blackicedbear/devine
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fix(Subtitle): Correct timestamps when merging fragmented WebVTT

Browse Source 
This applies the X-TIMESTAMP-MAP data to timestamps as it reads through a concatenated (merged) WebVTT file to correct timestamps on segmented WebVTT streams. It then removes the X-TIMESTAMP-MAP header.

The timescale and segment duration information is saved in the Subtitle's data dictionary under the hls/dash key: timescale (dash-only) and segment_durations. Note that this information will only be available post-download.

This is done regardless if you are converting to another subtitle or not, since the downloader automatically and forcefully concatenated the segmented subtitle data. We do not support the use of segmented Subtitles for downloading or otherwise, nor do we plan to.
This commit is contained in:
Shivelight
2023-11-17 11:27:34 +08:00
committed by rlaphoenix
parent af95ba062a
commit 0ba45decc6
4 changed files with 255 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
devine/core/manifests/dash.py
View File

@@ -285,12 +285,15 @@ class DASH:
segment_base = adaptation_set.find("SegmentBase")
segments: list[tuple[str, Optional[str]]] = []
segment_timescale: float = 0
segment_durations: list[int] = []
track_kid: Optional[UUID] = None
if segment_template is not None:
segment_template = copy(segment_template)
start_number = int(segment_template.get("startNumber") or 1)
segment_timeline = segment_template.find("SegmentTimeline")
segment_timescale = float(segment_template.get("timescale") or 1)
for item in ("initialization", "media"):
value = segment_template.get(item)
@@ -318,17 +321,16 @@ class DASH:
track_kid = track.get_key_id(init_data)
if segment_timeline is not None:
seg_time_list = []
current_time = 0
for s in segment_timeline.findall("S"):
if s.get("t"):
current_time = int(s.get("t"))
for _ in range(1 + (int(s.get("r") or 0))):
seg_time_list.append(current_time)
segment_durations.append(current_time)
current_time += int(s.get("d"))
seg_num_list = list(range(start_number, len(seg_time_list) + start_number))
seg_num_list = list(range(start_number, len(segment_durations) + start_number))
for t, n in zip(seg_time_list, seg_num_list):
for t, n in zip(segment_durations, seg_num_list):
segments.append((
DASH.replace_fields(
segment_template.get("media"),
@@ -342,8 +344,7 @@ class DASH:
if not period_duration:
raise ValueError("Duration of the Period was unable to be determined.")
period_duration = DASH.pt_to_sec(period_duration)
segment_duration = float(segment_template.get("duration"))
segment_timescale = float(segment_template.get("timescale") or 1)
segment_duration = float(segment_template.get("duration")) or 1
total_segments = math.ceil(period_duration / (segment_duration / segment_timescale))
for s in range(start_number, start_number + total_segments):
@@ -356,7 +357,11 @@ class DASH:
Time=s
), None
))
# TODO: Should we floor/ceil/round, or is int() ok?
segment_durations.append(int(segment_duration))
elif segment_list is not None:
segment_timescale = float(segment_list.get("timescale") or 1)
init_data = None
initialization = segment_list.find("Initialization")
if initialization is not None:
@@ -388,6 +393,7 @@ class DASH:
media_url,
segment_url.get("mediaRange")
))
segment_durations.append(int(segment_url.get("duration") or 1))
elif segment_base is not None:
media_range = None
init_data = None
@@ -420,6 +426,10 @@ class DASH:
log.debug(track.url)
sys.exit(1)
# TODO: Should we floor/ceil/round, or is int() ok?
track.data["dash"]["timescale"] = int(segment_timescale)
track.data["dash"]["segment_durations"] = segment_durations
if not track.drm and isinstance(track, (Video, Audio)):
try:
track.drm = [Widevine.from_init_data(init_data)]