All state that needed to persist between calls to decode_block was
previously stored in plain Vector fields. This moves them into a struct
which sets a more explicit lifetime on that data. It may be possible to
store this data on the stack of a function with the appropriate
lifetime now that it is split into its own struct.
The default intra prediction mode was only used to set the sub-block
modes and the y prediction mode. Instead of storing it in a field, with
the sub modes are stored in an Array, we can just pull the last element
to set the y mode.
With the addition of this struct, both the bool to determine if coefs
should be parsed and the token parse itself can take specific
parameters.
This is the last step in parameterizing all the tree parsing, so the
old functions in TreeParser are now unused. This patch is very
satisfying :^)
There's still more work to be done to clean up how the parameters are
passed from Parser, but that's work for another day.
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.
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. (!!!)
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.
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.
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.
This allows runtime strings, so we can format the errors to make them
more helpful. Errors in the VP9 decoder will now print out a function,
filename and line number for where a read or bitstream requirement
has failed.
The DecoderErrorCategory enum will classify the errors so library users
can show general user-friendly error messages, while providing the
debug information separately.
Any non-DecoderErrorOr<> results can be wrapped by DECODER_TRY to
return from decoder functions. This will also add the extra information
mentioned above to the error message.
Reads will now be done in larger chunks at a time.
The public read_byte() function was removed in favor of a private
fill_reservoir() function which will be used to fill the 64-bit
reservoir field which will then be bit-shifted and masked as necessary
for subsequent arbitrary bit-sized reads.
read_f(n) was renamed to read_bits to be clearer about its use.
The interpolation filter value is not set when reading an intra-only
frame, so printing this for the first keyframe of the file was printing
"220", which is invalid.
With this patch we are finally done with section 6.4.X of the spec :^)
The only parsing left to be done is 6.5.X, motion vector prediction.
Additionally, this patch fixes how MVs were being stored in the parser.
Originally, due to the spec naming two very different values very
similarly, these properties had totally wrong data types, but this has
now been rectified.
Though technically block decoding calls into some other incomplete
methods, so it isn't functionally complete yet. However, we are
very close to being done with the 6.4.X sections :)
These elements were being used in the new tokens implementation, so
support for them in the TreeParser has been added.
Additionally, this uncovered a bug where the nonzero contexts were
being cleared with the wrong size.
This was required for correctly parsing more than one frame's
height/width data properly. Additionally, start handling failure
a little more gracefully. Since we don't fully parse a tile before
starting to parse the next tile, we will now no longer make it past
the first tile mark, meaning we should not handle that scenario well.
The class that was previously named Decoder handled section 6.X.X of
the spec, which actually deals with parsing out the syntax of the data,
not the actual decoding logic which is specified in section 8.X.X.
The new Decoder class will be in charge of owning and running the
Parser, as well as implementing all of the decoding behavior.
