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.
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.
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.
This is a demo. Some issues:
- When sharing desktop, cursor is still relative to slides, and not to deskshare video;
- Need to show whiteboard canvas on top of deskshare video as well;
- Need more testing (audio/video sync, playback perfomance, multiple presenters and multiple deskshare events).
Instead of assuming that wav files have 44 byte headers (they usually
don't - freeswitch adds some metadata tags), add a super-simple wave
file parser that just finds the offset where the audio data actually
starts.
Main change is to rewrite the start/stop event handling to do fewer
passes and use simpler logic (it no longer has to track durations).
The temporary work audio codec is switched to flac; slightly lower hard
drive use and it avoids the 4-hour length limit of wav.
Some improvements to the video seeking when processing deskshare and
webcam videos, to avoid video dropouts.
Tweaks to the audio encoding quality settings.
Remove an unused function.
