The filenames now represent composite ids (stream id + recording id) rather
than a separate uuid system with its own reservation for a few benefits:
* This provides more information when there are inconsistencies.
* This avoids the need for managing the reservations during recording. I
expect this to simplify delaying flushing of newly written sample files.
Now the directory has to be scanned at startup for files that never got
written to the database, but that's acceptably fast even with millions of
files.
* Less information to keep in memory and in the recording_playback table.
I'd considered using one directory per stream, which might help if the
filesystem has trouble coping with huge directories. But that would mean each
dir has to be fsync()ed separately (more latency and/or more multithreading).
So I'll stick with this until I see concrete evidence of a problem that would
solve.
Test coverage of the error conditions is poor. I plan to do some restructuring
of the db/dir code, hopefully making steps toward testability along the way.
The idea is to avoid the problems described in src/schema.proto; those
possibilities have bothered me for a while. A bonus is that (in a future
commit) it can replace the sample file uuid scheme in favor of using
<camera_uuid>-<stream_type>/<recording_id> for several advantages:
* on data integrity problems (specifically, extra sample files), more
information to use to understand what happened.
* no more reserving sample files prior to using them. This avoids some extra
database transactions on startup (now there's an extra two total rather
than an extra one per stream). It also simplifies an upcoming change I
want to make in which some streams are not flushed immediately, reducing
the write load significantly (maybe one per minute total rather than one
per stream per minute).
* get rid of eight bytes per playback cache entry in RAM (and nine bytes
per recording_playback row on flash).
The implementation is still pretty rough in places:
* Lack of tests.
* Poor ode organization. In particular, SampleFileDirectory::write_meta
shouldn't be exposed beyond db. I'm thinking about moving db.rs and
SampleFileDirectory to a new crate, moonfire_nvr_db. This would improve
compile times as well.
* No tooling for renaming a sample file directory.
* Config subcommand still panics in conditions that can be reasonably
expected to happen.
This is still pretty basic support. There's no config UI support for
renaming/moving the sample file directories after they are created, and no
error checking that the files are still in the expected place. I can imagine
sysadmins getting into trouble trying to change things. I hope to address at
least some of that in a follow-up change to introduce a versioning/locking
scheme that ensures databases and sample file dirs match in some way.
A bonus change that kinda got pulled along for the ride: a dialog pops up in
the config UI while a stream is being tested. The experience was pretty bad
before; there was no indication the button worked at all until it was done,
sometimes many seconds later.
This avoids having codec-specific logic to synthesize it in db.rs. It's not
too much of a problem now with only H.264 support, but it'd be a pain when
supporting H.265 and other codecs.
This allows each camera to have a main and a sub stream. Previously there was
a field in the schema for the sub stream's url, but it didn't do anything. Now
you can configure individual retention for main and sub streams. They show up
grouped in the UI.
No support for upgrading from schema version 1 yet.
This is a wash in terms of lines of code now, but it makes it a bit easier to
maintain as I make changes to the schema (such as separating out streams from
cameras), and it helps ensure the tests reflect reality.
My odroid setup has been occasionally (about once a week) losing about 15
seconds of recordings on all cameras. I'm not sure why. So I'm labelling all
the likely suspect spots and logging if any of them takes longer than a
second. I think this will give me more information; hopefully narrow it down
to network or local disk I/O.
* the "lib: {}" print didn't do anything. It turns out that the pkg-config
crate emits the necessary metadata for linking automatically. I had the
wrong format and didn't notice because something else did it correctly.
* gcc::Config is deprecated; the new name is Build.
* and the crate is now called cc, version 1.0.
Stuff found while looking at #11. Still haven't figured that issue out.
* make "yarn build" cmd work on first run.
(it was installing a hardlinked file where the dir should go, yuck)
* remove an obsolete ui/index.html; it's ui-src/index.html now
I'd temporarily pointed this to a local path for development and didn't notice
it was still in place when committing. Back to the git path that works for
everyone.
