Since these two types are often passed around as a pair, it's easier to
handle them with a simple pair struct, at least for now. Once things
are fully being passed around as parameters wherever possible, it may
be good to change this type for something more generalized.
This adds a tree-parsing function that can be called statically from
specific trees' implementations in TreeParser, of which Partition is
the first. This way, all calls to tree parses will take the context
they need to be able to select a tree and probabilities, which will
allow removal of the state dependence in TreeParser on fields from
itself and Parser.
The two different mode sets are stored in single fields, and the
underlying values didn't overlap, so there was no reason to keep them
separate.
The enum is now an enum class as well, to enforce that almost all uses
of the enum are named. The only case where underlying values are used
is in lookup tables, but it may be worth abstracting that as well to
make array bounds more clear.
Frames will now be queued for retrieval by the user of the decoder.
When the end of the current queue is reached, a DecoderError of
category NeedsMoreInput will be emitted, allowing the caller to react
by displaying what was previously retrieved for sending more samples.
I've realized that it probably makes more sense to change the input
transfer characteristics to treat these as sRGB since color conversion
in linear converted from BT.709 doesn't really make sense. If content
creation applications expect media players to display BT.709 without
conversions, this means they expect applications to treat it as sRGB,
since that's what most displays use. That most likely also means they
process it as sRGB internally, meaning we should do the same for our
color primaries conversion.
No longer will the video player explode with error dialogs that then
lock the user out of closing them.
To avoid issues where the playback state becomes invalid when an error
occurs, I've made all decoder errors pass through the frame queue.
This way, when a video is corrupted, there should be no chance that the
playback state becomes invalid due to setting the state to Corrupted
in the event handler while a presentation event is still pending.
Or at least I think that was what caused some issues I was seeing :^)
This system should be a lot more robust if any future errors need to be
handled.
Otherwise, we end up propagating those dependencies into targets that
link against that library, which creates unnecessary link-time
dependencies.
Also included are changes to readd now missing dependencies to tools
that actually need them.
This file will be the basis for abstracting away the out-of-thread or
later out-of-process decoding from applications displaying videos. For
now, the demuxer is hardcoded to be MatroskaParser, since that is all
we support so far. The demuxer should later be selected based on the
file header.
The playback and decoding are currently all done on one thread using
timers. The design of the code is such that adding threading should
be trivial, at least based on an earlier version of the code. For now,
though, it's better that this runs in one thread, as the multithreaded
approach causes the Video Player to lock up permanently after a few
frames are decoded.
This moves the setting of code points in CICP structs to member
functions completely so that the code having to set these code points
can be much cleaner.
The class is virtual and has one subclass, SubsampledYUVFrame, which
is used by the VP9 decoder to return a single frame. The
output_to_bitmap(Bitmap&) function can be used to set pixels on an
existing bitmap of the correct size to the RGB values that
should be displayed. The to_bitmap() function will allocate a new bitmap
and fill it using output_to_bitmap.
This new class also implements bilinear scaling of the subsampled U and
V planes so that subsampled videos' colors will appear smoother.
This adds a struct called CodingIndependentCodePoints and related enums
that are used by video codecs to define its color space that frames
must be converted from when displaying a video.
Pre-multiplied matrices and lookup tables are stored to avoid most of
the floating point division and exponentiation in the conversion.
Previously, some integer overflows and truncations were causing parsing
errors for 4K videos, with those fixed it can fully decode 8K video.
This adds a test to ensure that 4K video will continue to be decoded.
Note: There seems to be unexpectedly high memory usage while decoding
them, causing 8K video to require more than a gigabyte of RAM. (!!!)
Previously, saved probability tables were being inserted, causing the
Vector to increase in size when it should say fixed at a size of 4. This
changes the Vector to an Array<T, 4> which will default-initalize and
allow assigning to any index without previously setting size.
Integer overflow could sometimes occur due to counts going above 255,
where the values should instead be clamped at their maximum to avoid
wrapping to 0.
This fixes an issue causing frame 3 of the test video to fail to parse
because a reference vector was incorrectly within the range for a high
precision delta vector read.
This allows the second shown frame of the VP9 test video to be decoded,
as the second chunk uses a superframe to encode a reference frame and
a second to inter predict between the keyframe and the reference frame.
This enables the second frame of the test video to be decoded.
It appears that the test video uses a superframe (group of multiple
frames) for the first chunk of the file, but we haven't implemented
superframe parsing.
We also ignore the show_frame flag, so for now, this
means that the second frame read out is shown when it should not be. To
fix this, another error type needs to be implemented that is "thrown" to
decoder's client so they know to send another sample buffer.
The above interpolation filter mode was being taken from the left side
instead, causing some parsing errors.
This also changes the magic number 3 to SWITCHABLE_FILTERS.
Unfortunately, the spec uses the magic number, so this value was taken
instead from the reference codec, libvpx.
This gets the decoder closer to fully parsing the second frame without
any errors. It will still be unable to output an inter-predicted frame.
The lack of output causes VideoPlayer to crash if it attempts to read
the buffers for frame 1, so it is still limited to the first frame.
This changes MotionVector by removing the cpp file and moving all
functions to the header, where they are now declared as constexpr
so that they can be compile-time evaluated in LookupTables.h.
For testing purposes, the output buffer is taken directly from the
decoder and displayed in an image widget.
The first keyframe can be displayed, but the second will not decode
so VideoPlayer will stop at frame 0 for now.
This implements a BT.709 YCbCr to RGB conversion in VideoPlayer, but
that should be moved to a library for handling color space conversion.
The first keyframe of the test video can be decoded with these changes.
Raw memory allocations in the Parser have been replaced with Vector or
Array to avoid memory leaks and OOBs.
