This replaces the riscv specific handling from
7212466e73 (which essentially is
reverted), with a different implementation of the same (plus a bit
more), based on the corresponding feature in dav1d's checkasm,
supporting both Unix and Windows.
See in particular the dav1d commits
0b6ee30eab2400e4f85b735ad29a68a842c34e21,
0421f787ea592fd2cc74c887f20b8dc31393788b,
8501a4b20135f93a4c3b426468e2240e872949c5 and
d23e87f7aee26ddcf5f7a2e185112031477599a7, authored by Henrik Gramner.
The overall approach compared to the existing implementation for
riscv is the same; set up a signal handler, store the state with
sigsetjmp, jump out of the crashing function with siglongjmp.
The main difference is in what happens when the signal handler
is invoked. In the previous implementation, it would resume from
right before calling the crashing function, and then skip that call
based on the setjmp return value.
In the imported implementation from dav1d, we return to right before
the check_func() call, which will skip testing the current function
(as the pointer is the same as it was before).
Other differences are:
- Support for other signal handling mechanisms (Windows
AddVectoredExceptionHandler)
- Using RtlCaptureContext/RtlRestoreContext instead of setjmp/longjmp
on Windows with SEH
- Only catching signals once per function - if more than one
signal is delivered before signal handling is reenabled, any
signal is handled as it would without our handler
- Not using an arch specific signal handler written in assembly
Signed-off-by: Martin Storsjö <martin@martin.st>
This was accidentally removed in a prior revision of the series,
alongside the corresponding (separate) version bump. Instead coalesce it
into the follow-up commit's entry, since that's the lowest version
actually supporting the new fields.
Adding my new gpg key that I will be using from now on.
This key is ed25519, which is more secure than the old rsa4096.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
The layout for the frame flags is as follow:
chroma_format u(2)
reserved u(2)
interlace_mode u(2)
reserved u(2)
chroma_format has 2 allowed values:
0: reserved
1: reserved
2: 4:2:2
3: 4:4:4
interlace_mode has 3 allowed values:
0: progressive
1: tff
2: bff
3: reserved
0x80 is what we expect for "422 not interlaced", and the extra 0x2 from
0x82 is actually writing into the reserved bits.
This byte represents 4 reserved bits followed by 4 alpha_channel_type bits.
alpha_channel_type currently has 3 differents defined values: 0 (no
alpha), 1 (8b alpha), and 2 (16b alpha), all the other values are
reserved. The 4 initial reserved bits are expected to be 0.
This byte represents 4 reserved bits followed by 4 alpha_channel_type bits.
alpha_channel_type currently has 3 differents defined values: 0 (no
alpha), 1 (8b alpha), and 2 (16b alpha), all the other values are
reserved. This part is correctly written (alpha_bits>>3 does the correct
thing), but the 4 initial bits are reserved.
Quoting SMPTE RDD 36:2015:
A decoder shall abort if it encounters a bitstream with an unsupported
bitstream_version value. If 0, the value of the chroma_format syntax
element shall be 2 (4:2:2 sampling) and the value of the
alpha_channel_type element shall be 0 (no encoded alpha); if 1, any
permissible value may be used for those syntax elements.
So if we're not in 4:2:2 or if there is alpha, we are not allowed to use
version 0.
Quoting SMPTE RDD 36:2015:
A decoder shall abort if it encounters a bitstream with an unsupported
bitstream_version value. If 0, the value of the chroma_format syntax
element shall be 2 (4:2:2 sampling) and the value of the
alpha_channel_type element shall be 0 (no encoded alpha); if 1, any
permissible value may be used for those syntax elements.
So if we're not in 4:2:2 or if there is alpha, we are not allowed to use
version 0.
Move section to the top of the file, use table in place of subsection
to list the comprising muxers, and show media type information and
extensions in the item entry names.
