole is found and allow_holes is False"""
 
 
+def get_best_segments_for_frame(hour_path, timestamp):
+	# Add some leeway before and after so that we don't have errors related to
+	# landing on a segment edge.
+	leeway = datetime.timedelta(seconds=1)
+	return get_best_segments(hour_path, timestamp - leeway, timestamp + leeway)
+
+
 @timed(
 	hours_path=lambda ret, hours_path, *args, **kwargs: hours_path,
 	has_holes=lambda ret, *args, **kwargs: None in ret,
@@ -765,19 +772,11 @@ def extract_frame(segments, timestamp):
 	# Remove holes
 	segments = [segment for segment in segments if segment is not None]
 
-	# Find segment containing timestamp
-	segments = [
-		segment for segment in segments
-		if segment.start <= timestamp < segment.end
-	]
 	if not segments:
 		raise ValueError("No data at timestamp within segment list")
-	if len(segments) != 1:
-		raise ValueError("Segment list contains overlap at timestamp")
-	(segment,) = segments
 
 	# "cut" input so that first frame is our target frame
-	cut_start = (timestamp - segment.start).total_seconds()
+	cut_start = (timestamp - segments[0].start).total_seconds()
 
 	ffmpeg = None
 	input_feeder = None

cutter/cutter/main.py

@@ -17,7 +17,7 @@ from psycopg2 import sql
 
 import common
 from common.database import DBManager, query, get_column_placeholder
-from common.segments import get_best_segments, archive_cut_segments, fast_cut_segments, full_cut_segments, smart_cut_segments, extract_frame, ContainsHoles
+from common.segments import get_best_segments, archive_cut_segments, fast_cut_segments, full_cut_segments, smart_cut_segments, extract_frame, ContainsHoles, get_best_segments_for_frame
 from common.images import compose_thumbnail_template
 from common.stats import timed
 
@@ -275,7 +275,7 @@ class Cutter(object):
 		# Also check the thumbnail time if we need to generate it
 		thumbnail_segments = None
 		if candidate.thumbnail_mode in ('BARE', 'TEMPLATE') and candidate.thumbnail_image is None:
-			thumbnail_segments = get_best_segments(hours_path, candidate.thumbnail_time, candidate.thumbnail_time)
+			thumbnail_segments = get_best_segments_for_frame(hours_path, candidate.thumbnail_time, candidate.thumbnail_time)
 			if thumbnail_segments == [None]:
 				raise ContainsHoles
 		return segment_ranges, thumbnail_segments
@@ -762,7 +762,7 @@ class VideoUpdater(object):
 							if thumbnail_image is None:
 								self.logger.info("Regenerating thumbnail for {}".format(job.id))
 								hours_path = os.path.join(self.segments_path, job.video_channel, job.video_quality)
-								segments = get_best_segments(hours_path, job.thumbnail_time, job.thumbnail_time)
+								segments = get_best_segments_for_frame(hours_path, job.thumbnail_time)
 								frame = extract_frame(segments, job.thumbnail_time)
 								frame = b''.join(frame)
 								if job.thumbnail_mode == 'BARE':

restreamer/restreamer/main.py

@@ -17,7 +17,7 @@ from gevent.pywsgi import WSGIServer
 from common import dateutil, get_best_segments, rough_cut_segments, fast_cut_segments, full_cut_segments, PromLogCountsHandler, install_stacksampler, serve_with_graceful_shutdown
 from common.flask_stats import request_stats, after_request
 from common.images import compose_thumbnail_template
-from common.segments import smart_cut_segments, feed_input, render_segments_waveform, extract_frame, list_segment_files
+from common.segments import smart_cut_segments, feed_input, render_segments_waveform, extract_frame, list_segment_files, get_best_segments_for_frame
 from common.chat import get_batch_file_range, merge_messages
 
 from . import generate_hls
@@ -423,7 +423,7 @@ def get_frame(channel, quality):
 	if not os.path.isdir(hours_path):
 		abort(404)
 
-	segments = get_best_segments(hours_path, timestamp, timestamp)
+	segments = get_best_segments_for_frame(hours_path, timestamp)
 	if not any(segment is not None for segment in segments):
 		return "We have no content available within the requested time range.", 406
 
@@ -454,7 +454,7 @@ def get_thumbnail(channel, quality):
 	if not os.path.isdir(hours_path):
 		abort(404)
 
-	segments = get_best_segments(hours_path, timestamp, timestamp)
+	segments = get_best_segments_for_frame(hours_path, timestamp)
 	if not any(segment is not None for segment in segments):
 		return "We have no content available within the requested time range.", 406