The Javascript is pretty amateurish I'm sure but at least it's something to
iterate from. It's already much more pleasant for browsing through videos in
several ways:
* more responsive to load only a day at a time rather than 90+ days
* much easier to see the same time segment on several cameras
* more pleasant to have the videos load as a popup rather than a link
that blows away your position in an enormous list
* exposes the fancier .mp4 generation options: splitting at lengths
other than the default, trimming to an arbitrary start and end time,
including a subtitle track with timestamps.
There's a slight regression in functionality: I didn't match the former
top-level page which showed how much camera used of its disk allocation and
the total duration of video. This is exposed in the JSON API, so it shouldn't
be too hard to add back.
The recording::Segment was constructing a segment with no frames in it, which
was causing a panic when appending a zero-length stts to the Slices. Fix this
in a couple ways:
* Slices::append should return Err rather than panic. No reason to crash the
whole program when we have trouble serving a single .mp4 request.
* recording::Segment shouldn't produce zero-frame segments
I had an assert that fired in this case, dating back to when I hadn't plumbed
Result returns through much of .mp4 construction. Now I have, so there's no
excuse in having an assert here. Change to an error return, and tweak it to
not fire in the zero-duration case.
Also fix a problem in the test harness; I hadn't finished converting it for
multi-recording tests, and it was returning the wrong recording.
Because of that, I seem to have stumbled across a related problem in which
asking for zero duration of a non-zero duration recording will return a
recording::Segment with no frames, which will cause panics because its
corresponding .mp4 slices are zero-length. I just adjusted the panic message
here; I'll follow up with changes to address that.
* CameraDayKey::bounds (used to generate the start and end times of days in
the returned JSON) returned UTC, not matching what recordings were mapped
into that day. So fetching a day with its given bounds would return
something different. Test and fix it.
* Several time-related tests weren't calling testutil::init(), so they weren't
fixing the time zone to the expected America/Los_Angeles. If the machine
time is set to something else, they would break.
I think this is an ffmpeg bug, which I plan to report. In the meantime, this
makes the tests pass. Long-term, even if ffmpeg fixes this, I probably don't
want to continue doing acceptance tests against whatever version of ffmpeg
happens to be installed - my real targets of interest are the latest versions
of Chrome, Firefox, Safari, QuickTime, and VLC.
This was causing Firefox to fail to play multipart .mp4s which trimmed away a
prefix. In the developer console, it said NS_ERROR_DOM_MEDIA_METADATA_ERR
without giving any RESULT_DETAIL, making it a pain to diagnose. Given that the
stss is supposed to be needed for seeking, I'm surprised it didn't have any
immediately obvious impact on Chrome or VLC. Maybe they just took longer to
seek than otherwise necessary.
The bug was that when keeping track of the "next frame num" while constructing
the .mp4, I appended the number in the underlying recording, not the number
post-trimming. That meant following segments used the wrong numbers. In some
cases, it caused it to exceed the total number of samples in the generated
.mp4, which seems to be what Firefox was complaining about. Running the result
through "ffmpeg -i bad.mp4 -c copy -f mp4 good.mp4" just trimmed away the most
obviously invalid ones, leaving others that didn't point to the frames they
meant to. That was enough to make Firefox start playing the file. /shruggie
The existing tests were all with a single segment, so I added a new one to
catch this. I also added a Debug implementation to recording::Segment and
mp4::Segment.
This was totally broken in commit 1cf27c18. It would serve bytes from the
beginning of the sample file in question, not from the start of the given
range.
it should be exactly 1, but was slightly more because the fraction was
incorrectly 1 rather than 0. I'm not sure if any actual players care about
this, but it was something I noticed when looking into strange edit list
behavior.
This is intended to support HTML5 Media Source Extensions, which I expect to
be the most practical way to make a good web UI with a proper scrub bar and
such.
This feature has had very limited testing on Chrome and Firefox, and that was
not entirely successful. More work is needed before it's usable, but this
seems like a helpful progress checkpoint.
Scott Lamb