In some cases when there is a slight mismatch between audio file
duration and event timestamp difference, and we have a record
status or chapter break event in a certain location, it could
trigger a seek past the end of an audio file. Detect this
condition and just render silence instead.
Also adjust the thresholds for the audio length scaling - they
were being triggered on short recordings that should be correct.
Red5 sometimes writes webcam video files with a large offset in the
video frame offsets, sometimes up to 30 or even 60 seconds. However,
the start event in the events.xml file corresponds to the time at
which red5 received the first keyframe (recorded frame) in the video.
The end result is that the video will sometimes appear to be
delayed (out of sync) in the processed recording.
The correction is simple: We're already reading video metadata,
including the timestamp of the first frame, so we just have to apply
a correction during video processing to undo the frame timestamp
offsets in the video file.
If you're inserting at position 0 (and there was no previous deleted text
from that position), you can't use the timestamp from the previous character
position, since there's no previous character. Use the timestamp of the
following character instead.
In some unusual cases, the recording start can be the last event in the
events file, or at least have the same timestamp as such.
Add some code to check the array bounds and break if needed, so we
don't check the timestamp on the (non-existant) event after the last
event.
The previous code looked for stop events and tried to find their
associated start event. This obviously doesn't work if there was
no stop event. But if there was a start event, we need to show the
deskshare… so rework to code to try to find the matching stop to each
start instead, and use the end of the meeting if no matching stop was
found.
Some old recordings might have invalid or legacy encoding stuff
in the text files. To allow processing to continue, just re-encode int
UTF-8 with the invalid option set to replace, to remove the invalid
characters.
In BBB 2.0, the cursor positions are given relative to the page
size (like annotation positions). Since the recording cursors
aren't actually drawn in the page like annotations, it's more
convenient to have them relative to the visible area (viewbox),
so do that conversion.
While I'm in here - since we switched to new incompatible scripts
for BBB 2.0 anyways - remove an extra factor in the cursor positions
in cursor.xml, and just use a simple ratio of width/height instead.
This is just a bundle of a few things I've been fixing up in the past
while.
= Workaround for BBB 1.1 beta deskshare timestamp bug
This is unlikely to be used, but I have the code for it, might as
well merge it in.
= Rework video tiling code for ffmpeg
Render video using the 'hstack' and 'vstack' filters rather than the
'overlay' filter. This is somewhat faster, particularly with lots of
videos.
= Etc.
- Remove usage of the streamio-ffmpeg gem.
The video rendering code has some stuff to directly read 'ffprobe'
output, so re-use that instead of this gem (which is kind of old and
has issues with newer ffmpeg versions).
- Don't hardcode the deskshare video area size, pull it from the
properties file
- Remove some code that worked around missing video end events.
In some cases this could cause flickering or strange video issues.
It's no longer strictly needed, the new tiling code doesn't break if
the seekpoint is after the end of the video.
The new shapes code, required for handling smooth shape updates & multi-user
whiteboard in the 2.0 BigBlueButton, hits a bug in old recordings where
the pencil tool incorrectly used "line" in its shape names, meaning that
there could be both a pencil mark and a line with the same shape name.
The old recording code didn't rely on the shape name to match shapes, since
there was no chance of concurrent shapes. As this is an incompatible playback
change, we need to make a new playback directory for the updated files.
The old code was very difficult to follow, and I couldn't figure out
a good way to retrofit the BigBlueButton 2.0 undo by shape id and clear
by user id into it - so I rewrote the entire thing instead.
It now generates the shapes.svg, panzooms.xml and cursor.xml all at the
same time during a single pass through the event.xml file. The result
is compatible with the existing recording javascript (at least once a few
minor issues in writing.js were fixed by earlier commits).
The previous code would cause shapes to "blink" during updating if
the updates weren't continuous - in a gap between updates, the shape
would disappear.
Rework the logic for looking up "current" shapes to return the
nearest previous update rather than only exact matching timestamps,
and simplify the logic that decides whether to make a shape visible
or hidden.
Current BBB client is generating invalid indexes when characters are
inserted with an IME - the edit indexes are as if the preedit text was
being removed, but the preedit text was never sent in the first place.
For now, just don't crash if there's an edit that would remove text
which is past the end of known text. The result might be broken, but
it won't prevent the rest of the recording from working.
